Ya I use same. Even hooked up manometer and test pressure drops across a bunch of different ones to be sure
I think I overthink some things
Time to change the furnace filter
- Thread starter Snagglefoot
- Start date
I think I overthink some thingsMerv 8 filter here, change every 3 months. Anytime I've tried a higher Merv rated filter the furnace sounds like it's working harder. Most hvac people I talk to recommend low rated Merv filters such as 4 or 5. A furnace filter wasn't designed to filter the air in your house, it's job supposed to protect the equipment.
YUP..............
The filter at one of my labs after a couple years (I got tired of waiting for the HVAC boys):
I change every 90 days. With two dogs, there is plenty of dust on the element.
I use a 1-inch low-MERV fiberglass for higher flow as per instruction manual and HVAC guy recommendation.
I change it when I sense it has been enough time. Summer and winter when the unit runs a lot, it is changed every month. This fall, It was mid-August and will probably go until the end of October. It has been fair/mild this fall. I do spritz it with non-stick cooking spray which does hold a bit more dirt.
I am contemplating having the return elbow (where the filter is inserted) modified to take a 4-inch so I can have a filter that lasts up to a year, filters better, and has high flow. You know... something I would totally forget about after that length of time.
I change it when I sense it has been enough time. Summer and winter when the unit runs a lot, it is changed every month. This fall, It was mid-August and will probably go until the end of October. It has been fair/mild this fall. I do spritz it with non-stick cooking spray which does hold a bit more dirt.
I am contemplating having the return elbow (where the filter is inserted) modified to take a 4-inch so I can have a filter that lasts up to a year, filters better, and has high flow. You know... something I would totally forget about after that length of time.
Same here, though mine doesn't get quite that bad after a month. We have a boiler and radiators for heat, so our furnace filter is only used for A/C, which means I change it monthly from about May through October, give or take a month.Monthly here, filter is located in the hallway, with carpet, dogs, cats and high volume traffic.
View attachment 73945
Have you looked into the deep filters?
Like these, they come in pretty much all sizes, just super deep, but fit into most "regular" openings.
@alarmguy turned me on to these in THIS THREAD.
I was a fiberglass filter guy for a long time for the same reason as you, a close friend in the A/C business that installed my system told me the fiberglass are the best for flow and filter good enough if changed frequently. He checked my coils after about 8 years and said they were still clean.
I have an electrostatic filter in my attic that was in the unit when I moved in and it seemed to filter well, but I could tell by sound it was very restrictive and was a hassle to clean.
Here is a 3 month use in the winter fiberglass one next to the new deep filter.
I am at ~5 months use now on the deep filter, and it is just fine, and this is through the summer when the A/C is running at least 10-12 hours a day.
Higher merv does not always mean more restrictive. As I stated above did a lot of research before deciding on the filtrete 1900(merv13). The restriction is actually lower than most other low merv filters. They(filtrete) actually have pressure drop ratings listed on side of filter, and are accurate according to my testing.
My house is 3 years old , and we bought it from a guy that owns a large local hvac company. It has a very nice propane boiler/hydronic/air handler system. He left me a case of plain old filters, and rec I use those. I noticed by 3 months they were bent in from restriction, but not all that dirty looking. So hooked up manometer, and new I was at about .25.....3 months I was up to about .40 I was going to have a 4in housing put in instead of the 1in, but after research, found these.
With the above 1900, new I'm about .015, 3 months about .20 and darker looking than the plain ones. Also they stay flat, dont get bent it. I could prob go longer, but I like the low restriction. Was also a slight decrease in current draw, due to it being variable speed fan. This is a newer fairly tight house, so prefer to keep air clean as possible.
Nice chart below.
https://www.iallergy.com/pages/compare-3m-filtrete-filters
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How well does that lower initial restriction hold up over time? I use the same filters for the same reason, they have the lowest pressure drop of the options at Meijer.
Added more to my post
I use the simple fiberglass ones as well. If you put a high MERV filter in, then if there is any leaks in the duct work, it will pull air in from there. My HVAC person said to just get the tumbleweed catchers. So that is all I used on our last house for 20yrs and no issues.
Not true....it all comes down to restriction.
Not saying there is, but if there is a weak joint and the filter is restricting flow, you don't think it would pull air from that joint? I know it is unlikely, but some are using those super restrictive HEPA style filters on systems over 40yrs old. To me that isn't a good thing, but then why worry. What works for me might not for someone else.
But if you read what I posted above, the filter I'm using has LESS restriction, than the plain cheapies I was using.
I change my parents each every 3 months except for april to about october since we dont have AC. I use the Dupont filters at least at a merv 5
