I was using this filter thinking I was doing my family good by blocking allergens and then my furnace stopped heating my house, I had to call a repair man out to find out that my furnace was in perfect shape, but the air filter I was using was too dense to allow proper air flow and this was causing my furnace to overheat, then blow cool air for an hour to cool off the furnace, then it would try it again and overheat in 4 minutes, do the safety shut off and then run through the cycle again. Save yourself and your wallet and use a thinner filter that actually allows air to flow through your furnace (and your furnace to do it's job), otherwise it will overheat and eventually burn up your motor because it's working too hard. We were lucky that we found out before it led to costly repairs on our 4 yr old furnace. I'm still irritated that I'm having to pay for a service call when there was nothing wrong with our furnace except we were fooled into buying a product that doesn't work because it blocks the proper air flow.
