Annual filter changes?

dko

The exception doesn't make the rule. You can choose the filter for your situation.

General charts are just that.. general. For practicality/value. What would generally apply to more homes than not.

JakeCK

I forgot about dust mites, another thing that set off my allergies, while the mite themselves are quite large at 200-400 microns their feces is what causes the problem. Which when excreted is about 10 microns, but that rapidly dries up and breaks down into much smaller particles, small enough to reach the alveoli. 

So to sum it all up to those who are recommending Merv8, ya'll can keep breathing in dust mite poop💩. 👍

JakeCK

dko said:

The exception doesn't make the rule. You can choose the filter for your situation. General charts are just that.. general. For practicality/value. What would generally apply to more homes than not.

The difference in merv 8 and merv 13 filters is less than 10 dollars. If you change it out everything 3 months it's ~ 40 dollars a year more for cleaner air using the homes HVAC system. Now how many people go out a spend a grand on a portable HEPA filter that's light on details, and the ones given being questionable at that? And how much do those filters cost for something that might not even move enough air to effectively filter one room? If static pressure and premature failure of the blower is a concern I'd rather spend the cash on upgrading the plenum and blower so it isn't a concern. Just building a filter box that can handle multiple filters can alleviate most of those issues. 

OR! Since this is a site full of HVAC professionals, how much would it cost to design such a system from the getgo when replacing a HVAC or installing a new build? We're always harping on about doing quality work, doing the heat and cooling load calculations and so on and so forth. So how much more would it cost at initial install to design a plenum that can handle the high merv filters without issue? 

ChrisJ

JakeCK said:

ChrisJ said:

Those are also MERV 13 which has no business on any residential system.

Do you have any data or sources to backup that claim?


Do I have data to back up the claim?

Typically residential systems want no more than 0.5" WC total static pressure as per the manufacturers.
Can you achieve that with a MERV 13 filter?

A MERV 13 Air Bear filter has a tad over double the pressure drop of their MERV 8.

My system runs about 0.4" with a new MERV 8 25x20x5" and I oversized the ductwork according to almost everyone. I change the filter when I see it running around 0.55 to 0.6".

That 25"x20"x5" filter is rated for 2000 CFM and I'm using it on a 1200 CFM system.






I'm not sure what you would upgrade. I'm running an ECM blower, and all of the ductwork was oversized and space was an issue. You can only go so big. There's also a point where it just becomes stupid. There's nothing smaller than 8" in my house and I went as big as 10" in spots. If I can't run higher than MERV 8 without exceeding 0.5" it's unlikely anyone can honestly. Commercial is a different animal with blowers that handle multiple inches of static pressure without an issue.

How many are running MERV 13 filters without any gaskets in leaky housings so it performs like a MERV 3?

JakeCK

Increase filter surface area. Using 5" helps a lot but it isn't a linear relationship with deeper filters. 

ChrisJ

JakeCK said:

Increase filter surface area. Using 5" helps a lot but it isn't a linear relationship with deeper filters. 

I'm using a 25x20 5" filter............
How big do you want to haul up into my attic?


As many have said on this forum, a residential HVAC system is not an "air purifier" and has no business being treated as one. Hospitals and clean rooms do not use the same equipment.

Not to mention, personally I think such things in homes are gimmicks and do not work, but that's a whole other subject. Again, hospitals, clean rooms etc, totally different. Those setups are real and work and do their intended jobs. I have no doubt about that.

@pecmsg @ratio You guys do much hospital or cleanroom work?

ratio

ChrisJ said:

@pecmsg @ratio You guys do much hospital or cleanroom work?

Not really. Did a drug storage unit at a pharmaceutical outfit, but that was turnkey, we just bolted all the parts together. Did a humidity-controlled room for an additive manufacturing facility too. That was kinda fun, humidity ran in the low to mid 30s. (12-14 DMLM machines, really neat to watch—for a few minutes. They had demo products laying out, nested buckyballs. Awesome.)

pecmsg

ChrisJ said:

Increase filter surface area. Using 5" helps a lot but it isn't a linear relationship with deeper filters. 

I'm using a 25x20 5" filter............ How big do you want to haul up into my attic? As many have said on this forum, a residential HVAC system is not an "air purifier" and has no business being treated as one. Hospitals and clean rooms do not use the same equipment. Not to mention, personally I think such things in homes are gimmicks and do not work, but that's a whole other subject. Again, hospitals, clean rooms etc, totally different. Those setups are real and work and do their intended jobs. I have no doubt about that. @pecmsg @ratio You guys do much hospital or cleanroom work?

10 years at Plum Island Animal Disease center

100% outside air

JakeCK

The argument that a HVAC isn't meant to provide clean air is BS. If you want to make that argument then any house built prior to say 1970 shouldn't have AC because the system wasn't built for it, any houses built before the turn of the 20th century shouldn't have indoor plumbing or electric, houses built even earlier shouldn't have any central heating at all, and our inner city streets shouldn't allow cars and trucks because they were meant for horse and buggy. See the logical fallacy? Ok they weren't designed for that purpose originally because the technology didn't exist and we didn't know how important clean air is. So what. Now it's time to make them with that purpose in mind and when opportunity provides upgrade the older systems.

That said I doubt going to merv13 is going to cause premature failure if the filters are changed when they're supposed to. How many homeowners neglect to change their filter over the course of a year... Do the blowers suddenly explode? How often are homeowners actually having to replace the blowers? And it sounds like you keep on top of that, have you tried to run a merv13? 

As someone who has suffered with allergies my entire life I can tell you there is a difference. A huge difference. Living in various houses with different HVAC systems none of them have ever alleviated my symptoms during the peak season of spring and fall. But that stupid looking box fan with four filters duct taped to it and the box fans in the windows have. I actually forgot to take Claritin today, that is until I went outside. 

If I were to design an HVAC system the filters wouldn't be at the plenum. They would be behind the air return grills in every room. In my house that would allow me to use at least 5 filters at whatever thickness I choose. The filter surface area would be significant. But pricey every few months with filters? Maybe but pharmaceuticals aren't cheap either, or healthy.

pecmsg

An A/C unit CAN supply clean air but not your residential models?

JakeCK

That is the box fan in my son's room with a single 1" merv13 filter. That filter has been on it less than 3 weeks. What do you see?

pecmsg

A residential A/C filter is NOT designed to replace a vacuum cleaner, it’s designed to protect the equipment!

JakeCK

pecmsg said:

A residential A/C filter is NOT designed to replace a vacuum cleaner, it’s designed to protect the equipment!

No body said anything about using an a/c filter as a vacuum cleaner. I use that multiple times a day too. My kids trash the house hourly and I vacuum almost every other hour. But a vacuum cleaner is not going to stop the constant infiltration of pollen, dust, automotive and industrial particulates and you know that.

A HVAC filter can help protect the equipment and the occupants however. They are not mutually exclusive.

And I'm sorry but I have to disagree with that sentiment just on principle alone, even if that is what the HVAC industry intended or believes. First off the entire system is there to improve our health and environment, the  statement that it isn't meant to provide clean air kind of negates it's purpose to exist. Second HVAC ducts and everything in them are hardly ever cleaned in a residential setting so absent impossibly perfect filtration they will get nasty sooner or later regardless of the filtration level. Even a merv 14 hospital grade filter is going to let in dust over time. I bet for most homeowners the plenum isn't ever opened up except for when something breaks after 10, 15, 20 years. And I bet it's all coated in a fine layer of nastiness. And the evaporator coil is probably pretty nasty too. I wonder how long it took to get like that.

ChrisJ

@JakeCK

Ok.
The good news is when you install ductwork in your house and a ECM blower with a $800 motor you can go ahead and install a MERV13 filter or filters on it.  You're 100% allowed.


Please let us know how it goes.  I honestly would like to know how many filters you use etc and how it works out.

JakeCK

Digging into the weeds a bit and I'm sure to ruffle some feathers, but simply put the idea that the filter is meant to protect the equipment and not the people is wrong. And the minimum is Merv8 for a new build. As in builder grade. If I'm building a new house or adding a HVAC system I don't want builder grade.

ANSI/ASHRAE Standard 62.1-2022, Ventilation and Acceptable Indoor Air Quality

Standard 62.1 specifies minimum ventilation rates and other measures intended to provide indoor air quality (IAQ) that’s acceptable to human occupants and that minimizes adverse health effects.

ChrisJ

JakeCK said:

Digging into the weeds a bit and I'm sure to ruffle some feathers, but simply put the idea that the filter is meant to protect the equipment and not the people is wrong. And the minimum is Merv8 for a new build. As in builder grade. If I'm building a new house or adding a HVAC system I don't want builder grade.

ANSI/ASHRAE Standard 62.1-2022, Ventilation and Acceptable Indoor Air Quality

Standard 62.1 specifies minimum ventilation rates and other measures intended to provide indoor air quality (IAQ) that’s acceptable to human occupants and that minimizes adverse health effects.

Sounds good.

Keep us posted.

pecmsg

JakeCK said:

pecmsg said:

A residential A/C filter is NOT designed to replace a vacuum cleaner, it’s designed to protect the equipment!

No body said anything about using an a/c filter as a vacuum cleaner. I use that multiple times a day too. My kids trash the house hourly and I vacuum almost every other hour. But a vacuum cleaner is not going to stop the constant infiltration of pollen, dust, automotive and industrial particulates and you know that.

A HVAC filter can help protect the equipment and the occupants however. They are not mutually exclusive.

And I'm sorry but I have to disagree with that sentiment just on principle alone, even if that is what the HVAC industry intended or believes. First off the entire system is there to improve our health and environment, the  statement that it isn't meant to provide clean air kind of negates it's purpose to exist. Second HVAC ducts and everything in them are hardly ever cleaned in a residential setting so absent impossibly perfect filtration they will get nasty sooner or later regardless of the filtration level.

Having worked Hospitals and Bio labs where 100% outside air is the norm depending on the definition of "Clean" nothing gets by the filter system.

A simpler solution for you is to install a whole house dehumidifier with an outside air connection. Filter the outside air duct. When running it will maintain positive pressure in the envelope. Now all those nasties you're expecting the HVAC to take care of Do NOT enter the structure. It will also maintain a better RH during mild seasons.

ChrisJ

pecmsg said:

Having worked Hospitals and Bio labs where 100% outside air is the norm depending on the definition of "Clean" nothing gets by the filter system.

A simpler solution for you is to install a whole house dehumidifier with an outside air connection. Filter the outside air duct. When running it will maintain positive pressure in the envelope. Now all those nasties you're expecting the HVAC to take care of Do NOT enter the structure. It will also maintain a better RH during mild seasons.

It would also reduce radon concerns, if there are any.

Larry Weingarten

Zehnder? https://www.zehnderamerica.com/brochures/

Yours, Larry