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Multiple HVAC techs I've talked to have recommended against installing good/high quality filters in a forced air system. They've explained that high-MERV filter
by geoffeg 3y ago
Multiple HVAC techs I've talked to have recommended against installing good/high quality filters in a forced air system. They've explained that high-MERV filters reduce airflow which causes the fan to wear out faster and may affect the performance of the cooling/heating. I'm not sure how accurate that is, researching it seems to suggest a MERV 10 to 12 is a good balance, but I've been told to use a MERV 3 filter.
- jefftk 3y agoYou should be able to look in the manual and see the maximum MERV your forced air system is rated for. MERV 3 is really really minimal filtering. Your furnace almost certainly is designed to take better filters than that.
- sgc 3y agoIt is not actually as simple as looking at the manual. You need to take ducting layout into account, since there is a lot of air flow reduction from any ducting system, and some can be much worse than others. It definitely does cause your furnace to overheat if you drop below the required airflow rate, something that can lead to short cycling and even premature failure by cracking your heat exchanger. All of this is calculated out using HVAC software when a system is commissioned (in theory and in many building codes, but not so much in practice). As can be seen, this is an issue during the heating season, not the cooling season - which is when many people are fighting smoke. If you actually pay attention to home maintenance, you can go for the better filter in the summer, and drop down to the minimum or close to it during the winter.
- whycombagator 3y agoLast I looked it appeared you are safe to go MERV 8 for most residential HVAC units. MERV 3 is not filtering much