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John’s graph showing temperatures vs distribution equipment (around 10min mark) should have a dotted area instead of line at 120F for baseboards. The line implies can’t use below 120F when you can. It really depends on extent of weatherization, outside temp & set point. Here’s an example of old 180F baseboards powered by AWHP & well below 120F; start around 23min in ruclips.net/video/9SMxaOMX-oY/видео.html 9:58

Such a shame that we don't have R290 monoblock heat pumps in Canada or the US yet. They are super efficient, work in very cold weather and can heat water to 70/80C. In Canada more than 1/2 of your gas bill is fees unrelated to the amount of gas you use. I'm going to get rid of the gas completely. I have to replace my gas cooktop and my gas cloths drier. Will probably buy a heat pump cloths drier.

Brilliant video! So much ground covered in just 40 minutes.

If the designer follows the manufacturers recommendations for minimum fluid volume in the system, defrosting should not produce a noticable drop in termperature indoors, but North America typically has homes with much lower thermal mass than the UK or Europe, so it could be more of an issue in North America. A system volumiser or buffer tank is a reasonable solution, but in the UK some experts are actively trying to design out buffer tanks (and zone valves) from their systems. Perhaps the ultimate buffer tank configuration is no buffer tank! Great to hear that in John's experience home owners don't experience any cooling when the system is in defrost.

Panel radiators are very common in Europe and the UK in rooms where the home owner want thick carpets and thick underlayment. Combined with simple Thermostatic Radiator Valves, to avoid overheating due to thermal gain, they can be a very cost-effective solution were cooling isn't required. Radiant ceiling or fan coils are the best emitters for cooling applications. Radiant floors or panel radiators are the best for heating. Radiant walls might be a good in a few limited situations, but my sense is that there is more risk of a nail through a wall than through a floor or ceiling.

Another solution to the two buffer tank question is two heat pumps: one for space heating/cooling with a single buffer, and a ducted Heat Pump Water Heater for hot water. The ducted Heat Pump can be a CO2 model, so able to heat domestic water to a point where Legionella is not a concern. This avoids the need for the space cooling heat pump to have to switch to heating mode to keep a supply of hot water ready for use. This configuration also allows the heating heat pump to operate at maximum efficiency in heating mode because the flow temperature can be controlled by outdoor reset.

The Global Warming Potential of R410a is 2088, for R32 it is 675, for R290 (Propane) it is 3, and for R744 (CO2) it is 1. Propane is pretty much the ideal refrigerant for small residential monobloc systems where all the refrigerant can be kept outside of the home; although CO2 is better for high temperature applications. For split systems and larger commercial systems, Propane is not ideal and an alternative refrigerant is preferable.

In Europe, many manufacturer are recommending Anti-freeze Valves instead of anti-freeze fluid. Anti-freeze fluid lowers the performance of the system whereas anti-freeze valves don't. The valves need to be good quality and protected from water & snow. They are fitted on the supply & return lines to the outdoor unit outside of the home. They release some water from the system if the outside temperature drops below 38F. If the outside temperature is below 38F, you can be certain that the heat pump will be running UNLESS it has a fault or there has been a power cut. If the heat pump is running the valves won't open, but in the even of a fault or power cuts they will open just enough to let a little water out to stop the outdoor unit from being damaged. The system needs to be topped up when the fault or power is restored, but you only need to top it up with fresh water, not a solution of water and anti-freeze.

Dales question at the 28:35 mark. I recently noticed my transfer plates are falling off. Staples were used. I plan on using screws to re-attach the plates. Is it possible that the contractor set the compressor too high and used too narrow of a staple? Please help. I've got twins on the way and the plates are above their cribs

Since I'm a student of technology, the smart circulolator pump is the new way to heat your house. Electronics is taking over. ECM circulator pumps are here, and it will take a greater technology to put it to the side.

Boiler vs tankless? What are your thoughts?

Subscribed and appreciate the channel! John, my daughter will build a 1200 sf ICF house soon. Hydronic heat for sure. Better to put radiant wall panels on the outside walls or interior walls. House located in upper Michigan, 3-5 days get to -20 F, most winter is 0F-30F. Thanks in advance!

THANK YOU. 🤟 🤜🤛

Builders and quality don't usually go hand in hand. Personally, I want it to look good, but before that I actually want it to work. Without that, effiency goes out the window.

Do you have more information on how to install the insulation? I've seen some places saying you should put in a reflective layer before the insulation... some say that reflective layer should also be a few inches below the plates to create a hot air pocket. But that would mean the insulation isn't pushed up right against the plates. Thoughts?

Thanks for the video. There is much good information here. However, John Siegenthaler is wrong about the fin efficiency of heavier gauge extruded aluminum heat transfer plates over very thin inadequately formed heat transfer plates. Also the FEA (finite element analysis software) that he is using is not appropriate for making the predictions and close comparisons that he made. A look at the color fea plot that he produced shows 100% heat transfer for the aluminum across it's width and 100% contact of the tubing with the aluminum plate for both samples. He' made these assumptions he is unable to adequately mesh (model) the heat transfer plate and has no idea what to input with respect to tubing contact. At that scale, he is attempting to evaluate and resolve differences in aluminum thicknesses as little as .040" or less. This is a wildly inaccurate representation of the real 3 dimensional world where these assumptions may or may not hold true along the length of fin/tubing. This is a well known limitation of 2 dimensional FEA analysis. Errors are magnified when extrapolated to the 3d world. ie. btu/ft2 It's easy enough to understand that given the same heat transfer across the tube plate then the wider plate would produce higher output and it's not necessary to go through this convoluted reasoning to establish that fact. All panel heating systems have heat affected zones surrounding the tubing and it's common practice to vary tube spacing and tube diameter to achieve the desired result. However, it is strongly misleading to make claims regarding variables that weren't even studied and assumed to be equivalent at 100%. That's not fair. Any fair empirical race would reveal that the extruded plates, even with reduced width produce far higher outputs and greatly reduced water temperatures. Empirical, hands on investigations easily show the truth behind how the performance of these heat transfer plates compare with one another. Please see my blog at radiantdesignandsupply.com/theheatexchanger for a simple infra red empirical study of different heat transfer plates and how they compare. Any proper FEA analysis must use variables that have been determined and verified from empirical experimentation. Full disclosure, I developed the original and still the best extruded aluminum heat transfer plate - the ThermoFin. These heat transfer extrusions were designed to provide a very tight rigid snap grip of the various tubing types used in floor heating including PEX and copper. These plates are rigid, tempered tempered extrusions that are available in 4' and 8' lengths and designed to eliminate any differential expansion between the tubing and the plate regardless of the tubing used. They are available in the U or omega shape similar to the the sheet metal plates that John showed. They are also available in the C shape which grips the tubing while holding it away from the substrate. These plates are 4" wide, .050" and .063" thick and 4' and 8' long compared with the 5"-6 wide x 20" long, .020" typical plate that John is talking about. Our original development of the ThermoFin family of extrusions resulted from our terrible experiences with the folded sheet metal plates. The fact is, they don't work much better than no plates at all. Dale Pickard President Radiant Design & Supply

Why don't you use CO2/R744 or propane/R290 for your outdoor mono-block heat pumps? R410 has very high GWP.

Hi guys, great video, thanks! You answered many of my questions. I am not an HPAC professional, just a homeowner researching hydronic radiant heating +/- hydronic cooling for a new build cottage/retirement home. Also looking to supply DHW with heat pump, but having a hard time picking out the best system: one oversized heat pump? separate heat pumps for each, or a heat pump for one and tankless electric for the other? I need help with that one. I will have a solar PV powering the large majority of whatever equipment I end up choosing so all electric makes sense (with wood stove or propane fireplace for backup heat). I also will need a cooling solution which I suppose shouldn't be a problem if I have a separate heat pump for the radiant... also need to decide on hydronic cooling for the slab vs air cooling! John I could really use a consult, what is your hourly rate to pick your brain? hahaha Oh good timing, RUclips just showed me a preview for your air to water heat pump webinar, guess I'll watch that and then the video on tube depth. Thanks again! ... update: I just googled hydronic cooling and a link to your article on "small scale hydronic cooling" came up. John you are a gold mine of information!