How far does a furnace input/output vent need to be from my gas dryer vent outside my house?

Are they venting on the side of the house or the roof?

Don't know that there is an exact number. A couple of feet should be more than sufficient. Dryer vent gas is hot and would rise and be dissapated through normal air movement. Even if some dryer vent exhaust were to be sucked into the intake side, heaters using this type of system are sealed so that the dryer exhaust would be run through the heater flame and reburn anyway. Are you worried about CO getting into the house? Dryers exhaust is very low CO, probably no more than the gas burner in your house and that just goes into the home air. Primary vent component is CO2 and water vapor. Hope this helps.

IRC 2009 - M1502.2

"Exhaust ducts shall terminate on the outside of the building. Exhaust duct terminations shall be in accordance with the dryer manufactures's installation instructions. If the manufacture's instructions do not specify a termination location, the exhaust duct shall terminate not less than 3 feet in any direction from openings into buildings."

I wonder if they would consider a sealed air intake as an opening. Hmm.

Hi all...

Dannac, that information is good for the dryer but this question is asking about distance between a furnace dual pipe air inlet/exhaust system and a dryer exhaust.

Patty, today's newer hot air furnaces have all the information you need in the installation manual. Here, somewhere in the instructions you should find a picture clearly showing where the furnace piping needs to be in relationship to windows, doors, skylights and even dryer vents... ;) For dryer vents vs furnace in/out I have seen 3 feet to 10 feet depending on the local code.

If this is an older model furnace (doesn't sound like it) then you may want to call your local building department and ask them for the requirement in your area as each city/town does things differently, so best to stick with the local info. Here.

That's my input...

Mark

best to stick with the local info

+1