A Rather anal-retentive question re frequency of replacing furnace filters in CO condo

9 Replies

Hello BP Community,

Here I am reaching out to you again.

As a native Coloradan residing in Bangkok for 11+ years I am afraid I am out of touch with how to maintain furnaces.  I believe I misinformed my tenants that 1x per year is adequate. I am now thinking 2x per cold season is actually the correct amount, based on my assumption that a person in the Denver-Metro area is likely only needing their furnace from Nov - May (unless they are super-wimpy like I now am, with tropical blood).  So in a 6-month period of usage 2 filters would be sufficient.  

What do you say, BPers?  I am refining my Lease Agreement requirement with my excellent tenants of my so far only rental unit, in anticipation of a pending 2nd purchase soon.  I just want to give them appropriate guidance.

Details, details - hope this is not too boring of a request...

I would recommend every 3 months and schedule a filter change and unit inspection, so you can check for anything obvious such as water leaks, guttters need cleaned ect. This is what I do and I supply the filters.

Some people will say "every month" but we will replace filters when we do quarterly inspections.

In my experience most tenants won't replace filters, even if it's in the lease. In that case you could serve a lease violation, but still risk damage to your furnace. With the furnace being such a costly item, and filters being so cheap we choose to do that ourselves.

Once every 3 months, but as it was stated before it is likely that most tenants won't actually do it. Does the condo have AC or just the heat?

@Mike Freidenberger and @Tyson Luther - Thank you very much for the feedback.  The lease agreement stipulates that the tenants will purchase and replace the filters, but I have actually purchased some and left them conveniently near the furnace to make it easy to replace.  So far it seems to be working, however, I appreciate that when I have more properties and different tenants it may be better for my peace of mind to simple handle this task myself or via property manager.

@Dan Mackin Yes, central A/c is also a feature of the condo unit.  

@Judy Mitchell since the AC is part of the system then I would stick with the 3 month system if possible. The air runs through the filter when the AC runs as well so it'd be a good idea to replace during the hot months. Plus it's been quite toasty here lately so there's a good chance they've been running it.

Just as an additional thought - if your furnace can accommodate a thicker filter, you can get by with changing them far less frequently.

@Dan Mackin and @Corey Westermann  - Good advice, which I will take - thank you for taking the time to respond. 

I'm going to throw another question out there that's a little related. I've been a renter myself for quite some time and most apartments I've lived in use those cheap blue filters that looks more like a blue spiderweb with a lot of big holes. Don't those cause more damage to the A/C units over time by allowing bigger particles into it? I've always taken those out and replaced them with a good filter to filter out all the dust.

Three months is usually right... Unless they have pets, burn candles, or smoke in the apartment. Then you should consider monthly. 

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