combi seems to heat house worse than old boiler

cheepskate_2

hi all

Looking for a bit of advice.

Maybe its just me but got a new combi boiler + all rads.
Before the old boiler took ages to heat up the house but seemed to keep it warmer longer. The upstairs was always nioce and hot due to the boiler room.

Since getting the new boiler and rads , they heat up near enough instantly , great heat out of them but when switched off the house seems to cool down quicker.

Is this just me or does a standard (non combi) boiler keep the heat in better.

ginvzt

Are you saying that the old boiler used to keep house warm after it is switched off?

If the boiler is off, it doesn't 'keep the house warm'. It is insulation of the house that doesn't let the heat to escape. Or am I missing something? Was it the hot water tank that used to loose heat and kept giving off some heat?

dander

Certainly a modern boiler is much better insulated and gives out virtually no heat itself, whereas older boilers used to get warmer - that's nothing to do with being a combi, that's just modern efficeincy standards. But that just means the heat is being sent out to the radiators more efficiently. If your old boiler was getting very hot, then you were still paying to produce that additional heat in the first place.

fred7777

Check the radiator temp setting on the new boiler. It could be that the newer boiler has been set to a lower radiator temp setting so although the new boiler warms up faster it's not getting as warm and so when it's shut down the rads get cold faster.

fred7777

One other thing, Combi's heat central heating or hot water but not both at the same time. When you switch on a hot tap the heat gets diverted from heating to water. So if all the family have baths or showers during the last 1/2 hour of the heating program the boiler won't be providing any heating and the radiators will be cooling down.

ukmike

Combi's heat central heating or hot water but not both at the same time.

Yes they do!

vaio

Conventional boilers used to give priority to DHW too

fred7777

Just to clarify in a Combi boiler priority is given to hot water so if your running the hot water in practice there won't be much heat left over for heating. Conventional boilers often have a hot water tank for hot water which is heated often at different times of the day so hot water demand doesn't necessarily take heat away from heating when the heating is in use.

gas4you

ukmike wrote: »

Yes they do!

No they don't!

gas4you

vaio wrote: »

Conventional boilers used to give priority to DHW too

Some did, depends what system you had fitted. If it had a proper diverter valve then it would be set up as you say.

googler

cheepskate wrote: »

Since getting the new boiler and rads , they heat up near enough instantly , great heat out of them but when switched off the house seems to cool down quicker.

Leave the boiler on all the time and regulate the rooms with the TRVs. We did this and saved a packet on our gas bill. Previously, we would run the heating in the morning, leave it off during the day, and back on in late afternoon/evening. Going on the theory that there's more energy expended in raising the house to temp from cold than in merely keeping it at the same temp, we left the boiler running 24/7. Result; lower gas bill.