In rural Canada you'll find plenty of oil furnaces with their own tanks as well. Some of those are 30 to 40 years old and all of them are terribly inefficient.
And they are expensive AF to run. I had family members who had an oil-heated house on the Northeast US, and it was close to $2k a month to hear in the winter months (the house was large, something like 3000-3500 sq ft, but that's still an astronomical cost for heating)
We're getting into similar territory in Europe with the current gas prices. 3 Euro / cubic meter at my supplier. I never thought that the cost of heating our house would become a factor again in my lifetime but here we are.
Plenty of these old houses have much bigger problems than just the windows (which, in Canada at least in all but the very oldest houses always was double glass, even if it came in the form of an inner and an outer window).
Crappy foundations without insulation, roofs and walls with poor insulation, front door directly opening into the house instead of a separate space, almost all of them freestanding (especially rural ones) and relatively large for the number of people living there. Heating in Canada is an interesting problem. -40 Celsius on the other side of a 4" barrier is nothing to take lightly. One elderly couple that I'm aware of had begun to dismantle their house on the inside and they were burning it all up bit-by-bit to stay warm, the two of them sitting around a shitty old pot bellied stove that moved the bulk of the heat generated straight out the chimney. Stuff like that breaks your heart.
My post was a little too quick… one of my good friends was an energy efficiency expert and when I asked him for advice on replacing a boiler in our “new to me” home and he goes “don’t!”.
We did an audit and spent about $4000 on efficiency retrofit - it cut our heating bill about 25%. That was 10 years ago, and we’ll probably start looking at replacement boilers when incentives ramp up for new tech.
That's the right approach though: any Joule you don't need to produce is one saved and even the most efficient furnace can not fix a leaky house. So the priorities are: economize (because it is free, and assuming you still can), insulate, high efficiency heat (depending on the age of the furnace, anything older than a decade is likely not HE+), self generated power in that order.
I had the full energy efficiency report with infrared camera and expert's eyes and blower door test. It was enlightening. I strongly recommend first thing get the expert report and follow the recommendations.
A few years later I got another report and fixed a few more things. House cold spots mostly went away, bills went down, less outside noise, and have the same windows and furnace.
The latest generation (HE+) is a lot better than the ones before it which tended to erode the inner liner of the burner vessel into a nasty aluminum rich sludge that ended up clogging the drain. The newer ones do not have that (much thinner drains too).
