Obviously, knowing where your air filter is an important step for maintaining your system, but something you may want to check is whether your air filter fits right. Having an air filter with a 'Bad Fit' can cause a number of problems which includes driving up your utility bill.
The furnace blower motor is located to the right of the filter, where a great deal of 'sucking' - negative pressure. If there are large gaps due to the sloppy fit of your air filter, you can see where it's going to pull a lot of air around the filter and into your heating and cooling system. That means less air will be coming through the cold air return ducts. Also, less airflow being circulated throughout your home and through your air filter.
Think of where it's sucking air from. The typical furnace is located in your basement, so a lot of air is going to get 'sucked' in from the basement area.
This increases the negative pressure in the basement which is already prone to lots of air infiltration, and what they call the "stack effect". This single problem can cause so many problems.
An Increase in Air Leakage
During the winter, outdoor air is much dryer than indoor air. When you mix that cold, dry air with your household air, you create uncomfortably dry conditions, leading to nosebleeds and cracked woodwork, among other problems associated with low humidity.
You might be 'sucking' 5º-20º cold air from the outside; that'll drive your heating bills up even more.
During the summer, your system will 'suck' 85-90º air from the outside instead of 75º air from your house; outdoor air is hot and humid. A big reason for having an air conditioner is to dehumidify your air. Instead, you’re 'sucking' in humid air into your house which leads to uncomfortable conditions and makes your air conditioner work harder.
Fix this simple problem:
Buy a properly sized filter that fits entirely within the slot and then ensure that the air filter slot is sealed air-tight; think of your heating and cooling system a little like your plumbing system.
If there’s a cover, check the weather-strip and make sure the cover seals air-tight. You may want to wipe down the sheet metal around the filter slot with cleaner and paper towel. Get it nice and clean.
If that doesn't seem to solve the problem, consider having one of our qualified techs look at your return air ductwork. We discover these situations all the time when we go out on a service call or do a tune up. We refer to it as the unsuspecting homeowner.