Updated: Aug 6, 2022
HVAC Systems are high risk areas for mold & bacterial growth & contamination if not designed or cared for properly. While it’s the super-tiny sub-micron sized particles & fragments that primarily cause health issues and inflammatory responses in the body, we want to be using a layered approach to lowering our overall home health exposures. One piece of that, is making sure your HVAC systems & vents stay clean. We know that’s a huge goal of great proportions so let’s just start with filtration. Buying Filters This takes just a bit of research ahead of time, considering the amount of brands, sizes & MERV ratings out there, it may create some initial overwhelm in a first timer. (Hence the guide). So what’s a MERV? To keep it simple, MERV is a means of measuring how efficient an Air Filter works. Check out our charts to help find which MERV meets your expectations. So should I buy filters with high MERV ratings?
You’d prefer a 5-star hotel to a 2-star hotel but should you prefer a filter with a MERV rating of 16 to one with a rating of 9? Probably not.
If your filter has a high MERV rating, you know it’s highly effective in preventing things like pollen, bacteria and pet dander from circulating throughout your home; however, it may be overly effective in preventing air itself from circulating, which is a bad thing. The end result of less air circulation may be poorer overall air quality in your home. Furthermore, more resistance means more work for your HVAC system. If you’re using a filter with a MERV rating that’s not compatible with your system, inefficiency and high energy costs may be the result. Over the long-term if your HVAC system becomes overworked, you may be faced with costly repairs.
☀️Tip: If your thermostat isn’t moving & your system is running hard over the summer, (not cooling like it should) select a lower MERV rating like an 8, which can help ease the pressure pushing through the filter. Once the season cools down, switch it back to a higher rating.
Is this your Household?
Perhaps one household is comprised of two newlyweds who are working hard to jump-start their careers. They have no time for pets, neither of them smoke and they rarely have guests over. They select an air filter with a MERV rating of 8. There are only two of them, they have no allergies, they don’t smoke and don’t often have guests over to bring in dust and dirt.
A family of five resides in the second household. The children are between the ages of 8 and 15. They’re all healthy kids who are into sports, and their parents enjoy hosting team dinners for each of their children, who have friends over often either way. They also have a young labrador retreiver. They select an air filter with a MERV rating of 11.
No one in this family suffers from a breathing condition that would warrant buying a filter with a higher MERV rating, but more dirt, dust and other contaminants find their way into this home every time they have guests over. Lucy the lab joins the guests and family members themselves in churning up these contaminants within their home, and she leaves behind pet dander. They need an air filter that traps a few more particles than our first household, but they don’t need the highest level of protection.
Finally, a family of six lives in the third household. Everyone chips in to take care of Grandma, who lives with them, and has emphysema. They don’t have any pets because the children seem to have the same allergies that their mother does, but occasionally host friends and family. They select an air filter with a MERV rating of 13. Because most of the family have allergies and the grandmother has a severe breathing problem, and because there are six people bringing contaminants in as opposed to one or two, a relatively high MERV rating is in their best interest.
Do some research about your system to find out what MERV rating is ideal for you. And, don’t forget to change your filters, otherwise the MERV rating will be the least of your worries!