Heating engineer advice? Most cost efficient temp to set boiler for central heating?

TomsMom

I'm hoping that a heating engineer may be able to help me.

I have a Vallaint Ecotec boiler with separate controls for temperature of water for heating and hot water.

The water for the central heating I put at 42 - 50 degrees depending on how cold it is.

I keep the temperature for the hot water at 45 degrees.

I've got this thread running over at Gas & Electricity and a couple of the replies have got me wondering whether the temperature of the water for the heating should be higher.

I don't particularly want to heat my house any warmer than it is but I'm thinking my bills are quite high compared to some people.

Is it more cost efficient to set the temperature of the water for the heating higher (and possibly lower the setting on the TRVs)?

HappyMJ

It'll heat up the house much quicker if you set the temperature higher. Mine is set at maximum and doesn't take very long to heat up from very cold.....last week it took 2 hours to heat to 16 degrees from a very chilly internal temperature of 4 degrees (I was away for a few days and turned the boiler off)...the usual temperature rise is 1 degree every 10 minutes....but it's not a very efficient setting for a condensing boiler.

Changing the TRV setting down will save money as the room won't get quite as warm....it won't change the temperature of the water though. Set it as low as you can and turn it up to a reasonable setting when required.

jayyar66

A house will require a given amount of energy (or fuel) to heat it up to a given temperature. If you set the boiler temp lower then yes it uses less fuel, because it's heating the water to a lower temp but it then takes longer to heat the house to the required temp. If the boiler temp is set higher, it uses more fuel but it will heat the house to the same required temp more quickly. The overall amount of fuel used in either scenario is, pretty much, the same.
As HappyMJ has said, reducing the temps on your thermostatic rad valves, or your room 'stat will save you money because the boiler will use less fuel as it doesn't have to heat the house as much.
As has also been said, a condensing boiler needs a relatively low return water temp to work at full efficiency anyway.
Hope this helps

TomsMom

Oh dear, I'm getting confused now, sorry .

The heating comes on about an hour before I get up and the temp is comfortable enough. The TRVs are obviously doing their job well as the rads come on and go off keeping the temp stable.

The temp on the dial goes from 30 to 75 degrees, so if I increase from 50 to 60 would that make any difference and would I turn down the setting on the TRV to maintain the temp as it is now or keep on the same setting?

jbainbridge

You should be heating your water to 60 or above ... otherwise you might have problems with bacteria.

TomsMom

jbainbridge wrote: »

You should be heating your water to 60 or above ... otherwise you might have problems with bacteria.

OK, I understand that thank you . Are you talking about the hot water for washing up, etc., only or both the washing up and the central heating.

jbainbridge

Oops ... is it a combi? If so you can ignore me.

I'm talking about a water tank.

TomsMom

jbainbridge wrote: »

Oops ... is it a combi? If so you can ignore me.

I'm talking about a water tank.

:rotfl: Makes me feel better that I'm not the only one who's getting confused (yes, it is a combi ).

Norman_Castle

TomsMom wrote: »

The temp on the dial goes from 30 to 75 degrees, so if I increase from 50 to 60 would that make any difference and would I turn down the setting on the TRV to maintain the temp as it is now or keep on the same setting?

Keep the same setting. TRVs are an on/off switch. When they reach the chosen temp they switch that radiator off. With higher boiler temp they will switch off sooner but not hotter.

ValHaller

Norman_Castle wrote: »

Keep the same setting. TRVs are an on/off switch. When they reach the chosen temp they switch that radiator off. With higher boiler temp they will switch off sooner but not hotter.

Actually, TRVs are not an on-off switch. It is not all or nothing - they can modulate flow between 0% and 100% according to temperature.

OP, as you have TRVs, I suggest just running the boiler at maximum temperature. The TRVs will do the rest - as the rooms heat up, the TRVs will cut the flow quite substantially and the return water temperature will be quite low, which as already stated is helpful to run a condensing boiler at a low temperature.

TomsMom

Norman_Castle wrote: »

Keep the same setting. TRVs are an on/off switch. When they reach the chosen temp they switch that radiator off. With higher boiler temp they will switch off sooner but not hotter.

Thanks. So am I right in thinking that having the water set at 60 then the rads reach the right temp quicker but it's not going to be more cost efficient and the cost will be the same?