Sounds like the consumer didn't appreciate the thermal inertia of the building either. My parent's old cottage would take many days to heat up if they ever let it get stone cold in winter (even using and oil boiler & radiators) - just due to the vast amount of stone (and clay) in its old thick walls. If you add good thermal insulation on outside of the walls you reduce the heat loss, but the heat needed to raise the temperature of the walls themselves will still be the same. Make the new heating system much smaller to match the now reduced heat loss (as is usual, as it's cheaper that way) and heat up times will naturally be extended. Typically not a problem of course, if the house is kept warm in the first place (as most homes are).
Sounds like the consumer didn't appreciate the thermal inertia of the building either. My parent's old cottage would take many days to heat up if they ever let it get stone cold in winter (even using and oil boiler & radiators) - just due to the vast amount of stone (and clay) in its old thick walls. If you add good thermal insulation on outside of the walls you reduce the heat loss, but the heat needed to raise the temperature of the walls themselves will still be the same. Make the new heating system much smaller to match the now reduced heat loss (as is usual, as it's cheaper that way) and heat up times will naturally be extended. Typically not a problem of course, if the house is kept warm in the first place (as most homes are).
