How often should I change the filter in my geo? I had a new geo installed back in Sept. It has 28x30x2 MERV 11 filters. I have read anywhere from 3 to 6 months. I still have the original filter in it and looks clean, but the unit is running a lot in the colder weather. Thanks
I have heard anywhere from 1 month to a year! I personally have one central return for which I use a 24 x 30 x 1" pleated filter in. At $3 each, I don't let them go too long before replacing, usually each month. I feel that time alone is not the best determinant on when to replace the filter, but it's the simplest to abide by. You could get technical about it and place a manometer downstream of the filter. I had intended on doing the same. Something like this https://www.amazon.com/Dwyer-25-Manometer-Inclined-Vertical-Measuring/dp/B009PAN3C8
Pull out the filter(s) once a month and look at them for dust bunnies or pet fur if you have long haired pets. You can vacuum the surface if the filter looks clean but has a lot of the above is building up on them. Hold the filter up to a light and see how much light is blocked. As the months wear on you'll see them change from white to a brown look. When they look dirty by your standards replace them. Running too long with dirty filters makes your fan motor use more energy and it gets hotter which shortens the life of a motor compared to if you had a clean filter. I write the date on the edge of the filter so I can see the date installed and how long they lasted. As you would expect, the more your Unit runs, the quicker the filters get dirty. I don't use the "horse hair" filters, the ones that have a lot of air and very little material. They're made for those who don't like changing filters. Years ago a company made a green whole house filter called the Dust Stop that was very good at catching dust. They stopped making them due to customers complaining that they got dirty too quickly. Duh! isn't that why we use a filter in the first place? Later 3M started making a range of filters that you probably use today. Keeping the dirt in the filter is better than circulating it through the air, into your duct work and on your furniture requiring increased house dusting. I don't know what the customers were thinking when they complained to the point of the Dust Stop being no longer produced.
I've read about filters almost ad nauseum. What I've come away with is that their purpose is to protect the equipment. What type, how thick, etc... appear to be a matter of opinion or preference. The most in-depth conversation I was involved in is here: http://www.diychatroom.com/f17/filter-strategy-363385/
