Mathew, sorry my bad. You had mentioned these in your last message, after having a look, they do seem very very smart indeed. Two questions though, how good are they lol. I mean I have a 15x5 room (hall) which even i must have to finally confess is extremely cold. Would a single unit do the trick or would i need 2 or more?
That's hard to say, as I'm not an A/C engineer by trade (although I have DIY'd a couple of units at a previous house). Calculators such as
this one are one simple way of calculating the necessary heating/cooling capacity for a given space, but you do need to know a little about the building's construction.
In any case, you'll need an engineer to fit and gas the unit, so he/she will be able to tell you how many and what capacity units you should fit.
Furthermore, I have realised that if these are fixed to one particular side i.e. the side next the the road, I have a decent cut in on the building which used to be an external flight of stairs. The big fan/extractor units whatever they are called can be attached there.
Sounds sensible.
Following on from this, is it normally one extractor unit per air con unit indoors i.e. if i was to have four air con units i.e. 2 downstairs and 2 upstairs would i have 4 extractors.
No, LG will manufacture multisplit condensers (the outdoor unit), these usually allow connection of up to four indoor units. You would have to specifically state to the engineer that this is what you want, otherwise it could go either way, as depending on the building layout it may be less hassle (pipework and cabling wise) to install four independent condensers.
Anything more than this and you may be looking at a VRF system, which uses a much larger condenser and varies the refrigerant to each indoor unit as necessary.
How much do these cost on average per unit system?
How long is a piece of string? Depends on the difficulty of the installation, only an A/C engineer will be able to tell you that. In terms of material costs, I expect the indoor units start at £500, and multisplit condensers £1000 upwards.
Finally, is there a lot of wiring reqired or do they just need a main feed going to a spur with the rest of the wire work being done outside with the extractors.
Usually, power is fed to the outdoor unit, and then a multicore cable links to the indoor unit to provide power and control signals. If you can mount the indoor units on external walls the interior wiring should be at an absolute minimum.
