Home Air Filter Advice Please

Aug 27, 2007 57 Replies

I have 3 returns in my house. I was told that I do not need an air filter in my main unit (which is in my attic) if I have a filter in the returns. However, when I had a filter in the main unit, I noticed it was dirty....even though I had filters in all the returns. So currently, I replace all 4 filters regularly. Is this ok? I use MERV 8 pleated filters.



I want to start using MERV 10 filters. Is it okay to still use one in the main unit?


When filter media accumulates dust the pressure drop across the filter increases. This increase in air velocity then increases the amount of dust entrained in the air. And a dirty filter will be indicated by dust coming out of entrainment at the diffusers. In a practical sense having a filter on the main unit will not effect the system to any great degree however the filters in the returns will require more frequent cleaning

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Don't know, what type of equipment do you have? I will say that most systems are not designed for such a restrictive filter. Let alone, using one after another!

No filter is going to work 100%. The ones that filter better tend to block flow and this is bad. Two filters block more flow than one. They may trap more dirt, but life is full of tradeoffs. I would stick with just return air filters or a single filter at the furnance.

I like MERV8 as a good compromise between cost, back pressure, and particle size. MERV8 is usually the most porous of the widely available paper pleated types and will stop most pollen and all visible dust. Pollen is my main concern (due to hay fever) and they do a good job. The next smallest particle filter practically doubles in price, and causes over twice the back pressure but the extra dust it captures is not worth the price or backpressure IMO. The next filter down is usually a fiberglass pad that has little back pressure and is cheap but doesn't catch most visible dust and no pollen. An alternative would be to use a cheap pad filter on the ducts and a MERV8 on the air handler, this will keep the big "dust bunnies" out at the beginning so the MERV8 only has to do the pollen and small dust at the fan.

wrote in news:a392f$46d39b67$9440c41e$ snipped-for-privacy@STARBAND.NET:

That's a little better tone. Try to keep improving.

I have a Heritage 13 Heat Pump but I am not sure about the air handler in the attic.

The reason I was thinking of going to MERV 10 is because the MERV 8s are not capturing visible dust.

Where are you located?

Do you just have the HP, or do you have a backup source for heating?

I just have the heat pump. I live in the south eastcoast.

wrote in news:7b01b$46d4d368$9440c41e$10272 @STARBAND.NET:

Oops! There you've gone and lost all the brownie points you had picked up for offering a pleasant post. Back to training for you. Do try just a little harder next time.

wrote in news:79252$46d62211$9440c41e$28353 @STARBAND.NET:

restrictive

You really are bi-polar aren't you. Do try to take your meds dancing monkey boi.

Whats-a-matter, your boyfriend busy giving head to a *bigger* guy tonight?

wrote in news:18d6a$46de4009$9440c41e$22754 @STARBAND.NET:

Posting drunk again? Just keep dancing monkey boi.

Geez, you're totally incompetent (no surprise). I guess you never retain *anything* that you read.

wrote in news:2d692$46dec3d5$9440c41e$18900 @STARBAND.NET:

And still drunk in the morning. Maybe it's off to rehab for you.

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