bathroom's ambient temp colder

[rh71]

Anyone else deal with this every winter where it's colder in a bathroom than the rest of the house? Seems the vent fan lets in the cold air - do you guys in cold climates seal it off (at least for a few months) like I have to? It doesn't have a duct to the outside, but an attic space that isn't well insulated (I know it's not properly designed, but we don't use the vent for moisture that often). Also 2 of its walls are the exterior of the house but I know there's insulation since we remodeled. Problem with insulating its attic space - the insulation goes on the attic flooring (ceiling of the bathroom) and you can't do that at the vent fan. How do you guys manage this vent issue, assuming yours goes outside?

 

[NetWareHead]

Anyone else deal with this every winter where it's colder in a bathroom than the rest of the house? Seems the vent fan lets in the cold air - do you guys in cold climates seal it off (at least for a few months) like I have to? It doesn't have a duct to the outside, but an attic space that isn't well insulated (I know it's not properly designed, but we don't use the vent for moisture that often). Also 2 of its walls are the exterior of the house but I know there's insulation since we remodeled. Problem with insulating its attic space - the insulation goes on the attic flooring (ceiling of the bathroom) and you can't do that at the vent fan. How do you guys manage this vent issue, assuming yours goes outside?

The vent fan is your problem. You said it lets air into the bathroom. Cold air from attic wants to drop and hot air wants to rise. The hole in the ceiling is the best place for this exchange to happen.

You need to duct the bathroom fan to the outside. Not a good idea to get bathroom moisture into the attic. Once ducted, you can thoroughly insulate the bathroom ceiling including directly over the fan housing.

 

[utahraptor]

The reason it is colder in the bathroom is because of the sink. Ever hear of a "heat sink?" This is a little known fact, but every heat sink that goes in a PC actually has a small piece of an old bathroom sink integrated into its construction. The sink in a bathroom does not just drain water, but heat as well. It is constantly pulling the temperature down in the room.

Ever wonder why so many people are found dead in the bathroom? The sink also slowly drains away one's life essence. If you have an underlying health condition it can siphon away just enough health that it can push you over the edge to death.

 

[DrPizza]

If the housing of your attic fan isn't rated for insulation contact, then you should build a box out of rigid foam to go over it (a roomy enough box so the box leaves a couple inches of space around the box. The box shouldn't have any gaps for air penetration, other than the duct going out of the box. If you're using thinner rigid insulation, then wrap it with some fiberglass insulation. While you're at it, you can probably wrap the duct with insulation as well, so the only place heat exchange is happening is where it exits the house.

edit: at least 3" of clearance.

 

[jaha2000]

There should be a flap on the box as well. I would guess yours is stuck open.

 

[boomerang]

There should be a flap on the box as well. I would guess yours is stuck open.

This

 

[rh71]

There should be a flap on the box as well. I would guess yours is stuck open.

On the vent fan itself? This is our 2nd one (remodeled) - the first one still resulted in a cold bathroom. Chances are slim that's it again if that's what you mean.

 

[Greenman]

Fan should have an exterior outlet with a flapper in it, there should also be one right at the fan itself. In cold climates, it's a good idea to but a thermal break in the outlet pipe, a couple of feet of plastic pipe just before the outlet. Then cover it with insulation. If you can access the top or bottom of the exterior walls, check for holes around the pipes, great place for air to enter.

Never ever vent a fan into the attic, you're actually better off not having a fan than one that dumps in the attic space.

 

[Red Squirrel]

It sounds like the fan is not properly sealed with the vapour barrier, or as suggested the flapper may be getting stuck. Also how long is the pipe going outside, and is the pipe properly insulated? While a shorter pipe is more efficient for a fan, it also means a shorter path for cold air to enter. The entirety of this pipe should also be under the insulation, idealy venting through the soffit, to prevent the cold from getting in thermally through the pipe itself. Even if it's insulated pipe, that's like maybe R5 or something.

Do you have any appliance in the house that creates lot of suction, like a low efficiency furnace or fire place? That will encourage air to enter the house through any area that is not properly sealed, as well.

My bathroom fan is a special case as it's an inline fan, the unit is actually in the basement, and I ran some pipe through a wall chase, so it never even sees the cold till it gets to the vent on the side of the house. Even if the flap in mine gets stuck, most of the inside of the pipe is the same temp as the house, except for the lenght in the basement that's closest to outside. I find since I made that upgrade it made a huge difference, the fan itself is also way better than the typical "ceiling shakers" bathroom fans .

 

[Binky]

First floor? If yes, what about heat loss from under the bathtub or shower enclosure? My (LA) house sits on a crawlspace and the insulation under the bathrooms is terrible to non-existent. Of course, if your house sits on a basement or solid foundation, which is likely on the east coast, this is irrelevant.

 

[TheGardener]

Our condo just got a new roof 2 years ago. The roofer prior to doing the job, told us that the bathroom vent only went to the crawl space above. Since we got a new roof, it was easy for the roofer to extend the vent to the outside. What a difference. Once you do that you can fix the problem of not having enough insulation. You might be able to get insulation through your electric company at no cost or low cost. Expect blown in cellulose.

 

[slag]

The reason it is colder in the bathroom is because of the sink. Ever hear of a "heat sink?" This is a little known fact, but every heat sink that goes in a PC actually has a small piece of an old bathroom sink integrated into its construction. The sink in a bathroom does not just drain water, but heat as well. It is constantly pulling the temperature down in the room.

Ever wonder why so many people are found dead in the bathroom? The sink also slowly drains away one's life essence. If you have an underlying health condition it can siphon away just enough health that it can push you over the edge to death.

Sounds like it might also kill brain cells....