What is the best air filter that you can buy?

I'm having to change my air filter every 2 or 3 weeks. My townhome is about 1200 square feet, but I don't understand why I have to change the filters so often. I have tried the air filters that are about $20 for one, and the cheaper ones that are $15 for 3. The $20 filter lasted about a week longer than the others, but for the cost it doesn't really add up. Home depot sells an air filter that costs $100, and it's suppose to be for 30 years or something. Anyway, what's the best air filter that I can buy?
What is the best air filter that you can buy?
In the past 7 years I have never seen a $100.00 filter at the HD. But to answer you question on the effectiveness on the filters, which by the way should be changes every 90 days, the spun fiber glass is the cheapest and worst filter you can buy. One way to see for yourself is to take baby powder and sprinkle it over the filter, just about all the powder fall through. With the 3 for $15.00, naturalaire filters, they fare better in stopping the talc powder. The best would be the 3M Electrostatic filters. Take a look at the MERV rating on your filters when you buy them. If you are asthmatic or have severe allergies, I would recommend the 3M filters, otherwise the Naturalaire filters work just fine. By the way I use the naturalaire.



Edit: An air filter is just that, it filters out particulates in the air when the A/C or Heater is run, thus clearing out any particulates in the air. An air purification system does the same thing without heating or cooling and is more efficient in cleaning the air. It is something i would recommend only if the buyer is a smoker, has allergies or respiratory ailments.
What is the best air filter that you can buy?
My personal experience with Home Depot is that they sell the cheapest junk they can get their hands on. Their sales personnel usually know about 20% of what they should know about their job and products. They have misled me and given me outright false information in the past. Stay away from them.



I assume you mean a furnace or air conditioning unit air filter. A filter is supposed to pull dirt and dust out of the air. If it gets clogged every few weeks, that does not have nearly as much to do with the cost / quality of the filter as it does the amount of dirt / dust in your air. It seems to me you have a lot. Check your ducts for dirt and dust. Sometimes during construction a lot of dirt and debris gets into the ducts. The ducts need to be clean. Also, check the area where the equipment is for sources of dirt. For example, if your furnace room has a door to the outside, and there is a louver in the door, you could be getting a lot of dust from outside. A lot of townhomes have a crawlspace, and the furnace is in the crawlspace. Sometimes these crawlspaces have a dirt floor - and that is a source of dirt and dust to clog the best of filters. If you have this condition, cover the dirt floor with minimum 6 mil thick plastic from wall to wall. Seal all the seams/overlaps with tape. That should help. If your doors and windows are always open, that is a source of dust. Maybe you just need to vacuum more often. Remember, if a filter is getting clogged, it is because it is removing a lot of dust, not because it is a cheap filter. Look for the source of the dirt/dust.
Most people are confused about he purpose of the %26quot;Air Filter%26quot;. It is not to clean the air but to filter out larger dirt particles to protect the furnace/ evaporator coil. If you are looking to clean the air then invest in an electric air cleaner. these run about $1000.

The more restrictive filter you use the less efficient your system is.