Are filtrete filters bad?

November 21, 2007 5:44 AM

Do 3M Filtrete furnace filters put a strain on the blower motor? I've heard this from more than one HVAC technician. Some techs like the cheapo 50 cent filters. Why is that? Do they see a lot of failed motors due to insufficient air flow? I would think a well run company like 3M would know how to design a proper filter.
posted by qsysopr to home & garden (8 comments total)

Yes, if people don't change them when they're supposed to, they get clogged with dust and then reduce airflow and strain the motor.
posted by SpecialK at 5:54 AM on November 21, 2007

I believe it's all in how the system is sized and installed - it's not that it isn't a "proper" filter, it's that it's too good. The pressure required to push air through the filter is larger since the filter is thicker and denser, so if your system is at the edge of its operating pressure range it may cause problems. They're just being cautious and not doing the math - I have to be extra careful as I have a spacepack (high velocity AC) and some filters WILL put a big strain on the system.
posted by true at 5:56 AM on November 21, 2007

Most 3M filters are massive overkill, designed to prey upon the germ-phobic, anti-bacterial handsoap using Soccer Mom.

A cheapo filter will work just fine.
posted by unixrat at 6:29 AM on November 21, 2007

One thing you can do to prolong the life of your blower motor is to let the blower run all the time. Most of the strain on the motor comes during start-up. The furnace and AC don't have to run all the time, just the fan.

I learned this from a guy who owns an electric motor shop, not an HVAC tech.

You will have to change the filter somewhat more often and it will use a bit more electricity, but you should still come out ahead.
posted by OilPull at 6:41 AM on November 21, 2007 [1 favorite]

unixrat: Actually, they're really helpful for someone like me that has a heinous dust allergy.
posted by SpecialK at 8:41 AM on November 21, 2007

Our HVAC tech was servicing ours and didn't remark on the Filtrete filter prominently visible (except to remark that it needed replacing, which it most definitely did).

Not a soccer mom, not germ-phobic. I do have allergies, though, and the Filtrete helps. "Cheapo" filters don't filter as much.

Sadly, I don't live in a clean room as others here seem to.
posted by RikiTikiTavi at 8:48 AM on November 21, 2007

I've been told by more than one AC tech to just buy the cheapest pleated-paper filters I can get, and change them regularly. Avoid the blue-fiberglass filters, they don't work well at all.
posted by mrbill at 9:08 AM on November 21, 2007

We had precisely this worry about Filtrete filters and asked our HVAC guy (whom we trust) this fall. He said they do put a higher load on the system, but it's not a problem if you have appropriately sized air returns. (My wife has bad allergies, and they do seem to help.)

I'm also considering an Aprilaire Whole-Home Air Cleaner. The HVAC company installs it, then you pay just $60 once a year for replacement media. The whole-home cleaner is much more effective even than Filtrete, and the media are cheaper, so in my house getting it installed would pay for itself in five years, not even counting any benefit to the home's value. More info.
posted by futility closet at 9:31 AM on November 21, 2007 [1 favorite]