Help sizing an air-to-air heat pump

ispookie666

A2A ASHP are the way to go. 
 Its either Daikin or Mitsubishi according to one of the installers.  
The fine print and specs are very important - importantly the  lowest temperature they would be able to run. 
I had two daikins installed last year.  When I was looking into these, I found panasonic used older generation of gas with very high GWP.
 
One word of caution -  Larger units require planning permission and are not permitted development.  If installing more than one unit, you would definitely need one. 
 Most of the councils are very vague on the planning requirement.  The outdoor units are very quiet but over time they can get noisy.  If you have difficult neighbours, this can end up as a noise issue down the line.  

2nd_time_buyer

ispookie666 said:

A2A ASHP are the way to go. 
 Its either Daikin or Mitsubishi according to one of the installers.  
The fine print and specs are very important - importantly the  lowest temperature they would be able to run. 
I had two daikins installed last year.  When I was looking into these, I found panasonic used older generation of gas with very high GWP.
 
One word of caution -  Larger units require planning permission and are not permitted development.  If installing more than one unit, you would definitely need one. 
 Most of the councils are very vague on the planning requirement.  The outdoor units are very quiet but over time they can get noisy.  If you have difficult neighbours, this can end up as a noise issue down the line.  

Thanks. Good info. I have;just checked and the Panasonic operates down to -15 C. It uses the newer R32 gas so fingers crossed.

1961Nick

ispookie666 said:

A2A ASHP are the way to go. 
 Its either Daikin or Mitsubishi according to one of the installers.  
The fine print and specs are very important - importantly the  lowest temperature they would be able to run. 
I had two daikins installed last year.  When I was looking into these, I found panasonic used older generation of gas with very high GWP.
 
One word of caution -  Larger units require planning permission and are not permitted development.  If installing more than one unit, you would definitely need one. 
 Most of the councils are very vague on the planning requirement.  The outdoor units are very quiet but over time they can get noisy.  If you have difficult neighbours, this can end up as a noise issue down the line.  

My neighbour is an FGAS engineer so I don't have any problems in that department. 

mickyduck55

2nd_time_buyer said:

Thank you both. Install of the 3.5kw booked for next Saturday. 

We don't really need it as we have GCH. But we have excess solar and it seems to be the right thing to do to reduce gas consumption. 

I have been doing this for a few months now and it has really cut down my gas usage.  The prices you quote seem very good I paid just under 3K for a split double system

https://forums.moneysavingexpert.com/discussion/6318615/using-the-ac-to-provide-more-direct-targeted-heating-possibly-lowering-my-expenditure#latest

JKenH

2nd_time_buyer said:

Thank you both. Install of the 3.5kw booked for next Saturday. 

We don't really need it as we have GCH. But we have excess solar and it seems to be the right thing to do to reduce gas consumption. 

We found our ASHPS considerably reduced our oil consumption, particularly in the shoulder months (like now) when we now often don’t need the CH on. They work very well with our solar panels. In winter having E-W panels we don’t have much spare solar but still use them as it is more efficient to run the ASHPs on solar and heat the hot water on Octopus Go Faster. 

2nd_time_buyer

In the end I went for the slightly more efficient 3.5kw Panasonic for a little extra cost.

https://www.orionairsales.co.uk/panasonic-air-con-etherea-cs-z35xkew-white-wall-mount-heat-pump-r32-a-35kw12000btu-install-kit-15284-p.asp

The input power for heating is 0.9kw and the heat output is 4kw. Which I think makes it roughly on par with gas heating in terms of cost. 

And if using solar that would otherwise be exported, I think it works out cheaper.

ed110220

2nd_time_buyer said:

In the end I went for the slightly more efficient 3.5kw Panasonic for a little extra cost.

https://www.orionairsales.co.uk/panasonic-air-con-etherea-cs-z35xkew-white-wall-mount-heat-pump-r32-a-35kw12000btu-install-kit-15284-p.asp

The input power for heating is 0.9kw and the heat output is 4kw. Which I think makes it roughly on par with gas heating in terms of cost. 

And if using solar that would otherwise be exported, I think it works out cheaper.

Mind if I ask how much it was to have installed?

Also, does anyone know how realistic the SCOP figures are? This one is given as 5.2. Our electricity is going to be 28p/kWh when the cap ends and gas 7p, so if realistic would be cheaper to run than gas (28/5.2 = 5.4p). That's not even factoring that gas CH is only ~80% efficient as even modern boilers waste a fair bit of the heat in the flue gases.

2nd_time_buyer

Hi. I have been quoted £1520 installed. Worth mentioning that the install couldn't be easier: ground floor, indoor and outdoor units on the same external wall, power nearby.

It should be installed on Saturday. I'll let you know how it goes.

I will be using it as much to reduce carbon emissions as cost reductions i.e. 20-25% of the carbon emissions not including that some of it will be generated by solar.

As you say it would be interesting to see the real world efficienc though. 

ed110220

2nd_time_buyer said:

Hi. I have been quoted £1520 installed. Worth mentioning that the install couldn't be easier: ground floor, indoor and outdoor units on the same external wall, power nearby.

It should be installed on Saturday. I'll let you know how it goes.

I will be using it as much to reduce carbon emissions as cost reductions i.e. 20-25% of the carbon emissions not including that some of it will be generated by solar.

As you say it would be interesting to see the real world efficienc though. 

Thanks! Let us know how it goes and who did it too if that is OK. 

2nd_time_buyer

ed110220 said:

2nd_time_buyer said:

Hi. I have been quoted £1520 installed. Worth mentioning that the install couldn't be easier: ground floor, indoor and outdoor units on the same external wall, power nearby.

It should be installed on Saturday. I'll let you know how it goes.

I will be using it as much to reduce carbon emissions as cost reductions i.e. 20-25% of the carbon emissions not including that some of it will be generated by solar.

As you say it would be interesting to see the real world efficienc though. 

Thanks! Let us know how it goes and who did it too if that is OK. 

So the AC was installed today. I couldn't be more impressed with the service and unit. The guy who installed it, Ryan, works for an AC company during the week but is working for himself at the weekends.

I was impressed that he put the external pipework in the ducting which looks very tidy.

He is based in Farnborough (we are in Southampton). Photos below. Feel free to message me if you want his contact details.