Personally, if it was me, I would close up the vent to the attic, and put the vent in the door of the HVAC closet.

 

Are these gas appliances? If it is, the vent supplies fresh combustible air. I would not rely on the vent in the closet door to provide adequate amount of new air unless your house is REALLY drafty. Rather go into the attic and extend the vent through the roof and put a 180* degree turn to keep water out (the inlet is now pointing down). This way your pulling in outside air and at least not super heated attic air.

Ideally there would be a PVC pipe doing this and not a chase in the closet wall...but it's cheaper and easier.

Inspector no. HVAC pro yes.

 

I spoke to the city inspector this morning and he let me know that it does need to be vented to outside air. I like your idea of venting it directly outside instead of from the attic. Can I just use a simple single wall metal duct pipe that is flashed on the roof with a cap? I would then just extend this straight down into an AC supply box attached to the closet ceiling. I could trim it out in the closet with a grill. Think that would be a safe solution?

Thanks for the help!

 

It sounds like it could work...it may be worth consulting with a HVAC pro to see if there's some other option out there that might be able to slow down the convection air flow especially in the winter.

In one house I had a similar vent that was just a metal pipe that terminate in a 5 gallon bucket. On the end of the pipe, there were very long triangles cut out with the points resting on the bottom of the bucket. When there was no call for air, the cold air would settle in the bucket, and create an air dam.

Maybe someone else here will chime in and offer some advice...

 

If your house is so airtight, that fresh air needs to be exchanged with inside air for the Furnace & Water heater, then you may want to look into a fresh air exchange system. Otherwise, the combustible gases from the exhaust will go out the flue system to the outside, and the inside air will supply combustable air for the use.

Problem with running a duct down from the outside for use by the units, would be if there was no dampner in place to close in case of fire, you would be supplying fresh air to feed a already out of control situation.

 

Combustible air.... sounds bad and dangerous

COMBUSTION AIR: You need to know the input btu's of the furnace and water heater. Then you need one square inch of free air space for every 100 btus of burner. Technically you need one vent within one foot of the floor and one with in one foot of the ceiling. The amount of free area is also cut down by the face of a grill, so size for that as well. Have a longer talk with your local authority if you are going to do this yourself.

 

I have seen some fresh air installs in mechanical closets where as I described that it is a duct that brings in the fresh air, but has a damper to close in case of fire, and also does not allow for direct to the outside air without the use of an air exchanger system.

 

You don't need a damper in a residential installation.

 

You guys are giving incorrect answers. The reason the door vents have been sealed off is because of safety concerns. There is a chance that carbon monoxide could leak into your house. It is code in my area to seal the door vents and drop a high and low combustion pipe. Single wall pipe is all that you need. Double wall pipe would be a waste of money. Also, do not run your combustion air to the outside. This is another way for you to throw away your hard earned money. I would shake my head if I ever saw this. I was a little confused by your post. You say the furnace and hot water heater are in the hallway closet yet the attic air heats your master bedroom closet. The furnace and hot water heater should be in a closet of their own and sealed. I hope they aren't in your master bedroom closet. You need to think of it as a separate room that is to be left unconditioned. That air should not come in contact with you heated/cooled air. There should be a divide. Your return air that goes into the unit should not be pulling in through your combustion air vents. If so, you need to seal the closet better. Your attic has enough ventilation to provide combustion air. Do not risk roof leaks by cutting in a goose neck flashing.

 

How would you know that his attic is ventilated enough to provide combustion air without seeing the house?
And I guess you can start shaking your head now, newsflash.... more often than not outside air is used for combustion air, most new furnaces are piped directly to the outside for combustion air and it doesn't change the heating output of the furnace. Check your facts.

 

If you have any questions, here are the Dallas, Tx Building Codes http://www.dallascityhall.com/building_inspection/plumbing_mechanical.html direct from their offices.