On Sat, 31 May 2008 20:05:05 +0000 (UTC), Jonathan Grobe
1. Anywhere there is a wall penetration. Outlet & switch boxes are
leaky, and not just those on exterior walls. Any outlet box has a
piece of conduit or Romex that ends up going through a hole into the
attic. Thus the outlet leaks into the wall which leaks into the attic.
Put those foam outlet seals on all your outlets. If you cant use the
foam seals, get into the attic and caulk around all the conduit
penetrations into the attic.
2. Around the foundation perimieter where the foundation meets the
wall. Seal the sill to the foundation with caulk. I had an added
benefit when I did this. I've been plagued by mice in the basement
ever since I bought the house. Never could find how they were getting
in. Havent had a single mouse since I caulked around the foundation.
3. Where plumbing penetrations go through the wall. Seal all pipes and
4. Ceilling can lights into the attic.. Replace your fixtures with
IC-AT, insulated ceilling-air tight, fixtures
5. Around doors, particularly at the door sill. Weatherstrip all
6 Around windows. My new energy efficient double hung windows leaked
horribly where the 2 window panes came together. I ended up shoving
cotton balls in the cracks.
7. Fireplace Flues. leakage out of these is major cause of heat loss.
At a minimum, make sure the damper is closed. But dampers really are
bad at sealling. Google on Chimney Balloons and install one of
8. Bathroom Ventilation fans. Dont know what you can do there. I dont
know if there are models with built in dampers or not.
9 Attic entrances in the ceilling. Especially the pull down stairs ,
They leak like a seive. weather seal the perimeter and build yourself
an insulated box around the stairs itself. I think you buy kits for
that at some home centers.
10. Medicine cabinet recessed into the bathroom wall.
11. The bathroom wetwall. Does it connect with the basement and the
attic? This is a major leak site. The hollow wall acts like a chimney
between the basement and the attic in many houses. Seal both the top
Do you get the idea now when I said any penetration through the wall
into the interior living space is a candidate for a leak.
If you have some rooms that are not totally plastered/drywalled, like
with a wood ceiling instead of drywall, then all around the perimeter
of the room is a candidate for leaking.
I had a blower door test doneon my house and frankly, I could have
done without the test. Just seal up every penetration. The operator
of the test already knows where all the leaks will be, but he has to
convince the homeowner of that. So the blower shows the homeowner the
leaks. But as others have said, you dont want to totally seal a house.
You have to allow for fresh air and combustion air to replace that
which goes up the furnace flue.
My house, according to the test was leaking at roughly 3 times the
rate of todays standard for a tight home of its size. After sealling
most of what the test found, I was still at twice the current leak
standard. But it would be too costly to replace the bathroom vents
and the can lights, so I decided that was enough. Frankly, I saw no
reduction in either my heating or gas bill last winter so air leaks
must not place a big role in heating problem. Its a 50 yr old ranch
house. What I did notice is that it became more comfortable. Cold
spots were gone.
Google on Blower Door Test. There's some good information on the Web
explaining what is expected to be found and where the common leaks