Posted by: @ivanopinion

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Posted by: @allyfish

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or their guarantee is riddled with get-out clauses, especially the performance and efficiency guarantees. 

Good point. I'll ask to see a full copy of the wording. And get clarification whether they are guaranteeing efficiency.

The true test will come with time and results, but based on my discussions with Aira, they appear genuinely committed to improving the standards of heat pump installations in the UK and Europe. Their goal is to elevate the industry's benchmarks, contrasting with Octopus, whose focus seemed to be more on quantity. Although the quality of Octopus' installations remains unclear to me, Aira aims to not only scale up and drive high-volume installations but to also ensure these are of high quality. I'm hopeful for their success, as the industry could greatly benefit from major players stepping in to mitigate the issue of poorly executed installations.

Posted by: @editor

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Their goal is to elevate the industry's benchmarks,

@abernyte a fair point. As you've mentioned, there's been a lot of talk and flashy marketing so far, so it'll be interesting to see the outcomes once they begin installing heat pumps. While I have reservations about their use of buffers (which are part of their product lineup), hopefully, they'll be utilised only when necessary.

Buffers can be effective in heat pump systems if installed and balanced properly. However, my observation is that most UK installers either lack the skillset or the willingness to do so. As far as I'm concerned, it's better to omit them, saving homeowners money on unnecessary equipment, and potentially enhancing the system's success.

Regarding Aira, their comfort guarantee means they must rectify any issues if the system fails to heat properly, especially if problems arise from the buffer or other installation aspects. It remains to be seen how they'll perform once they start installing units and the extent to which they honor this guarantee. The fact that they've recruited some competent installers for senior roles is promising. The coming winter will be a significant test.

They do seem to hit what might be a sweet spot for a chunk of the market. I've had 5 quotes for a heat pump and they are cheaper than all except Octopus.
They have specified a buffer in their quote to me, so I've asked them to explain why it is better.

@editor A guarantee of comfort levels is one thing but… is this going to be achievable at a decent COP? Is COP featured as much in their flashy presentation as comfort levels are? Cynically yours, Toodles.

@toodles indeed. Just another piece of this complex heat pump puzzle.

@editor It is a physical and practical impossibility to balance a buffer in all instances and with varying loads, flow rates, temperatures and compressor outputs. It is quite simple really, if you have 1 side fixed, and the other variable, or the 2 side vary independently, there is no chance of maintaining a balance. To balance the buffer, the flow rates, temperatures and load have to be identical, on both sides, all the time without exception. Any variation, causes a reduction in efficiency. Basic Thermodynamics.

@heacol is that Zeroth Law of Thermodynamics?

The Aira website now has an installation manual for the new ASHPs, which includes detailed specs:

Download direct:

Or find it here: https://www.airahome.com/en-gb/heat-pumps/outdoor-units

Caution everyone, this manual stipulates the installation of a buffer tank, so, the promised guaranty of supplying sufficient heat, may come at a very high price.

The unit is no quieter than any other unit out there (57 DB)

It says it has an "Operation limit temperature (TOL) -10ºC" then says "Operating limits -25°C to 45°C"  Take your pick.

The 10 Kw does not comply with permitted development, it is 0.72 m3, therefore needs planning permission for every installation.

It is not on the ENA database yet so connection may be an issue.

Just pointing the facts out, there is a lot of sales BS out there.

Posted by: @heacol

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Just pointing the facts out, there is a lot of sales BS out there

You surprise me, @heacol 🥸

I've learned some more from my discussions with Aira.

They still fit Vaillants if the customer prefers. The warranty is reduced to 5 years, compared to 15 for the Aira own brand. For me, a Vaillant would be about £1k higher price.

The 8kW Aira ASHP has a minimum output of 3.8kW. I'm surprised that it can only modulate down by a half. This seems to raise concerns about cycling in mild weather.

Their reasons for specifying a buffer tank are to guarantee minimum volume in the system for defrost and stop regular start-stops of the system which affects COP and wear on the compressor. I'm going to ask for more details of how they ensure balanced flow rates both sides.

The customer cannot adjust the weather compensation curve. This seems to mean that if actual heat loss is different from the modelled heat loss (as it often will be), the weather compensation will be sub-optimal and the customer cannot do anything about this. Perhaps their system can automatically tweak the curve - I'm going to ask.

Although they quote a firm price based on a short inspection, you don't find out what SCOP they expect until they do the heat loss survey. To do that, you need to accept the quote, so you need to sign up without knowing one of the most crucial aspects of the system design. However, you do have the right to cancel. They seem to think that once the design is done you would owe them £500 if you cancelled then, though I don't think that's the effect of their T&Cs. (To be fair, Heat Geeks require you to pay £350 for them to come and do the survey, so not that different.)