Heating from Aircon unit

[mikea11]

Can someone tell me if it would be as expensive to use a 1kw aircon unit for heating in the winter as it would be to use the cold air for summer? Thanks

[TRNCVaughan]

Modern air con units are very efficient, especially in the heating mode.

Efficiency is as high as 4:1

i.e. put a kW of electricity in and get 4 kW of heating out.

[Ragged Robin]

There was a long discussion on this on Cyprus 44 and the consensus of apparently informed opinion was that air con was one of the more efficient forms of heating, and certainly least expensive of electric heaters.

I suspect,however, it may depend on the space to be heated. I have air con in the bedroom only and use it for heating in winter for safety and putting it on for ten mins before I go to bed warms the room nicely. I suspect however it would be too expensive to heat the larger, high ceilinged "reception" rooms of my old house, and have to stick to huddling over gas heaters or log fires, with draughts in all the corners.

[TRNCVaughan]

Large, high ceilinged rooms are difficult to heat as warm air rises and there can be a very wide difference of temp between floor level and at high level. The use of ceiling suspended de-stratification or "punkah" fans will go a long way to reversing this difference.

[CatalkoyChris]

First law of Thermodynamics

[Ragged Robin]

Yes, I do realise that hot air rises. Actually I have one of the large fans on the ceiling of one room, brilliant in summer, but it has no heat control, ie only distributes air at ambient temperature. Would using it in winter actually improve the efficiency of other types of heating?

NB they are heavy things and you need to check you have something in the ceiling strong enough to attach to before installing one. As a matter of interest, can you still get them, mine is over 10 years old.

[Keithcaley]

RR,

Most ceiling fans have a 'reverse' switch on them, for winter use.

When used in this mode, instead of blowing air downwards, and creating a draught, they pull the cold air upwards, displacing the hot air near the ceiling, which is then forced outwards, and down the walls towards the floor. Basically, you are using mechanical energy to overcome the natural convection currents in the room.

I know that it sounds weird, but it works!

[CatalkoyChris]

No I meant 1 kW electricity in and 4 kW heat out

[Keithcaley]

No I meant 1 kW electricity in and 4 kW heat out

As your responses are rather short - almost to the point of being 'cryptic' - I am finding it difficult to ascertain exactly what you are trying to get across...

So, I hope that you will forgive me for elucidating: -

If you are saying that "1 kW electricity in and 4 kW heat out" violates the "First law of Thermodynamics", then you have rather missed the point that the aircon (somewhat like a refrigerator) is acting as a "Heat Pump" see this link - so effectively you are 'stealing' the heat from outside - using mechanical power supplied by the electrically driven compressor, and an expansion/compression cycle to move the heat from outside the house to inside the house, not getting it 'for free'...

If I have completely misunderstood your comments, could you please elaborate?

[MoonageDaydream]

We went to our apartment in the TRNC in February, and initially tried using the aircon unit, but I have to say it was very inefficient and expensive to run as a heater.
After a trip to the local 'yapi' we bought a good old stand alone heater that ran on bottled gas. Cheap to buy and cheap to run. Its what most of the locals seem to use, and they should know what is best in their limate.

[Maisiemoo]

Trouble with the gas heaters is they smell and cause a lot of condensation. We use the halogen heaters now and hot water bottles!

[TRNCVaughan]

We went to our apartment in the TRNC in February, and initially tried using the aircon unit, but I have to say it was very inefficient and expensive to run as a heater.
After a trip to the local 'yapi' we bought a good old stand alone heater that ran on bottled gas. Cheap to buy and cheap to run. Its what most of the locals seem to use, and they should know what is best in their limate.

Have you had your a/c checked lately? The first symptom of lack of gas is loss of performance in the heating mode.

[meldy]

Got 2 new aircon units last year and am not impressed with them for heating - did not feel any decent warmth coming from them even at highest setting.

[Repent at Leisure]

The old "re-gassing" chestnut!

So how does anyone know if it needed it or how much gas was used - if any?

Obviously finding the leak first should be the the priority...

[Groucho]

Got 2 new aircon units last year and am not impressed with them for heating - did not feel any decent warmth coming from them even at highest setting.

How long did you run them? It takes time to start pumping out hot air - but once it comes it is very warming - not that we use it much (only two times this year because we've closed down our log burner for summer)....

Really if it doesn't heat or cool properly then something is wrong...

[TRNCVaughan]

The old "re-gassing" chestnut!

So how does anyone know if it needed it or how much gas was used - if any?

Obviously finding the leak first should be the the priority...

The suction pressure will be lower than it should be if there has been a loss of gas. We use digital scales to weigh the gas in. The spec plate on the side of the outdoor unit shows the quantity of gas used in the system.

Leaks below a certain rate are often undetectable and can take years before all the gas has leaked out.

[TRNCVaughan]

Got 2 new aircon units last year and am not impressed with them for heating - did not feel any decent warmth coming from them even at highest setting.

If there is a leak on the units, heating will deteriorate before cooling does.