Heating, Air Conditioning, Fridge, HVAC/Furnace Filters


I am getting a new gas furnace and have an option to install a cabinet for a 4-inch thick MERV-10 disposable pleated filter.  My indoor air has a lot of dust and mold and I was wondering if this would help with indoor air quality.  I was concerned,however, that as the filter gets progressively clogged with particles, that there could be a potential problem that this would harm the furnace components.  I was wondering about the trade-offs involved with this kind of filter, which, depending on what you read, is changed every 6 months to 1 year.  

Thank you for any information.

Hi Eric,

I am not a big fan of the 4" filters. Your furnace is all about airflow. The thicker the filter the less air flow. When you really think about it, once the dust settles on your coffee table there is no way the furnace can pick it up. So I don't think you would see much improvement.

Most filters say they can last up to 3 months. That would be the longest I would leave a filter in. You need to check the prices on these filters, you might be surprised.

I hope this helps

Heating, Air Conditioning, Fridge, HVAC

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Jim S.


I can answer questions on gas or electric furnaces, ac units and heat pumps. I don't work on boilers,chillers,or home appliances.


I have been in the HVAC trade for over 35 years. For the past 15 years I have owned my own business. I am semi-retired so I can answer questions in a timely manner.

I attended trade school for 5 years on weekends and evenings. This was very hard to do, but well worth it!

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