Heat pump / inverter DIY

Regarding DIY install... it is straightforwad to install the ashp's described as such because they come precharged. An aircon engineer is not required as you just drill the big holes in your property, mount the units and hook up the pipes - job done. Seen it, a mate did his own - it was inspirational.
The problem arises if you get it wrong. You need good diy skills to get the mounting, pipework & electrics right, and if you get a refrigerant gas leak you're screwed with out professional help. BTW there's a £5,000 fine for letting the gas escape.
I went for a professional install for 2 reasons:

Firstly, there is an extremely limited range of units described 'DIY Install'. The most desirable units are pro install only - ie not pre-gassed.

Secondly.. I didn't want the layout of the units limited by my own technical abilities. By using pro installers, I got the unilts neatly mounted in the correct & difficult to reach locations.

What I really don't understand is why these ashp's are so ignored as an amazing way to heat your home sooooo cheaply. This country is hypnotised by decades of cheap North Sea Gas, so we're all buying condensing burners. Why?? The Gas industry's established, huge and influential; the (mainly) Japaneese aircon manufacturers are invisible. Ever seen an aircon ad on TV?

Thank god for Google. I now know that I can heat my home to just-a-shirt comfort for peanuts by using electricity.
More specifically... I have a wallmounted unit in the (open plan) living room and one at the top of the stairs. They are set to 25/24 degrees (low power). Whilst on, they pull between 8 and 360 watts each. Thats 720 watts heating my whole house!
This is far greener / cheaper than any gas anywhere, and is feasably user-generatable.

But nobody I know gets it. A typical reaction would be "I bet they're expensive to run" or "had those on holiday to keep cool". I'll just smile a lot this winter when I look at my credit-crunched heating bill.

stevehead wrote: »

Regarding DIY install... it is straightforwad to install the ashp's described as such because they come precharged. An aircon engineer is not required as you just drill the big holes in your property, mount the units and hook up the pipes - job done. Seen it, a mate did his own - it was inspirational.
The problem arises if you get it wrong. You need good diy skills to get the mounting, pipework & electrics right, and if you get a refrigerant gas leak you're screwed with out professional help. BTW there's a £5,000 fine for letting the gas escape.
I went for a professional install for 2 reasons:

Firstly, there is an extremely limited range of units described 'DIY Install'. The most desirable units are pro install only - ie not pre-gassed.

Secondly.. I didn't want the layout of the units limited by my own technical abilities. By using pro installers, I got the unilts neatly mounted in the correct & difficult to reach locations.

What I really don't understand is why these ashp's are so ignored as an amazing way to heat your home sooooo cheaply. This country is hypnotised by decades of cheap North Sea Gas, so we're all buying condensing burners. Why?? The Gas industry's established, huge and influential; the (mainly) Japaneese aircon manufacturers are invisible. Ever seen an aircon ad on TV?

Thank god for Google. I now know that I can heat my home to just-a-shirt comfort for peanuts by using electricity.
More specifically... I have a wallmounted unit in the (open plan) living room and one at the top of the stairs. They are set to 25/24 degrees (low power). Whilst on, they pull between 8 and 360 watts each. Thats 720 watts heating my whole house!
This is far greener / cheaper than any gas anywhere, and is feasably user-generatable.

But nobody I know gets it. A typical reaction would be "I bet they're expensive to run" or "had those on holiday to keep cool". I'll just smile a lot this winter when I look at my credit-crunched heating bill.

Stevehead, are your units INverter units? I.e the compressor speed varies on the load required. Or are they simple on off, once it reaches temp the comp switches on and off? I find it hard to believe that an air conditioner in reverse cycle (heat mode) uses as little as 8watts. 24/25C is very hot indeed for a room? To reach that setpoint your units would prob be running flat out. I have a £3000 equipment alone installed, latest technollogy inverter scroll compressors. WHen it first switches on uses soemthing like 1.5kw but as it reaches the temp ive set it to it winds down the speed of the compressor outside and can run at 600watts. That is to power 2 indoor units off 1 outdoor unit. Total 7.5kw for only 600watts input!

The reason I disagree is because I work in this trade my self we sell and maintain and design air con systems so I have had to gain all sorts of qualifactions. Ac heatpumps are the most efficient way of heating but at present are no where near running at 8watts!

Steve, sorry mate I completly understand when you put it in HVAC terms that I understand, most people will not understand the 2nd reply you put but I completly understand now.

So your saying that to run the indoor unit on fan mode is just using 8w, that is great I think mine are the same the motors are the new style motors that use very little power even when on high speeds.

I also understand now the reasons you put set points at 25, obviously a lot of heat is going to be lost in the open space so you have to set a higher temperature in order to heat the areas furthest from the units.

We had a similar problem in heating mode only, we would set 22C on the controller in heat mode, and the units are low wall mounted so mounted at radiator height just aboveskirting board, the air flap would point air at an angle towards the floor and the unit would heat the floor area quick and reach setpoint and the return air sensor would read 22C however where the seats are in the lounge would only read 20C so still chilly, we had to set the controller to 24C to compensate for the distance furthest from the unit.

We found that areas nearest the unit were overheated to 24C and the seating area was comfortable 22C.

We spoke to the installer who has now installed remote air sensors which has extended the temp sensor inside the unit into a little box that is mounted on the wall near our seating area so if we set 22c on the controller the unit will heat until the remote sensor senses 22c on it, we have also found this has made the inverter units work much more efficiently as the sensor feeds temperature info back to the outdoor unit so for instance in your case your unit is set at 25C, if the unit senses a 3C difference below the setpoint the outdoor unit will run at full speed to bring the room temp up, as it starts approaching the set point of 25c the inverter will start to ramp down. So because your room is cooler at the point where you want 23C the sensor is thinking that its above 23C because its reading it from the unit so slows down. if you had the unit measuring the temperature from the area where you want 23C it would be much more accurate in reaching that temperature as it would be specific to the area your wanting heating. Basically your unit will run for longer to achieve 25C when really if you had it measuring the temp from the location where you want 23C you would be able to set 23C and get an even temperature through the room. Also have the flaps set on auto in heat mode so they move up and down to distribute heat.

Hope that makes sense ive had quite a few beers tonight! IN cool mode we have no problem at all as the air is circulated up from the unit around the ceiling area and blankets the room in cool air, whereas heating mode it has to force it to the floor area and for it to rise, but because the units are so powerful it doesnt rise quick enough for it not to affect the sensor inside.

Rich.

Steve were talking 2 indoor units running off 1 outdoor unit. Combined duty is 7kw at a push we get 7.5kw.

Max power usage at fully duty is 2.3kw winding down to 600w.

Not sure what the cop is of that as the multisplits i have are not given a COP marking as its a mix and match system. There are many different combinations of indoor units to attach to the outdoor unit you see so depending on what units are attached to the outdoor unit affects the cop.

Ah if your units are wall mounted then it makes sense that the air is already being blown down anyway, its harder for my unit to get the air flow down without it sucking it back in..

The remote sensors work very well, basically all it is a longer cable with the thermister on the end of the wire.