I am living in a 1971 "California split", a raised bungalow with a grade level living room at the front; 2x4 construction with poorly applied bat insulation in the walls (frost in the corners and floor to wall joint at -30). There is a total of 1100 sq ft in the home (upper floor and grade level living room (another 800 sq ft or so in the basement). I just had an energy audit with blower door and got a few surprises including...

-big time air infiltration through main floor pot lights, at exterior wall electrical plug boxes  and around doors/windows.
-three inches of wood chips covered by 5 1/2 inches of fiberglass bats in the attic (R20ish according to the appraiser)

and

-major air leaking down the chimney of what was a wood burning fireplace in the L/R; it was capped and now has a gas fireplace (sealed unit with inlet/outlet air)

He also pointed out the brick wall (inside the house, from floor to vaulted ceiling (north wall of the L/R) either has very little or no insulation. It is also brick on the exterior rising to about 6 ft above the roof. In the winter I have to keep the gas fireplace on to keep that brick wall from cooling off the main floor. The brick is ice cold and cold air just sheds off of it.

I know to...

-increase insulation in the attic (code minimum is R50, I'll see if I can squeeze in R60),
-use foam gaskets behind the cover plates of the exterior wall switch/plug boxes,
-caulk and seal the windows the best I can

but have no idea what to do about that cold brick wall or how to seal the pot lights.

Ideas?

I am in Winnipeg, Canada. It gets darn cold here :)

edit; I tried to post a picture but its not working :(                          ........ figured it out!

here is the exterior of that wall......

It would be interesting to calculate exactly what insulating that brick would save.

how would I calculate that?

The can lights can ce replaced with IC cans which then can be encapsulated with insulation. To calculate the brick heat loss you would need to know the total construction assembly of the wall and their combined u rating. Then you would need the difference in outside and indoor air temperatures.Your project looks like a job for Mike Holmes. Your best bet would be to strip back the drywall on walls and ceilings and then spray foam stud and rafter spaces paying close attention to all corners.

I would estimate that the brick is about like a good window of the same size in terms of heat loss. Perhaps some of the cavities in it can be filled with insulation for some improvement.

If that wall were in my home, in Winnipeg, the first cold night would have me thinking about having that chimney torn out and a properly framed, insulated, and air-sealed wall put there in its place. A freestanding gas fireplace and the heating system can be vented with an external chase. I don't see any good way of insulating the brick face that wouldn't cover it up from view anyway.

Pot lights in a cathedral ceiling in Winnipeg is an energy-disaster, even if air-tight. When it's time to replace the shingles you could add 6" of exterior rigid polyisocynurated insulation above the roof deck and seal the venting and do OK.

If they're in an attic floor, short of replacing them with gasketed air tight versions, they can be sealed over with an air-tight box caulked/foamed to the interior gypsum and you can heap copious quantities of insulation over them. In most of the US you'd need at least 75mm of clearance between the box and the fixture to meet code- it's probably similar in Manitoba.

What DickRussell said about the chimney. Mine is only half as wide, and in a much warmer climate (central Massachusetts), and it's a HUGE heat leak. I'm negotiating with my wife to forgo some of the charm in favor of efficiency. The amount of effort & cost it takes to keep it and insulate it is just plain crazy. This type of architecture is marginal efficiency-wise even in a coastal-California climate, but a bit maladapted to the Canadian Midwest. You might be able to keep the inteior brick face and rip out the exterior and put something different that still harbors the flues. In cold climates the drafting capacity of any flue on an exterior wall is much reduced compared to one that runs up somewhere on the interior of the structure, and backdrafting & condensation in the flue is common.

Insulate the brick from the outside and let the brick add thermal mass to the interior. Also correcting the can lights and fireplace issues is integral as part of the solution.

A common retrofit you see a lot in Germany is adding thick sheets of EPS foam to the outside of the brick, using long screws with plastic washers, then covering it with a modified stucco.

Jelly
Did you get a look at the clay block they use? With about 6" EPS they are talking about walls in the R40-50s range. The blocks have vertical air holes and some brands have the holes off set.

SCIP Panel, yes, the whole wall assembly would either be clay block with vertical air spaces, or solid masonry or stone in older construction. The difference here for the original poster would mean careful attention to water shedding if the underlying structure is a North American type stud cavity wall.