Exterior Intake Vent Optional For HE Furnace?

[dtontarski]

I inspected a home over the weekend with an ICECO natural gas fueled furnace. This is a new manufacturer for me - any opinions on these?

To my question - This was a 90+ AFUE furnace and appeared to have the option to be installed with pvc pipes for both intake and exhaust, yet only the exhaust was installed. Opinions on this? Is this optional for all high efficiency furnaces, or particular to specific models? If optional is there a best practice and why? No manual was available for me to review, so I plan to google this a bit this morning, and I was hoping that I could get some opinions here as well.

The notched floor joists, the poor pitch on the exhaust, the lack of an exterior 90 all screamed for me to delve into this a bit.

Thanks!

[dtontarski]

Googling away...This appears to be a WeatherKing product.

Yes I realize the direct versus nondirect classification and how this determines inside versus exterior intake air, but when it is optional with an indirect - is one method better that the other? I'm still trying to find the manual for the ICECO unit I saw.

[Terence McCann]

Googling away...This appears to be a WeatherKing product.

Yes I realize the direct versus nondirect classification and how this determines inside versus exterior intake air, but when it is optional with an indirect - is one method better that the other? I'm still trying to find the manual for the ICECO unit I saw.

If only the exhaust is piped outside then the furnace is getting it's combustion air from indoors. The furnace then falls under all the rules for proper room size for the BTU of the furnace (combustion air).

I've seen this done quite a few times but now you're pulling conditioned air out of the home instead of outside air. Be careful too, I've seen the rubber boot still in place on fan (the one you would remove to attach the PVC to for intake air) when it was not piped outside.

[dtontarski]

Thanks Terrance - good tips on what to look out for.