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timkins4292

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Location
Victor, NY
Have a Fan Light Night Light just above my shower stall. Went outside this morning and I have a huge icicle in my gutter just below the roof cap exit for fan. Took the fan down from the ceiling and tried to insulate the housing. There is a 4watt incandescent bulb for a night light and a 26 watt fluorescent light. They are both housed in a metal cabinet. How would I insulate the housing to prevent heat loss thru the duct. I am reluctant to use duct tape or anything flammable to stop the flow to the outside. We have stopped using the fan and only use the night light sparingly.
 
How would insulating the fan housing stop ice from forming outside ?

You need a HVAC person for advice. Sorry I couldn’t help.
 
So if you insulated the fan it then that would cause more ice it seems.

It should have a damper in the fan to prevent the free flow of air to the outside.
 
How do you figure that? If the source of the heat thru the housing and then the duct is blocked then no heat transfer takes place so then no defrosting takes place and no icicles appear.
 
Ok great. The fan should have a damper built onto the outlet.

If it’s not there then install one.

This stops a warm draft from exiting through the fan.

That’s all I can help with. Have a great day.
 
It would seem the melting of snow is causing your giant icicle.

The snow is likely melting from the fan’s warm exhaust blowing onto the snow on the roof.

Stop using the fan, just leave the bathroom door open during showers if you can.

Insulating the fan box or the duct will not stop that melting problem.

The reason people insulate the fan box and the duct is to stop condensation from forming inside the cold duct, which then can run down into the fan and cause a drip, drywall damage, or rust out the box or fan motor.

All this heavy snow is giving millions of people a big problem with giant icicles and ice dams, just look at your neighbors’ houses, that’s just how it goes.
 
I truly don't see how you can do that even if the housing is taped directly to the 4" duct to the roof cap.
 
In cold climates the best way to handle an exhaust fan is wrap hvac foil tape at all seams or holes in housing, wrap with 6 mil poly and seal that to ceiling vapor barrier with red barrier tape or accoustic sealant and finally surround in insulation to same level as the rest of attic. Then use pvc or abs smooth wall pipe routed to a gable end with a slight grade down and penetrate through the wall. Insulate and seal pipe the whole distance with no less than r8 foil backed. I don't know of any bath fans that are not rated for ic(insulation contact). Just because you have cold climates and snow accumulation doesn't mean you automatically get icicles. No ice dams or icicles on houses I have built,repaired, owned for 30 plus years -40 temps and 2 plus feet of snow every year. Insulate well, build tight, ventilate right and no issues.
 
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I truly don't see how you can do that even if the housing is taped directly to the 4" duct to the roof cap.
I asked my brother about that, as he is an HVAC specialist, and he was like, "well, it's not impossible, but he has to take a look at that."
 
I asked my brother about that, as he is an HVAC specialist, and he was like, "well, it's not impossible, but he has to take a look at that."
He also said that first of all, and you need to have a damper built onto the outlet, either way, it won't be possible to realize this thing.
 
He also said that first of all, and you need to have a damper built onto the outlet, either way, it won't be possible to realize this thing.

Not sure what you are saying here. All exhaust fans I have seen have a damper built into them its in the plastic transition piece that adapts the housing to the duct.
 

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