Turning off spare radiators = Cheaper Gas Bills???

macman

Cardew, why not just disconnect the room stat?

Cardew

macman wrote: »

Cardew, why not just disconnect the room stat?

It makes no difference if I do.

Either way the pump is running!

Canucklehead

katrina1979 wrote: »

Hi

I am new to this but desperatley trying to save money on just about everything so was wondering if i turn off the raditors in spare bedrroms will this mean my gas bills should be less? My radiators are the olsder style so they do not have a thermostat but i reckon i am able to turn off 4 which would leave 5 still on.

Good afternoon: accurate advice is available here.

HTH

Canucklehead

Cardew

macman wrote: »

Surely the only argument against turning them off, is that boilers and CH systems are designed to run under a certain load. If you had say a 10 rad system and ran it with only 1 or 2 rads on, it would be way under it's output for efficient running. However that's an extreme case, and I can't see that turning off say 3 or 4 rads out of 8 or 10 could do anything but save energy overall.

My 450bhp Ferrari(I wish) only needs 62bhp to cruise at 70mph. However I need the 450bhp when accelerating to 60mph in 3.8 seconds.

A central heating boiler is specified to heat rooms in the house to xxC and yyC when the temperature outside is -zzC. Also to provide hot water.

Thus for any particular house it will need xxxxxxxBtu/h(or xxkW) to meet that worst case scenario of extreme weather and all rooms in use.

So 99% of the time the boiler is only operating at a fraction of its capacity - by that I mean it is not modulating on modern boilers or on all the time. For instance putting the heating on when the outside temp is, say, 15C.

Whilst it is true that at lower outputs the boiler is a little less efficient, it is a compromise and it is not a valid argument to put more radiators on to increase the efficiency.

e.g. Using 5 radiators producing a certain amount of heat(xBtu) might have the boiler operating at, say, 75% efficiency and use, say, 10kWh.

Using 10 radiators and producing double the heat(2xBtu) might allow the boiler to operate at, say, 80% efficiency and use only 19kWh, but it is still using 9kWh more.

A Ferrari engine(the boiler) is actually more efficient at higher BHP outputs. However the Ferrari gives more mpg(which is how most people look at efficiency) at lower speeds because it is doing less work.

Fire_Fox

jamesdrew wrote: »

As stated, we will wait and see what others have to say, it is always an interesting topic because allthough I respect your view, it is not necessarily correct. What I will say is many years ago I did a 4 week study on heating 7 radiators in my house (half of them) and then 14 radiators (all of them) The difference in the amount of gas used was negligable.

What kind of study - a proper research project? How did you ensure that the weather remained constant? How did you ensure other gas use remained constant, did you time your showers, eat the same meals?

Cardew

jamesdrew wrote: »

As stated, we will wait and see what others have to say, it is always an interesting topic because allthough I respect your view, it is not necessarily correct. What I will say is many years ago I did a 4 week study on heating 7 radiators in my house (half of them) and then 14 radiators (all of them) The difference in the amount of gas used was negligable.

OK let us take a silly example.

Say Buckingham Palace has 1,000 rooms.

Which do you feel will cost less. Heating them all or just the Corgi's bedroom?

Once you establish that principle(I assume you concede that heating one is cheaper than heating 1,000) then your argument falls apart.

Heating 14 radiators cannot possibly cost the same as heating 7 radiators(given the same conditions) - it defies the laws of physics.

Depending on the characteristics of your boiler, it may not use double the heat, but it won't be far short!!

Biggles

jamesdrew wrote: »

What I will say is many years ago I did a 4 week study on heating 7 radiators in my house (half of them) and then 14 radiators (all of them) The difference in the amount of gas used was negligable.

Four weeks isn't long for a useful test and you would need the weather to be identical for the 'test' to be any use. But, even so, there was a difference, then?

stokefan wrote: »

surely it just depends where your thermostat is in your house, if its in a cold part of the house and you switch the radiators off in that room the boiler will be consistantly boiling??

I think you mean 'the boiler will be constantly running' (rather than 'boiling', as Cardew pointed out) but apart from that you are right.

EdInvestor

For an outlay of £56 (DIY) and £156 (professional fitting) a saving of £10 a year on your gas bill does not seem adequate to attract many other than the most dedicated greenies..

greenbee

If you are turning off the radiators in spare rooms, which from my unscientific and undocumented (except for bills) research, appears to work (and yes, I do understand the science behind it and why it works - which has helpfully been illustrated by Cardew), I suggest that you close the doors to those rooms.

Otherwise the radiators in the rest of the house will be trying to heat the unheated rooms (it's a mistake I quite often make )

thor

greenbee wrote: »

Otherwise the radiators in the rest of the house will be trying to heat the unheated rooms (it's a mistake I quite often make )

Actually I think it would be more accurate to say that the rest of the house will be trying to heat itself rather than the unheated room. It is just that the unheated room will be having heat channelled to it if it is not sealed off and thereby cooling the rest of the house.