I'm in my first winter in a ~140 year old home and attempting to improve efficiency / comfort.
The home has a concrete basement (originally sandstone foundation) which is conditioned space, but in practical terms the ceiling is too low for it to be living space. A home heating audit tells me that the basement should be insulated because it is a major source of heat loss.
I've investigated spray-foam insulation along the foundation wall and sill, but recently I've been thinking that for our purposes it may be more economical to consider the basement's ceiling as the 'envelope' to be insulated, with the following considerations / benefits:
- We don't care if the basement itself is cold - it is unoccupied
- fiberglass batting in the (exposed, accessible) joists will be much cheaper to install. Specifically, it won't involve hiring anyone
- the overall insulated cubic footage will shrink, which I presume can only be a benefit
- batting will also provide some soundproofing against the furnace + dehumidifier which kick in intermittently from the basement