Rough running cost?

[Ben23]

Been asked if I could install a wall mounted system to provide heating for winter and cooling in summer time for a small barber shop. Room only needs a 3kw unit at most now he’s getting a bit nervous with it as 3kw sounds like a lot of power but I was trying to explain it doesn’t actually use 3000w an hour it’s inverter driven and will just maintain a set room temp.

I’m right in thinking it’s going to cost less than the 2 electric radiator things he currently has that cost him around 5-6 pound a day to run. Plus they can’t cook the shop in the summer. Is there any rough way of working out running costs of a/c I know it’s going to fluctuate a bit.

It’s not a over crowded place he works by himself and max maybe 3-4 people in there at any one time so nothing too major.

[RANGER1]

This may help, inverter reverse cycle best option.
Inverter keeps running cost down overall.
Manufacturer should be able to supply running cost!


https://www.confusedaboutenergy.co.uk/index.php/cooling-and-humidity-control/air-conditioning

[frank]

this link may help...http://www.refrigeration-engineer.com/forums/showthread.php?1261-Electric-costs-running-an-air-conditioner

[r.bartlett]

Been asked if I could install a wall mounted system to provide heating for winter and cooling in summer time for a small barber shop. Room only needs a 3kw unit at most now he’s getting a bit nervous with it as 3kw sounds like a lot of power but I was trying to explain it doesn’t actually use 3000w an hour it’s inverter driven and will just maintain a set room temp.

I’m right in thinking it’s going to cost less than the 2 electric radiator things he currently has that cost him around 5-6 pound a day to run. Plus they can’t cook the shop in the summer. Is there any rough way of working out running costs of a/c I know it’s going to fluctuate a bit.

It’s not a over crowded place he works by himself and max maybe 3-4 people in there at any one time so nothing too major.

The clue is cop. The unit will give out 3kw of heat but consume approx 1kw as an average. Therefore his electric cost will be 1/3rd if what he now has but this will be offset by the electricity it consumes when he uses it on cooling.

[back2space]

Been asked if I could install a wall mounted system to provide heating for winter and cooling in summer time for a small barber shop. Room only needs a 3kw unit at most now he’s getting a bit nervous with it as 3kw sounds like a lot of power but I was trying to explain it doesn’t actually use 3000w an hour it’s inverter driven and will just maintain a set room temp.

What is the wattage of each heater as that's also important. If he is using 2 x 3kw electric heaters, with them both on full you will use 6kw per hour and get 6kw per hour of heat out of them. An air con unit will use 1kw and give 3kw back out so make sure you have done your load cals correctly.

I’m right in thinking it’s going to cost less than the 2 electric radiator things he currently has that cost him around 5-6 pound a day to run. Plus they can’t cook the shop in the summer. Is there any rough way of working out running costs of a/c I know it’s going to fluctuate a bit.

It’s not a over crowded place he works by himself and max maybe 3-4 people in there at any one time so nothing too major.

Come on dude, an engineer shouldn't need to ask this question as you know how the refrigeration cycle works and efficiency.

1kw in approx 3kw back out, check the wattage of the unit and it will show you what it will use to give 3kw of heat back out.

Running in cooling in the summer will use less power than heating as the unit does not have to work as hard due to the ambient temperatures. Remember it is just moving heat from one place to another, not creating heat. So at an ambient indoor temp of say 25C it finds it really easy to move that heat, at a temp of 5c outside when your moving that heat inside, the unit has to work a little harder so uses a little more power.

An electric 3kw heater is 100% efficient, using 3kw and giving 3kw of heat out. An air con unit "moving heat from outside in" only drives the compressor and the refrigerant does the rest. So 1kw in approx 3kw back out at a very rough guess. So thats 1kw per hour to give 3kw back out per hour whereas the 3kw electric heater will use 3kw per hour.