53 votes

Gas clothes dryer is venting into the crawl space

I don't like the "OMG" abbreviation and seldom use it, but in this case OMG! It would have been bad enough to vent an electric dryer into a crawl (lint, moisture, fire danger), but to vent a gas ...
user avatar
28 votes
Accepted

Is it safe to use Category 1 80,000BTU furnace with 2 inch PVC exhaust?

HELL NO Whichever joker is installing an 80% furnace with a PVC pipe for the exhaust needs their license revoked pronto, because that's a patent CO hazard. Non-condensing appliances operate at flue ...
user avatar
26 votes

Why is a gas furnace vented but a gas dryer is not?

Your gas dryer vents its combustion products outside along with the moisture from your clothes, so it is vented to the outside. Your oven doesn't vent out mostly for sake of having limited combustion....
user avatar
  • 2,639
24 votes

Why do gas water heater exhausts have an air gap before the chimney?

The actual amount of combustion air - i.e., air flowing past the burner to provide oxygen and leave with less oxygen but more CO2 and possibly other combustion byproducts - is very little. The gap ...
user avatar
22 votes
Accepted

Using old vent pipe as TV antenna

There is a LOT that goes into making an antenna work properly. That's why the old-school TV antenna has so many little rods sticking out the sides - they have to be certain fractions of the wavelength ...
user avatar
  • 29.2k
16 votes

Do you to block a unwanted 4 inch hole or reuse it for something else?

Yes, you can cover it up with plywood. However: was made by builder for no reason No, it was for a reason. If it was for no reason, they would have likely just covered it with regular siding. When ...
user avatar
13 votes
Accepted

Why do gas water heater exhausts have an air gap before the chimney?

This is a draft diverter. If the heater was connected directly to the chimney, the hot flue gas would rise, creating draft in the heater. While that is a good thing, the amount of draft would depend ...
user avatar
12 votes

Why do gas water heater exhausts have an air gap before the chimney?

manassehkatz covered a lot, but the simple answer is constant air flow The draft will change in the chimney as exhaust vents towards it – especially when going from cold air to hot. A draft hood is ...
user avatar
  • 19.7k
12 votes

Gas clothes dryer is venting into the crawl space

As George Anderson's answer says, this is extremely unsafe and must be fixed. But don't try to fix it by making expensive modifications to your home. Gas and electric dryers are inefficient anyway, ...
user avatar
10 votes

Why is a gas furnace vented but a gas dryer is not?

This appears to be a simple misunderstanding of how a gas dryer works. The gas dryer creates heat by burning air and the gas together, then blowing the heated air and combustion mixture through the ...
user avatar
  • 3,223
9 votes

Can I route coaxial cable for tv through a gas fireplace?

DO NOT DO IT!!!! Chimney vents must not be compromised! All heat and gas related stacks must be left intact. No additional venting or other holes may be put in them. As the comments have noted, you ...
user avatar
  • 33.1k
8 votes
Accepted

Bathroom Vent Fan Upgrade

You can install a reducer, but you'll cut your flow volume by an equal proportion: 28.3in2 - 7.1in2 = 21.2in2 (an area reduction of 75% when going from 6" to 3" duct) This will negate a significant ...
user avatar
  • 104k
7 votes

Can I vent a bathroom through the soffit if I use a product designed for it?

In the past I was a big fan of soffit vents. I figured if you used quality vents with a good back-draft damper, and sealed and insulated the duct well, it was a great way to vent bathrooms. There are ...
user avatar
  • 71
6 votes

Fast trick to figure out to where bathroom fan vents out

If you have access to the attic; and presumably the top of the bathroom fan, you may be able to follow the duct. If you don't have access to the top side of the fan, you could remove the cover and ...
user avatar
  • 128k
6 votes
Accepted

Is a dryer vent tube being compressed like this up to code?

I can't answer whether it complies with code or not since that depends on where you are, but I doubt it would matter. It's compressed some, but the volume is the same; it's just a different shape, ...
user avatar
6 votes

Range vent hood pipe

According to IRC, the duct must be made from galvanized steel, stainless steel or copper. It must have a smooth interior, and be air tight. Which means you're not going to want to use a flexible ...
user avatar
  • 128k
6 votes
Accepted

Direct stove/kitchen exhaust into kitchen sink drain

No. Your traps need to have water in them to prevent sewer gasses from getting into your home. If your vent "seal" was strong enough, you could "clear" the trap allowing gas into the home. Flammable, ...
user avatar
  • 1,976
6 votes

Is it safe to use Category 1 80,000BTU furnace with 2 inch PVC exhaust?

Are you sure that contractor is not secretly a hitman? I give him props for creativity, that's for sure! On a serious note, furnaces with efficiency of less than 90% must be vented via metal pipe ...
user avatar
5 votes

Home inspection requires exhaust to attic exterior

You'll want to check with your local government. The sale of a house often requires some things to be brought up to current code. What things are required, depends on the local government. For ...
user avatar
  • 128k
5 votes
Accepted

Dryer exhaust from 2nd floor through crawl space, out roof

If possible, you want everything rigid: the connection from the dryer to the wall, the duct in the wall, and the duct in the attic. Sometimes rigid for the connection between the dryer and the wall is ...
user avatar
  • 18.8k
5 votes

Bathroom Vent Fan Upgrade

Let's back up here for just a second and note something You almost certainly don't need a 150CFM fan. So your original fan was a stock 50CFM (probably NuTone or one of its predecessors) that's a 4-...
user avatar
  • 19.7k
5 votes
Accepted

Multiple concentric vent kits

You're fine IFGC 503.8 is the governing Code passage here, and it sets no minimum spacing for direct-vent terminations from each other, just from features that could draw combustion gasses into room ...
user avatar
5 votes

Using old vent pipe as TV antenna

If you want to try this and see what happens, all you need to do is take the end of your coax and touch the center part of the connector to the pipe, while making sure the outer sleeve of the ...
user avatar
  • 3,479
4 votes
Accepted

How to fit 4" rigid aluminum duct vent in between walls when there is an angle brace?

I wouldn't build it that way in the first place. Hiding a dryer duct within a wall and venting it through the roof (I'm guessing here, but that's what it looks like to me) is just begging for nobody ...
user avatar
  • 12.2k
4 votes

Can I vent a bathroom through the soffit if I use a product designed for it?

OK--the UCC code specifically says: • Section 1501.1 Outdoor discharge – Air removed by every mechanical exhaust system shall be discharged to the outdoors • Air shall not be exhausted into an ...
user avatar
  • 41
4 votes
Accepted

Can I vent my dryer 'up'?

It really doesn't make any difference when it comes to lint build up. But you might consider putting a secondary lint trap near the dryer to help reduce the amount of lint trapped in the line.
user avatar
  • 4,356
4 votes
Accepted

Connect 4" Dryer Vent Duct to 4" Exhaust Pipe

At the least, buy this. The reason it is the least, is lint will still get trapped in the edge that goes into the flexible part. Joints should be placed so the moving air flows over the joint, not ...
user avatar
  • 31.2k
4 votes
Accepted

What type of duct should I use for a clothes dryer exhaust?

Assuming the 16' distance, plus any other lengths and elbows falls within the manufacturer's guidelines, I would use sheet metal round ducts, usually 4" diameter. If you mount them so the ...
user avatar
  • 3,959
4 votes
Accepted

Are exhaust fans inter-connected in a 3 stories condo?

Many building like that were built without actual duct work but used the space between the joists, ceilings and floors. Running your fan would increase the pressure in that space and smoke would find ...
user avatar
  • 53.3k
4 votes

How to re-route range hood ducting to my vent?

Get custom. Despite the tubular similarity, ducting isn't rocket science. So grab some straight pipe and a tin snips, put on some good gloves and start cutting. You could even make some template ...
user avatar
  • 104k

Only top scored, non community-wiki answers of a minimum length are eligible