result of experiment? timed V on all the time

patty65

I was reading previous posts about leaving heating and hot water on all the time versus timed and some posters were saying that they were going to read their meters then switch to timed after being on all the time.

However they never seemed to post back with their results.

Is that because they discovered that timed was using less gas so they don't want to report a failure?

Until my wife and I retired our heating was timed now it is on all day and we are using more gas than before.

Patrick

Cardew

Despite the fact that having heating on all day is very clearly more expensive than having it timed, the Urban Myth - that it takes less energy to keep a house at a constant temperature - is still believed by many people.

The Energy Saving Trust wrote this:

Question

Is it more economical to leave my heating on 24hrs in the winter?

Answer

No. It is a common misconception that it is cheaper to leave your hot water and heating on all the time. Boilers use more power initially to heat water from cold, however the cost of this is greatly exceeded by the cost of keeping the boiler running all of the time.

The best solution is to programme your heating system so that it comes on when you need it most (possibly early morning and in the evening), and goes off when you don't need it (when you are out of the house or asleep). There are a range of controls that can be used and your heating engineer will be able to provide you with the most appropriate solution.

Depending on your circumstances it may be necessary to keep the heating on all day during winter but it will cost more than if you turn the heating off when you don't need it.

mech_2

patty65 wrote: »

I was reading previous posts about leaving heating and hot water on all the time versus timed and some posters were saying that they were going to read their meters then switch to timed after being on all the time.

However they never seemed to post back with their results.

Is that because they discovered that timed was using less gas so they don't want to report a failure?

An experiment can only be a failure if you get no data. Otherwise a result is a result.

Until my wife and I retired our heating was timed now it is on all day and we are using more gas than before.

Patrick

I found I used a little under 13% more gas with the heating on 24/7 in comparison with having it on 1.5 hours in the morning plus 6.5 hours in the evening, 7 days a week. The same thermostat setting was used in both cases.

The figures are going to vary from property to property because there are so many variables (timer settings, thermal mass of the building versus heat loss; draughts versus insulation; secondary sources of heat when the heating is off; the type of heating system; the relative proportions of total heat demand used for heating versus domestic hot water; etc).

Also note that many people want to compare timed with "low and constant". The rule of thumb is that a 1 degree Celcius reduction in thermostat setting lowers energy usage by 10%, so it might not have to be set hugely lower to override the increase. An 11.5% decrease from the higher consumption level would reverse a 13% increase, but as the 13% figure is not likely to apply to every building, this is not a guarantee of anything.

My preference is to just set back the temperature 2 or 3 degrees at night (otherwise it's too warm to sleep comfortably) or whenever I leave the house. I have a programmable thermostat that does allow me to do this to a set program every day, but I prefer to do it manually as I don't have a very constant routine. This has not been a controlled test as I have just been turning the thermostat to whatever figure I liked at the time, but it has resulted in a fairly consistent 1%-2% increase in gas usage compared to the timed on/off scheme in the test above, so I have stuck with it as it has provided far and away the best level of comfort overall.

Note that these figures have only been gas usage measured during the heating season. I ignored standing charges and summer hot water use, so the effect on bills is probably smaller.