radiator temperature

eddieace

hi all

this is my first post, and basically i'm trying to save money on the heating bill and keep the house warm at the same time.

so far i have replaced my old boiler, carried out a series of draft excluding measures, and now looking into having the cavity walls insulated as well as increasing my loft insulation.

i have also been monitoring my usage on a spreadsheet, all i have to do is input my water, gas and electric readings as well as the date and it can calculate all the bits and tell me my average daily usage as well as average daily costs. i have just purchased a usb thermometer and i'm hoping i can incorporate the outside temperature as well this will help me to work out what heat saving measures are working and what aren't.

ok.

my question is radiators what temperature do i set them too? i have recently had them set to 70C but i'm wondering now if i set it to something cooler it would be more effiecient?

anybody have any ideas?

Cardew

There is no set answer as all boilers are different, and all CH layouts are different.

Some(most?) boilers are slightly more efficient at higher temperatures.

You can argue that the hotter the water in the pipes leading from the boiler - the higher the loss; but in most cases the 'lost' heat warms up the fabric of the building.

All in all I believe the differences will be very small.

eddieace

yeah i'd have thought the savings would only be small if any, just thought someone might have covered it!

mech_2

You say you replaced your boiler recently? If it was within the last three and a half years it will almost certainly be a condensing boiler. You can tell because the flue will produce a plume of visible steam when the boiler is lit. The more water vapour it can condense out of the flue gases the more efficient it is. The lower the temperature of the water returning from the radiators, the more flue gases it can condense. So in that case you want the water to be at as low a temperature as you can get away with.

However, the lower the temperature of your radiators, the longer it will take to warm up a cold house after the heating has been off. If it's set too low the house will refuse to warm up to comfortable levels at all. It's a trade-off between effectiveness versus efficiency.

As an aside: are there really any boilers which are more efficient at higher water temperatures? I've tried to find some hard evidence, but apart from a kind of word-of-mouth consensus I can only find evidence of the opposite, even for non-condensing boilers.

PS: Don't turn the temperature down too far on a non-condensing boiler. If moisture starts condensing in the exhaust it will eventually rot the insides of the boiler. They're not designed for it.

PPS: http://www.rmcotton.com/_mod_files/ce_images/compeff2.jpg

Cardew

mech wrote: »

As an aside: are there really any boilers which are more efficient at higher water temperatures? I've tried to find some hard evidence, but apart from a kind of word-of-mouth consensus I can only find evidence of the opposite, even for non-condensing boilers.

Interesting.

My non-condensing Ideal boiler can vary the temperature between 54C and 82C.
I had just this query as to which was the most efficient temperature many years ago(BI = Before Internet) I couldn't find the definitive answer at the time, and had no confidence in the BG fitters who clearly didn't know.

So I contacted the technical department of the manufacturer who were quite clear that there was a slight advantage by running it at max water temp.

Like you I can't find anything to confirm this on the net - it seems to 'major' on condensing boilers. However the SEDBUK site implies that higher temperatures were better for non-condensing boilers to prevent problems.

If the information Ideal gave me was wrong I will sue;)