I had been working with Heating and Air Conditioning technicians for years in the bookkeeping department. And so I really thought I knew all there was to know about Heating plus Air Conditioning, but I was wrong. I had never even heard of MERV. I had a shopper call to ask me what MERV would be best for her new oil furnace and I didn’t even know what that meant! She was confused by all of the different color ratings on the air filters and also by the MERV. I told her that since I was unsure about it, I would call a Heating plus Air Conditioning worker into the office to have him provide her with some advice. Apparently, the higher the MERV rating is, the more efficient the air filter is. And while listening to him talk to her on the speaker phone, I found out that MERV is an acronym for Minimum Efficiency Reporting Value. And the company she was ordering her air filters from, made it fairly straight-forward to know if you had a high MERV rating or a low one. Their Bronze air filters had a MERV of 6, the Silver air filters had a MERV rating of 8, and the Gold air filters had a MERV rating of 11. The rating was developed by a group of Heating plus Air Conditioning engineers to help them rate the effectiveness of the air filters, and not all air filters are alike. There are many unusual sizes plus there even are those that are HEPA filters. The HEPA filter has one of the highest ratings of all, meaning that it can pick up germs and microorganisms that can contaminate the air quality. From now on, whenever I go buy our air filters for the oil furnace or for our air conditioner, the first thing I will be sure to do is check the MERV on them. Why even have an air filter, if it isn’t doing a fantastic job?