We recently came across a reader question in a common publication, which asked the question of whether or not it was wise to turn a residential boiler off for a period of time over the course of a day, or to use it on a timer, so that is only runs while the house is occupied.

As a general rule, it is not wise to operate the boiler like this.  Turning the boiler off, especially during the warmer daytime hours can actually harm your home’s efficiency more than it will help.  Setting back the temperature in the evening is commonly done, and this may be something to consider, but during the day, the home (as with any commercial space) is absorbing radiant heat from the sun.  Therefore, it requires very little energy for the heating system to maintain a comfortable environment. Setting the boiler back at night, but a few degrees can actually result in a boost in efficiency, because the boiler won’t have to work as hard to maintain the environment, and those residing in the space will be under covers anyway.

Rather than a timer that shuts down the boiler for periods of time, it would be better to invest in a new thermostat.  Programmable thermostats are readily available these days and can be used to create a heat schedule.  That is to say that you can have the set temperature automatically drop during the nighttime hours, but return to the desired daytime temperatures just before you get up in the morning.  The same can be applied to an office building that is left vacant during the evening hours.  Less money is spent on heating the space during that time, but the building will be warm when workers arrive, thanks to the automated controls.  That is opposed to relying on an occupant to change the thermostat settings each morning, which would mean arriving to a chilly office.