dkatz (01/15/83)
1. My apologies to Courtney. I should have said 'a major source of heat loss'
not 'the greatest', but I was assuming most of the rest of his comments
were true - eg. vapour barriers are MANDATORY in Saskatchewan.
2. To avoid the problem of wiring and plumbing interfering with the vapour
barrier, it can be placed inside the walls as shown in the following sketch.
~ ~ ~ ~
|))))| : )))) "
|((((| : (((( "<-------- Wall Finish (interior)
|))))| : )))) "
Vapour ---------->: (((( "
Barrier |))))| : +--+ "
|((((| : |\/| "
|))))| : |/\|<------- 2X2 Cross Bracing
|((((| : +--+ "
|))))| : )))) "
2X4 --->|((((| : (((( "
Framing |))))| : )))) "
|((((| : (+----
Insulation ----->))| : )|
|((((| : (| <------- Electrical Box
|))))| : )+----
+----+ : +--+ "
| \/ | : |\/| "
| /\ | : |/\| "
+----+ : +--+ "
........:
:+---------------------------------------
:+-+-------------------------------------
:| |
:| |
:+-+--------------------------------------
:........
This method allows the electrical boxes to be placed on exterior walls without
worrying about the vapour barrier being interrupted. The actual wiring is not
shown, but would either run along the cross bracing or through it and down to
the joist space below. The cross bracing is set roughly 2 feet apart vertical
and spans the entire length of the exterior walls. In fact, the electrical box
should be placed on the cross brace at 2 feet above the floor.
The diagram shows 2X4's and 2X2's. One could use 2X6's and (2X3's or 2X4's).
The important things to consider are:
- if you use 2X2's inside, you have to use the shallow electrical boxes
rather than regular issue.
- the vapour barrier must be located on the warm side of the dew point.
To assure this, the temperature gradient is calculated as a function
of difference between inside and MINIMUM EXPECTED outside temperatures
and of the r-value of the insulating materials used. For Saskatchewan,
with inside at +20 degrees C and outside at -40 degrees C, the dew point
is 1/3 of the way in from the warm side for uniform insulating material
(hence 2X[4|6] and 2X[2|3] are optimal).
3. An energy efficient house should have a chimney to vent the gases that are
produced by your energy ( ~92% ) efficient natural gas furnace.
A wood-burner may be nice, but when the temperature drops to -40 you are
likely to want a back-ups system for bad weather, times when you are away,
and just plain supplemental heating. I also wonder, although I have never
seen any figures, how good the wood burners are. If you drive 200 miles
to cut trees with your Poulin Chainsaw, and haul 'em home and cut 'em up
etc., etc. how much did you really save. No comments about health and
heart please, you can get exercise in a lot of ways and I'm talking about
energy.
4. Given that you have a furnace, then an air-to-air heat exchanger can be
installed directly on the air circulation fan of the furnace as shown
below:
Furnace
+---------+
Air-to-air | +---
Heat | +----------> Warm Air to Rooms
|| Exchanger | | +---
|| +-----------+ | | |
Outside || | fresh | | | |
-------+ air +----------+ | |
--------------->------------->--------->| |
-------+ +----------+ ^ |
-------+ | | | |
<----------------------+| | | |
-----------------+|| +---+|+---+
||| |||
| |
| |
Return Air
from House
In the systems that I am familiar with - as above - the heat exchanger has a
pair of fans to move air through. These run at sufficient speed to exchange
air equal to the volume of the house about once per hour. The motors are
also connected to humidistats so that the speed steps up when the moisture
level becomes to high.
5. I know one is supposed to give references for comments like this, but I
don't have it at hand. Anyways,... A study was done by a fellow who carried
a portable pollution detector around with him all day. The amazing
discovery was that his highest exposure to carbon-monoxide (and I think
other pollutants) was while talking to his wife in the kitchen while she was
cooking supper. Higher even then when stuck in a traffic jam behind a bus
on the way to work. Reason - natural gas stove w/o ventilation.
6. The best suggestion so far for my window contest was to install valence
(?sp) boxes above windows to stop convection when curtains are drawn.
A good idea!!!
Dave Katz