So we are stuck in our homes for at least a few more months due to the cold weather. The doors and windows are closed and the storms are up. Unfortunately as we keep the cold out we also keep dust and other airborne contaminants in. So we try to clean the air in our homes with our furnace filter. But which one should we choose? Well be careful, as I often see furnace filters that do more harm than good.

Since air has to pass through the filter we must be careful that the filter does not become too restrictive. If a filter is going to stop dust particles efficiently its media must become dense which hurts airflow. When a filter restricts airflow it cuts the operating efficiency of your furnace or air conditioner. Some of the worst filters we have tested are the pleated 1” filters you can buy at the DIY stores for about 10 or 12 dollars. Sure, these filter the air better, but they also severely cut efficiency and can even damage your furnace. So we recommend if your filter is only 1” thick, stick with the inexpensive throw away fiberglass filter or the filter that came with your furnace from the manufacturer. Replace it once a month or wash it if it is a permanent filter. Remember though that typical fiberglass filters are only about 10% efficient and should really be called hair and lint filters as the dust particles that really affect our health get blown right back into our homes.

If you would enjoy the benefits of cleaner air in your home without affecting air flow, you might consider replacing your skinny 1” filter with a deep pleated media filter. Deep pleated filters are at least 4” thick and around 85% efficient. Most deep pleated media filters last 6-12 months so the yearly cost is actually less than the 1” DIY filters.

If allergies are a concern, consider having an electronic air filter installed. These are up to 95% efficient and trap even the smallest allergens. Plus, they keep your systems fan and coils clean which extends the efficiency throughout your systems lifetime. Electronic filters are permanent, will last about 20 years and only require cleaning every few months.