[scotchmatt]

I have a forced air furnace that is located in the crawl space--which makes it difficult to access the furnace for routine furnace filter changes. Can I install a furnace filter slot upstream so the filter can be more easily changed via the cold air return vent?

 

[Windows on Wash]

Yes. Make sure it is well sealed as well as the one downstream. At the end of the day, its the same air.

 

[scotchmatt]

Thanks for the response--that was my logic, it's the same air. Since you mention the one downstream I assume you mean sealing the access door to the former filter location. I would not be using 2 filters, correct?

 

[surferdude2]

That's where I like to put them... keeps the ducts cleaner.

 

[Old Thomas]

It should be upstream of the furnace, it’s function is to keep the furnace clean. If you have one return vent, it is ok to have it behind that vent.

 

[user_12345a]

if your return duct is not perfectly sealed, it's a bad idea.