Can I 'stack' radiators?

[iep]

I need a lot of BTUs in an area with limitted wall space for radiators. If I installed two 700x600mm (wxh) double radiators with one mounted immediately above the other (effetcively creating a 700x1200mm double), would this cause any issues?

iep

 

[JMLanders]

A lot of BTU's indicates a large volume of room and/or poor insulation, in which case having a heat source in only one part of the room may not be the most efficient nor effective convection current design.

 

[iep]

Hi JMLanders. Agreed, but the space I'm trying to work with is very awkward and this may be the only feasible means of getting heat in there.

The space I am trying to heat is the loft extension in our bungalow. It is not a proper room (by buildings standards) because it can only be accessed by a ladder from the hallway below. However, the ladder is permanently installed and the loft hatch is permanently open (and is very large at 2m x 2m). The hatch allows light to flood down into the hallway from the velux windows above and was made large so that heat would naturally rise from the hallway up into the loft (so says the architect who did the renovation in 1978).

There are no vertical walls in the loft extension so radiators cannot be installed up there. It is a very large room though (5x10m at the floor) and gets very cold in winter.

My idea is to install the two double pannel radiators downstairs behind the ladder (which sits at quite a shallow angle so lots of space behind it). The convected heat should then rise up into the loft space and hopefully take the chill off in winter.

Obviously, it would be better to add insulation to the loft extension but this is not possible wihtout removiong all the plasterwork etc and we can't affor this in the near future.

iep

 

[D_Hailsham]

It might work, but in a room that big with the heat coming up through an opening in the floor - presumably somewhere in the middle - there will be a wide temperature difference over the room. It would be better to have two or more (preferably four) radiators in the room if you can.

You can often get floor standing brackets for radiators (see Stelrad Elite Catalogue page 6).

Is your heating system open vented (small tank in loft) or sealed?

If it is sealed there's no problem; but if it's open vented the small tank will have to be raised so it is higher than the radiators.

 

[iep]

Thanks D_Hailsham, useful info. As it happens, it is an open vent system so that would further complicate the addition of radiators in the upstairs space.

We may well be looking at a new boiler soon so I guess I could convert to a sealed system but TBH, I was hoping to make minimal changes.

Additionally, the celing slopes all the way down to the floor so even small radiators would stand proud of the walls by quite a large distance.

I think we might have to take the hit in terms of the temp difference over the room and see how it goes. With an unusual house like ours (it's a whacky 1970's revamp of a 1741 cottage) you do have to make compromises.

Purely from a technical standpoint though, I'm guessing I should get roughly a doubling in BTUs by stacking the radiators and hopefully a good increase in convected output?

Either way, it has to be better than what we have at the moment which is one single 600x600mm radiator at the other end of the hallway.

Cheers,

ip

 

[JMLanders]

In terms of medium term cost effectiveness, would one or two cheap fan heaters do the job?

 

[iep]

That is what we are doing at the moment. When we are up there, we heat the space with the fan heater(s).

However, we need to heat the space a bit even when we are not up there as, in the winter, it becomes a massive heat sink for the hallway and bedrooms (which are directly below).

Basically, we need to put enough radiators in that half of the house to heat the whole space including the loft. I'm just trying to work out the most practical way of doing that.

Cheers,

iep

 

[D_Hailsham]

Many boilers can be converted to sealed system, so it would not be wasted when you come to install a new boiler.

You suggested two 600x700 double rads, which is a total of about 2,500 Watts. This does not sound much for a room which is 5m x 10m. How did you calculate the requirement?

Why not use 300mm high rads? They will have to be longer, which will give better heat distribution, but they will not stick out into the room so much. You could even install skirting radiators.

I don't think you will get a doubling of output by stacking two rads. Have you thought about a vertical radiator? It would look better.

 

[JMLanders]

Is there any way in which you could install some transparent cover - maybe made up from twin or triple wall polycarbonate sheet?

It sounds like one curious design by the architect

 

[iep]

The room has a large floorplan but is only 2m tall in the middle and has approx 45 degree sloping ceiling down ot the floor. A a result, it has considerably less than half the volume of a 'normal' 5x10m room with a normal 2.5m height ceiling.

Given this, 2.5kW is actually about right.

Any 'topping up' can be done with a fan heater when we are up there but simply raising the room temp from 8 degrees (as it was last winter) will hopefully make a huge difference to the temperature of the hallway and rooms below.

I've looked at a few vertical radiators but these seem ot mainly be designer radiators which are optimised for aesthetics over thermal efficiency (and are usually 3 x the price). For example, one 600x700mm double rad can achieve about 4000btu while the 450x 1800 designer rad I looked at only had 3500btu. Even if the stacked standard radiators only combined to 6000btus they would still be nearly double that of the designer unit (and less than half the price in this instance).

If you know of any suppliers of good vertical radiators though I'd be keen to have a look.

Cheers,

iep

iep

 

[iep]

JMLanders, thanks for the suggestion but we use the room as a second living room and an office for my wife's business so we are keen to avoid adding a cover or hatch as we go up and down the ladder countless times each day.

Yes, it is a very unusual design but it's an unusual shape of house so I guess the architect simply did what he could. It's actually a very succesful layout (in terms of making the most of the space), we just nee dot work out how to heat it.

ip

 

[JMLanders]

Have you considered stacking radiators one above the other........

 

[ColJack]

stupid question from a sparky, but do rads HAVE to be vertical?
can't they be mounted on a sloped roof?
presumably it will affect the water flow a little bit but the heat would still rise.

 

[iep]

There's no reason why it wouldn't function that way but there are two difficulties I would think of:

1. Convection would be reduced a little (affecting kW output).

2. The mounting brackets would probably fail. The way they are made means that they can handle a lot of weight provided it is applied at 90 degrees to the bracket's mounting screws. Mounting at 45 degrees would mean half thweight would be applied in-line with the mounting screws. Neither the brackets or the screws would be able to handle this load.

Point 2 might be less of an issue with 30cm single rads but you would at least need the brackets to line up with the rafters (which would be unlikely) in order to be able to take the weight.

Having said that, I'm sure I could come up with a better bracket that would work (or just double up the existing brackets).

However, to do any of this, I would need to convert the system to a sealed one which I am keen to avoid if I can.

iep

 

[wilson121]

purmo do vertical panel rads in many sizes try here www.purmo.com
look for vertical type 21c