> The upshot is that if you set the thermostat to warm the lower 2 floors to, say, 65F, the 3rd floor main bedroom will be intolerably warm and dry.
Every townhouse I've ever lived in had this problem. The thermostat is on the ground floor or 2nd floor, which results in the bedrooms upstairs being oppressively hot. I will drop the temperature by 5+ degrees before retiring for the night. I hear you about the cold office floor - I have hardwood over a slab and I'm thinking of ordering a heating pad like the one the cat has.
There are many intersecting problems here - the main one is that the standard building code in the South requires a minimum of R-15 insulation in the walls, so that's what the builders put in to remain cost-competitive. You can't get much more than that in a wall cavity framed with 2x4's. Builders and owners need to be incentivized to super-insulate. Not necessarily to a "Net Zero" standard, but increasing the minimum to R-21 (which requires going to 2x6 framing) would help in both heating & cooling seasons.
The other problem is that I have had only a single heat pump for the entire house. It would be much better to have a variable-refrigerant-flow (VRF) system where you have multiple "heads" with their own thermostats that run independently (commonly called a Mini-Split although there are differences). And then you can close the doors to rooms that aren't being used, dropping the thermostat in them to reduce usage.
Yeah, you get hosed on insulation if you buy a spec build. Custom homes are often built better, but come at a premium.
Larger townhouses -- say, 2500sqft & up -- are often zones more reasonably, at least here, such that heating/cooling can be managed with more granularity. But doing it really requires multiple units, not a single big unit.
Every townhouse I've ever lived in had this problem. The thermostat is on the ground floor or 2nd floor, which results in the bedrooms upstairs being oppressively hot. I will drop the temperature by 5+ degrees before retiring for the night. I hear you about the cold office floor - I have hardwood over a slab and I'm thinking of ordering a heating pad like the one the cat has.
There are many intersecting problems here - the main one is that the standard building code in the South requires a minimum of R-15 insulation in the walls, so that's what the builders put in to remain cost-competitive. You can't get much more than that in a wall cavity framed with 2x4's. Builders and owners need to be incentivized to super-insulate. Not necessarily to a "Net Zero" standard, but increasing the minimum to R-21 (which requires going to 2x6 framing) would help in both heating & cooling seasons.
The other problem is that I have had only a single heat pump for the entire house. It would be much better to have a variable-refrigerant-flow (VRF) system where you have multiple "heads" with their own thermostats that run independently (commonly called a Mini-Split although there are differences). And then you can close the doors to rooms that aren't being used, dropping the thermostat in them to reduce usage.