[ganicus99]

Hello,

My house was built in 1977, but within the last couple of years we have had a HE furnace installed and recently a tank-less water heater.

Both the furnace and the tankless now have separate ventilation running outside the house.

The guy who installed my tankless told me that it was ok to plug up the air intakes that feed air from outside the house to my furnace room as they are no longer needed and just bring in cold air.

Before I acted, just wanted to make sure this is sound advice, before I block the hole up with a towel, etc.

Thoughts? Thank you.

 

[Yodaman]

Generally speaking plugging the intake on anything is probably not a good idea.

Is this intake piped directly from the furnace to outside? If yes then definitely not ok to plug. If you just have a hole in the wall that brings some fresh air in it may or may not be ok to plug.

Can you put up some pics

 

[ganicus99]

Thanks, the intake currently runs from my furnace room up and then directly outside and is covered up with a grill and mesh wire to keep stuff out.

I'm thinking the original intent was to provide outside air for the old/original furnace correct? But now the furnace and the tankless bring in outside air via the PVC pipes.

 

[ganicus99]

http://postimg.org/image/axmcnb83j/

Here is a photo of the pipe in question, in my furnace room. Thanks!

 

[Yodaman]

Thanks, the intake currently runs from my furnace room up and then directly outside and is covered up with a grill and mesh wire to keep stuff out.

I'm thinking the original intent was to provide outside air for the old/original furnace correct? But now the furnace and the tankless bring in outside air via the PVC pipes.

If you are certain that both the furnace and tankless are bringing their own combustion. Should be safe to close off the other vent.
The pic is of little value. Do your new appliances have 2 pipes each leading to outside? One would be combustion and one would be exhaust.

Have a carbon monoxide detector?

 

[ganicus99]

Yes, they both have an intake and outtake PVC leading outside the house. Yes, we do have a carbon monoxide detector close.

Thanks for your help!

 

[beenthere]

As long as both the furnace and water heater have their own combustion air intakes. No problem plugging that combustion air intake.

 

[Bud9051]

When air is vented directly in, like the pipe you describe, the two possible needs are combustion as you suspect and/or meeting the needs of a very air tight home. If you have been air sealing to reduce the leakage and reduce heating costs, then that fresh may have been helping to meet the necessary air exchange rate.

Since you have already gone through one set of appliances it is unlikely your home was built exceptionally tight, they just didn't built them that way 30 years ago. In any case, if it is contributing a necessary flow of fresh air you may see signs of increased humidity. Good to a point, but window condensation can become a problem

Don't remove it until you have gone a year with it plugged. If you plan on an extensive air sealing effort you may need to open it slightly in the future.

Bud