Why NOT to ZONE Heat Pumps! or boilers.. (SURPRISING RESULTS!!)
HTML-код
- Опубликовано: 30 июн 2024
- We take a look at a section from our online heating design training which forces us to question just how efficient zoning heating systems is. Using a heat pump for an exaggerated example but also applies to gas boiler heating systems.
In the video, we reference these two articles
www.heatgeek.com/weather-comp...
www.heatgeek.com/benefits-of-...
Find out more free information at www.heatgeek.com/ and also find out more about our courses. 
Наука
As a lay person trying to better understand heating system design it is so good to be able to access such high quality very informative videos. Thanks
I will never understand the mindset of installers who fit an ASHP in a home and expect it to be a direct replacement for a gas boiler. Gas boilers and ASHP's operate differently, therefore they must be installed, designed and operated differently. All the buzz about how horrible ASHP's are can be directly equated to this. Excellent video! To be honest most gas boilers out there are not designed, installed or set up correctly either causing them to operate inefficiently. Here in North America everybody seems to think zoning is the greatest thing in the world when really all it does is cause boilers to cycle with micro loads and gives a fancy little box on the wall for homeowners to play with, which we all know is the cause of most comfort issues.
Very clever working this all out and putting into layman's terms. Looking forward to part 2 👌
Can’t wait to explain this to the other lads over a pint on a Friday afternoon !!,
You'll be the life and soul mate lol 😜😜😜😜
I welcome the thinking here, and I have seen plenty cases of inefficient operation due to too many stats turning on and off too much. However, I think we need to be careful. As Adam says here, zoning is needed in many situations, and lack of control could be wasteful. There are a few oddities too.. given the calcs require a high vent rate in kitchens, they (if normal design procedures are followed) will probably overheat overnight (assuming the cooker hood is off overnight!) . Emitter design needs to allow for any anomalies like this, and consider not only steady-state emitted heat, but buffering in the screed etc. We still have a lot to learn.
Just had a long and very informative conversation on the phone with Tommy from Alton and Tommy from Wokingham in Berkshire. About problems with our gas central boiler and operation. This is going to lead to solving a problem that’s been going on for nine years. One reason came to light in the conversation, is that the problem was never solved by people who came to service the boiler, because they don’t have the knowledge of systems, they just come to make sure the boiler is safe. Yes, our boiler is coming up to ten years old, so may mean a replacement, but it will be of the correct size and output and work correctly. Thank you Tommy.
Tommy is a great engineer!!!
Very interesting and thought provoking. Refreshing to hear your thoughts. Thank you. Heating controls are really in their infancy. We have a lot to learn
Thanks John! Means alot coming from you.
I continue to be amazed about heating controls. I started working for a heating company in 1965 and we had weather compensation then . My dad worked for a controls company and they had compensation controls for at least ten years previously. After over sixty years I still see new heating systems with just a single on/off thermostat!
Your channel need more views, really great and honest information.
I would love to see somebody to the calculations, tests and physics/maths on the exact losses between rooms. This would make a big difference in the calculations.
Also, I would imagine the temperature differential would affect the heat loss in that it changed the heat gradient for the heat to travel through essentially acting as insulation between rooms.
This is important stuff for the future when we inevitably get off gas.
I wonder what is the best way to ensure people are getting the proper installs done with good due diligence.
Excellent video, thanks. There are a few of points that could do with further clarification.
The efficiency loss from heat pump short cycling is significant, but the graph in the video showing a massive effect (75% vs 10%) isn’t representative. Modern heat pump algorithms prevent short cycling, and controlled cycling a few times an hour appears to have a minimal effect on efficiency. John Cantor has a video on this with data from a Samsung Gen 6 showing that even when cycling around every 10 mins it’s only approximately 3% less efficient than steady state.
What is said about highest compressor efficiency being at “maximum output”, if by that is meant maximum power, doesn’t appear to be universal. For example published Vaillant data for the Arotherm plus ASHP shows maximum efficiency at mid range compressor speed at around 40-50% maximum output.
The final thing is that the higher compressor power needed to come out of a setback is certainly a little less efficient, but if that recovery happens during a low tariff period, which can be just 25% of standard electricity cost for EV tariffs, then even though less efficient overall, it can still be lower total cost than a strategy aimed at maximising COP.
Well explained. Thank you for uploading this.
Just watched this and my brain exploded. Absolutely amazing information to have when considering a heat pump. Thanks 🤩
Brilliant presentation and is understandable for us laymen. Thanks
Very informative video. lots of factors to be consider. Adam covered them all. thanks Dave
Dear Adam and Heat Geek team, first just want to say that I love what you are doing, the enthusiasm, the myth busting, all sorely needed and much appreciated, I've learnt a whole bunch from watching your videos.
I did however want to raise with you that I've seen in a few places that you have been saying something like: "Turning off unused rooms doesn't save energy!"
I think there is possibly some confusion here, or at least this may cause some confusion for your viewers about: Heat pump or boiler performance VS total domestic energy usage (and the resulting energy bill).
I've been asked a few times by people why the COP of their heat pump isn't that great, turns out that they barely use it because they are very frugal with their energy consumption so it doesn't spend much time at its designed operating point.
I've also seen people boasting about their amazing heat pump COP (no names mentioned!) only to discover they are using about 8 times more energy to heat each individual than the frugal people I mentioned before.
The critical takeaway is that COP is NOT particularly important. People being at safe temperatures (and humidities ) while minimising their energy usage (and cost) are the two important things.
If someone has an open plan bungalow with no internal walls or doors...then they should definitely turn all their radiators on and run their heat pump low and cold...rather than running one radiator hot and occasionally, trying to heat the same space to the same temperature at the same times. They might also be well advised to consider putting in some internal walls and doors if they are interested in reducing their heating costs/ primary energy carbon footprint.
However, many people have multiple internal rooms, with relatively low occupancy (especially the people with enough spare cash to be installing heat pumps). In many cases they will use less energy by just heating the room they are using, rather than the whole house. Sure, their COP/ efficiency might be worse, but as we've already covered maximising COP isn't really of interest to anyone other than tech geeks. While internal walls and doors don't typically have the same insulation value as external walls and doors, heating a single small room in the evenings should use substantially less energy than heating the whole house to the same temperature for that same duration.
Pleasingly you say "it depends" a lot, which I strongly agree with, for high occupancy homes (lots of people per square meter), for very open plan homes, for homes where doors between rooms can't be closed for some reason and for situations where the heating system can't respond particularly rapidly, then low, slow and steady is probably your best option for staying safe and minimising your energy usage...but for anyone with lower occupancy, more rooms with doors that can be closed, and where a heating system can respond more quickly (e.g. reasonable sized radiators and a gas combi boiler) then having all the rooms off except the one you are in, can be safe and use the least energy...in that scenario, dehumidification may be required in the winter to avoid relative humidity problems (compared to heating, a condenser dehumidifier uses a tiny amount of energy).
N.B. Efficiency is NOT the same thing as COP, I recommend not to confuse the terms, see: en.wikipedia.org/wiki/Coefficient_of_performance for an explaination of this)
Hi. Thabkyou. I believe all the points are addressed in the video. I also believe scop does relate to fiscal efficiency.
Didn't work out so well for me with a condensing boiler heating system.
Collapsed most of my zones. I changed my flow temperature to 50C too (Got tado in modulating bus control). Yet, according to Tado, my gas consumption over the last 30 days is dramatically higher compared to the same time period last year. 2-3 times higher. I'm putting things back the way they were!
😃 great, great, great video, you put in numbers crystal clear almost everything I always try to explain, zonification most of the times does not turn into significant lesser expense, it can even be more expensive
and about your 2 degrees recomendation por night/day temperature differences matches my own experience after 3 years using a heat pump with radiators, when cold is intense I even reduce it to 1.5 degrees
thank you so much por sharing your knowledge and numbers, it is a shame many people won't understand it, even if your exposure is so well documented and prepared, but anyway congratulations
We're currently going through the consultation phase for trying to get a heat pump. This video has really helped me get my head around some of these concepts.
The one thing that I'm still unsure about is how best to ensure each of the rooms in the house hits the target comfort temp whilst running the pump at a constant state. Part of this is to do heat loss calculations for the house, and try to ensure correct radiator sizing for the required wattage. But what about the margin for error in these calculations. What if certain rooms are too hot? What if we want to have the stove on in the living room?
Is it a case of having TRVs, but only using them along with the lockshied valves to fine-tune the system, rather than to try to force zones?
Beautiful mate didn't even need to log in either 😂😂👌
Lolol have you finished yet!!!?????
Mr Heat Geek ..... Excellent presentation as usual. Thank you for your gel stuff, as most things on the web are unscientific opinions instead of in depth analyses. I have a stupid question that I couldn't find an cogent answer in spite of searching the web for a week. I think my questions relates to people who upgrade from cast iron boilers to hi-efficiency boilers. I have a 1980s 4700 sf house with lots of triple pane windows. There are 2 zones upstairs, 6 zones in main floor living area, and 1 zone in basement. The main floor is ½ heated with in floor heating. It faces the south, and so heats up much faster than the rest of that floor. Hence the zones. I am replacing my 40 year old cast iron boiler with a high efficiency Lochinvar KHB110. My contractor tells me it will costs $22,000 for the upgrade which includes all valves, pumps, etc. he wont just replace the boiler. I replaced all the ball valves and zone valves a couple of years ago, so I know they are good. So I am planning to DIY and keep as much of the existing valves/plumbing as possible. The questions is: why do I want or need a primary/secondary loop? I thought the biggest reasons for P/S were to 1) reduce the temp of the inlet water (shock to the heat exchanger), and also create a path for the boiler circulator. Well, if I ran the system temp as low as possible (based on the fact that I have 40 year old baseboards tha are not something I will replace), why do I need to reduce thermal shock? Ultimately the goal is to have boiler/system pump should run 4 hours or more without start/stop. Also, Low outlet temps = low Delta T. So no worries of thermal shock to the heat exchanger. Also , If I turn OFF the included boiler pump, and have a variable system circulator that runs only if there is demand from the thermostat, why do I NEED a primary loop? Balancing the primary/secondary for all system demands with 8 zones would be virtually impossible with a low loss header. Even if I were to power multiple zones on my main floor from a single thermostat to increase heat dissipation, the system circulator would either be overpower or under powering the boiler circulator based on heat demands (single or multiple zones demanding heat). As long as the goal of a homeowner is to provide efficiency over matching instant heat supply to demand, it seems the P/S loop doesn't make sense. Or am I missing something?
Live in a flat where the trv heads don't match their lowers, so they turn off at 15c. Council fixed the problem by repeating the mistake. Lazy plumbers... I was going to replace them myself but now I see that I can just slacken them off and control the general temperature via the boiler. Thanks
Very interesting. Thank you
Excellent video!
Outstanding video
Multiple heat sources like your office experiment!!!! Way to go.
Now I'm exited about part 2
Pt2 is sooo good nigel!!!
To zone bedrooms for a set back at night (or any time) you could fit a 3 port mixing valve for the respective circuit, obviously controlled by sensors / software.
Thanks for another great video ! So tado on a heat pump is not a good idea is-that right ?
I very thought provoking video. But as you mention there are lots of variables. I am particuarly thinking about the weather. Recent mild winters, mean that running at design temperature can be a rarity. I wonder if increasing room temp in mild weather might actually use less power...?
I’m new to all this and I’m a bit confused.
I have a Worcester Bosch 42cdi gas combi boiler and 14 radiators. We have hive thermostats and it’s zoned for upstairs and downstairs. We then further zoned everything and put hive TRVs on each radiator and it was horrendous…they’d come on when they weren’t meant to, not come on when they were meant to and the rooms rarely reached their temperature. Hive were adamant everything was working properly but it was so bad we took them all off and put standard TRVs back on. We did notice that having 1 room on upstairs and the rest off, it was all just a bit of a waste of time even if you shut the door on that room, but I couldn’t say for certain whether we saved any gas or not. I’ve been looking into alternatives to hive and maybe tado TRVs…are you generally saying that zoning each radiator is a waste of time, and that we’d be better off just sticking to upstairs and downstairs or even heating the whole house at once?
Great video, for installing heat pumps into an average size modern home. And the 'when to zone' video is interesting too.
However could you make a video where you re-run the calcs based on a older house, with solid external walls, running a gas boiler. Also for the situation when it's a 'six room' box shape house and the two 'off rooms' are at the end. Maybe even with 3 or 4 rooms turned off.
This is more like the situation we have with our house, and my gut feeling is that, while everything in this video is right. With an older larger house, and gas boiler, turning off half the house will save quite a bit, especially if fitted with decent size rads in the heated rooms. I've not run the sums however.
An interesting control mechanic I set up on my DIY system is what I call "Sympathetic heating". If you have a room with a set temp of 20*C and it triggers a heating demand at 19.9*C, this is normal. However the room next door might be set to 18*C and it hovering around at 18.2*C. To prevent 2 independent boiler runs in this scenario my Sympathetic heating schedule goes looking for other zones which will "accept" heat while it's available, even though they might not demand heating themselves. They all have an "accept heat" value 1*C higher than their set-back temp. As soon as the original "demanding" zone reaches it's set temp, the sympathetic heating is cancelled also. This has reduced the number of heating cycles by about 50%.
I figure this little bit of software would be much more useful with heat pumps and zoning for the reason it effectively combines zone requests to run in parallel rather than in series.
Trying to understand the logic here. So on your example with two rooms/zones with 19.9 and 18.2 ° C. Why would there be a boiler run? Typically there are some sort of hysteresis, which will make sure to not demand heat too early and accept higher values that are set. What is better about your approach then?
@@kbabioch Hysteresis is so often miss understood. But if you run through the state machine for hysteresis you will find it too has a hard floor. At some point there is a temp below which is will demand heat.
Also, my hysteresis does not come from temperature, but via time. Hysteresis is only used to prevent short cycling and micro-demands from temp fluctuations.
Instead I set minimum run times on heating elements.
In my example the zone minimum target for the office is 20.0. That is a hard limit. Once it goes below that it will request heating. However, if it immediately rises back up to 20.1, the heating it requested will still run for 5 minutes regardless. If you think it through it does the same job as hysteresis.
The sympathetic schedule is just to catch those zone which are not yet at demanding temp, but as heat is available and they are close, they get their radiators switched on.
All this stops is the scenario where:
Office hits 19.9 requests heating and get it.
The bedroom at 18.2C is not requesting heating as it's floor is 18C.
Without intervention, the office will consume 5-10 minutes heat and switch off. Then some short time later the bedrom hits 17.9 and demand heating for 5-10 minutes. Then an hour later the office goes again, then the bedroom and so on.
By letting zones "accept" already available heat when they are within N degrees of set temp saves all those unnecessay cycles.
This removes the problem heat geek are describing around zoning creating more cycles. I'm saying I fixed that.
It's easy for me to do these things as I have the source code and there is no cloud or third party selling me spyware devices.
I'm not saying my 5 minute minimum run time is perfectly balance hysteresis, it works. I've toyed with expanding it to 10minutes minimum in run time.
The indication I will be looking at is the number of demands per hour. Ideally that should not exceed 1. If it is, then I will extend the minimum runtime.
Of interest the minimum run time mechanic is there not just as hyteresis. It was selected as a "mechanic" for other more important design reasons. Doing multi-zone heating software design is not easy. It looks easy until you start designing it. Then you discover it has some rather complexly interacting state machines. It's very, very easy to forget each of those state machines have two sides. The side people forget about is the "OFF" side. WHen you have multiple competing zones with some saying ON and some saying OFF it gets really tricky to know when to run the boiler.
Instead I just opened up the side of the state machine and added a timeout system down the off side.
This means if my system fails in some software way, the control messages etc used to turn the boiler on will simply expire and the system will revert to a safe OFF.
Think zoning on heat pumps needs a lot more discussion. I'm close to taking out my evohome kit and going back to trvs and a stat.
As a complete layman with a full tado setup that runs most rooms cold overnight this is a bit of an eye opener but actually makes good sense. Checking my temps and heat demand curves on the app shows a steep decline in temps overnight then a few hours of high heat demand inthe morning to bring them back up. I'll have a play about and adjust the overnight temps up a bit and see how it pans out over the next few months. Love a good experiment.
Hi Adam. Great video. This situation would only come into play when the radiator was at its maximum requirement. Anything less than the coldest day of the year would mean that the radiator would have the capacity to warm the room without having to raise the flow temperature. Is that right?
Yes but you want to lower the flow temperature for the rest of the year to gain condensing efficiency...
Yes if you use thermostatic valves on radiators you must be running higher flow temp so radiators themselves regulate temp.
Also 150w increase in losses to unused rooms is very much ovestated, losses are nowgere near linear, but work same way radiator emmited power. So this is completly wrong
This makes me wonder about the flow and return pipes in the floor for our rads on the upper floor (we have UFH downstairs). Should we lag the pipes in the floor void or is that helpful as an emitter?
I have a netatmo 'smart thermostat' which has hysteresis mode for heating my gas combi. Is this a modulating stat? It seems very good and keeps a steady smooth room temperature without any huge overshoots of set temperature. Thanks.
Join 'Heat Geeks Heating Help for Homeowners" on Facebook for bespoke advice on YOUR specific system.
To find out what the variables are and whether you should zone or not check out this article on our website www.heatgeek.com/weather-compensation-or-load-compensation/
Most heating engineers only have 3 cse's
We are never going to understand this .
@@mgbroadsterJ should all articles be written for the lowest common denominators?
Fyi we have a little more faith in our workforce.. infact we have 297 students who have passed out training and completely understand this and waaayy more.. and 127 on the way to passing.. ✌
I have 16 radiators with 2 zones ,ground floor and first floor .
It all works well and the return temp to the boiler are a bit to high .
I'm adding 35 square meters of under floor heating .
I'm aware the Worcester 8000 35 kw system boiler is to large .
I've been advised to buy a lower output boiler and go PDHW .
That system is very old ,they were called W plans .
I'm not sure if it's the way to go .
Cylinder hot water set at 85 ,so no condensing when it's on hot water .
To much choose.
Do I or dont I fit a LLH ?
@@mgbroadsterJ lots to go through there mate! First off.. why is your hot water at 85!!!?? Should be 50-60!!!
The best thing I can suggest is to find a heat geek who will be able to answer all this based on a survey.. (too many variables) www.heatgeek.com/find-a-heat-geek/
Where are you perhaps I can suggest someone?
I just did a test in our semi detached house with standaard insulation, 6cm eps in cavity wall, 8cm pir on the Floor of the loft wich also has 10cm wool in the roof.
this weekend we had an average of 3degree celsius outdoor.
Started our boiler at friday afternoon and kept It on full time, 10m3 of gas where used/day. Last year we had 7m3 as average gas-use/day.
I will do another test next week, to see wich is cheaper to do for us,, i hope to get the same weather to compare with. What i can say is we had a more comfortabel house, finally our bathroom was at 23 degrees and 21 in our 56m2 first Floor 😅
I Dislike that tado asks the boiler to put more power in for a few minutes and than drop to the lowest modulatian again,, i think this costs me more gas than neefjes,, is There a way to adjust this?
Can we take it one step further, say for a large old house with 25kWp ground solar, in place. Few zones but with multiple heat sources (solar/heat pump/battery) but non optimal insulation initially could be a reasonable initial approach?
I have a 12 month old Vaillant eco Tec boiler and the fitter put a weather compensation sensor outside but I’m not sure what it does. I have underfloor heating across 8 rooms and 11 zones. Each zone has a Heatmiser thermostat which we use to control the room temperature. If I understand what you are saying should I turn off the stats and let the weather compensation control the room temperatures as they are making the boiler less efficient?
Thanks!
As much as I understand and agree with the physics, doesn’t Part L dictate that certain rooms should have room temp stats, are you advising minimal control in retrofit as you won’t be able to do this on a new build?
With this in mind, our Ecodan heat pump can either be set to only run when the thermostat is calling for heat, or just run when the delta t requires more heat.
Would it make sense to do the latter and remove the stat control so the stats just control the secondary circuit?
Yes.
How does this effect work at lower room to outdoor dt? Since the benefit of heat loss is better and potential increase in COP is (I think) lower.
Thank you! I am having a Vaillant Arotherm plus fitted next month, wet underfloor system is already in place - what do I do with the manual room thermostats? Set all to same temp or bin them for something else?
Set them 1 or 2oc above your weatger compensated target room temperature and use them as temperature limiters.. but only after you have dialed in your weather compensation curve perfectly
I say you.. this is an installer thing... not a customer thing..
Thanks for your replies Heat Geek!
I guess all those smart rad valves people install on gas boilers are really a waste of time as well?
As always, depends on the house usage and layout.
Thanks Heat Geek, these videos are invaluable. Can I ask a question about my proposed development, I will be having an ASHP installed early next year with Underfloor Heating downstairs and Radiators on the 1st and 2nd floors.
From watching this video is the ideal setup just having a single thermostat for the UFH downstairs (located in the family room) and no thermostats or TRV's on 1st and 2nd floor radiators. Therefore the only thing that will stop the ASHP will be the UFH thermostat from downstairs?
This seems like a very simplistic setup BUT is it actually the best one?
Have trvs. But as a temperature limiters not a targeter.
@@HeatGeek - Thanks for that. Probably a silly question, but is there something different to be done to make the TRV's act as temperature limiters and not targeter?
@@darrenanvoner9115 yes. Follow the 3 simple steps video and use weather compensation
Does this also apply to Underfloor Heating?
What about the scenario where you work from home and only really use 1 room. Sure the overall efficiency of the boiler might drop if I’m running my radiators hotter. But if my other 3 rooms are basically not on at all for a large portion of the day surely I’d still save quite a lot?
You're modelling the building heat loss as a constant. Is that true if two of the rooms are at a lower temperature?
No we arent. The heat loss is adjusted when the two rooms are dropped in temperature
It would be interesting to learn when it would make sense to zone a condensing gas boiler or heat pump. For instance, we have a 2 story house with the leaving room and kitchen downstairs and all the bedrooms upstairs. Currently both floors sit are on one zone with a thermostat in the leaving room. But I imagine it would make sense to have 2 separate zones, each with its own thermostat. This way we can heat downstairs during the day and upstairs during the night.
I've installed actuators on all the underfloor heating circuits, so I could program all the actuators from one floor to close during the day or night. But I'm afraid this might increase the main return temperature and cause the gas boiler to cycle more often. I guess the best option would be to have zone valve for each floor. What do you think?
Unless I've missed the point, I think the take-home point for when you genuinely need to zone is to make sure that you insulate between your zones. And whatever your radiator sizes are (Or underfloor pipework length is), increase them.
Zoning 100% saves energy this video is false
@@Boz1211111 Do you have any evidence, reasoning or calculations to support your statement?
What do you recommend in a situation where there is a lot of solar heat gain on one side of a house, say a house that has a north-south orientation? If the temperature is set based on the sunny south side of the house, the north facing rooms will be too cold. If the temperature is set based on the north-facing rooms, the south-facing rooms could be too hot
You would zone.. this is about comfort too not just saving money..
That would be a poor property design also
@@HeatGeek Pretty common though. South facing garden with big glass french doors
Would internal ventilation help maybe? Cycling the air around the house would surely help equalise the air temperatures between hot & cold?
@@Loopyengineeringco How would you do that? Keep the doors open? Or something more invasive?
Ive been experimenting with a drayton wiser system for the last year or so with an oil condensing boiler. previously I had NEST. I found in some cases my oil usage per week was higher... and Ive put it down to cycling, but this is interesting and would suggest quite a bit is to do with the varying load. I still prefer the Drayton wiser system, but I think to work optimally other factors need to be accounted for. You mention a lot in yoru videos between heat pumps and gas boilers... but what about oil boilers?
Hope you have a buffer if your multi zoning a oiler like that
@@HeatGeek No I don't yet, but that is what I have been looking into. BTW great channel and website. lots of good information with robust technical foundation.
Yes indeed, and what about the elephant in the room: Ventillation. No one seems to ever consider that. Air changes per hour???
@@jesserawson898 good point, it kind of goes hand in hand with insulation and hence the need for a heat recovery and ventilation - most people are told to 'just open their windows' to ventilate which probably throws the calcs way out from the ideal!
Thanks
Very informative and useful and indeed a very surprising result. But I think you did not factor in all the variables so the result is not actually true for many of your viewers. My flat was left uninhabited for the past 2 winters with zero heating, unlike other years, this time the outside temperature rarely dropped bellow zero, but inside.... I think 16 or 18 degrees was the minimum on cold days with a rough 20 degrees when it was not too cold outside. So even though I am at the last floor I was getting a lot of heat from my neighbors. I have many rooms and if I just set the temperature in two of them at 19 degrees there will be very little heat migrating from the warm rooms to the cold ones, since 19 degrees is roughly the temperature with the heat turned off throughout the house. The more probable outcome is I won't be able to keep the temperature at 19, it will always be hotter even with the radiators off in those rooms. So the math you outlined only applies to houses, but flat owners are also watching these videos and they are getting the wrong impression.
Hi, this is a great content. I have a Tado smart thermostate and smart radiator trv's (which adjusts the water flow per each radiator based on how I set the room temp). So this setup enabled me to have different temperatures per each room in my house with different times. We have a house with 190m2 floor space and 3 floors. During the day we mostly live in the first floor and during the night we go to the 2nd floor to sleep (3rd floor room is rarely occupied). I had close to 30% reduction in gas consumption last year, simply adjusting the room temperatures for each room differently and lowering the temperature when we're not at home. So in your video basically this contradicts with what I have experienced physically last year. I was planning to install a heatpump and continue using Tado thermostate with smart radiator thermostates but should I replace them with flow limiters as TRV's?
I'm not a heating engineer, but I think it depends on your property and setup. If you can be sure the heat from the rest of the house isn't getting to that third floor then yes, you're heating a smaller area at the same efficiency and you'll save money.
If you've got a load of doors open for example or the heat rises up there anyway, then you're still heating those rooms but because your heating system is smaller (the radiators are off) then you're needing the same amount of heat from less radiators and it's less efficient. That's an especially big problem with heat pumps where the temperature of the water is colder and radiator size matters more.
@@chrisfletcher86 But in any case the heat will go higher and this time I'll first indirectly heat the rooms upstairs and then heat those rooms again with radiators don't I? I couldn't understand the logic there. Maybe what heat geek is saying could be true for houses with 1 flat but since heat goes up always, I don't think zoning is a bad idea (at least my experience and savings prove me that it's the case for my house. I saved 30% by turning off the radiators for specific rooms on specific times). would be great if @heat geek can elaborate on this type of setup.
All sounds good but can you explained the electric running costs
That's explained in the video lol
I take it then it's still useful to have zoning when it comes to gas boilers but that's not necessarily the case when it comes to heat pumps?
No this applies to condesning boilers with low temp control too. But just slightly less so
Ok, I get all this. However, if my house generally holds heat to 18 degrees pretty well after a very minimal burn for about 3 hours at night to get it to about 20, do I get a situation where - naturally - the heat pump won't be coming on that much and then, when it does, it has that inefficient start up because it will have been fully off for so long?
No.. its will just come one at Al lower rate..
@@HeatGeek thanks man, fascinating to get into the maths here. But does that mean when I dont actually need heat there is still an electricity draw by the unit?
I'm planning an upgrade to my thermostat to make it smart and I was thinking of getting the Tado V3+ with TRVs for zonal heating. However, I'm not sure if this is the best option in my use case and would appreciate your recommendations. About my property, its a 5 bed bungalow. The property is pertty old (1946 build) and majority of the rooms are only used occassionally hence why I thought a zonal would be a good idea. The boiler I have installed is Worcester Greenstal i ErP and I've read online that Tado will be able to modulate all boilers. Could you give me your recommendations on what would be best smart thermostat for me?
We have a video on this.. search when to zone
Be careful with which Tado system you buy. If you have a wireless thermostat you need the EU extension kit (not the UK) which has opentherm/ebus modulating ability. If you have a wired thermostat the UK version is fine. You'll also need to check compatibility - look up your model and make sure the Tado can connect to it digitally.
@@Leonards-leopard thanks for this - I've also been looking into getting a Tado and was disappointed by ghe fact that the UK wireless version doesn't have modulation capabilities. I've just had a Vaillant combi boiler installed with three heating zones - any idea if the wired Tado will be able to modulate the boiler based on my set-up?
@@afnankhokhar5578 the Tado system is let down badly by the bridge, which drops connection to the router every couple of days. It’s a known problem since a firmware upgrade a couple of years ago that the company have yet to fix. I would steer clear.
@@afnankhokhar5578 I’m afraid not, you’ll need wired thermostats going into the zone valves. If you can get a wired thermostat directly to the boiler that has opentherm.
Most of this makes sense, I can see the importance of defining zoning requirements prior to radiator installation, especially on modern smart systems where you program for say 1 or 2 rooms to come on in the morning, the heat requirement of those rooms is going to be higher as you point out due to unheated adjoining rooms.
However, one thing that is not clear on this that maybe you could help clarify, is in your example when you reduce temperature of radiators or turn them off
1. There is a total property requirement given in watts, this applies IF i want to heat the entire property to a certain temperature.
2. If I turn off two rooms in your example, the rooms that remain want to heat to the desired temperature, that will require more energy for those rooms compared to what they had previously, as there will be heat loss into the unheated room.
3. So I need to account for the heat loss to the internal room
4. But I am not trying to heat that internal room to 21 degrees
5. So, why is it the total property requirement split over two rooms?
I understand why it goes up, what I don't understand is why you have defined the increase as the total property requirement split over two rooms.
Because heat is lost in to those other rooms.. weather you want to loose heat in to them or not
@@HeatGeek I have a similar question. Can you please explain further? On the surface, its seems, like adding that rooms heat loss when not in use to the total is wrong. Does the unused room/s not become more like an 'large insulated air space' and more part of the exterior wall, if unused, and as such it's heat requirements are less?
@@HeatGeek hi, thanks for the response but that doesn't really answer the question. heat is lost into the outside world whether you want it or not, obviously.
look at it this way, party wall, neighbours heating is off. you are suggesting that my heating now as to provide the energy to heat both premises heat requirements to 21 degrees? obviously not. the neighbours heating being on or off will impact the heat loss of my premises, but that amount is not equal to heating the neighbouring premises to 21 degrees.
so internal partition will have a heat loss consideration/impact, but it is not equal to the full premises heating needs
@@davidk4078 yeah, CIBSE domestic heating guide covers this. It is a lot closer to how you describe. Basically same way you account for a neighbouring premises
@@nezhad11 no.. as per the video the calculations amount for the other rooms to be at a lower temperature, not 21c.. you need to follownthe video closer.
Over 1000 heating engineers have undergone this course and training.. there is no errors or one of them would have pkinged it out .
What if you're away from home for a long period, say, over winter, and want the equivalent of 'frost setting' to protect the system, but, no more to save energy? Is a much lower set-back the answer?
Yes lower set back
@@HeatGeek Thanks. Presumably, controls allow you to that for a particular period, then readjust to a more normal setback? Also, what would be the lowest setback you would recommend?
Does this cycling inefficiency apply to air to air minisplit ductless heat pumps?
Less so
If zoning is not the best why have Honeywell/tado etc made a market it of it?. Or is it house specific?
Because they cater for consumers demand. Not what's best. It's mainly heat source specific but also goose yes
Very Interesting... However...
This will be totally lost with the Home owner.
There are situations that can't be accounted for like in Terraced Houses or Flats.
Your neighbour might or might not Heat the rooms with party walls.
My Neighbour doesn't have heating in some of our party walls so they get some of my heat.
The unpredictable UK climate keeps throwing a spanner in the works too.
One day it's minus 5 a couple of days later it's plus 10.
Yet still I have customers, who after I explained, I leave, they turn off nearly all rads in the house, and turn heating on very infrequently 🤦🏽♂️
Genius
👌🏼👌🏼
Man... I wish your thumbs/titles were less clickbaity. It took me a long time to actually trust your content because at first glance it looks like you're trying hard to sell something. I was avoiding your videos because of all the OMG YOU WONT BELIEVE WHAT HAPPENED NEXT. I know it's effective, but you guys are well credible now, maybe you can take it down a little 🤣🤣. Not really talking about this video in particular, but this video and all the maths have finally convinced me you guys are legit, after watching maybe 10 other videos
Came here to work out if I need to close a door to keep a room warm that is always cold while using a trv in that room.
Came away with a degree in maths and engineering 😂
I now see why you guys are called the heat geeks.
2nd law of thermodynamics
THERE IS ALWAYS A FLOW FROM A WARMER TO A COOLER CLIMATE.
At 12:50, your assumption about the heat loss of the building, 1874 watts, is incorrect. If 2 rads are in frost protection mode, the building heat loss will be much lower as the temperature in those rooms drops.
That's acoubted for. Please rewatch.
You assume that the two 'off rooms' settle at the same 18deg, which they might in a house with a well insulated external wall and studwalls internally. However in many older houses, with solid 9inch external walls and 4inch or thick lath and plaster internal walls, they would settle at much lower than that.
@@dhutch2000 yes they will, please insulate
@@jbtl1130 insulation would be lovely, but much easier said than done. Period house, with original plaster mouldings around the wall which make internal insulation impractical and undesirable above the normal distribution of that job. External wall insulation isn't practical for a number of reasons, the flooring is period oak tiles which makes lifting the ground floor impractical at present, we're on bedrock with no crawl void to speak off. Loft insulation is good....
Can we counter this with buffering?
Cycling yes.. low temperatures no...
I have a tado system for wife compensation. Zero efficiency in heating a room with a window open.
I'm still confused. It just doesn't make sense. I have 3 rooms upstairs not used so of course turning off those rooms will save me money. Even though turning those on may save 6% but turning them off must save 20% probably
As we say, sometimes it does work. The deeper video we reference will tell you more
15p kwh... Those were the days
I would have liked to see this repeated with much larger radiators, different heat losses and some more information about how compressor speed affects efficiency. Also how will outside temperatures and different set back temperatures affect efficiency when zoning?
This example is far too limited and obviously not designed for zoning. A gas boiler would have been far more suitable.
Being a Refrigeration engineer, I am all for heat pumps but you need huge radiators and/or UFH to make them viable. This is why they have such a bad reputation. People swap a gas boiler for a heat pump without doing anything else. Anyone who installs a heat pump that has to run 24/7 has designed the system wrong.
If you do the example with a has boiler you come to the same answer. A video changing all the variables would be horrendously long.. we did this to show people how to do it themselves
What do you mean by anyone that designs a system to run 247 has designed it wrong? All systems shoudl be designed gor stable state heating except in extreme circumstances
@@HeatGeek Thanks for your reply.
The example you gave is simplified but it is of a very poor system that proves your point perfectly. Would you get the same results if the radiators had 3 times the capacity, outside temperature of 10 degrees and turning off the heat pump for 8 hours overnight?
The reason heating must shut down is because it is wasteful. People are used to only heating their house when it is needed. Instead of forcing people to run them continuously you should be trying to copy how gas boilers are used.
Say you are designing a heat pump system for an old couple in a 3 bedroom house. They are at home almost 24 hours a day so need constant heat. It is a 40 year old detached house with wall and loft insulation. You size up the heat pump and radiators to do the job and they are happy customers. 5 years later they have moved out and a young man buys the house. He works so the house is empty all day and he is used to no heating at night. He is now forced to run the system continuously. If that house had a modern gas boiler it would be only needed to be on when he is needing heat and a little warning up time. This is how people compare the 2 systems. Electricity is about 3 times more expensive than gas so the COP advantage is almost non existent.
I am all for heat pumps they are the future but they are being installed inappropriately too many times giving them a bad reputation. You could get away with small radiators with gas or oil but not with heat pumps.
Personally I think radiators are not suitable for the job. Fan units like air conditioners have are the way to go. They give heat far quicker and are compact.
Heat pumps work better in new builds with excellent insulation but that covers only a small proportion of housing which will not change for many years.
Basically, I am saying heating should be made to work how people want it to not the other way around. Undersized components are a false economy.
@Foxy The Dirty Dog your confusing running 24hrs with a 24hr fixed room temperature. You can, and should run both boilers and heat pumps 247 but with a nighttime and/or day time set back temperature, the unit still runs during these times but at reduced flow temperatures, it doesn't turn off perhaps for the comfort flow temp to drop to the setback. Ife advise reading up on advanced weather compensation..
This video is also good
ruclips.net/video/kGs_biFA87Q/видео.html
@@HeatGeek As your linked video says all situations are different. Most people don't need continuous heat. If heat pump radiators are undersized, which I am saying they usually are, this causes the problem you highlight in this video. If you turn on an air conditioner in heat pump mode it will heat a room in a few minuets. This is because the indoor coil has a large surface area with air blown over it. A radiator is designed for very hot water produced by a flame. They are not suitable for heat pumps unless they are much larger than would normally be fitted to conventional systems. Heat pumps are also nowhere near as efficient in low temperatures. Your example of an ambient of -3 degrees would be off of that COP chart so the losses may not be that high. As R744 (CO2) is rolled out these higher temperatures should be more attainable.
Are you sure heat pumps have a higher COP when running at full capacity? I am pretty sure it is the opposite - the slower the compressor runs the higher the COP. Also is cycling a problem? The compressor should slow down for low loads and even if it stops it will not be long enough for it to cool down so it is not the same as a cold start each time.
Heat pumps have their place but. at least until R744 is rolled out, they are not suitable for most people because radiators are usually way undersized. Heat pumps are competing with gas not electric heaters and we are all used to rooms heating up quickly. My 180 year old 6 bedroom house has 3 zones, one for each floor and 6 of the 13 radiators turned off. It would be crazy expensive to change from gas to a heat pump and keep this whole house warm 24 hours a day with a night setback.
As an example of how I can save, My sons bedroom, top floor, is not heated at night (like the rest of the house) and has a huge radiator for the room size - 2.4m double convector. On school days it comes on 15 minuets before he has to get up. It is then turned off with enough thermal mass to keep the room warm until he leaves and it is also heated in the evenings. The other 2 top floor rooms are unoccupied so only heated when needed. If you tried to sell me a heat pump that needed to heat that entire top floor all day even with a night set back, you will have a hard job convincing me I will save money over staying with a gas condensing boiler.
I do already have a heat pump to heat our hot tub - Heating water directly to 37 degrees is where heat pumps shine and due to the thermal mass I only have to run it on electricity costing 8.25p per kwh at night.
Instead of radiators, heat pumps should be connected to finned coils with fan units. Water outlet temperature could be controlled with a thermostatic valve and the fan speed modulated in relation to room temperature. I already have an ancient version of this instead of a radiator so it is nothing new but it is the only one I have ever seen. I think it was made by Myson and of course has no electronics just a rheostat for fan speed and a thermostat for the fan.
Heat pumps are like electric cars Great for some but not practical for most. I have a plug in hybrid so a combination of gas and heat pump is what I am considering - heat pump (with a large buffer tank to maximise use of cheap electricity) for when it is not too cold and gas to take over when it is cold and to do the initial boost when first needing heating. Sorry, I don't want to give up my zoning and turning off at night just yet although my wife would love it.
What is this man going on about! 🤒
It makes sense if you work in heating
Ah. But EPCs say install TRVs. 😖
Install them sure. Just use them as limiters not targeters
@@HeatGeek whats the difference?
@@handle1196 limiter is set 1 or 2 c bove target temp. Targeted is at the target temp
@@HeatGeekif you have a DIT of 21c for the house with weather comp but prefer bedrooms to be a couple of degrees less, whats best to achieve this?
Setting a temperature limiter?
Changing the bedrooms from 21 to 18/19c when completing heat loss calcs & sizing the emmiters to suit this?
Other?
@@handle1196 either sizing the rads originally or balancing.. you'll find you can lower the curve doing this too
Or you could just run the heating longer at a lower temp. You don't need to increase the temp just because you aren't using a room. Heating less rooms help to run at a lower temp.
It's a false dichotomy.
Plus you've done loads of maths in some points while getting hand wavey about insulation. An internal wall doesn't have zero insulation value.
I don't think you've followed the video. You can't have as low flow temp with less rads. It's breakdown physics. I also calculated internal wall insulation.. perhaps worth watching again
@@HeatGeek you touch on internal wall insulation at 4:25 ? but you just make the assumption that the cool rooms only reach 19c. And there isn't really a basis for that.
I know what you're saying. You're saying in simple terms if you double the area of a room the heater has to emit twice the energy to heat that room. That I agree with. What I disagree with is that you have to increase the wattage (flow temp). The other option is to increase the run time. This for me is where the entire premise breaks down. That's before we get into the details.
If your heating only has a 50% duty cycle your own later comments show that this makes the overall system more efficient.
Are there scenarios where you're correct? Probably yes. But as a general rule I think it's incorrect.
The optimum is to only heat rooms you use. Have a set flow temp on your boiler and have it run for longer.
The down side it that you may be outside of the comfort zone for longer. But its the same as driving a car. It's more efficient to accelerate slower. Yes you're not at the 'optimum' speed as quickly but that's a tradeoff. From the metric of efficiency that is the best advice.
As a concrete example for my own house. I basically have the upstairs radiators off. When I turn the heat on in the evening it's heating the down stairs where I want it, the heat rises. So when I go to bed the bedrooms are warm. My heating has not had to work harder but it does work longer because the heat rate loss to the upstairs is greater than what it would be through the attic. Does it potentially cycle more? Yes, but then you should be turning down the flow temp to equilibrium.
@@benholroyd5221 you're forgetting the the whole house still loses heat at not that much lower a rate.
If your house has a heat loss with all the rooms on of 2000W but that drops down to 1500W with the upstairs off (random numbers, not accurate)
You still have to put in at least 1500 to keep your downstairs at the same temperature. So you can't just cut the heating down to half the amount because you're heating half the rooms.
@@hk78901 your example is still a 25% reduction. If I run my existing heaters for 50% longer my heating isn't becoming less efficient and I'm saving 25% energy.
And there aren't any circumstances where you can make your condensing boiler 25% less efficient anyway so it's a win whatever.
At points you managed to turn the English language into something foreign.
Alot of customers would be mortified if the gas boiler came on in the .iddle of the night . .
What is wrong with you, why did you make pictures so small?
Its your sceen size. Buy a bigger phone or use a computer.