How long you should go between changes will depend on several factors including the type of filter you have and how much use your system gets.
Why You Need Fresh Filters
Clogged, dirty air filters in your heat pump, air conditioner or furnace can lead to several problems.
Energy efficiency. You’ll lose energy efficiency if your system is forced to work with a dirty filter. Your HVAC or heat pump will have to work twice as hard and the strain may cause permanent damage, meaning an expensive repair or replacement.
Dirty air. You and your family will be breathing dirty, allergen-filled air. A clean air filter is especially important if your home has smokers or pets, or if you live close to pollen-producing plants.
Mold and mildew. A poorly working air filter can’t keep out mold and mildew, and leaving an air filter in too long could cause it to develop mold itself.
What Type of Filter Do You Have?
Common fiberglass filter. Available at most home and discount stores, these inexpensive filters will keep large dust and debris particles out of your home but allow smaller ones through. You should replace them monthly.
Box pleat filter. Mid-range filters that are usually made of fabric, these allow for better protection from small dust particles. You should change them every three months.
HEPA filter. HEPA stands for “high efficiency particulate resistance.” HEPA filters were designed to protect people from the effects of radioactivity and other highly toxic substances. A true HEPA filter can trap 99.97 percent of dust particles. A HEPA filter should last up to a year before you need to replace it.
You Have Some MERV
MERV stands for “minimum efficiency reporting value.” It’s a standard set by the America Society of Refrigeration, Heating and Air Conditioning Engineers (ASHRAE) to measure how efficiently a filter prevents mold spores and other allergens from entering the unit.
Higher-MERV filters need more frequent replacement. You will have to change them out every three months.
Also keep in mind that higher isn’t always better. A MERV setting that’s too high for your particular unit can make it run less efficiently. Always consult an electrical or HVAC specialist to know exactly what level will work for your unit.
What Happens in Your Home?
Certain activities can cause more allergens to be stirred up. Change your filter monthly if:
- someone in the home has allergies;
- you have pets;
- you allow smoking in your home;
- you use a fireplace;
- you’re doing construction in or around your home.
When you add up the benefits of a clean air filter, it’s easy to see that this is an easy and inexpensive way to keep your home healthy. Get on a regular schedule of air filter swaps and breathe easy.