Your HVAC (Heating, Ventilation and Air Conditioning) systems air filters should be changed not when they’re dirty but on frequently planned intervals. Your home’s air filters are like your cars oil filter. Only clean oil works effectively as a lubricant. If you wait to change your car’s oil and filter when it’s dirty, the performance and fuel efficiency of the engine decreases. This is the same for your home’s HVAC system.
Filters should always be changed or cleaned based on the manufacturer’s recommendations. It is probably the easiest thing to do to keep your HVAC system clean, running efficiently, reduce your maintenance costs and extend the overall life of your system.
Most homes have the filters located as the first point of air intake but some have them located near the main HVAC system as an inline box. If yours is not part of an inline system, it will be located on a wall, on the ceiling, under the furnace or more rarely, in the floor. It is almost always located near the HVAC unit’s thermostat. Since room temperature air is pulled from the house into the return plenum where the filter is located to be heated or cooled, measuring the air temperature with the thermostat near the return is just makes sense.
It’s always a good idea to have more than one filter on hand for each size your house uses. This will save you from having to make special trips to the hardware store for this frequent and very important task. Filters are not created equal so decide which system is right for your home but try to choose a filer with a sturdy frame. Your HVAC specialist will be able to recommend the right filter for your home.