just installed new windows, double glazing, now I can say that the stove heats well, I had read that double glazing, compared to single glass, (and drafts of air) I would have earned 40 percent, I don't know however, the difference is evident. I measure temperatures in the kitchen, which is another room than the stove, and now it is over 70s previously it was difficult to exceed 60s I have no other insulation