Double radiators - more expensive to run ?

[swayzak]

hi

I've just upgraded several of my singles to doubles - kick out a lot more heat & now nice and snug

However, it has occurred to me that these may be a bigger draw on the boiler & therefore more expensive to run.

Is this the case or are they just a more efficient use of the heating system ?

thanks

 

[Diyisfun]

They give out more heat (and you cant get something for nothing) so they cost more to run.

The reason for doubles is to give a high output for taking up less wall space.

If you put a long single in a room as against a small double (both with the same btu rating). The net result would be the same.

 

[swayzak]

They give out more heat (and you cant get something for nothing) so they cost more to run.

The reason for doubles is to give a high output for taking up less wall space.

If you put a long single in a room as against a small double (both with the same btu rating). The net result would be the same.

Thanks - better keep an eye on that heating bill then !

One more thing - the double that was installed in the hall (near front door) was not fitted with thermostatic valve (the others were).

The main thermostat is also situated in the hall.

Was this an oversight by the plumber or could there be reason for this ?

 

[bonnieg]

I'm no expert, but I believe this is fairly standard. When we had our central heating re-done five years ago, the plumber said they always leave one radiator without a thermostatic valve, so that if the heating's on, the hot water has somewhere to go and circulate - so if the heating's one, we can't turn off our hallway radiator. We've recently had another fitted on the upstairs landing and that's the same.

I think they make it the hall/landing one(s) as you don't really spend time in those "rooms" so it's less important to be able to control the temperature of them.

 

[Diyisfun]

Yes, but the hall rad is the rad that is controling the whole heating system.

 

[D_Hailsham]

One more thing - the double that was installed in the hall (near front door) was not fitted with thermostatic valve (the others were).

The main thermostat is also situated in the hall.

Was this an oversight by the plumber or could there be reason for this ?

It is correct. If you have a thermostatic valve on a radiator near the main thermostat then either the main stat or the TRV will be in charge.

The purpose of the main stat is to turn of the boiler when the house is up to temperature; without it the boiler would continue to run, even if all TRVs have reached temperature, until the boiler's own thermostat shuts off.
If there was a TRV on the hall rad and it was set to a lower temperature that the wall stat, the wall stat would never reach temperature; so the boiler would never turn off.
On the other hand, if the TRV is set to a higher temperature than the wall stat, the TRV will never operate as the wall stat will turn the boiler of first.

 

[tryitandsee]

However, it has occurred to me that these may be a bigger draw on the boiler & therefore more expensive to run.

Thinking about what has been said, in an ideal environment ie 100% insulated house, by increasing the size of your rads would mean the rooms get to the required temperature faster, thereby shutting down the boiler in less time than with the smaller rads. Therefore no savings in fuel but equal cost.

Or have I got that totally wrong (again).

 

[swayzak]

One more thing - the double that was installed in the hall (near front door) was not fitted with thermostatic valve (the others were).

The main thermostat is also situated in the hall.

Was this an oversight by the plumber or could there be reason for this ?

It is correct. If you have a thermostatic valve on a radiator near the main thermostat then either the main stat or the TRV will be in charge.

The purpose of the main stat is to turn of the boiler when the house is up to temperature; without it the boiler would continue to run, even if all TRVs have reached temperature, until the boiler's own thermostat shuts off.
If there was a TRV on the hall rad and it was set to a lower temperature that the wall stat, the wall stat would never reach temperature; so the boiler would never turn off.
On the other hand, if the TRV is set to a higher temperature than the wall stat, the TRV will never operate as the wall stat will turn the boiler of first.

That makes sense - thanks !

 

[D_Hailsham]

in an ideal environment ie 100% insulated house, by increasing the size of your rads would mean the rooms get to the required temperature faster, thereby shutting down the boiler in less time than with the smaller rads. Therefore no savings in fuel but equal cost.

If a house was 100% insulated, i.e no heat loss at all, then, once the house was up to temperature you would never need any more heat!

Unfortunately that's just impossible to achieve as people are going in and out, so warm air leaves and colder air enters the house.

Another advantage of over-sizing radiators is that condensing boilers can be run at lower temperatures, so they will be in condensing mode more often.