Rebecca Norman wrote:Well, my house isn't exactly a double envelope, but it's entirely solar heated and the whole north side is what we call the thermal buffer zone, which I think is a similar idea. I'm sorry I don't have any technical specs for you, but I can share my experience from living in it.
The kitchen, bathing room, living room, bedrooms and little study or bedroom are in the south side of the house and as such are solar heated. The northern unheated buffer zone includes corridor, storerooms, stairs, and the two-story dry composting toilet. The upstairs cold corridor also has a washing machine and a handwashing sink outside the dry compost toilet room.
My contractor used only "straw clay" for insulation above the horizontal roof beams, and didn't insulate below the beams; insulated between the heated space and the buffer zone, but didn't insulate the outer walls of the buffer zone; and used single glazing on all the windows in it. Last winter the bottom of the corridor under the stairs did just touch freezing, but the upstairs corridor was a few degrees warmer, and the sink and washing machine had no trouble. This year hopefully the buffer zone will stay warmer, because we've put up white foam insulation mat on all the windows in the buffer zone. I hope to add roof insulation between the beams next year which I hope will also keep the house warmer.
In New Hampshire I think there are local habits and requirements for insulation that will be great. If I try to suggest that much insulation in the roof here people would be shocked and think it sounds completely unreasonable. I wish I could get good northeast US type insulation. Like, a foot thick, or R50. I just wish. My climate is high desert and good 10-15 degrees south of you (10,500 feet high and 34N), so the solar gain in winter is still pretty good, and being made of rammed earth my thermal mass is good. If only I could manage a LOT more insulation I think it would be a lot warmer in winter in this house.
The 3D picture below is not exactly what finally got built. We included an 18 inch overhang over both ground floor and upstairs on the south face, and all the upstairs windows on the south face are half-trombe wall, which in the 3d drawing is only shown on the leftmost window.
I insisted on single glazing on those upstairs south windows but maybe I regret it, because the bedrooms really do get damn chilly in the winter. Down in the low 50s F on January nights last year despite the wool curtains. Maybe even 40s. I don't want homemade double glazing because it gets moisture, dust, and insects inside, but if professionally made double glazing becomes available here I think I'll replace them. The east and west windows in the southern rooms are double glazed, but I wish we'd done double glazing on the windows of the buffer zone, too.
Edited in 2026 to add: The house has performed great. I'm adding a comment about it below.
William Bronson wrote: I tried to access the article again and it seems to be gated now 🤬
Ah, well, googling del monte bankruptcy and peach farmers gets other sources.
Burra Maluca wrote:And also establishing things like a chive bed, which will give me green onions to use for many years to come with no extra effort.
Haha, I only just tasted bittercress for the first time a few days ago and it was delicious, not bitter to me at all! It tastes like arugula (rocket) when it's just right and not spicy at all. (And BTW arugula was rarely too spicy/hot when I grew it in the high desert. Go figure!)I find wintercress, Barbarea vulgaris, to be horribly bitter when raw (but tasty cooked) while a friend of mine insists that it just tastes sweet to him.