Optimum Height Of Window Radiator

[Usenet Nutter]

Prior to getting new windows in my Living Room on 11th Jan I am doing some prep work and am siting a new radiator below the window .I did try a 600 x 900 that I had for the other end of the LR but it was going to be too tall so I ordered a 500 x 1000 that arrived unscathed this morning ...well done to the Fed-Ex one man team who carried it on his shoulder up 2 flights of stairs ... The new windows includes a new hardwood sill so I don't want it to be above the rad but is there an optimum position for the height of the rad or is it just down to personal choice .I don't know what thickness the new sill will be but working on it being the same as the old one ..about 20cm...the top of the rad will be about 20 cm above the sill. Does that sound about right . That lets me get rid of the full length curtains that I have now and get ones down to the sill ( or slightly below) which will close with the rad in front of them .

[The Natural Philosopher]

why ever NOT?

Souds crap to me. You want it below the sill so that it still heats the room with curtians drawn, at least.

I dont follow this. If they are below the cill and the rad is above, then you are pumping heat into the windows, not the room.

[F]

Stelrad specify the *bottom* of the radiator 200mm above the floor for optimum effectiveness.

[Usenet Nutter]

Those should be 20mm not cm

[Usenet Nutter]

Well there's no way I can do that with this 500mm rad as that would make it look silly given the height of the bottom of the windows ...It's about 115mm in it's temp'y position and looks ok.....Having said that the other old rads I still have in use are about 8" above the floor

[Usenet Nutter]

Well you tell me .

>> but is there an optimum position for the height of the

Well there is a gap behind the rad between it and the sill but the above site suggests closing the curtains along the sill and not tucking them behind the rad as this restricts the air flow .

[Cicero]

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You're not actually bound by Stelrad's recommended optimum height which may be based on the height of older types of skirting boards. A radiator closer to the floor is not likely to suffer any serious loss of efficiency.

For what it's worth, I have a 400mm x 1500mm double at 6" above the floor under one window and it works very adequately although I have nothing to compare it with.

You might consider exchanging your radiator for a smaller (lower)and longer to fit the available space. I think a radiator above cill height will look a bit odd and it will still be close enough to the new cill to cause damage if that's what you're concerned about.

Cic.

[Usenet Nutter]

I can still drop it down a bit yet and that'll probably make it pretty much in line with the new sill . I did think of a 400 high rad but Screwfix don't list one and I had to consider the heat output as well The size of this rad is ok and the length is good as it works in well with where the joists are ( they are not immediately below the inlet/outlets )

[dennis]

The optimum height is zero. Its a real waste of energy to heat a window, even a double glazed one. You want floor to ceiling curtains to keep the heat in and then the radiator is covered. The alternative is a wide shelf and curtains down to the shelf, not something I like.

>

[Usenet Nutter]

When you say "zero" do you mean rad and sill should be same height ?

I'm confused by what you say ..why would you want to draw the curtains in front of the rad ...if that's what you are suggesting ?

A shelf over the rad is something that seems not to be recommended judging by what I read when I Googled for this although it also throws up as many differing opinions as days in the week....I guess you pays your money and takes your choice .

[TheScullster]

You don't say whether the rad is single or double! I have a 300 x 2000 double under a low window - this is comfortably more output than 500 x 1000 single. Curtain goes passed the sill and sits just above top of rad. Most heat comes into room that way. Enough height from ground to rad and from rad to sill!

Phil

[Andrew Gabriel]

If the clearance at the bottom (from the floor) or at the top (from a shelf) is less than the depth of the radiator (distance from the wall to the radiator front), the power output is reduced below that specified in the datasheet. That's not necessarily a problem, but it's something you may need to consider when sizing a radiator.

When fitting a radiator into an unfurnished room, remember to allow for the additional thickness of the floor covering.

[Usenet Nutter]

It's a double .

[Usenet Nutter]

That's a new piece of the jigsaw ...never seen that mentioned anywhere before . :-)

[Andrew Gabriel]

I think most manufacturers have something along these lines in their datasheets (or at least did 8 years ago when I was doing mine). Exactly how they specify the clearence varies.

[The Natural Philosopher]

half truths and ecobollox.

what you have to appreciate, is the difference between an inneficient radiator, which doesn't matter (much*) as long as its big enough, and heatloss to the outside of the house, which costs money.

That ecobopolox site is dumbed down to the point here it basically confuses them, and it also takes no account of second order effects.

• higher return temperatures due to inefficient rads ,may make boilders and pipework less efficient. Its genarally accepted that lots of luke warm water is easier to make efficiently than a little very hot water. Especially if you have a heat pump.

[The Natural Philosopher]

It is almost totally irrelevant frankly.

The main thing is not to convect you seriuously hot air off the rad straight past an ice cold window where it will lose more heat to the outside world. I.e. rads should never be placed under windows at all.

They used to be because leaky draughty windows produce massive downdraughts, and in the days when oil grew on trees, that meant more comfort and sod the cost.

[Usenet Nutter]

Yeah whatever !!! How about explaining in plain English what you reckon my problem is with what I asked .

[Alan Braggins]

Maybe he means the best radiator is underfloor heating, zero height above the floor? (Which would allow full length curtains.)

[Usenet Nutter]

Well hopefully he knows what he means ....anyway it helps me not at all