Switching gas heat on and off=higher gas bills?

Cardew

Pont wrote: »

I've just had a quick search on the web and there is loads of conflicting advice out there! It seems that if your hot tank is well insulated that the leave on theory is perhaps best - if it isn't the swith on/off theory is perhaps best. I think I will try both over the next 2 weeks and monitor the useage. Whilst I take on board what my plumber said, there's a part of me that doesn't feel comfortable with leaving the hot water on when there's nobody in the house.
Just noticed the OP was asking about CH and I'm waffling on about water!

I have lost count of the number of times this has come up. This is one of many threads to save repeating the same points

http://forums.moneysavingexpert.com/showthread.html?t=1398809&highlight=energy+saving+trust

This quote is from the Energy Saving Trust which is the body set up by the Government to advise us all on energy.

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.

macman

Pont wrote: »

I'm now totally confused! I had a plumber at my house this week and asked him the same question. He told me that it is more cost effective NOT to turn the boiler off but to leave it on at all times on a lower setting. The reasoning behind this, according to the plumber, is that it costs more energy (money) to heat the water up from cold rather then to 'top up' the already hot water (if you see what I mean). What he said seems to make sense but it seems there is a different wave of opinion out there.
Btw, the plumber also told me that it's not a good idea to have the central heating and the hot water coming on at the same time in the morning as the system is working at maximum capacity in order to serve both. It's apparently much better to stagger the times by 30 minutes if possible.

A plumber does not necessarily know the first thing about cental heating or boilers. Ask the same question of a CH installer.

Cardew

Pont wrote: »

I'm now totally confused! I had a plumber at my house this week and asked him the same question. He told me that it is more cost effective NOT to turn the boiler off but to leave it on at all times on a lower setting. The reasoning behind this, according to the plumber, is that it costs more energy (money) to heat the water up from cold rather then to 'top up' the already hot water (if you see what I mean).

Although this has been said before, let us just take 2 examples.

HOT WATER
As mentioned above - do you keep a kettle boiling all day "because it costs more energy to heat the water up from cold rather then to 'top up' the already hot water"

It is exactly the same principle with a big tank of hot water. If you were to go away from your house for a year, would you leave the boiler heating for the year "because

---

from cold"

How about a month? a week? a day? - at what point does the law of physics change and make it cheaper to leave the boiler heating water?

CENTRAL HEATING
Exactly the same argument - Going aaway for a year, a month, a week, a day etc.

cattie

I've followed Canuklehead's link & according to info given there it seems it could be more cost effective to have heating on all the time depending on age/construction of house & other factors. http://www.centralheating.co.uk/heating-advice/is-it-cheaper-more-efficient-to-leave-the-heating-on-or-to-have-it-come-on-and-off-twice-a-day

Barneysmom

It might be worth one or two of us testing this theory so we know either way?
Take a reading, leave it on for a week then take a reading, see how much gas has been used and how warm the house is.
Then do it using the timer for an hour in the morning and three or four at night?

Cardew

cattie wrote: »

I've followed Canuklehead's link & according to info given there it seems it could be more cost effective to have heating on all the time depending on age/construction of house & other factors. http://www.centralheating.co.uk/heating-advice/is-it-cheaper-more-efficient-to-leave-the-heating-on-or-to-have-it-come-on-and-off-twice-a-day

I am sorry but you have not understood 'the exam question', and the answer in that link.

The question posed in Canucklehead's link was:

if it is cheaper/more efficient to leave the heating on but at a lower temperature or to have it come on and off twice a day but at a higher temperature?

As a stupid example, I can confidently predict that it would be cheaper to have the temperature on 24/7 at 5C, than twice a day for 8 hours each time at 30C!!!!

You simply cannot answer the question posed without knowing how low a temperature? how high a temperature? how long the timed high temperature periods? and insulation properties of the house?

It is like asking is it quicker to travel by car from point A to Point B at a steady slow spped, or travel in short bursts at very high speed with stops in between;) (answer on a postcard please)

Pont

Cardew wrote: »

This quote is from the Energy Saving Trust which is the body set up by the Government to advise us all on energy.

........any Government run body makes me instantly dubious as to their reliability!;)

Pont

macman wrote: »

A plumber does not necessarily know the first thing about cental heating or boilers. Ask the same question of a CH installer.

This 'plumber' is also a registered 'central heating installer'.;)

Pont

Barneysmom wrote: »

It might be worth one or two of us testing this theory so we know either way?
Take a reading, leave it on for a week then take a reading, see how much gas has been used and how warm the house is.
Then do it using the timer for an hour in the morning and three or four at night?

I'm going to do just this as I think it's quite interesting to find out. This afternoon I asked a group of friends the same question. Guess what - 50 % said to switch on/off via a timer, and 50% said to leave on. OK, not exactly a scientic survey (as there were only 8 people questioned) but nonetheless that was their responses.

Pont

cattie wrote: »

I've followed Canuklehead's link & according to info given there it seems it could be more cost effective to have heating on all the time depending on age/construction of house & other factors.

This is exactly what my plumber/CH installer said. Factors to take into consideration, according to him, included:-
The age of the property
The insulation of the property generally (double glazing/cavity wall insulation etc)
The number of people living in the property
The efficiency of the hot water tank/system (age, model, lagging etc)
In MY case, after weighing up the above, in his opinion it would be more efficient/cost effective for me to leave my hot tank switched on. However, as I posted earlier I'm going to try both over the next two weeks to see what's what.