Radiator postioning

[GraemeS]

Folks, looking for some advice, originally posted in plumbers forum, but I think that was the wrong Screwfix forum to post this question, so hopefully get a response here...

Downstairs bedroom.is 2.75m x 3.5mx 2.7m high

2 external wall (brick cavity with cavity wall insulation. One double glazed window 1150mm high x 1200mm wide

Radiator used to be at the door on left as you walked in, opposite the outside wall with no window (coldest wall). Room was always cold. Radiator was replaced with a larger one (800 wide x 600 high type 22) placed under the window so more into the room and to optimise space better.

Room is still not the warmest and one external wall (the one without the window) is still cold to the touch, noticeable more than the other external wall.

Radiator under window means when curtains are closed the heat often rises up behind curtains instead of room.

Looking at BTU calculator, it looks like we need around 3300 btu

We are about to completely redecorate the room so considering moving the radiator again. Where would the best place to locate the radiator.

Would on the wall where the radiator was originally be the best to get convection over to the colder wall opposite?

Tried to attach a layout of the room!for reference

Any advice gratefully appreciated

Cheers

 

[billysloke]

Under the window is conventional (and convectional) for good reason
Is the cold wall north facing? What's the situation like in the room above it?
Why not get a thermal blind to go in the window reveal?
Have you considered a booster fan for the radiator?
I don't think one typically expects to move the radiators around when redecorating..?

 

[MGW]

The text book show the thermal flow but today with double glazing and cavity wall insulation not so sure it works any more as the books say. But still the thermal flow means the thermostat needs to be in the flow.

I have two radiators in my living room, and I have been considering putting a second wall thermostat in that room as well as hall so the boiler runs longer. So I have an old damage TRV head which I have placed it where I think would be a good place for the wall thermostat.

So the three TRV heads at this moment show the first two are actually controlling the room, the last one is just so I can see the temperature at that point.

The one showing 18.3ºC is in the same room to the one showing 20ºC and 22ºC and there is the ability to correct the TRV heads so it shows the real temperature of the room.

Setting the radiators lock shield to ensure they do not over shoot is easy enough when you have an electronic TRV head, but setting with mechanical heads is not so easy, one has to be careful that the wall thermostat does not turn the boiler off before all rooms are warm, and setting the lock shield, TRV and wall thermostat in the same room to ensure the boiler turns off on warm days, but does not turn it off on cooler days takes some doing.

 

[Cris 11]

Have always found btu calculators to be under.
My theory is btu calc +20% seems to work.
If the rads too big you can always turn it down if it's too small your stuffed.
Probably not the most efficient but I dont care if it costs a couple of pounds more I just want the house to be warm.

 

[MGW]

Have always found btu calculators to be under.
My theory is btu calc +20% seems to work.
If the rads too big you can always turn it down if it's too small your stuffed.
Probably not the most efficient but I don't care if it costs a couple of pounds more I just want the house to be warm.

I agree with you, large radiators allow one to select which rooms are heated and when, without the boiler modulating or cycling.

 

[GraemeS]

I agree with you, large radiators allow one to select which rooms are heated and when, without the boiler modulating or cycling.

Yup agreed, I always use the calculators then take the next size or 2 up

Just need to decide where to put it... Current place or previous position

 

[MGW]

There two schools of thought.
1) Place so whole room is warmed as even as possible.
2) Place so cold areas of room can stay cool.
Pros and cons for both, 1) uses more energy, and 2) can leave areas around windows cool.

With my mother's house the morning sun could raise the area around the bay window to 32 degs, when other areas in same room down to 17 degs, clearly in that room to put a radiator in the bay window is wrong, it was placed 90 degs to bay window, and the bay window could get warmer or cooler to rest of room.

This house sun comes in much latter in the day, December it is some thing like 10:30 am before the sun gets over the hill, so it does not matter having radiators under the window.

The big mistake is to try and treat all homes the same. Seem likely your problem is balancing the radiators, I use the info given by the TRV to decide if crack open more or less. 4 out of 9 electronic TRV heads show target and current, so current should not exceed target, but always the exception as with mothers house.

 

[GraemeS]

Under the window is conventional (and convectional) for good reason
Is the cold wall north facing? What's the situation like in the room above it?
Why not get a thermal blind to go in the window reveal?
Have you considered a booster fan for the radiator?
I don't think one typically expects to move the radiators around when redecorating..?

Sorry been out a bit and now coming back to this.

Room is southwest-ish facing, recently realised that the roof space that takes up about half the space above it wasn't insulated (it is now!!) I also noticed whilst insulating that roof space that the cavity wall insulation, doesn't fill the cavity that well ( I can see into the cavity from that roof space)

Radiator was originally moved from the wall facing the colder wall, to under window, as the room was colder, just wondering if we should now move it back to there again ..

And yes if it stays at the window, will be removing curtains and changing the blinds

Not sure the 'design authority' aka wife will think window looks right without 'dressed' by curtains right enough....