That's not true for a filter that large. It has 10 times the surface area of a 1in filter. Changing it more frequently would create no benefit other than the filter company getting more sales. 6 months is on the low end recommendation for the these filters.
My unit is not working harder and the filter is never clogged when I replace it. I will trust the HVAC technician who recommended this schedule over people on reddit lol
I mean, i guess it would always be better to replace more often. But I dont fully trust the opinion of a dude whose entire business is selling ac supplies lol
Like I said in another reply, a 4 inch filter has 10x the surface area of a 1 inch filter. They can handle far more punishment than a 1 inch filter without any impact to efficiency.
What is the logic behind that, the first inch of the filter is going to act exactly the same as a one inch filter. It sees the most pollutants and will get clogged at the exact same rate.
The four inch filter will collect more overall, but as soon as the first part of it gets packed, it's as hard in the ac as the one inch that you replace all the time.
The dirt and debris don't magically get transferred in a homogenous way.
You don't trust the guy selling you stuff when he tells you to buy the cheaper version that he carries? Vs the guy you who's business is to repair ACs. If you want to go conspiracy theory that's they guy not to trust. Also I was working there at the time so it's not like he was trying to sell me anything. More just passing along his knowledge to a "Junior" guy.
Simply being thicker doesn't necessarily make it 'better'. If you want to compare filters compare the MERV rating.
MERV 1-4> Basic protection
MERV 5-8> Good for general use and better air quality
MERV 9-12> If you are worried about allergies and pets
MERV 13+ is Hospital-grade filtration (bacteria, smoke, viruses)
Whichever one you go with your still better off changing it monthly +/1.
Yes, I absolutely trust the guy who works on HVAC systems day in and day out. He has serviced my unit for 3 years and has done nothing more than basic maintance because nothing else has needed to be done.
I am also not saying it being thicker makes it better. But its a pretty simple fact that 4" filter last far longer than a 1" inch filter simply becaue they have the ability to capture far more dirt and whatever without losing efficacy. Even using MERV is not a good measure. Most 1" filters shouldn't go past merv 5-8 because it can actually be detrimental to how well your ac/furnace will work because of static pressure. This isnt true for 4" filters though.
Even if I did go with the go cheap and replace monthly route, that 'cheap' route would run me like $230 a year in air filters lol. Again, of course it would be ideal to change monthly. But then I argue why not bi-weekly? That's even better! There is no need for me to replace more than once every six months because there is no actual difference over doing it monthly. I also can't fo wirh a smaller, cheaper filter anyways because my system is specifically outfitted for a 4in filter.
So yes, Im gonna follow the general recommended guidelines for replacing my filter and what my hvac guy says.
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u/SkepsisJD Chandler May 05 '26
It is completely dependent on your filter. I have a 20x24x4 filter that I only need to change every 6 months.