Replacing AC Filters (price, inspector, very expensive, cheap)

[spalam01]

What is the recommended frequency to replace AC Filters to ensure the efficient working of A/C unit and the electric charges.

I heard conflicting answers.

a. Per one answer, it is 1 month if one go with cheap ($1) air filter
b. Per another answer, it is 3 months if one go with little costlier (say about $5 to $7) air filters.

Which one is right?

I am wondering if one needs to replace air filter once a month regardless of the price of the air filter

How often do you replace the air filters and what is the cost of your air filter?

[yiplong]

replace filter once or twice a year unless you live in the middle of the desert where there is constant blowing dust.

[hml1976]

Originally Posted by yiplong

replace filter once or twice a year unless you live in the middle of the desert where there is constant blowing dust.

Or you have a ton of animals.

[Tardislass]

My home inspector told me to always change HVAC filters once a month.

[Rakin]

I buy medium priced 90 day filters by the case and replace them every 60-90 days depending on how much my central AC is running. I have no pets.

Don't buy the high $$ filters, they restrict too much air flow.

[Rabrrita]

For the cost of a filter, I change them every 30 -60 days even though they may be rated for longer use. Its cheap protection for a costly system.

[cully]

I think you use heat where you are. Just to say these things are for year round anyway.

One indicator is how dirty/full they look. After a few of them, unless things change you can get pretty much of a system down. Depends on pets, whether they are shedders, whether it's shedding season, fans, dust, pollen, how often one cleans that dust, windows open, humidifier, etc. and on the occupants' ability to tolerate a certain amount of allergens or not.

This will change based on the type filter and can change from month to month or season to season. But you'll get it down eventually. More often in summer or more often in winter, etc. For our needs we like the more expensive one.

[marksmu]

The actual answer depends heavily on the type of unit you have.

Older units have only the cheap pre-filter type filters that are accessible from inside the house. These should be replaced monthly, bi-monthly at worst.

Newer units do not use pre-filters and have one 6-8" thick filter in the air handler in the attic....these type are very expensive, on average $100/each and should be changed annually....every 6 months if you have dogs/cats or other furry animals whose hair clogs up the units.

If you do not replace your filters, they will clog and impede the flow back to the coil...when this happens you reduce the air flow across the coil and therefore reduce the air coming into your house...In addittion to reducing the air flow you strain your blower motor by putting too large of a load on it....finally because the coil is not getting adequate air across it, your coil may become too cold, causing ice to form on the coils...when this happens you put serious strain on your compressor.

So bottom line is that the answer varies based on your unit and type of filter - but failure to change your filters can be very costly as it increases your bills and adds unnecessary strain to your unit.

[Ted Bear]

I live in a moderate climate, keep a clean house, and don't overload the HVAC with A/C or Heat....78-80 in summer; 65-67 in winter.

My air handler uses one of the large filters.....6-8", and each of my three cold air returns has a one inch filter on it. I buy a better quality filter for these returns.....runs about $25.00 each.

I change all of the filters twice per year. They certainly have started to "gray" by this time, but still have plenty of life left in them. I like to think they filter out a lot of the finer particles, as well as trap some of the micro "stuff" that is floating around.

Seems to work fine.

[cully]

Originally Posted by Ted Bear

I live in a moderate climate, keep a clean house, and don't overload the HVAC with A/C or Heat....78-80 in summer; 65-67 in winter.

My air handler uses one of the large filters.....6-8", and each of my three cold air returns has a one inch filter on it. I buy a better quality filter for these returns.....runs about $25.00 each.

I change all of the filters twice per year. They certainly have started to "gray" by this time, but still have plenty of life left in them. I like to think they filter out a lot of the finer particles, as well as trap some of the micro "stuff" that is floating around.

Seems to work fine.

We're pretty much the same as you. Some people think I'm crazy putting filters in my returns. But it works well for us.