Switching off radiators…or not?

QrizB

DVN999 said:

We have a 4 bed, Edwardian semi with a gas combi-boiler and Selus smart thermostat. The thermostat is located in the handheld control unit and we keep it in our toddler’s bedroom, as that is our only ‘critical’ room to ensure temp in. 

My question, with our current setup, is: is it worth switching off the radiators in rarely visited rooms (guest bedroom, office) or does it make little difference?

Personally, I'd turn the TRVs in the rarely used rooms down to 1 or "frost".

Also, it's almost May. Unless your toddler is particularly vulnerable, can you turn the CH off completely and leave it off until at least October?

Ultrasonic

I don't suppose I've ever had a situation where all my TRVs were completely 'off' but I'd thought what would happen in that situation would be that the water would keep circulating but obviously lose little heat, leading to the boiler switching off fairly quickly?

I don't have a fixed thermostat so there is no obvious single room to have a radiator without a TRV in it. I understand the logic with a fixed thermostat though, and setting a TRV to max in a room where a movable thermostat is place probably makes sense.

Reed_Richards

QrizB said:

Also, it's almost May. Unless your toddler is particularly vulnerable, can you turn the CH off completely and leave it off until at least October?

N. Hampshire must be a lot warmer than here in the north of England.  My smart thermostat maintains a weather report (presumably taking data from a nearby weather station).  In the last 30 days the maximum reported temperature was 16 C and the minimum was about 1 C.  It is 10 C outside at the moment and would be much the same inside if I turned the heating off.

And if you have thermostatic control there should be no need or reason to turn the heating off.   

k_man

Reed_Richards said:

QrizB said:

Also, it's almost May. Unless your toddler is particularly vulnerable, can you turn the CH off completely and leave it off until at least October?

N. Hampshire must be a lot warmer than here in the north of England.  My smart thermostat maintains a weather report (presumably taking data from a nearby weather station).  In the last 30 days the maximum reported temperature was 16 C and the minimum was about 1 C.  It is 10 C outside at the moment and would be much the same inside if I turned the heating off.   

I was just about to post something similar.
A big proportion of the UK is barely into double figures today.

Zandoni

Ultrasonic said:

I don't suppose I've ever had a situation where all my TRVs were completely 'off' but I'd thought what would happen in that situation would be that the water would keep circulating but obviously lose little heat, leading to the boiler switching off fairly quickly?

I don't have a fixed thermostat so there is no obvious single room to have a radiator without a TRV in it. I understand the logic with a fixed thermostat though, and setting a TRV to max in a room where a movable thermostat is place probably makes sense.

It wouldn't be dangerous it would just mean that your boiler will be constantly coming on heating a small amount of water.

Olinda99

In simple terms, if you turn a radiator off then the circulating radiator water will cool down more slowly.

Thus the boiler will fire less often to heat it back up again and you will save gas / money.

BUFF

Kim1965 said:

BUFF said:

I wouldn't turn them off personally but if you have TRVs on the rads turn them down to 2 or even 1 (or inbetween). You will save a liitle energy, minimise chance for mould etc. 

The roomstat (& programmer) will detemine whether the boiler runs or not but it's wrong to say that the no. of radiators being powered doesn't matter. If e.g. 1/2 your radiators aren't in use then less water will be circulating through your boiler & it will have a minimum output which it can turn itself down to. This means that if the boiler's minimum output is higher than the system can emit it may start to overheat, shut itself down for a period to cool then restart & do this repeatedly "cycling" - this is inefficient & not great for boiler/system life.

N.B. if you have a TRV on the rad in your child's room set that to it's max setting & let the Salus mobile unit have full control (if you have the TRV set to close at lower temp than the Salus is set to your boiler could still be running & pumping heated water around the rest of the system when you don't need it to).

Disagree with this. 
If your boiler is modern (less than 15 yrs old) its min gas rate could be 4 kw, equivalent to 4 medium rads. All modern gas boilers have modulating gas valves/ condensing boilers have modulating fans their speed controls tge imput of gas on "forced draft boiler". It wont overheat. 

You are assuming that the boiler was properly sized in the first place - in the UK very many are oversized (especially on a combi to get the dhw demand flow rate).
Whilst the latest boilers may do 1:10 modulation or even more older ones may not (1:5 may be more typical) & we don't know how old the op's boiler is.
Also, we don't know for sure how many rads (but at least 2) the op is talking about shutting down e.g. I have a 3-bed Edwardian house with 7 rads but only 2 would be deemed "essential" to keep on.

OK, it doesn't overheat but the flow temp. in the system reaches a higher level than the set flow temp. & the boiler turns the burner off. 

BUFF

Ultrasonic said:

I don't have a fixed thermostat so there is no obvious single room to have a radiator without a TRV in it. I understand the logic with a fixed thermostat though, and setting a TRV to max in a room where a movable thermostat is place probably makes sense.

If you don't have a roomstat (but only TRVs on rads) I strongly recommend that you get 1. It will save you energy.

Ultrasonic

BUFF said:

Ultrasonic said:

I don't have a fixed thermostat so there is no obvious single room to have a radiator without a TRV in it. I understand the logic with a fixed thermostat though, and setting a TRV to max in a room where a movable thermostat is place probably makes sense.

If you don't have a roomstat (but only TRVs on rads) I strongly recommend that you get 1. It will save you energy.

I do have a thermostat, it's just wireless and I can place it in any room I want. What I said was I don't have a 'fixed thermostat'  .

BUFF

Ultrasonic said:

BUFF said:

Ultrasonic said:

I don't have a fixed thermostat so there is no obvious single room to have a radiator without a TRV in it. I understand the logic with a fixed thermostat though, and setting a TRV to max in a room where a movable thermostat is place probably makes sense.

If you don't have a roomstat (but only TRVs on rads) I strongly recommend that you get 1. It will save you energy.

I do have a thermostat, it's just wireless and I can place it in any room I want. What I said was I don't have a 'fixed thermostat'  .

The thought had occurred but I was just checking.