radiators

[paradox]

This isnt an alternative energy but i thought i would let you all know and see if any one does the same?

I have wrapped corrugated cardboard in baking foil and stuck it behind my radiators so that when they are on the heat gets reflected back into the room instead of being soaked up by the wall and lost to the cold outside.

[Stonehead]

This isnt an alternative energy but i thought i would let you all know and see if any one does the same?

I have wrapped corrugated cardboard in baking foil and stuck it behind my radiators so that when they are on the heat gets reflected back into the room instead of being soaked up by the wall and lost to the cold outside.

You could also put a cover over the radiator or even just a shelf above it. The idea is to stop the heat rising directly to the ceiling and deflect the air flow into the room. But don't put anything on the shelf that would be damaged by heat.

[Muddypause]

I'm not too certain about these ideas. Despite their name, comparitively little of the heat from a radiator is given off by radiation - most of it is given off by convection - moving air currents. This means that interrupting the convection current (a shelf over the rad.) is going to be a bad thing - you want to encourage that convection, not hinder it.

Ideally, a rad. is positioned under a window, so that the cold air from the window moves down, and over the rad., and the upward convection happens further into the room. A similar effect may happen if it is on an un-windowed outside (cold) wall, but I can't say for certain. But I'm pretty sure that putting a shelf over it cannot be helpfull to the net result. But it could be interesting to see what happens if you hold a smoking spill in various places in the room to see how the air is moving.

The carboard behind the rad. will certainly add a little to the insulation of the wall, and should help, and I guess the foil will do something, too - but probably not as much as you would hope. But there is one more thing you can do to encourage radiation - paint the radiator matt black, particularly the surfaces facing into the room.

[baldowrie]

these days due to insulation and good double grazing it unnecessary to put rads under windows..flipping nuisance when they are positioned there any way

[red]

yeh its my personal bug bare about radiators.. I thnk internal walls are much better place.
we just bought this house and the radiators are all under the windows.. and there are window seats.. how's that going to work? and when you shut the curtains.. (left behind by previousownder thanks goodness cos neighbourhood may have been startled...)the radiators are shut between the lined curtain and window.. in one room - that was at least a foot behind the curtain. doh! - moved two so far, shortening curtains in other rooms...

[baldowrie]

my last house all the rads were in corners that furniture wouldn't fit, like behind doors etc. Made life a lot easier. Come to think of it so does my new house but the big old fashion cast iron rads, real ones not reproduction ones. Although some are not in the most convenient places

Modern houses no longer have drafts so with building regs more air vent have to be built into bath rooms and kitchen to prevent damp build up. So even with the good insulation and double glazing we still have not got the balance right between air flow and insulation.

[Muddypause]

You are right to say that insulation and double glazing will make a difference. I'm not sure how that latest type of DG (K-glass - reflects the heat back into the room) compares to masonary, but I reckon that the window will probably still be the coldest surface in the room.

The trouble with putting the radiator on an internal wall, particularly if the house has poorly insulated, or solid brick walls, is that you may end up with an uncomfortable temperature gradient in the room. That is to say, it will be warm in one part of the room, but towards the external wall it will get noticeably colder. The colder the weather, the more noticeable this will be.

You're right about a modern house being hermetically sealed - so much so that building regs now stipulate that there has to be some sort of built in ventilation, usually in the form of a trickle vent in the top of all the windows frames. Otherwise condensation becomes a problem. This degree of sealing has only been possible since we stopped using open fires, which depend upon a flow of air, and installed central heating boilers with balanced flues.