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When to change 25x16x5 furnace filter

  • Last Updated:
  • Aug 2nd, 2020 1:58 pm
[OP]
Member
Jul 14, 2017
363 posts
58 upvotes
Ontario

When to change 25x16x5 furnace filter

Just curious as to to how long I should use this 25x16x5 MERV11 Lennox furnace filter,as I would like change them on Daylight savings time...house 1250 sq' bungalow with mostly hardwood floor,two adults,no smoking,no pets and pretty dust free. I don't want to use them for too long,but I don't want to change them when it's not really time. I replaced the last one on July 4,which was in since March(5 months)and looked pretty clean,but changed it anyway. How long do you run yours? Thanks!
Last edited by Huck50 on Jul 6th, 2020 10:49 am, edited 2 times in total.
33 replies
Sr. Member
Jun 23, 2019
537 posts
394 upvotes
I had an Aprilaire 2410 which uses a 5" filter and I would change it every 6 months.
Deal Addict
Nov 17, 2012
4587 posts
4015 upvotes
Toronto
Just a note - March to July would be max ~5 months (March 1 to July 31). If you replaced July 4, it was at best 4 months.
[OP]
Member
Jul 14, 2017
363 posts
58 upvotes
Ontario
This 25x16x5 Lennox filter replaces the two Honeywell electrostatic cells,which seems to have waay more surface area of filtration media.The Honeywell cells were constantly snapping,even after a good cleaning/drying,but apparently I didn't clean them good enough,so after another cleaning ,no snapping.All wires looked good.This new Lennox filter HAS to catch more dust,etc than the electrostatic cells,just based on the larger surface area of the filtering media,I would think. H50
Last edited by Huck50 on Aug 3rd, 2020 6:31 am, edited 2 times in total.
Deal Addict
Jun 16, 2009
3788 posts
2325 upvotes
Woodbridge
One should change the filter when its dirty. Filter longevity depends upon several factors and is different for an individual situation. Some factors that have big impact on filters are:
1. Overall cleanliness of the house
2. Pets ( worse if hair shedding)
3. Smoking
4. Construction in or around the house
Huck50 wrote: Just curious as to to how long I should use this 25x16x5 MERV11 Lennox furnace filter,as I would like change them on Daylight savings time...house 1250 sq' bungalow with mostly hardwood floor,two adults,no smoking,no pets and pretty dust free. I don't want to use them for too long,but I don't want to change them when it's not really time. I replaced the last one on July 4,which was in since March(5 months)and looked pretty clean,but changed it anyway. How long do you run yours? Thanks!
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Sr. Member
Dec 4, 2009
640 posts
621 upvotes
I’ve been using 1” MERV 8 filters, swapping them monthly.... Cheap, non restrictive and reasonably effective, IMO.
Member
Mar 9, 2019
225 posts
118 upvotes
I buy a 3 pack from Home Depot and change them monthly.
Deal Addict
Feb 10, 2006
2597 posts
536 upvotes
Kitchener
There is a significant difference between a 1 inch filter vs the one the OP has. Every home will be unique but Based on the conditions you described it likely will last a year. Having said that check it every 6 months to make sure. Personally I do mine at 6 to 12 months because I have a family of 5 and 2 pets.
Tired of renting from Reliance? This might be useful reliance-home-comfort-2464779/2/#p34473179
Deal Addict
Mar 10, 2011
2491 posts
671 upvotes
Toronto
During the warm months, May - Sep , I run the furnace air circulation fan continuously to recirculate cool basement air to the rest of the house so need to change the filter more frequently, every 2 months. During the winter, I change it every 3-4 months. No pets, no smoking, but we do have carpeting in the house. I also use the 3 pack basic filters from Home Depot.
Deal Fanatic
Aug 29, 2011
8397 posts
5255 upvotes
Mississauga
Mines a 20x25x5 and I change it in the spring and fall.
[OP]
Member
Jul 14, 2017
363 posts
58 upvotes
Ontario
rogerrabbit168 wrote: we change ours to coincide with daylight saving time, MERV 8
What size is your filter? Thanks,H50
Deal Addict
Feb 25, 2007
3026 posts
734 upvotes
Huck50 wrote: What size is your filter? Thanks,H50
16*25*4, merv 8. i used to use 16*25*5 merv 11 and only change it once a year, but l like the merv8 more, more air flow, we only use air con in summer when its really hot, hence the summer months daylight is longer period but filter not as dirty as winter months constantly furnace running
Deal Addict
Nov 2, 2005
4825 posts
2083 upvotes
WFH
16x25x5 merv 8 annually. Higher merv may need replaced more often. I monitor the heat rise in my furnace continuously so have a good measure of how dirty they are at any time.

Note that the purpose of the filter is to protect the furnace, not the resident's of the home. Higher merv ratings are not necessarily better for your furnace.
[OP]
Member
Jul 14, 2017
363 posts
58 upvotes
Ontario
dirtmover wrote: 16x25x5 merv 8 annually. Higher merv may need replaced more often. I monitor the heat rise in my furnace continuously so have a good measure of how dirty they are at any time.

Note that the purpose of the filter is to protect the furnace, not the resident's of the home. Higher merv ratings are not necessarily better for your furnace.
I agree...I was a little leery about going with a Merv11,but Lennox furnace was suppose to be able to handle it,( I won't go any higher than 11) some higher Merv rating may overheat the heat exchanger ,which would not be good. H50
Deal Addict
Feb 10, 2006
2597 posts
536 upvotes
Kitchener
Most 4 or 5 inch filters are fine because you have lots of surface area. I'd be more concerned with a 1 inch m3 filter.

If you want the added indoor air quality keep the merv11 and add on a bypass HEPA. They provide far better filtration but do not cause restrictions in airflow.
Tired of renting from Reliance? This might be useful reliance-home-comfort-2464779/2/#p34473179
Deal Expert
Aug 2, 2004
36154 posts
9417 upvotes
East Gwillimbury
I switched from 1” filters to a 4”

The bigger filters offer more surface area and more air flow.

I’m using MERV 11 as I found that to be the best balance. I check every 4 months, but the best gauge is to hold the filter up to the light. If you can clearly see through the media to the light you should be good for a little longer. If the light is not that bright then it is clearly dirty and needs to be changed.
Deal Addict
User avatar
Nov 7, 2016
2587 posts
1491 upvotes
Ontario
We change our 16 x 26 x 5 1/4" MERV 11 every 6 months. Same size/spec at my folks place and their stupid plan with Reliance changes it every 6 months too, but I think theirs should be more often as their house is older and seems to make the filters dirtier quicker.
Last edited by IcarusLSC on Jul 11th, 2020 12:14 am, edited 3 times in total.
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