Radiator placement - where is the best position?

playaz

I am having central heating installed in my home later this month, my lounge has bay windows (double glazed) and I am trying to work out where I should place the radiators for the optimum effect to keep the room warm (especially during the cold winter months).

I am getting conflicting information from people - some are saying I should place the radiators directly under the windows and some others are saying the radiators should be as far away from the windows as possible (as the windows produce the coldest air).

Can someone (ideally someone in the trade) clarify this for me, I live in an old 1930's house (solid wall rather than cavity) and would like to find the optimum solution for placing the radiators.

P.S If a bay window radiator is best... do I need a particular type of bay window radiator (curved obviously)

Thanks in advance

katipip

I'm not in the trade - just a female with commonsense who would like to point out the following:-

Many of us use curtains which are much longer than the window - if you are likely to do this then the curtains will cover the radiator and prevent the warmth from getting to the rest of the room.

Also have you planned what furniture will sit in the bay. A large armchair is equally likely to block the heat from getting to the rest of the room.

Plan ahead and envisage where your furniture will be.

DandelionPatrol

playaz wrote: »

and some others are saying the radiators should be as far away from the windows as possible (as the windows produce the coldest air).

The radiators should be closest to the windows precisely because the windows produce the coldest air. Putting the rads furthest away from the windows is about the daftest idea because it guarantees that the hot air from the rads goes up and across to the windows and brings cold air back to the rads across your feet. Hot head and cold feet is about the worst.

As for curtains and bay windows, either you select radiators and curtains not to interfere with each other or you put double or triple radiators either side of the bay.

manda1205

When we had ours fitted the fitter suggested not putting them under windows. We decided not to and chose places that suited the room, eg, where we didn't want to put furniture. We have thick, lined curtains and they do a very good job of keeping the cold from coming off the windows, although our windows are not that old and even in the middle of winter don't seem to feel cold. If I had the choice again I wouldn't put them under windows.

pendragon_arther

manda1205 wrote: »

When we had ours fitted the fitter suggested not putting them under windows. We decided not to and chose places that suited the room, eg, where we didn't want to put furniture. We have thick, lined curtains and they do a very good job of keeping the cold from coming off the windows, although our windows are not that old and even in the middle of winter don't seem to feel cold. If I had the choice again I wouldn't put them under windows.

Our plumbers did exactly the same. They said in the old days rads were always placed below windows but the best place is actually away from them. With double glazing nowadays cold air doesn't come from them.

lstar337

Putting them under windows is old fashioned advice.

If you have leakey old windows then putting rads under them creates a nice convection current.

If you have good quality DG that doesn't leak air, then you should put your rads on an internal wall to save the amount of heat lost to the outside world.

I live in a new build (EPC A Rated) and all of our rads are on internal walls.

DandelionPatrol

lstar337 wrote: »

Putting them under windows is old fashioned advice.

If you have leakey old windows then putting rads under them creates a nice convection current.

If you have good quality DG that doesn't leak air, then you should put your rads on an internal wall to save the amount of heat lost to the outside world.

I live in a new build (EPC A Rated) and all of our rads are on internal walls.

It is certainly not old fashioned advice - it is advice which is as valid as ever particularly for older houses. In EPC A rated, putting the rads on inside walls may be satisfactory because there is not much temperature gradient to get a convection current flowing.

But your argument that you should put your rads on an internal wall to save the amount of heat lost to the outside world is false. In the final analysis, all rads ever do is feed losses to the outside world. If you put the rads on the inside wall, then there is a temperature gradient to the outside wall and a circulating convection current, with the cold flow from the window to the rad across your feet and a hot flow from the rad to the window across your head.

If you do not want to be in that convection flow, do not put yourself between the rads and the outside wall. put the rads between you and the outside wall.

macman

Windows don't 'produce cold air'. Single glazed windows produce cold spots because the heat loss is greater than through a masonry wall, and because they're probably draughty too, if old and poorly fitting. A modern double glazed unit will leak far less heat.

psychic_teabag

DandelionPatrol wrote: »

But your argument that you should put your rads on an internal wall to save the amount of heat lost to the outside world is false. In the final analysis, all rads ever do is feed losses to the outside world.

The wall immediately behind a radiator is noticably warmer than the ambient air temperature, unless you have foil or some sort of barrier. Surely that patch is going to conduct more heat to the other side than the other bits of wall. So if it's an external wall, net heat loss increases ? Heat flow being proportional to temperature gradient, etc.

DTDfanBoy

DandelionPatrol wrote: »

The radiators should be closest to the windows precisely because the windows produce the coldest air. Putting the rads furthest away from the windows is about the daftest idea because it guarantees that the hot air from the rads goes up and across to the windows and brings cold air back to the rads across your feet. Hot head and cold feet is about the worst.

Your reasoning is flawed, unless the OP has some hideously old heavily leaking double glazing their windows will be more energy efficient than their external walls

The cooler the external walls the slower they will loose heat to outside, so there should be smaller losses with the radiator situated on an internal wall.

DandelionPatrol

DTDfanBoy wrote: »

Your reasoning is flawed, unless the OP has some hideously old heavily leaking double glazing their windows will be more energy efficient than their external walls

The flaw in what you are saying her is that the argument is actually between inside wall and outside wall inclusive of windows. Assuming that the room on the other side of an internal room is similarly heated, there are no steady state losses though internal walls.

The relative losses of external wall and window have no bearing whatsoever on the choice of internal wall vs external wall or window. They only come into play if the choice is between placing radiators on plain internal wall or under widows.