Moving radiators / rad naming conventions

[Colin Wilson]

I discovered today that SWMBO is really REALLY annoyed about the central heating we had put in, and she wants different rads in a new location...

The plumbing is in copper, so soldered joints shouldn't be a problem, and i'm guessing that it should just be a case of draining the system, altering the pipework to suit, refilling / draining / adding corrosion inhibitor (after checking for leaks), and Bob's your aunties live in lover.

Would this be about the size of it ? - how hard would this be for your average non-diy fanatic, given my grasp of the situation as above ? :-}

Also... naming conventions for rads - she wants them to go under windows with quite low sills, so they'd have to be 300mm rads I reckon. Can someone clarify how double rads are "measured" - ie. Screwfix have an item ref 32733, Double Radiator 300 x 1400mm - would this be 300mm tall

1400mm wide, or 300mm tall 700mm wide ?

ATM, i've got 500mm tall x 600mm wide double rads - i'm wondering how smaller rads might fare in their heat output in comparison...

TIA :-}

[Colin Wilson]

Haven't got got a tape measure to hand - they might be 600mm*700mm...

[Lurch]

On Sun, 6 Feb 2005 15:34:03 -0000, Colin Wilson strung together this:

Theoretically, yes!

Depends how your plumbing skills are, it is simple enough if you know how to do it, as is everything.

A double rad is two panels one in front of the other so a 300 x 1400 double rad would be like two single 300 x 1400 rads in front of each other.

Depends how much smaller, and what type you've got at the moment, and how old they are. Smaller, newer rads with fins will need to be about

30-40% ish smaller, (from memeory), to give the same output as an older non-finned rad.

[Colin Wilson]

I guessed the second measurement was the "width", but it was whether they combine both panels for this given width, or whether it is a "true" width, i.e. 300mm*1400mm being equivalent to 300mm*2800mm

If you know what I mean :-}

Oh, and I suck at most DIY things - especially plastering :-}

[Lurch]

On Sun, 6 Feb 2005 19:11:40 -0000, Colin Wilson strung together this:

Yes, I do now, sort of. Do you know what I mean? The double rad you saw in Screwfix will take up 300mm x 1400mm of wallspace.

Ah, not a good start then!

[Colin Wilson]

Yeah, I think we`re on the same wavelength, unless that`s the beer interfering with my head again :-}

Out of interest, would one of the full bore taps be usable in a CH environment ? I may need to alter another rad at some point in the future, and while its drained down, if I could fit a couple to the leg I have in mind (the bypass rad) it`d make re-doing the bathroom a lot easier (might need to move it depending on what type of bath we go for - normal or jacuzzi style depending on money at the time)

I`d offer pics, but I really don`t have the nerve :-}

[Lurch]

On Sun, 6 Feb 2005 20:55:05 -0000, Colin Wilson strung together this:

Yep, that'd be fine.

!

[Greg C]

The peculiar aesthetic requirements of the lay-dees aren't necessarily practical. She probably wants more room along the walls for furniture you are gonna have to pay for. And she thinks rads must go under windows because her dad said so. The old school insisted they should go there to heat the colder air whereas modern thinking says you loose too much heat through the wall.

Before you embark on an expensive project that may be out of your depth consider if it might be easier just to give her a slap.

Greg C

[Roger]

The message from Greg C contains these words:

So in your house the windows have a better U value than the walls. How odd!

[Set Square]

Did he say that? Walls have a better U value - but there's also usually a lot more wall area than window.

[Roger]

The message from "Set Square" contains these words:

So?

If you have a limited number of radiators why deliberately avoid putting them under the windows unless the walls really are less good insulators than the windows?

[Christian McArdle]

The reason to put them under windows is to counteract the excessive convection that can occur if you put them opposite, causing draughts (hot air rises above rad and falls by window). The reason not to put them under windows is that it overheats the least efficient part of the room and can prevent the efficient use of floor length curtains, which will shield the room from the radiators and ensure all the heat goes outside.

My house, luckily seems to have had a well thought out compromise. The rooms to the rear have rads under the windows. The front rooms, which have rather elegant bay windows, have radiators on the wall, as it is likely that the bays will benefit from floor length curtains that would not suit the sash single windows to the rear.

Christian.

[Andrew Gabriel]

The former

(Ignore the actual Watts figure which are calculated using unreasonable water temperatures -- just look at the percentage difference.)

500x600 double is 971W

300x600 double is 631W, 35% less 300x600 triple is 872W, 10% less

Obviously, triples stick out more, but this need not necessarily show with appropriate provision of a shelf above. I used 3 triple radiators when I designed my heating system a few years ago, which helped with the oversizing for efficient condensing boiler operation.

[Roger]

The message from "Christian McArdle" contains these words:

Now that appears to be moving the goalposts somewhat (see also below) but I would take issue with you about the desirability of not putting radiators under windows. It does however depend I suppose on what you want. Full length curtains over a radiator are indeed a waste of effort but when the curtains are not drawn the problem of a greater temperature gradient between the radiator(s) and the window(s) remain.

In heating terms the worst case scenario is the one many of us grew up with - a roaring fire in the fireplace and sub arctic outside walls. The best case scenario (if what you want is as little variation in room temperature as possible) is to have perimeter heating which matches the heat loss of each section of wall exactly. Personally I think perimeter heating is a PITA but I see putting the heating between the room and the least well insulated part of the perimeter as a reasonable compromise as it will give a smaller temperature gradient across the room than mounting the radiators on an outside wall where there isn't a window. Mounting a radiator on an inside wall makes even less sense.

However the remark I actually replied to is repeated below and it still seems to me to be saying that walls are less effective insulators than windows which we know is not the case today (and may well not ever have been but I can't be bothered to look up the U values of 9" brick vis a vis modern double glazing).