DIY Chatroom Home Improvement Forum

DIY Chatroom Home Improvement Forum (
-   HVAC (
-   -   old furnace with bizarre filter setup (

utek 11-14-2010 02:29 PM

old furnace with bizarre filter setup
1 Attachment(s)
I just moved into an older home that had extensive renovations, but the furnace is quite old. I went down to change the furnace filter, and I was surprised what I saw.. refer to the attached diagram (basically saw two 15x20 filters taped together and not actually on the the metal meant to support them).

I then found out that getting 15x20 filters is difficult: they seem to be very uncommon (not at home depot in any brand/style etc). So i figured the easiest/cheapest thing to do would be to convert the slots to fit a more common size.. (i had in mind 14x20 since the metal railings would support it with minor tweaking). I went out and bought a bunch of filters (was out of town and there was a fantastic sale - 3m filtrete micro allergy). This represents idea #1.

I later started thinking about the reason why they would setup the furnace in such a way (something i should have thought of earlier).. and figured it is probably an airflow thing (more surface area.. more air flow). THEN I read that the filtrete filters are considered crap by some hvac people because of airflow. So then I started thinking about doing idea #2...

I basically have 3 questions:
1. I was hoping to save money by using one filter at a time and changing it out as needed (originally thinking along 3m's recommendations of 3 months). If I used idea #2, would I need to change out the filters less often then idea #1?

2. If I use idea #2 then would I get more airflow (and less stress on the system)?

3. Why would they (the maker of the furnace) make such a setup?

Recommendations? Keep in mind that I don't want to toss the 10 filters I already bought. Please excuse my grade 3 level paint skills. Thanks for any help!

kenmac 11-14-2010 03:52 PM

I see no problem with Idea 2 or 3.. Filter replacment depend on how dusty / your filter gets 1mo 2mo 3mo etc. Doesn't matter what the filter says

hpyjack2013 10-14-2013 08:49 PM


All times are GMT -5. The time now is 03:33 AM.

vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
User Alert System provided by Advanced User Tagging (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.

Search Engine Friendly URLs by vBSEO 3.6.1