When to Change Your HVAC Filter


Be good to your HVAC system

We like to compare changing your HVAC filters to getting an oil change in your car. Does replacing your oil give you better performance from your car? Sure. But the bigger benefit is what it's doing for you car: improving the life and helping to avoid bigger maintenance issues.

In the same way, changing your HVAC filter, although it does give you a little cleaner air, is more about protecting your HVAC system than delivering the purest air possible. Replacing your HVAC filters on a regular basis (more on this, below), will keep your HVAC system running at its best. That means lower electricity bills and lower repair bills through this key maintenance task.  


When should I change my HVAC filter?

You should be changing your HVAC filter every 1-3 months for the best possible performance. This may feel like a lot, but it is necessary to keep your HVAC system clogged up with airbone dust and debris.  In addition, HVAC manufacturers that the cost of replacing filters is a lot less than replacing or repairing your HVAC system. 

It's always a good idea to know what the manufacturer recommends. Some systems are intentionally heavy duty, and consequently use a beefier filter that doesn't need to be changed as often. Know your system to get the most precise answer as to when to change your HVAC filters...and then mark your calendar accordingly. 



HVAC filters aren't created (or rated) equally

If you've done any shopping for HVAC filters, you have probably noticed that they really vary in terms of pricing and claims.

In part, this is because different filters are rated by different standards. The three main standards on the market are MRP (Micro-Particle Performance Rating), MERV (Minimum Efficiency Reporting Value) and FRP (Filter Performance Rating).

For all three ratings, the lower the number, the lower the efficiency. MRP is a standard created by 3M, while FRP is used by Home Depot. Most other HVAC filter manufacturers use MERV.

Low efficiency, though, isn't necessarily a bad thing. In fact, you might want to choose a lower efficiency filter unless your HVAC system is specifically built to handle a heavy-duty filter because lower efficiency also means higher airflow (which in turn, means your HVAC system doesn't have to work as hard). Lower efficiency (lower number) filters do need to be changed more frequently, but they are also often much cheaper, too. 

For quick comparison:

8 600
11 1000-1200 7
13 1500-1900 10

Pack Size

How many should I buy?

If you've walked into your local hardware store or grocery store, you may have noticed that HVAC filters come in a variety of pack sizes. They can come as singles or case packs of six or more. Typically, the more you buy, the cheaper they are per filter.


The bottom line

We definitely recommend that you change your HVAC filters regularly. We recognize that HVAC filters do not provide the same kind of air purification that a dedicated air purifier can, but the benefit of a more efficient air conditioning system AND capturing large particles like dust are two benefits we can all get behind.