Most efficient Air (to Air) Source Heat Pump Aircon/ heater? 16 July 2022 at 10:22AM in Green & ethical MoneySaving 10 replies 223 views

Screwdriva

Greetings,

We're keen on installing an airconditioning/ heating air to air heat pumps on a property that gets quite warm. The goal is to be able to cool (or heat) rooms like a split AC would. 

Is there a brand/ product line known to be the most efficient to help achieve this? Many thanks in advance!

2nd_time_buyer

I did a fair bit of research on it. Daikin, Mitsubishi, and Panasonic are well regarded and do A*** versions. Interestingly, the energy rating does not necessarily apply across the range. For example our Panasonic Ethrea is 3.5kw and is more efficient than the 5kw version (and quieter). When I was looking, the Panasonic was quite a bit cheaper than the other A*** offerings from other brands. It has exceeded my expectations in terms of noise, efficiency, and general performance.

Screwdriva

2nd_time_buyer said:

I did a fair bit of research on it. Daikin, Mitsubishi, and Panasonic are well regarded and do A*** versions. Interestingly, the energy rating does not necessarily apply across the range. For example our Panasonic Ethrea is 3.5kw and is more efficient than the 5kw version (and quieter). When I was looking, the Panasonic was quite a bit cheaper than the other A*** offerings from other brands. It has exceeded my expectations in terms of noise, efficiency, and general performance.

Thanks alot for sharing. I think the Ethrea is ideal as the rooms aren't very large. That said, would it be available with a single outdoor heat pump shared across multiple in-room blowers? Or are those shared designs inherently inefficient?

2nd_time_buyer

Screwdriva said:

2nd_time_buyer said:

I did a fair bit of research on it. Daikin, Mitsubishi, and Panasonic are well regarded and do A*** versions. Interestingly, the energy rating does not necessarily apply across the range. For example our Panasonic Ethrea is 3.5kw and is more efficient than the 5kw version (and quieter). When I was looking, the Panasonic was quite a bit cheaper than the other A*** offerings from other brands. It has exceeded my expectations in terms of noise, efficiency, and general performance.

Thanks alot for sharing. I think the Ethrea is ideal as the rooms aren't very large. That said, would it be available with a single outdoor heat pump shared across multiple in-room blowers? Or are those shared designs inherently inefficient?

I think it comes down as much to aesthetics as efficiency. In our case, two back-to-back installations would look a lot neater than a load of pipework across the house. 

However, there will be heating/cooling of the refrigerant in the pipework even if lagged. I don't think this is fully accounted for in the specs.

ispookie666

This is what an installer once told me "It's Daikin or Mitsubishi". There are plenty of manufacturers in the market, the larger the market share the better/easier the after sales support. Have a look at what the refrigerant gas is, R32 is commonly found buy some older ones have R410a. As @2nd_time_buyer says larger units are less efficient compared to smaller ones and will need separate spurs/wiring. 

I have two daikins installed and getting a 3rd Mitsubishi for the lounge (we have oil heating and trying to reduce usage).  

Multi splits are fantastic but have a big drawback - all the indoor units have to be on the same mode, this can be problematic in shoulder months. In addition to this, they are larger units. 

All A2A heat pumps need planning permission. 

Martyn1981

Can't add anything, only confirm what others have said - a multi split seems to be roughly the same cost as two separate units and requires its own spur, rather than just plugging in. Though I believe separate units need to be on different circuits, for instance our two plug into the kitchen ring, and the downstairs ring. Really simple.

Coastalwatch

S'funny, I wasn't going to reply seeing how our experience appeared to mirror previous posts. But then noticed a couple of differences, which may well be down to ignorance on my part! Firstly we've two x 2kW Mitsubishi units mounted on our gable end wall directly above the garage with no planning permission ever sort. They will have been in 5 years this November. Ssssh!

Secondly they are both on the same independent ring, but appreciate what Mart is saying about different circuits mixed with other high draw appliances. According to the energy monitors on each of our units they draw circa 1300W's max before settling back down to around 400!

But, they are brilliant. So pleased the team here on the G&E thread introduced us to them, initially just for the shoulder months but they've been so good they cover all our space heating needs and we've disconnected from gas as a result. Now FF free.:)

ispookie666

Smaller units are perfectly fine on the usual rings.
I'm hoping to get a 7.1kw and this will need a dedicated line from the consumer unit. 
Some AirCon installers are qualified electricians and will do the work but some will need you to get the wiring done by someone else. 

PP is ideal but most people do not bother, as long as you have no intrusive neighbours things should be fine.

Screwdriva

I think we will need to have a dedicated line from the consumer circuit board just for the a-a heat pumps. Would the following seem sensible?

3 X smaller rooms are 20m2 - a 2.5 kW unit for each one.
1X medium room is 30m2 - a 3.5 kW unit
1X larger rooms 45m2 - a 5 kW unit

I've read endorsements for Panasonic, Daikin and Mitsubishi. Is there a difference in efficiency between them? We're keen to install the benchmark efficiency product, if possible.  

ispookie666

That is a fair number of units verging on small industrial installation,🤣. I don't think a single spur would be sufficient for this. Maybe they could pull power for each smaller units from the existing. 
Do you have a floor plan, maybe a multi split might work out ok for a few smaller and closeby rooms. Else you can look into ducting (with added cost). 

2nd_time_buyer

Screwdriva said:

I think we will need to have a dedicated line from the consumer circuit board just for the a-a heat pumps. Would the following seem sensible?

3 X smaller rooms are 20m2 - a 2.5 kW unit for each one.
1X medium room is 30m2 - a 3.5 kW unit
1X larger rooms 45m2 - a 5 kW unit

I've read endorsements for Panasonic, Daikin and Mitsubishi. Is there a difference in efficiency between them? We're keen to install the benchmark efficiency product, if possible.  

I recall the top of the range Daikin had the slightly better efficiency but there was not much in it.

For our pretty-well insulated 3 bed 1920s semis. Two 3.5kw units downstairs is sufficient to heat the whole house in winter (we don't actively heat the upstairs) and cool all of downstairs in summer. Although, we still have the central heating to supplement if things get Baltic.