Our downstairs air hasn't been running too efficiently lately, so I thought it was crapping out. It's about 14 years old at this point.. well I haven't changed the filter in at least 1 year, so my Dad told me to check that first..

Old filter for downstairs on the right/Old filter for upstairs on left



The downstairs air was the one having the efficiency problems!!

 

filtersnow.com is a great place to order an annual supply

I change mine monthly during the AC or heating season and bi-monthly during spring/fall when windows are open.

With 4 intakes that is about 24-30 filters per year, but the dust stays down and the HVAC person said my units looked new with no dirt on the blower motors. Worth every pennyor two

 

I can't see shit!

 

omg that's disgusting.
I change mine every 3 months without fail, and vacuum often... otherwise allergies start flaring!

 

 

Mine looks like that if I let it go more than a couple months.

 

Well I know they were in the house for at least 1 year.. don't know if the previous owners changed them during the selling process (they had already moved out). Doesn't help that my dog loves to shed

 

Change mine every 30 days, no reason not to since they are so cheap

 

Yep we had the same issue the AC couldn't pull the house my roommates and I live in under 78 and I'm like have you changed the filter this summer? Sure enough nasty filter.

 

Same here... except the upstairs filter's are only changed once every 6 months since we do not run the heat upstairs in the winter.... so I just change them twice per year (once before the A/C season and once during).

 

Perhaps I should stock up and change more often. August 18th will be 1 month. Hmm...

 

Don't know if anyone knows the difference, but my Dad told me to get the $3-$4 filters and just replace those every 2-3 months.. I got the 3M filters which were $9 each, since I figured those should filter better than the cheaper looking ones.

What kind of filter does everyone buy? Cheap ones ($4ish) or Expensive ones ( >$8)

 

^ I buy the more expensive ones and change them every 3 months (except as noted in my last post for the upstairs unit).

In fact, my thermostat has a built in filter timer (for lack of a better term), so when I replace the filters I set it to 90-days... then after 90-days it blinks filter to remind me to change them. I do not even need to remember!!

 

Very nice.. My 2 thermostats are older models.. may look into upgrading them, but don't know if it's worth it

 

i replace mine every 2-3 months. my co has an account at the plumbing supply place next door, so i get things real cheap. I get the 20x16x1 filters for $39 for a case of 12. Much cheaper than the $9 ones i was using.

 

I bought a nice filter...one of them Filtrete ones (or whatever), but it doesn't quite fit in my furnace. I was told that my furnace was designed for thinner filters, so I'd be better off buying the cheaper ones!

I think I'll end up stocking up on the cheap ones and change 'em monthly.

 

Buy the cheap ones always. The expensive ones restrict your air flow. My thermostat has the reminder as well but I never look at the thermostat so its useless to me. I just try to replace it on the first of each month.

 

Quality of the filter has no bearing on the thickness. You probably just got the wrong size. My blower uses a 16x20x1, which is 1" thick no matter which brand I buy.

 

As mentioned, the really high MERV value filter block everything, including airflow
filtersnow.com
has every conceivable size and many filter "levels" for each

I get a higher MERV for the one carpeted section and lower for all the hard floor sections.
figure about 4-7 per filter and you should be fine. Frequent replacement is cheaper than having the HVAC guy come and spend hours pulling the blowers out to clean them.

 

First thing we did when we moved in was change the thermostats.... and this was in a brand new house. Put in 5-2 programmable thermostats before the moving truck even showed up with our furniture...

 

My system has (2) filters. 1" X 20" X 25" and a 5" X 20" X 25". I change the 1" filter every 400 hours of the blower running (@ 90 days) and the 5" filter once a year. I use Merv6 for the 1" size. Purchase by the case to get the discount.

http://www.filters-now.com/products/mmb.html#products

http://www.filters-now.com/ld3mspec.php#3m600

 

Do you all use pleated or fiberglass air filters?

 

The one's I get are the 3M ones from like HD or Lowe's. They're not that expensive. They're better then the cheap blue ones, but not the most expensive one's they have there. They were actually recommended by our HVAC guy and our system runs great and we have zero airflow problems...

When I said I buy the more expensive ones... maybe you guys are thinking of something else?

 

At my Home Depot they had 3 types of 3M Filters ranging from $9-$19. I bought the $9 ones.

 

Fiberglass filters are bad, they don't block enough of the dust/dirty and will cause your evaporator to get clogged up with crap. If you have been running only fiberglass filters in your HVAC system for 5 years or more it's almost a guarantee you need to have your evaporator cleaned. Especially if you have pets.

Having your evaporator clogged is like running with a permanently clogged air filter. The air passes through the evaporator to transfer thermal energy for your A/C (or heat if you have a heat-pump).

If you fall into this category getting it cleaned will lower your heating and cooling bills and put less stress on your blower motor.

You can see here the evaporator has VERY small areas where the air passes to do the thermal exchange. Here' is a picture of a dirty one from using a fiberglass filter.



Here is what it should look like


On a side note that evaporator is damaged at the bottom and the fins need to be straightened. Glad that's not mine!

If you use a 3m 1" thick filer; do NOT use the sharp pleated ones. They are WAY too restrictive, use the round pleated ones.

 

someone needs a fin comb

 

I was cringing looking at it thinking the same thing. Best pics I could quickly find on google though.

 

@Siggy.. Is the evaporator easy to access? Is it a DIY cleaning or best to have someone come clean it?

 

If your able to get power near the filter access point i would suggest getting an electrostatic filter which are not that pricey but the air quality is awesome. I have two of these and they are awesome. You should see how clean my air coil is as compared to the standard paper or mesh filters. They not only help cool my home quicker but prevent the compressor from coming on alot more and prevent the compressor from burning out quicker.

 

I change mine every time i get my power bill. I would rather change them too frequently then to have my A/C working overtime and running up my electric bill.

 

I check mine every month. Usually change them every 6 months or so. Mine does not seem to get that dirty. It's in a room attached to my garage and I sweep the garage every week.

 

If you change them every 6 months, why do you check them every month?

 

It depends, on some systems it's easy. On others you have to take the air handler apart completely. Like the system in my house now I have to remove some ducts and the air handler Lucky mine is very clean thus far so I haven't had to do it.

The process to clean is pretty simple if you have access to the evaporator. Go out and buy some evaporator cleaner (know your make/model of your A/C unit when you go to buy it (just take it off the compressor outside); as some evaporators have special coatings on them that could be damaged by using the wrong cleaner).

You setup a plastic sheet under the evaporator to stop the cleaning fluid from going into your heat exchanger for the furnace. Then just spray down the evaporator from the outside in (spray from the side that isn't nasty looking) until it's clean. You may have to use a very soft bristle paint brush to get some of it off.

Just be aware it's extremely easy to bend the fins on the evaporator. Treat it like it's worth $100,000,000 when your working with it.

Also you could try and use a vacuum with a brush adapter if you have a bunch of build-up just to get that surface layer off. If so I'd do this before using the chemical cleaners. And always brush in the direction of the fins on the evaporator; never against. I'd really try to brush it as little as possible anyway...

 

6 months? that's way too long for a 1" filter. You *might* be able to make a 4" filter go that long.

1" should be done every 30-60 days.

If you want to really know if your filter is clogged up causing pressure issues in your furnace install one of these and use it as a gauge.

http://www.furnacefiltersoutlet.com/...lter-gage.html

 

Can I get a DIY w/ pictures? jk jk Thanks for the info.

 

Can you post a pic of a "sharp pleated" and "round pleated" filter? I use the kind with pleats that look like the ones in the the OP's first post. Are those "round" or "sharp"?

 

So after my $622 electric bill I posted on some HVAC forums and gathered the following info

- Generally people do not change their filters as they should [based on the photos above and after walking through various houses during my buying time]
(bad op!!!!! =p)
- It's better to buy the cheaper pleated filters.. I was previously buying the 3M Ultra Allergen 1800s; but i've read that they are too restrictive and create pressure issues that can reduce efficiency. The general recommendation was Naturaire or something

- The blue fiber glass filters are absolutely horrible

 

Check out the site above, it is worth it to buy the case and save some $$ and it helps promote changing the filters when they are in the house.

 

I have a 4" and change it every 60 days and vacuum regularly to help minimize the dust