We are looking to heat a flat roofed 5m x 5m x 8ft high, extension to our house (already built), which will be used as a study/garden room.(I work from home) it has patio doors:south facing.

We want it to be heated seperately from the house, (as I dont want to heat the whole house when I'm working in here all day) and someone suggested an air conditioning unit.

This somewhat confuses me as we want it primarily for heating, not cooling, do wall mounted air conditioning units heat just as efficiently as cool?

Is this more efficient than just extending our gas heating/radiators into the extension or is this air conditioning unit really a viable alternative?


Perhaps you could give me an idea if this is suitable and how much it would cost to install and heat this room with the above dimensions.

Look forward to hearing from you

[clk320audio]

I recently had fitted a Mitsubishi Inverter Wall mounted air conditioning unit, into a conservatory, which also provides heating. It as proved invaluable during the summer and the heating appears pretty good as well.
It cost just over £1000 installed and apparently is very energy efficient.
Suggest you contact your local Mitsubishi dealer.
P.S. If you go for one I suggest you get them to upgrade the 24 hour hand held remote control to a full 7 day wall mounted programmer, it is well worth the extra, in being able to fully programme the unit.
Hope this helps.

[rbartlett]

Originally Posted by greensusie51

We are looking to heat a flat roofed 5m x 5m x 8ft high, extension to our house (already built), which will be used as a study/garden room.(I work from home) it has patio doors:south facing.

We want it to be heated seperately from the house, (as I dont want to heat the whole house when I'm working in here all day) and someone suggested an air conditioning unit.

This somewhat confuses me as we want it primarily for heating, not cooling, do wall mounted air conditioning units heat just as efficiently as cool?

Is this more efficient than just extending our gas heating/radiators into the extension or is this air conditioning unit really a viable alternative?


Perhaps you could give me an idea if this is suitable and how much it would cost to install and heat this room with the above dimensions.

Look forward to hearing from you

Don't underestimate the heating requirement. If heat is the predominant requirment don't go for a cheap ebay one. Those tend to be far less efficient than the best - currently Daikin, although Mitsi are pretty good too..Which is why the govenment have them on the approved ECA list.
This drops the VAT to 5%. However this 5% can be applied to the whole project of putting in a heat pump thus a clever builder can off set more costs than just the heat pump itself.(whilst remaining legal of course)

Be careful because not all systems are on the ECA list and ebay cheapies will almost certainly not be covered.

Http://www.eca.gov.uk

Also make sure it's R410a and inverter as this means 'state of the art' and not yesterday's hero (or zero!!)

Heat is 'supposedly' free as 'energy in v heat out' can be as high a '1kw in to 4 kw heat.' However be aware that the heat rating is at 7 deg's c outdoor temperature.

Whilst they work down to -15 C outdoor temp performance and efficiency drops off rapidly and you get to a near 1-1 energy in v heat out.This makes them far more expensive than gas in a long cold winter.

Many of our customers struggled during the long cold snap in Febuary because of this and more than a few needed back up heaters.

The best thing is if you need 5 kw get a 7 installed etc..

Cheers

Richard

[davee]

Good post from Richard on the a/c (heat pump) however as you were asking about cost the reality is that if heating is your real concern then its going to cost less to extend your existing wet system providing you have a couple of pipes locally that can be teed off. As you dont want to run the rest of the heating sustem at the same time you will need to factor in a couple of motorized valves and possibly a new programmer though. As you face south however the a/c could be a good soultion.
Cheapest solution however would be an electric convector heater

[davee]

oops sorry about spelling, its getting late