where best to put radiator - on internal wall, or under window?

Where is the best place to position radiators. I have always maintained it is on internal walls, because then the heat energy actually heats the air in the room before going out of the window, and you don't throw half of it out of the window before it does any good.

Am I right?

And does the correct answer change depending on climate?

Cheers,

John

Reply to
John Nagelson
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The slightly counter-intuitive theory is that it's better under the window. Otherwise you tend to get a much greater temperature gradient across the room - around the rad will be nice and cosy, by the window will be icy.

Cheers!

Martin

Reply to
Martin Pentreath

I've heard it said that the rad under the window stops the draft... Well if you tuck the curtains in behind the rad maybe it does.

Reply to
Mogga

My windows don't have a noticeable draught from the outside (I live in Lapland, so if they did, I'd be in trouble for most of the year), so I guess this refers to the downdraught caused by convection, with the cold air from above being sucked down and heated up, rather than just whizzing across the floor, still being cold before it reaches a radiator on the internal wall. But I've never been convinced by this argument, because if you position radiators on internal walls you can afford to turn them up higher and leave them on longer purely because you are not chucking a large proportion of their heat straight out of the window (or up behind the curtains). There is usually a fair amount of air circulation in a room, people are opening and closing doors, moving about, etc., so it's not as if all the warm air concentrates by the ceiling to let the downdraught at the window and external wall have its dastardly way with everyone's feet. Also the internal walls act as storage heaters during the night.

Other people's experiences may differ, but I have always noticed a big difference with coal and wood fires too, according to whether their chimneys are on internal walls or external ones, with rooms heating up much better (faster and warmer - I can't say I've noticed much difference in terms of gradients) in the former case.

John

Reply to
John Nagelson

I would think that with double glazing the effect is much less of an issue than without, too... I daresay that if all windows had been double glazed when central heating first came along, the habit of positioning radiators in this way would never have happened.

David

Reply to
Lobster

|!Martin Pentreath wrote: |!> On 1 May, 22:43, John Nagelson wrote: |!>> Where is the best place to position radiators. I have always |!>> maintained it is on internal walls, because then the heat energy |!>> actually heats the air in the room before going out of the window, and |!>> you don't throw half of it out of the window before it does any good. |!>>

|!>> Am I right? |!>>

|!>> And does the correct answer change depending on climate? |!>>

|!>> Cheers, |!>>

|!>> John |!> |!> The slightly counter-intuitive theory is that it's better under the |!> window. Otherwise you tend to get a much greater temperature gradient |!> across the room - around the rad will be nice and cosy, by the window |!> will be icy. |! |!I would think that with double glazing the effect is much less of an |!issue than without, too... I daresay that if all windows had been double |!glazed when central heating first came along, the habit of positioning |!radiators in this way would never have happened.

Also in the bad old days, walls would also not be insulated as they are now, so IMO it is still worth putting radiators under windows because they still let more heat out of the room than any other common feature, causing draughts.

Reply to
Dave Fawthrop

window, and

gradient

positioning

Often siting under windows is the only realistic way of keeping enough wall uncluttered for furniture in a small room, so there are other considerations than just the heat loss.

AWEM

Reply to
Andrew Mawson

I am sure I read you get better air circulation effect, thus better room heating with a radiator positioned under a window, which is why its done. I have a faint memory that if against a wall the hot air just rises up the wall to the ceiling where as under a window the hot air disperses into the room more.

Reply to
Ian_m

They do, but the heat energy in the room comes from the radiator, so you might as well let it heat the house before it goes out of the window, which it will do anyway (second law of thermodynamics).

One thing you can say about putting radiators under windows is that they heat the air outside the windows better. Perhaps there is an argument that this is a desirable thing in cold climates such as where I live (where every winter there are some days when it's minus 30)? Maybe it means less condensation or chance of windows icing up? (I doubt this very strongly, but it's what some local people say who favour putting radiators under windows. In England, the usual argument from non-engineers has to do with memories of single-glazed poor- quality windows, I think, before most people had central heating at all. It is odd really, because most chimneys aren't near outside walls).

I have been in older houses with curved radiators under bay windows (!) that simply don't heat the rooms at all, even if they themselves are handburningly hot to the touch.

John

Reply to
John Nagelson

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Reply to
John Stumbles

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