I've got an 18-year-old furnace and I've always used decent filters, but not the priciest ones. Last winter, it started acting strange, turning on and off repeatedly. When I took out the filter, it worked perfectly again. Now, every time I try to use a good new filter, it starts that same on-and-off behavior. I'm at a loss about what to do next.
3 Answers
Using 'good' filters can actually backfire if your HVAC system isn't designed for them. Many people mistakenly think that higher MERV filters are better, but they can really restrict airflow, especially if your unit isn't made for it. Personally, I've found that MERV 7 works great for me—offers decent filtration without creating too much air resistance.
You might want to check if your air handler coils are clean. A dirty setup can restrict airflow. Also, look at your fan motor and its capacitor because if those aren’t working right, it could cause some of the cycling issues. Just a heads up, don’t run the furnace without any filter at all; a cheap, low-resistance mesh one can be a good temporary fix if you're having issues.
It sounds like you might be trying to use a high MERV filter, which could be too much for your furnace. Those filters can choke off airflow, leading to all sorts of issues. If that's the case, you should stick with the lower MERV rating your furnace is designed for. Around MERV 8 is typically recommended for regular furnaces.
Thanks for the tip! I’ll definitely check the coils and motor.