insulating double brick walls on the inside - yes or no?

[mvdm]

We will soon be moving into a yellow brick house (also known locally as "double brick", built circa 1900) in Southern Ontario. The house has about 50% original lath and plaster and 50% drywall on the interior side.

We're interested in improving the overall energy efficiency of the house for environmental and comfort reasons. However, there seems to be some conflicting and/or inconclusive information out regarding the pros and cons of insulating the inside of brick walls. For instance, the Canada Mortgage and Housing Corporation (CMHC) has a booklet, "Renovating Distinctive Homes: the Century Home" which states:

For the solid brick house [..] Insulation placed on the interior of the wall changes the dynamics of the wall. When the heat is held in by interior insulation, the wall may be subject to more of the freeze-thaw cycles of a Canadian winter. If the brick or mortar has absorbed water, the freeze-thaw cycle may cause the brick to spall or fall apart.

The report also states that studies are ongoing of buildings where insulation has been installed on the inside of solid brick walls. So, we are curious, is there any actual data on this? Good idea or bad idea?

PS: a case study on a brick house very similar to ours indicates that heat loss through the walls is the single biggest source of overall heat loss, so it seems beyond doubt that this is worth considering if it can be done without causing structural damage:

[Sombreuil_Mongrel]

Since the brick is thermal mass, once brought to a "room temperature" of 68*, if you add insulation to the outside, you will find it easier to maintain a year-round comfortable temperature thanks to that mass. That's the idea of "out-sulation". You limit the throughput of heat, and extend the number of hours where no additional heat input (or cooling) is required.
Casey

[Don M]

I've seen a stone house done with interior insulation & I live in one without. My house remains comfortable year round without insulated exterior walls. A friend's home had 2x4 walls constructed & insulated against the original stone & plaster walls. That also seemed to work but that made his rooms somewhat smaller---his rooms were fairly large so it didn't seem to be a problem. I don't really know if his house is more efficient than mine.