How to Compare HVAC Filters for Healthy IAQ + Ideal Airflow (aka Don't Kill Your Home's Air Handler)
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- Опубликовано: 12 сен 2024
- Saw a 'big' 5" thick filter installed on a client's home, but you might be surprised to know it won't work on their system. Here's how to evaluate what specific filtration system to put on your home's HVAC. That Aprilaire 2516 I show in the video is only $250 and comes with MERV 16 included, fyi. Do your research and make sure your healthy air doesn't hurt your HVAC's air handler.
Here's the current pressure drop chart from Aprilaire's All Product Catalog:
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Wished the photo of your filter box was better to understand what's really going on here (or a schematic). It seems that there is a short transition from the huge filter box to the air handler that would create a bunch of air turbulence post filter. Anyway, I am happy to see your work to learn more in the HVAC discipline. In my area of Wisconsin the local HVAC companies don't really care much about the science and just keep doing installs like it was 1970. I act as a consultant to owners for house issues and do some of the actual work within my capabilities, or oversee work when I hire an "expert", something I love to do even as a guy in his 60's. Keep up the good work and thank you!
Watching you and your wife for the last 3 years I was armed with the knowledge to install my 2 ton heat pump. I used the Aprilair 313 filterbox and it has worked great. Thank you!
Awesome!
This is why I have always used 2 to 3 of those Lennox air filters 16. In custom sheet metal boxes..
My father showed me and demonstrated using an old Dwyer Magnehelic back in the late 1970s.
Currently replacing a customers 20” x 24” x 1” Merv 11 filter for a 5 ton air handler
with three 20”X25”X5” MERV 16 with a
Dwyer Magnehelic permanently installed across the filter for the customer with a permanent ink marker line to tell the customer when it’s time to change the filter.
Yes found out my 4T had an undersized 4" Aprilaire cabinet, not even spec'd for 1600cfm. It took several calls to contractors to find one who understood *why* I was bothering to have return ductwork upsized + cabinet changed out.
Funny, I use the filter you are talking about from Lennox, the X6675 MERV 16 with my 5 ton system (2000CFM). Luckily it has been working fine for me for the past 12 years. I am getting a good nanometer to measure the static pressure, I can only guess that it is very high when running at 2000CFM. When I go to replace my furnace to a heat pump I will make sure I get a filter system that can handle it.
Based on the info presented here, that filter will be slowing down your airflow which will skew you Sensible Heat Ratio (SHR) towards dehumidification. It costs you some cooling efficiency but will dry the air more. This can actually be a benefit in cool damp climates (or shoulder seasons) where the AC doesn’t run too often.
@@superspeeder I was about to say the same. Don't be surprised if you open up that return that you start to witness symptoms of an oversized system (short cycling, poor dehumidification). Also with an ECM motor you may be configured to run at 2000cfm but measure those statics and it's probably more like 1800 or so. It will definitely improve the efficiency of the blower though!
Thanks for the info on Aprilaire! On 2 jobs recently I helped the clients swap out filters. They were using electronic filters, but never cleaning them because the installer didn’t say anything to them about it. They had zero filtration basically. On one of them, I was able to do a MERV 13 and the other a MERV 16 so they have some nice filtration. Crazy the stuff I see out there. Then they wonder why their drain line is always slimed up every few weeks.
I was happy to finally modify my 3 ton heat pump's two 16 by 20 inch return filter grills to accept 4 inch thick filters in lieu of the standard 1 inch filters. I already had standalone HEPA filters, dehumidifiers, and an independently ducted ERV but being able to run the air handler continuously with large MERV 13 filters has still made a nice difference with my air quality monitoring and the general feel of the air.
Is there a reason that we are still playing around with tiny filter cabinets in residential buildings? When you have an application like a basement or other place with lots of room and access why are we not using commercial pocket filters. In use they end up being far cheaper than residential filters and with the sheer filter area size pressure drop is not really ever going to be an issue and you have a plethora of filter types available.
I would have gone that routs on our house but it's an old 1960 house and an upflow and no room for anything mechanical related really. Oh and I hate upflows in the center of houses as the return side is so noisy since it's a direct path to the fan with nothing to stop the noise unless you make custom sound baffles to block the direct line of sight for the sound to follow.
I’m arm-chair HVAC’ing, but I agree. A lot of homes have dozens of cubic feet of return duct volume, but they only dedicate a fraction of a cubic-ft for the filter (e.g. 0.22 cu ft with a 16x24x1”).
They could even put multiple filters into a “V” or “A” configuration (like an A coil) to double the filter surface area.
I suspect one reason is many of the system/duct design guidelines (ASHRAE, etc) are based on a nominal 1" filter.
It's because residential HVAC is in the stone age... Commercial is definitely more advanced but still relatively primitive in terms of design and control compared to other industries.
We put in a heat pump (2022) to replace a spec system at the house which is doing great and saving money despite higher per kWH rates and I made sure that we had proper humidity control, fresh air (ERV) and HEPA filtration. Your content helped inform what I asked for and then asked about when looking at various system options from the local HVAC professionals. We live in a climate not too different from Atlanta and the system has performed flawlessly through everything from 110 plus (with very high humidity) down to -1 ℉.
The filter box is April Aire and is doing a great job.
Excellent video Corbett 🤜🤛
Corbett, it would be great if you could do a video on the IQ Air and Intellipure whole house filter systems, what they would need for air flow and if they are worth it. Also, I would love to see a home made ERV / HRV system, if you have ever done that by building a box with filters.
Sadly Intellipure’s HVAC Super V is commonly promoted by “influencers” that it can catch particulates below 0.3 microns (0.07 I believe), but if you read its stats closely, it’s actually 0.3 microns. Which is standard HEPA…
I really don’t like Intellipure’s household purifiers, I have a graveyard of them. They’re loud and the filters are INSANELY expensive. They’re air purifier’s CADR/CFM are weak also, unless you enjoy screaming to communicate with company when they’re over for a cup of tea lol
IQAir I guess is a better choice, but I think they’re both overrated imo. Even the IQAir household air purifier on 4 wheels. Their filters do not last as long as they say they do, they’re also expensive, there’s like 5 filters to change for one unit $$$, but the decibel level is better. Nice looking machine though, I’ll give it that.
Not a fan of those vacuum yourself HVAC filters either. I was always told vacuuming/washing filters affects the integrity/performance of the filter. I’d rather just change out new pleated media filters (4” thick MERV 11 is perfect for me imo) for my HVAC. And I’ll use aluminum tape to fill any loose gaps around the filter. What doesn’t get discussed enough is the air breach points that commonly surround HVAC filters (from poor filter cabinet designs). Contaminants can bypass around the filter, eventually creating mold food on our wet evaporator coils. What’s the point of any filter if air can escape around it… The filter should fit really snug, all filters should. The big misconception is HVAC filters are to clean our indoor air, but they’re not, they are really created to protect the air handler. And the big scam is these companies saying that their filters can go down to 0.07 sub micron sizes. They got everyone fooled in the mold community (fragments…)
HEPA with great CADR/CFM is just fine to clean our indoor air.
That’s my 2 cents, peace :)
@@sp1200M3D Thanks! Do you feel the IQ Air whole house filter is better?
@@naturalhealing9970 connected to the HVAC? Yes. But I would make sure who installs it knows how to balance your system after. Load calculations and all that fancy stuff. Some of these special hi-grade filters (even higher than MERV 13) can create static pressure issues. The thing about the HVAC industry is some of the equipment is great, it’s many of the installers who are not. And you’re welcome:)
Trutech now has a filter box with even lower pressure drop, at the cost of being enormous and expensive. It’s much more expensive than the AprilAire, but they claim annual filter changes so the TCO is roughly a wash on a 10 year time scale. I’m excited that there is now more than 1 option.
Corbett, do you have any opinions or existing videos on using wall or joist cavities as a return duct? Looks like it is not ideal but common practice. I am trying to understand how bad it really is though and if I should allow that in my home. Thanks!
👏👏 Nioce!
I am still working on the A-Pages of our new home. When I get to the M-Pages, we will be in touch.
Cool Brian!
Excellent video
Grace and Peace
Slick
This kind of calculation should fall on the sales person, not the technician running 8 calls a day. Sales people are literally there to find out the customer's needs, wants, and space and give them a price on it. Most customers not wanting this level of filtration is not an excuse considering how fast a sales person would jump to offer higher SEER equipment even though most people get the minimum.
Humble HVAC tech over here, it's funny I was just talking with my manager about this filter.
I believe that Healthy Climate has an 25x25x5 filter, I think that's the biggest they got, it would be interesting to see the pressure drop across it.
One question. I have a customer that suffers from a lot of allergies, they got someone to test their house for mold and found mold spores in the ductwork. I inspected the ductwork (it's In the attic) and it's probably the cleanest air handler and ductwork I've seen😊.
I'm thinking of recommending installing a filter like this. What are your thoughts on that?
"Great video as always, Corbett! Keep up the excellent work. I do have a point of contention, though. I believe you should be frustrated with any AC contractor who pulls this kind of stunt. They're definitely not doing it for free, and they're likely boasting about being the best. If I'm paying good money to a 'professional,' they'd better do their job. No excuses."
Point taken, AJ- won’t argue with you
Hi Corbett, thank you for sharing this! I’d be curious to do a mock up of both systems and see what the particle count is on the air coming out the other end. My thought is, since the filter is larger than the duct feeding it air, wouldn’t that mean that you’re basically only using part of the filter? So would that affect the filter’s ability to actually pull particles and contaminants out of the air?
Curious your thoughts on that and if you’ve tested (I know you love your testing haha)
I 100% agree with your assessment that bigger filters better; you get more filtration but less restriction on airflow. Question though: I hate buying expensive paper based filters all the time, do you have any suggestions for washable, reusable filters? I know reusable filters won't have as good a MERV rating, but I just haven't found many on the market. Thanks!
Can you please explain how your configuration works. Is the filter in the cabinet at a 45 degree angle?
The real question in my mind is why do residential air handlers have such abysmal static pressure performance? I don't think 2 or 3 inWC is too much to ask for.
Best i’m aware of is the high pressure mode on Mitsubishi that lets you go up to .8
@@nathanbarry9534 MRCOOL has one that can go up to 1 inch, apart from that the only options are the various high velocity systems, Spacpak, Unico, etc; which, to be fair have a lot of advantages. Personality, I'm planning on ether a high velocity system or a commercial style system from someone like AAON.
i agree. I guess it is a function of the blower type and seal. Look at automotive 15PSI (that is 50x the pressure drop), where they use the piston suction vs a squirrel cage.
The likely reason that 16 inch tall cabinet is not recommended for 2000 cfm: The typical gas furnace with a blower capable of 2000 cfm (or 5 tons of air conditioning) likely needs air to enter the cabinet into BOTH sides of the return or possibly into a single opening in the bottom of the cabinet (assuming upflow configuration). You have to carefully read the install instructions on the gas furnace or air handler to know for sure. Another lesson to reinforce the fact that good duct design for HVAC equipment requires a lot of nuance and very close attention to detail.
tell me where replacements can be had for around $25ea and i am all in. >$150, not so much. The science driven choice is spot on though. I like to see those tables use face velocity in addition to CFM. The lager the face area, the lower the face velocity (for a given pleat count and depth), and hence the lower the pressure drop.
If we had all the space in the world, can we not just build a bifurcated plenum where you split the flow 50/50 and just have two of the large filters? They would each get half the cfm, would that help with pressure issues? I did this with porcelain water filters on my home, where because they are so restrictive I just split the flow and then reunite them down the line.
I would be interested in the math behind that. A merv 13 multi pass vs merv 16 single pass.
MERV 13:
85% capture of particles over 1 micron, 25% capture under 1 micron
MERV 16:
95% capture of all particle sizes
Any chance you can link to that Aprilaire pressure drop chart, so we can make sure we're looking at the right one?
buildingperformanceworkshop.com/blog/2024/8/19/aprilaire-filter-pressure-drop-chart
Corbett, cost should be considered too. What do these large filters cost and how long between changes? Just using decent 1” filters can cost comfortably over $100/yr in filter costs.
Pro tip: All 1” filters cost the same regardless of size, so a 3M 1900 14x20 is the same cost as a 3M 1900 20x25. I see absolutely no reason for any furnace to use anything smaller! In fact, I’d say you could likely save your clients money with bigger filters and changing them every 4 months instead of every 3.
At 2000 cfm, would you rather have a MERV16 filter with a 0.21 pressure drop, or a MERV13 filter with a pressure drop of 0.13? Guess what I'm asking is the increased filtration worth it. Prefer to not run it all the time. Thanks
As mentioned by @KPHVAC you should start this process with static pressure testing bc you might be about to kill your system
@@HomePerformance thanks will test first. It will be a new system with multiple returns.
@djheckler92 then you should be able to design it with Manual JSD calcs and know it’ll be perfect.
Due to an odd ceiling lighting track in the way, I have two parallel filters on my split return. How should I calculate the math if I have filters working in parallel? Halve the resistance value? Trying to figure out the best filter I could run without stressing the air handler.
Halve the CFM through each filter.
To make this make more sense you should go through what the TSP for the air handler is. Then how to measure this. If you go through the Lennox equipment manual you will find that when you get to 2000 CFM it recommends that two filters be used. Next if your return ducts are not sized correctly it doesn’t make any difference how big the filter is. Picking out one component and calling it the answer is misleading, there so many things that affect the performance. I don’t know what area you located in but that insulation on the plenum doesn’t meet code here in TN.
What are your thoughts on the aprilaire 5000? EAC501
They only make that bc some HVAC guys insist on an EAC. It’s not a great product in general, and not something they’re too excited about at the company either I believe.
What about IQAir? They also make a hyper hepa duct cabinet for hvac that looks really nice
Those units START at $2000. The replacement filters are also quite pricey.
@@HomePerformance no doubt but you get what you pay for. Filtration quality and performance is top tier. I’d likely be paying around 20k for my next system once it’s all said and done any ways so it’s just incremental.
It’s not incremental though- HEPA starts at MERV 17 for $2k, or you can have MERV 16 for $250. I’m sure your system will kick ass no matter what.
@@HomePerformance Just want the best, that's all. Having hyper hepa in my hvac allows me to not have hepa units in each room as I do now.
@darylfortney8081 cool man
I tried to email you about engaging your services. But no reply. Did i get the wrong email?
Sorry to hear, it's just me here and I get flooded with messages. Try again or just go ahead and book a consult yourself directly at:
buildingperformanceworkshop.com/video-consulting
Step 1 = test static pressure first!!! 90% of the homes in my area have undersized ductwork that can't handle any upgraded filter. We are constantly adding another return air duct to get proper airflow.
Excellent point