Help please - how to heat my conservatory?

[apg]

I'm new to this forum, but it seems to have a lot of very experienced people on it, so I'm really hoping someone can set me straight!

I currently have electric heating in my conservatory, which is v expensive to run, so I'm planning to put in radiators instead. The conservatory is 21ft wide (along the house wall) x 14ft deep. Apart from the house wall of course, the other sides have a 14inch wall.

A plumber has advised I need about 13000 BTU. (My boiler is a potterton profile 60e - 60,000 BTU I assume?, and currently the radiators in my house add up to about 35,000 BTU, so presumably no capacity problem).

So - do I go for :
- the cheaper option of one big rad on the house wall (but will this just heat the roof, and give a big cold zone around the windows?)

- mini-rads, e.g. stelrad loline (144mm high) around part of the dwarf wall - I reckon 6 x 1.2m rads (but lots of exposed pipes to link it all up)

- skirting heating - which I can run all the way round the room (e.g., from googling, climaboard or variotherm), but which has lower heat ouput per metre and anyway I can't seem to find people who actually sell the stuff. Is it any good? Does long lengths of gentle heating (around 1000 BTU per metre) work better than one big rad because it is under the windows, or does it work less well because it is less concentrated?

I'm confused, and don't know which way to go - any advice would be very welcome!

 

[tryitandsee]

I think this one has been well discussed. It seems that you are 'on a hiding for nothing' (? right expression) trying to heat a conservatory. The insulation factor is not good with all that glass, especially if you have a glass roof (even if being all double glazed).

I have two dwarf electric dimplex heaters under the windows, timed and with thermostats and a large double radiator plumbed into the house central heating circuit with a thermostatic valve (so it can be shut off independently from the house.

The long winded point I'm trying to make is, the cost of building the thing in the first place was probably cheaper than a more traditional extension, therefore the money saved has to go on heating the thing.

It's a room in our household that is used all of the time and I must admit it gets a bit chilly in there on cold winter nights. Then out comes the blow heater Then watch the meter spin

 

[tryitandsee]

I forgot to mention, because I choose to ignore what building regulations comes up with, but I think somewhere it says that you are not allowed to heat conservatories with the main house circuit (ie central heating) due to the heat loss, hence the requirement to keep the external doors from the house into the conservatory.

 

[apg]

thanks - we use ours as a day-room as well (well, more a play-room for the kids). I wasn't aware of the building regs thing - like you, this isn't my primary concern though!
Heating it is never going to be cheap, be it electric or gas CH. At the moment I have two 2kw heaters in there. With gas costing maybe 25% the cost of electric though (?), I reckon if it costs me £1000 to put in rads it will pay back in under 5 years.

 

[Terrywookfit]

I have acheived good results by using a combination of a radiator and a Myson Lo line fan convector on a separate zone from the house!!

Not a quick fix but very effective!!

I find that many customers are happy to spend a fortune on a conservatory and blinds yet scrimp when it comes to heating!!

 

[Bahco]

I find a double 1200 x 600 does the job adequately in my 6m x 3m conservatory.

 

[tryitandsee]

Yes gas central heating is the best option, cost wise. I found that the pipework, to get under the windows, was going to be a problem, in that it would have run along the external walls, skirting height, french doors etc. getting in the way. Aesthetically, it wouldn't have looked that good.

 

[simond]

I suggest you look at www.smiths-env.com.

They make a range of heaters eg: Stirling wall hung for conservatories that have a low water heat exchanger and low speed fan assisted convection.

This is the product we usually recommend, and you can turn the fan on and off, so it is not wasting much heat.

 

[apg]

Thanks all - plenty of food for thought! These fan-assisted radiators seem like an interesting option - I'd never heard of them before.

I don't see how to control them though if I want to use a programmable wall thermostat, as there are now 2 seperate things to control, the control valve for the central heating (I definitely want the conservatory on a seperate circuit from the rest of the house), and the fan. Surely I'd need a wall-mounted controller that can control both (either both on or both off, with the option of a manual over-ride of fan only in the summer).

 

[Terrywookfit]

Fan convectors have their own thermostat and also one to stop the fan if the heating is off!!
A summer air recirculation switch is provided!
Your programmable stat should be used to control the conservatory zone!!

 

[Gasguru]

How about high level infra red ceramic heaters.

 

[apg]

Thanks guys - I've decided to go for rads on the house wall, but to add a fan in the conservatory roof, linked to a thermostat - so when the roof space gets warm, the fan comes on. That way, as the rad heats up the wall and top of the conservatory, the fan will recirculate the hot air. And in the summer, the fan will keep the air moving!

Given the size of the rad I need (about 13kBTU), I'm not sure about my boiler capacity(despite my earlier confidence!).
The boiler is a Potterton Profile 60e (presumably 60kBTU).
The rest of the rads in the house total about 35kBTU.
But how much do I need to allow for the hot water?
I've seen figures of 2kW/3kW (7-10kBTU), which would just be okay (I assume I can go to the max 60kBTU without problems?).

But I'm also having my hot water tank changed from a conventional tank to a Megaflow 210ME (so I get decent hot water pressure), and the spec sheet says the coil is rated at 12.9kW (45kBTU !!). If I need to allow for this, I'll need a new boiler as well - one capable of 100kBTU.)

What do you think? New boiler needed? Or will the current one be fine?
I'm out of my depth here, so I'd really appreciate your expert views!

 

[htgeng]

What do you think? New boiler needed? Or will the current one be fine?
I'm out of my depth here, so I'd really appreciate your expert views!

Also check out skirting heating products, eg climaboard, heatprofile, myson. That would be more effective than rads as its giving a perimeter heat rather than point heat from a rad. Of course underfloor is most effective, but I doubt you have any insulation under the floor??

 

[apg]

thanks - yes, I did start out by favouring skirting heating, but as I looked into it more, I wasd put off by a) the high cost, and b) the ugliness (the inconspicuous systems don't produce enough heat, and the systems that produce enough heat would dominate the draft walls. Also, the pipe-work would be ugly, and I'd have to get pipes across the internal and external doors. So in the end I gave in and went back to a rad and a fan.

If I was building a conservatory, underfloor would be a great option - but retro-fitting would be a pain and expensive. You-re right - the floor is just concrete screed at the moment (carpeted), so by the time I added insulation, heating, screed, and my carpet, I think I'd be stepping up into the conservatory!

 

[ianblue]

What about your carbon footprint?
Apart from it being against Building Regs its downright ridiculous to be trying to heat a conservatory .
A conservatory should be used only when the outside temperatures are suitable.
If you want an extra room to use all year round be sensible and build an extension which is properly insulated.
That way you will be saving the Planet and your wallet.
You will also be a lot more comfortable.