Jan Turner wrote:I have a Hearthstone wood stove. It has soapstone body. It is How can I retain more of the heat? Can I put thermal mass around it? If so what kinds?Here are some pictures of the area . I am hoping for some brainstorming.
I had a very similar situation a few years ago, but the alcove was a stone chimney with the fireplace walls, into which a 5kW metal stove was placed. On a cold night after it had been running a few hours, the chimney base was warm to the touch outdoors, even when breezy and the temperatures were around freezing point. I reckoned something like a third of the stove's heat was being lost, through the chimney stone and the stainless steel closure plate which closed off the chimney void.
Pulled forwards a foot and a half and sending the flue out of the rear, I surrounded it with something like 200 bricks with a piece of old fire guard to bridge over the top of the stove. Perhaps 60 heavy firebricks from an old "night storage heater", the rest older engineering bricks - as heavy as I could find. Behind them I slid in 6 or so sheets of cooking foil to reflect heat back into the room and a couple of old computer fans were rigged so they moved the air a little, more so than just the thermal currents alone would provide.
Result? I knew there would be an improvement, but didn't know just how substantial it would be. Coming into a very cold house, it perhaps took 10 minutes (35 instead of 25) for the room to warm to comfortable from lighting the fire, followed by a period of 45 minutes to an hour where things felt little different, perhaps slightly less intense heat. From that point onwards, the the difference was increasingly massive!
There was more heat, to the point the whole house (two other larger rooms downstairs, two really big ones upstairs) would be comfortably warm even in the coldest of weather when previously it was a struggle to maintain this. There wasn't the rise and fall of heat as the stove cycled and nights were fantastically comfortable, with mornings warm enough not to race to light the stove when otherwise that was the case.
It felt as if the stove was one third larger when running but the heat was a more pleasant quality, it felt more like central heating through the night and into the next morning. The computer fans failed in time and without, the effect was almost as good - to the point I didn't replace them. I was initially concerned that placing bricks to within three inches or so of the stove could be a problem, but not a problem. If they'd been touching, I could forsee potential probs.
Had we been staying, I would have built something a little more permanent (while retaining air gaps between bricks) and used some French multifoil instead of the cooking foil sheets - it's many layers, each insulated.
