Rob R. wrote:I vote no. I have experimented with setback temps. and the savings was very small...but the cold floors in the morning were very noticeable.
I should have been more specific. In my particular house a 2-3 degree setback resulted in small savings, and a larger setback resulted in long recovery times and a decrease in comfort that I didn't think was worth the amount of coal saved.
Mike is correct that the smaller the delta between the indoor and outdoor temps (isn't that the basis of a degree day?), the lower the heat loss. I think the best case for setback savings is a house that cools quickly, and has a high-output heating system that can quickly recover the temperature if desired. Such a home would quickly benefit from the reduced temp. setpoint, and the long burn required to get back up to speed might product better combustion efficiency than just banging on/off all day to maintain temp....that was the case for my house when it had leaky windows and was headed with an oversized oil boiler.
Can I change my vote to "it depends"?