Furnace filters… there is a difference

Walk into any hardware store or HVAC shop in Indianapolis and ask for a furnace filter. You’ll quickly learn there are many options with labels touting different benefits. So what’s the difference in filters all about? And there is a difference… read on.

There’s the good old 1-inch cardboard frame. These are the ones you buy in the neighborhood hardware store for a buck or two. They are rated at seven to eight percent efficient in catching large particles that are six to seven microns in size. That means these low-cost filters only catch the big stuff, which means you’ll need your vents cleaned more frequently. So something that costs less could end up costing you more.

Another option: go up to a 20 to 30 percent efficient one-inch pleated filter, which catches much smaller particles down to one micron in size. These cost about $15. The problem with this filter is that it has such a small surface area that it loads up quickly and needs replaced every 30 days, at the minimum. That can get expensive over a year.

The most popular option (and my recommendation as an HVAC expert) is the Merv 10 or Merv 16. Both are popularly sized at either 16x25x5 or 20x25x5. The Merv 10 captures particles down to one micron and is 95 percent efficient. The Merv 16 catches stuff all the way down to .01 micron in size and is 99 percent efficient. That means these filters are catching dust, pollen and more of that itty bitty stuff as it comes through your furnace system.

These filters offer some benefits and drawbacks though. They only need changed every eight to ten months. That’s a big benefit. The possible downside for some is that the cost is more, $50 for the Merv 10 or $145 for the Merv 16. But the overall savings on duct cleaning over time adds up fast. Factor that with the fact that you don’t have to change the $15 filter every month with a new one… and you’ve got a winner!