Electric Heaters......
Discussion
What are the cheapest electric heaters to run? Don't want storage heaters. But convector, oil radiator or what?? Currently have one 3kw heater in one office and 2 3kw heaters in the other and usually at this time of year they start costing a fortune!! Currently turn them on and off as required.
All 3kW electric heaters use the same amount of electricity, if running continously. It uses 3kWh(3 units) per hour. You can reduce running costs by 2/3rds by installing an air source heat pump(ASHP). i.e. you get 3 units of heat for the cost of 1 unit of electricity typically(depends on outside temperature). Initially you want to make sure your insulation is up to scratch.
You might feel more comfortable if you can feel heat radiated from the surface of the heater so a bigger heater might enable you to do that if you can sit within the range of the radiation. Otherwise you’ll want to heat the whole office and 1kW is the same as another in that case. The heaters should have thermostatic control to switch themselves off.
With an electric heater what you see is what you get, a 1kW heater of any sort uses 1kW per hour and gives out 1kW of heat. Fan type heaters can feel colder as they move air around.
As has been said the only electric heater that is more efficient is a heat pump, and some small units these days are over 500%. ie pay for 1kW and get 5kW out.
But, much higher capital cost - in the UK they will probably start at about a thousand pounds installed.
Therefore it's only worthwhile investing in a heat pump if it will pay for itself in the long term.
Sorry, didn't make myself clear.
A standard heat pump has an outdoor and an indoor unit - and basically will heat one room. As a rough guide you need 1kW of output per 10 sqm of floor area.
With standard units you end up needing one heat pump per room.
Yes it's possible to have one (large) outdoor unit heating radiators, but it can easily cost 10 thousand - and the savings compared with mains gas probably aren't that great in the UK.
A standard heat pump has an outdoor and an indoor unit - and basically will heat one room. As a rough guide you need 1kW of output per 10 sqm of floor area.
With standard units you end up needing one heat pump per room.
Yes it's possible to have one (large) outdoor unit heating radiators, but it can easily cost 10 thousand - and the savings compared with mains gas probably aren't that great in the UK.
caziques - So lets say I just want to heat the larger office with 1 unit. The office measures 8m by 6m inside and the ceiling is 2.30m high at its lowest point as the roof has a slight pitch on it where the ceiling height increases to 2.45m maximum. What would I need? If you have one that will heat and cool is that more expensive? Where does the heat come out of? The building is portable and is made up of 4 modules stuck together, it is insulated allbeit I think we lose a lot of the heat through the floor as that is not as insulated as the walls. This is the office where I currently have 2 x 3KW convector heaters.
F458 said:
caziques - So lets say I just want to heat the larger office with 1 unit. The office measures 8m by 6m inside and the ceiling is 2.30m high at its lowest point as the roof has a slight pitch on it where the ceiling height increases to 2.45m maximum. What would I need? If you have one that will heat and cool is that more expensive? Where does the heat come out of? The building is portable and is made up of 4 modules stuck together, it is insulated allbeit I think we lose a lot of the heat through the floor as that is not as insulated as the walls. This is the office where I currently have 2 x 3KW convector heaters.
If there is any way of you obtaining access under the floors, then the B&Q loft insulation offer of 3 rolls for 3.00, then shouldn't be missed.F458 said:
So could I use a "Bosch Worcs Greensource 6kw Air to Air Source Heat Pump" for the above? They are about £1k I think?
That will be a far east/eastern european 'cheap copy' unit, in all probability.Your best bet is to get a local air conditioning company to give you a quote.
Get a good brand make, e.g Daikin, Mitsubishi Electric, as the two best or others like Toshiba, Hitachi, Fujitsu as decent less expensive ones, I wouldn't bother with any of the really cheap stuff, it's ok maybe at first to buy, but they are worse to work on and when they have problems the back-up and parts suppliers etc are not as good.
Nearly if not all 'split system' air conditioning units heat as well as cool these days.
You could have a unit hanging on the wall, hanging below a ceiling, in the ceiling with a facia in the room (cassette), or concealed above a ceiling with small ducts distributing the air to various outlets.
If you have a ceiling void of about 500mm (the unit's not that big but makes it easier to fit and work on, install pipes and cables) then a cassette unit would probably be best, but will depend on excatly what you are looking for and need.
HTH
48 sqm with standard ceiling height, 5-6kw is ideal.
The lowest price type of heat pump is a split system high wall, the indoor unit goes up at the top of the wall, the outdoor unit outside!
All heat pumps are air conditioners, only when a reversing valve is fitted are they heaters as well.
One of the best units available in the world that size is an Mitsubishi Heavy Industry SRK50ZIX - rated at 4.44:1 efficient. And yes, named brands are the ones to go for, correctly installed they will last for years
Where does the heat come from? Cold air outside!
Very basically refrigerant is compressed which heats it up, take the heat out, let the refrigerant decompress and it goes very cold (say -30) - warm it up again with outside air - compress it etc etc.
I heat my water with a heat pump, only solar is cheaper and as you may have noticed solar doesn't work too well in the dark.
The lowest price type of heat pump is a split system high wall, the indoor unit goes up at the top of the wall, the outdoor unit outside!
All heat pumps are air conditioners, only when a reversing valve is fitted are they heaters as well.
One of the best units available in the world that size is an Mitsubishi Heavy Industry SRK50ZIX - rated at 4.44:1 efficient. And yes, named brands are the ones to go for, correctly installed they will last for years
Where does the heat come from? Cold air outside!
Very basically refrigerant is compressed which heats it up, take the heat out, let the refrigerant decompress and it goes very cold (say -30) - warm it up again with outside air - compress it etc etc.
I heat my water with a heat pump, only solar is cheaper and as you may have noticed solar doesn't work too well in the dark.
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