This looks quite interesting and would be ideal for those who choose an A2A ASHP rather than an A2W one.

@derek-m you ever heard of them ? as in hotwater tank only ASHP ?I just kind stumbled across them on the internet and thought damn where have you been hiding. They have been for a number of years now and seem to be an ideal fit for as you say people who dont want to add the complete ASHP for their central heating just yet. Air to Air sounds like a good mix as well there are so many options but understanding what will work out best and most economical is the hardest part. I really like the setup of the Dimplex Edel setup its a nice all in one solution and if you have the right space for them (outlet and intake pipes allowing) it would obviously be a good economical setup. I have been desperate to get rid of my expensive electric shower and my oil based hot water tank and this seems to fit the bill perfectly. The Sunamp is still very interesting but I think it wants at least 10kWh for each tank heat cycle and the cost for an install for some crazy reason as its simpler than a standard connection is total cost of circa 5k plus. I might look to get one installed in the next 3 months so I can see the worst case (Cold season) costs early on its life cycle. 

@boblochinver

I have been looking at the technical specification on the Dimplex website and the earliest document is dated 2020, also the refrigerant gas used is R290, which is a more recent, more environmentally friendly type. So that could be one reason why we have not heard of them, though I am surprised that Dimplex are not advertising them more actively. Possibly because many people have gas combi boilers, so hence no hot water tank.

There would appear to be three models available, 170L, 200L and 270L, with the 200L appearing to be the most efficient from the point of view of daily heat loss and stated COP.

 I was also interested to see that they not only have an ASHP installed, but also a 1.2kW immersion heater fitted, which makes them even more versatile.

For those who are fortunate to have a solar PV system, they could heat much of their hot water throughout the year from solar energy, using either the heat pump when less solar is available, just the immersion heater when there is an abundance of solar, or both when the water needs heating quickly. Even during the Winter months it may be possible to heat the water using the heat pump on a cheaper overnight tariff, and then any daytime solar energy, via a power diverter, to at least keep the water warm.

It should therefore be possible to install a DHW and CH system, utilising one of these tanks and A2A ASHP, at quite reasonable cost, though of course without the £5000 grant provided for an A2W heat pump system.

I think they’re just the newest models and they might have been going a lot longer. Im going to get one and ill put my journey up here 

Hey Bob, Did you get one? have you plumbed it in and got it up and running?

Also, why would you not receive a grant for it? I think it qualifies.

@avyg sorry ive been away for a bit busy with other things but I am planning on having the Dimplex installed within the next 2 months as well as a complete home A2A heating solution. I will let people know how things go and the whole process from start to finish. Things like completely rewiring my house will need to begin soon as the electrics are old !!

@boblochinver

Hi there, I would be very interested to hear how you're getting on with this.  I am looking to get rid of my gas boiler, which currently does DHW and space heating.  Plainly a heat pump is a more efficient way to heat water than any resistive immersion device, but there is an interesting issue regarding the optimum arrangement.

As I see it, there are two options.  First, a bigger ASHP handling DHW and heating. So far as DHW is concerned, this involves an outdoor ASHP feeding an internal UVC.  The ASHP brands are very keen to sell you a matched internal cylinder, which comes with immersion etc, but these don't seem to me to add much performence at all.  Indeed, their heat exchangers seem less efficient than eg the Mixergy cylinder which is designed specifically for use with ASHPs. 

The second option is the one you are intending to install.  There is a number of these inbuilt ASHP cylinders.  Vailant make one called the Arostor, which comes in 200L and 270L versions.  The COP curve for the 270L looks like this:

This video gives an idea of the sort of performance one might expect:

I have a good size boiler room on the top floor, which gets pretty hot in the summer.  In the winter, it's still quite warm from pipes and pumps etc, although that will drop when the gas boiler is removed.  However, it would still be quite easy to harvest some of that heat to assist this machine, and then draw the rest in winter from outside.  I am confident that annual COP would be above 3.5, and the annual consumption no more than 1200kWh.

What I would really like to know is: what is the typical annual COP for water heating from the first option - large external ASHP in combination with an internal unvented cylinder?  Alternatively, the annual electricity consumption for a family of 5 using that arrangement.  I wonder if any forum members can assist.

@wintergreen hi, I’m getting ever closer to the install for my A2A heating for my whole house which I already have done of the internal units but there’s a delay in the smaller ones so it won’t all be completed until June. I’m having the total rewire of house done starting May 8th and the new kitchen installed around same time. The choice of my hot water tank is still not finalised but the Dimplex is still the front contender, having said that Mixenergy has just come out with a all in one ASHP hot water tank so I want to find out more about that and compare them as the mixenergy might be more costly without much savings. I expect that to be installed in June hopefully then I’ll be able to give very detailed energy costs as I’m using an installed Emperia Vue gen 2 to track all my electrical circuits from the consumer box. Watch this space

When I was in Spain I came across this unit at the house we stayed. I had a look every new build was fitted with it. It sounds exactly what you described. It had a 1250 watt electric heating element and the hetpump would max consume 350watt. Just sounded amazing. It was a 110 liter tank. It was outside ofcorse. Right next to the air to air units. Wich was blowing out hot air on the the unit. Which I belive probably made the hot water unit even more efficient as the intake air was almost 40c at that time of year with the outdoor uni blasting it. I almost wished that the cold outlet would have been aimed at the condenser to help the AC. But ofcorse change that for winter.

https://www.manua.ls/ariston-thermo/nuos-evo-110/manual?p=37

Hi - I also came across these recently. I'm in Italy and someone on an Italian forum similar to this one said he'd installed one in the en suite bathroom to his main bedroom as he and his wife were only using one of the three bathroooms in his house (so a point solution), and if remember rightly he also had an ASHP but it was a long pipe distance to the bathroom. The manufacturer info (in Italian) is here:

https://www.ariston.com/it-it/prodotti/pompe-di-calore/acqua-calda/nuos-split-80-110

They come in 80 or 110L versions, with the larger unit retailing for around 1200 euros here. There's a govt incentive to replace old boilers here which gives 65% off the purchase price if certain conditions etc are fulfilled, which makes them even more compelling for certain use cases. We are considering building a small guest house here and my thinking is one of these would be perfect for that, possibly with a few solar panels as any guests who come to visit will do so in the summer months.

The other advantage in this machine is, there is one heatexhanger. In a normal Hetpump world to get hot water into our DHW tanks there are  two heat exchanges. In the hetpump, gas gives energy to water, then water goes in the big "pipe snake"  heat exchanger to give heat to the hot water inside the tank. Every time there is heat exchang there is heat loss. So having only one must must be a great advantage and better efficiency?