Using Aircon to heat - power consumption?

[CaptainJack88]

I'm currently looking at getting some Aircon installed in my external office which is about 15m2.

I'm looking at something like this:
https://www.aircondirect.co.uk/p/88...th-4-metres-pipe-kit-5-years-warranty#reviews

My concern though is whilst it can heat, is it going to be the equivalent of running an electric heater so I'm going to rack up a huge electricity bill.

Can't figure out if I'm better installing an electric panel heater inside or running an aircon unit like above to heat

 

[Notch7]

I'm thinking of something like that for a garden cabin I'm building so I shall be keeping an eye open on this thread.

In theory an air con unit that can operate as a air source heat pump should be efficient.....

(apologies for not being able provide any advice!).

 

[jackthom]

I've seen some online claims for a heat output of 3 times the electrical consumption but I've no experience of how realistic this is in practice.

 

[ianmcd]

I've seen some online claims for a heat output of 3 times the electrical consumption but I've no experience of how realistic this is in practice.

That is for an air source heat pump, not for this unit

 

[Notch7]

That is for an air source heat pump, not for this unit

I thought this unit can act in reverse to suck heat from the external air and heat the air inside?

 

[flameport]

is it going to be the equivalent of running an electric heater

No, it should be considerably better, as it's not heating the air directly, but moving heat energy from one place to another.

so I'm going to rack up a huge electricity bill.

At worst it will still be better than a direct electric heater, at best it may get near the cost of gas heating.

If it's a choice between an electric heater and the aircon, the aircon is cheaper.
If you have gas heating available, that will be cheaper than both.

 

[endecotp]

How efficient it is will depend on the temperatures inside and out.

It will certainly be more efficient than a regular electric heater - but it’s also more expensive to purchase.

You also have the temptstion to use it for cooling in the summer - that is certainly expensive.

 

[CaptainJack88]

Thanks all.

So the general consensus is to get an Aircon as it'll be cheaper in the long run as gas isnt an option.

Regarding heat pump aircon etc, is there a certain type of heating source I need to avoid or is that system I linked pretty much spot on.

Looks like it can go into the ring main off a fused spur too

 

[bernardgreen]

Air source heat pumps in heating node can ice up when water vapour in the external air condenses and forms ice on heat exchanger in the outside unit.

When this happens there is no more heating and often the external unit has to be electrically heated to melt the ice before the unit can be used to heat. Heaters are built into many of the external units. Or the system is run in cooling mmide to take heat from the room(s) to melt the ice.

Hence the running costs in winter can be higher than expected.

Ground source heat pumps ( providing there is enough ground area ) do not normally have this problem

 

[endecotp]

The unit you linked to has a min outdoor temperature of -10C. I guess there are parts of Britain where that might be limitting, but not many (for an office).
It claims a seasonal coefficient of performance (SCOP) of 3.8 to 4.0 for heating, depending on the model.
That means you get 3.8 to 4.0 units of heating for each 1 unit of electricity used, with the remainder extracted from the outside air.
Of course the real-world performance may not match the manufacturer’s claims.

I should have said before, the other practical disadvantage is that the units are noisy, both inisde and outside, unlike a normal heater.

 

[CaptainJack88]

The unit you linked to has a min outdoor temperature of -10C. I guess there are parts of Britain where that might be limitting, but not many (for an office).
It claims a seasonal coefficient of performance (SCOP) of 3.8 to 4.0 for heating, depending on the model.
That means you get 3.8 to 4.0 units of heating for each 1 unit of electricity used, with the remainder extracted from the outside air.
Of course the real-world performance may not match the manufacturer’s claims.

I should have said before, the other practical disadvantage is that the units are noisy, both inisde and outside, unlike a normal heater.

By noisy, i guess you just mean the external noise of the unit when it kicks in, and the fan sound depending on speed inside?

 

[Notch7]

By noisy, i guess you just mean the external noise of the unit when it kicks in, and the fan sound depending on speed inside?

These reviews include comments that suggests the units are quiet, bearing in mind the internal unit has a fan so there will be some noise.

I have an air con unit in my office which is pretty noisy when the compressor kicks in, but hopefully these newer units are quiet. Im not sure if the compressor is inside or out. In, I would think.

For the money it seems a good buy, Im certsinly going to put it on my shortlist. A garden office needs an air con unit in the summer, and since this model costs the same as an aiir con unit anyway, if the heater option works that seems like a free extra. If its not great a panel heater could be added as well.

 

[CaptainJack88]

These reviews include comments that suggests the units are quiet, bearing in mind the internal unit has a fan so there will be some noise.

I have an air con unit in my office which is pretty noisy when the compressor kicks in, but hopefully these newer units are quiet. Im not sure if the compressor is inside or out. In, I would think.

For the money it seems a good buy, Im certsinly going to put it on my shortlist. A garden office needs an air con unit in the summer, and since this model costs the same as an aiir con unit anyway, if the heater option works that seems like a free extra. If its not great a panel heater could be added as well.

That's what I figured.
Think I'll buy it in January then, need to spend the same about on insulation first

 

[Notch7]

That's what I figured.
Think I'll buy it in January then, need to spend the same about on insulation first

The garden office / cabin I am building is similar to yours in size, its 15.7 sq m internal. Im thinking of the 12,000 btu unit.

I am aiming for insulation to be similar to building regs for extensions. I work that out to be 70mm celetex in floor, 100mm in walls and 120mm in roof. I figure spending more on insulation will be cheaper to heat / cool and will maintain a more comfortable temperature inside.

 

[endecotp]

By noisy, i guess you just mean the external noise of the unit when it kicks in, and the fan sound depending on speed inside?

Yes. In comparison to something like an oil-filled electric radiator, which would be completely silent.

Noise from the extenal unit can have the potential to annoy neighbours.