Two comments:
Don't underestimate the potential thermal mass of a structure. I've been struck by the thermal cruise time that our house has due to masonry and plaster throughout. This can work against you though when you're trying to warm up a cold house. I continue to be amazed how long it takes to warm our place up. It makes it easy to appreciate the concept of a super insulated, low thermal mass house especially if your prefer your house cooler at night for better sleep yet warm when you wake up.
As solar PV costs fall, the ROI break-even point between investing in things like passive solar or insulation versus investing in PV continues to move in favor of PV.
Don't underestimate the potential thermal mass of a structure. I've been struck by the thermal cruise time that our house has due to masonry and plaster throughout. This can work against you though when you're trying to warm up a cold house. I continue to be amazed how long it takes to warm our place up. It makes it easy to appreciate the concept of a super insulated, low thermal mass house especially if your prefer your house cooler at night for better sleep yet warm when you wake up.
As solar PV costs fall, the ROI break-even point between investing in things like passive solar or insulation versus investing in PV continues to move in favor of PV.