Furnace Venting in Basement

[nofishfisherman]

I am working to finish/refinish my basement. Currently my furnace room is framed in and the walls are covered by peg board and there is no door, all of this I am told is to allow air intake for the furnace.

I want to put up drywall and enclose the furnace room and put in a door that will remain closed 99% of the time. What do I need to do to make sure the furnace has adequate access to the common air space in the basement?

I've been told 2 different things.

1. Just put in registers at the top and bottom of the wall to allow the air to move freely. (Not sure how many registers I'd need)

2. Cut into the duct work leading to the furnance and add a piece of duct work that extends to a large register that is installed in the wall with common air space on the back side. (not exactly sure what duct work to attach the new vent/duct work to).

[LightningBG]

Are you thinking in terms of cold air return or combustion air?

[Surface Tension]

Sounds like what you were told was to supply the furnace with combustion air.

If your furnace doesn't have its own combustion air intake from outside then for sure you need to allow air into that room. If you have a gas water heater or drier in that room it'll need combustion air too. This brings up the question, does your house suck?

Kitchen and bath exhaust fans, and furnace exhaust, drier vent create negative pressure.

Outside ventilation and makeup air into the cold air return will equal that out.

[CAMAN]

Like you already said, a couple vents in the walls will work. A louvered door will work fine also.

[shizzy]

A louvered door will work fine also.

This.

[nofishfisherman]

I believe how it was explained to me is that the air would be for combustion.

I was fairly certain I just needed to add in some sort of wall or door vent and didn't need to cut into the duct work and run a duct to a designated register.

I had a company out to quote me an AC unit this summer and one of the guys who came out was the one who told me I needed to run duct work to a register. Although everything the guy did just screamed overkill to me. Ended up not going with him for the AC unit.

[Surface Tension]

If you add up all the exhaust fans kitchen, bath, furnace, drier, water heater and so on in the house then think of where that fresh air is made up from, you might find that you should have more fresh air coming in. I don't know what you have but based on what the AC guy said it sounds like you might need to look into it a little closer. The outside air duct in the return being about the cheapest route.

Anyway say you restrict the air to the furnace room. If the drier and water heater are in there fighting for the same air that is getting pulled through louvered door or vent, it'll pull it from a draft hood and or gas burner too.

[delcecchi]

As I understand it, the air supply required is something that is in the code, if you live someplace that has one.

Would it be hard to for you to cut a hole in the rim joist and siding, or the block, and run a duct over near the furnace?

combustion air from Centerpoint Energy

And from the State

[nofishfisherman]

The water heater and furnace are in 1 room and the drier is in a different room on the other side of the small basement.

In the house there is a vent coming from the furnace room that vents to the east side of the house. There is a dryer vent and a kitchen vent that both vent to the north side of the house and there is also a bathroom fan but I'm not entirely sure where that vents to.

Just some background, its a small house 3 bedroom 1 bath two story plus basement home built in 1946. Alot of stuff has been updated over the years before I bought the place so its hard to know how everything was laid out throughout the remodels. So far I haven't come across anything done wrong and the AC guys that gave quotes looked over my systems and 3 seperate people verified it was done properly.

I may end up bringing in an HVAC guy to look things over before I finish up drywall to make sure I'm venting everything properly.

I guess that leads into a somewhat related question about permits. I know permits are required for the work I'm just wondering what stuff they'll need to look at. What I'm doing is tearing out old carpert and putting down new. I'm pulling off most of the wall paneling and insulating most of the outside walls (i'm leaving paneling in the furnace room with no insulation behind it) and then putting up drywall.

Also pulling down a drop ceiling and putting up drywall and moving the lights that are in the room and putting in recessed lights.

I'm not changing any wiring just moving the wiring that is already there a few feet one way or the other and putting in new fixtures.

I will also add in a new wall/door that seperates the basement from the upstairs to help hold the heat in the basement in the winter.

[nobody05]

or you can use a regular door but just cut off an extra inch on the bottom of the door

[Smoker]

From what I am reading it sounds like you have a open return air. By the Filter (blower area) do you have any duct work hooked up to the furnace that runs through out the house? If not you will need to get air into that furnace room to. I am thinking that is the reason for the peg board, to let the air into the room. A lot of older houses didn't get return air hooked up like they should have. You need to get that opening to a common area like a hallway. A large grill will work but it is always better to have a duct going to it. You need to make sure you have enough air for your furnace so it will not over heat.

[nofishfisherman]

I'll take a few pictures once my phone charges and post them so you can see what I'm looking at. Probably easier to show you than explain what I'm looking at..

[Mr Twister]

You will need to have a combustion air in the mechanical room atleast the same diameter as the flue going out the roof. Otherwise you will run the chance of a negative pressure in your home which will lead to having bad Windows and doors. Return in a mechanical room is nit a good idea. Message me if you want me to explain in more detail how to do this correctly.

[nofishfisherman]

Here are a couple quick photos of the furnace area. Maybe not the best but not alot of room to stand back and get a complete snap shot. Hopefully this helps show you what I'm working with. You can see some of the peg board in the background of the first photo.

Left side w/ filter

Top of furnace

Main ducting running down the middle of the basement. Looks like left side runs to top of furnace and right side runs to left side of furnace.

[WallEYES]

You have a sealed combustion furnace with seperate intake and exhaust....no combustion air required, but the water heater is probably atmospherically vented thru a "B" vent thru the roof...combustion air would be required into the space. A 4 inch pasive opening with insulated flex duct would be sufficient....a dryer or other exhausting equipment has nothing to to with combustion air...high exhausting cfm equipment would need to be provided with make up air

[hunt fish repeat]

If your house is breathing fine now (most easily defined by minimal condensation on your windows)simply cut the bottom of the door to the utility room off an extra inch and you will be fine.

[nofishfisherman]

There is little to no condensation on any window in the house.

Sounds like if I just add some sort of vent in the wall or door to allow air flow I should be fine. I could add a vent higher on the wall behind the furnace and sort of near the hot water heater as well as vents both high and low on the wall in the opposite corner of the room.

[hunt fish repeat]

You're over thinking it! Simply cut off an extra inch from the bottom of the door and you won't have any problems.

[nofishfisherman]

I realize I could do that as a fix. I'll likely opt to put in some sort of register in the wall to allow airflow between the rooms instead just so I don't have my cat squeezing under the door with the larger gap. The stupid cat already tries to squeeze under doors, don't need to make it any easier for her.

[WallEYES]

Get rid of the cat....

[Surface Tension]

Your furnace is setup as a direct vent furnace so your good to got there. If you had a non direct vent taking combustion air in an enclosed space then you'd need to add two vents. One within 12" from floor and One withing 12" from ceiling. Each vent should be a minimum 1 sq inch for every 1000 btu.

On to the water heater, since it shares that space your going to need to add vents for that. I would use same criteria as the non direct vented furnace.

[nofishfisherman]

Get rid of the cat....

That would solve a few problems but likely create several more, mainly with my wife. Besides the cat gives the dog something to chase, its good exercise for him.

[nofishfisherman]

Thanks for all the assistance. Sounds like I have a pretty easy work around for closing the room in. Not sure what the AC guy was talking about when he said I should cut into the ducts on the left side of the furnace. He was one of those guys who talked for an hour without really saying anything so I wasn't sure how much weight I should give his information.