Heat Pump.

Do people keep the heating on all the time nowadays even when the house is empty?

Most modern (programmable) thermostats don't so much switch on and off, as change the target temperature - lower when unoccupied, higher when occupied - the choice of the ‘setback’ temperature being influenced by typical warm-up times. Some smarter ones can even learn the room's typical response to heating and adjust the actual setback temperature and/or anticipate a programmed change to a higher temperature so the room reaches the required temperature by the required time.

A slightly different mind-set is needed when dealing with small heating systems in well insulated but high thermal capacity buildings, as compared with the large capacity heating systems in old leaky buildings we're perhaps more used to. It may well be more economic to keep the heating system running for a week or two when away (losing only a small amount of heat due to the good insulation) than let the building gradually get cold and then heat it up quickly again on return - as the latter approach would require a larger heating system which likely would not only cost more to install but run less efficiently during the rest of the year.

Good levels of insulation (and airtighness and controlled ventilation) can make huge difference to heating demand - e.g. a typical 1970s house might have a space heating requirement of something like 150kWh per sq m per year - nowadays we can achieve something closer to one tenth of that - around 15kWh/m2/y - at those sort of differences the savings from turning the heating off for a couple of weeks, only to have to re-heat the structure, really can be quite small. 

   - Andy.

Do people keep the heating on all the time nowadays even when the house is empty?

Most modern (programmable) thermostats don't so much switch on and off, as change the target temperature - lower when unoccupied, higher when occupied - the choice of the ‘setback’ temperature being influenced by typical warm-up times. Some smarter ones can even learn the room's typical response to heating and adjust the actual setback temperature and/or anticipate a programmed change to a higher temperature so the room reaches the required temperature by the required time.

A slightly different mind-set is needed when dealing with small heating systems in well insulated but high thermal capacity buildings, as compared with the large capacity heating systems in old leaky buildings we're perhaps more used to. It may well be more economic to keep the heating system running for a week or two when away (losing only a small amount of heat due to the good insulation) than let the building gradually get cold and then heat it up quickly again on return - as the latter approach would require a larger heating system which likely would not only cost more to install but run less efficiently during the rest of the year.

Good levels of insulation (and airtighness and controlled ventilation) can make huge difference to heating demand - e.g. a typical 1970s house might have a space heating requirement of something like 150kWh per sq m per year - nowadays we can achieve something closer to one tenth of that - around 15kWh/m2/y - at those sort of differences the savings from turning the heating off for a couple of weeks, only to have to re-heat the structure, really can be quite small. 

   - Andy.