Heating a home office

In article , Andrew writes

I've got a reversible air conditioner, cold in summer and warm in winter and it doesn't cost that much to run.

Takes the latent heat outside and brings it inside i.e. the reverse of what it does in summer.

Course a fair bit more of an expense than an electric fire but over the long term..

All electric heating is near 100% efficient - ie all the electricity gets turned into heat.

The choice then becomes whether to heat the entire room - as a conventional central heating system does - or concentrate that heat on yourself.

For the former, fan heaters are probably the cheapest way to achieve this. The second, some form of infra red heater.

because

heat?

'bottle inside them' jobs, but have you considered a caravan gas heater of the sort where bottle is out side, and they are room sealed so the combustion air and fumes all go outside?

AWEM

Different answers to those two bits...

The best solution (i.e. cheapest to run and most versatile in use) would probably be a heat pump air conditioner. The cheapest to install would be a fan heater!

The aircon would deal with both - being hot air based it would give fast warm up times.

Wood burning stove? May be handy to provide some top up heat, mop up free fuel if you have enough trees to provide the wood, and give a radiant heat focal point to the room.

sorry, I couldn't resist it ....

I saw the subject and thought "haven't they go enough hot air already ?"

I'll get my coat.

Radiant heaters are very good these days but you need two or three as they leave a chilly effect on the shadowed side.

I made a desk up out of old mirrors and put such an heater under there in really cold spells. It soon warms up so much I have to switch it off or move it. I'd recommend cladding the work unit in foil or some sort of reflective material if you can. But the colour of the light from them is horrible.

Woodburning stove.

On Fri, 03 Nov 2006 09:07:02 +0000 someone who may be Andrew wrote this:-

As a general rule, the more one spends on an installation the less it costs to run. You can decide on the balance you wish to make in this particular building by considering how long you think it will be in use.

You didn't say whether you have a one or two rate supply. If you have the latter then storage becomes possible. This could be either the traditional storage heaters or (more expensive) a heat pump charging a thermal store. With the right supply of wood a stove can be economic.

I'm assuming you want to spend all day in the office. If not various forms of instant heating on peak charges are probably the best.

The message from tony sayer contains these words:

Latent heat of what?

Something like a Baxi Brazillia has a balanced flue and shouldn't cause any condensation.

MBQ

One of these can be very economical and attractive, if troublesome to use. They are fairly easy to fit.

There are many models. A friend has a stainless cylinder shaped one that is very attractive and heats very well. One filling goes all day and the heat output is high.

Latent heat of evaporation or of condensation.

In AC mode, during the summer, the refrigerant evaporates inside the heat exchanger inside the building. It requires extra heat to change state from liquid to gas. in the condenser, on the outside, the gas is being compressed and condenses to a liquid, releasing the latent heat. Clever, isn't it...

It's also why a condensing boiler becomes more efficient below the dew point - i.e. that temperature at which the water vapour in the flue gases condenses inside the boiler and releases its latent heat of condensation inside the envelope of the house.

heat pumps are better than 100% efficient in terms of power in to useful heat out.

The message from Andy Hall contains these words:

Yes, but that's the latent heat of the refrigerant. To take the latent heat out of the outside world you'd have to liquify the air.

In article , Guy King writes

Perhaps not put too well but acts like its trying to cool the outside world in winter;)

Is that why you get the peculiar anomoly in power consumption that (Andy I think) related recently where you put say 1kw in and get 3kw out in this situation?

In article , EricP writes

Thats right. Like a fridge in reverse. You "pump" the "heat" outside into the room.

Large quantity of low grade heat outside into small amount of high grade heat inside...

Cheers. Makes them look an interesting proposition then. :))

When you are pumping heat in, you "win" the latent heat of evaporation of any water vapour which condenses on the outside heat exchanger. Of course the air outside may be fairly dry in cold weather.