A2W for HW only - already have A2A heating/cooling

SarahEmmm_2

I had aircon* put into half the house a couple of years ago, after nearly boiling in the summer.

It has been brilliant, both summer and winter. So I'm now looking at another unit for the rest of the house, which leaves me in HOT WATER!!

I've seen the videos from Heat Geek, but they really don't offer much detailed info unless you shell out for a consultation. Also had a quote for a system from Energie** and waiting for another local biz to come and suggest their offering.

The Heat Geek sounds great, but the lack of detailed info and some reviews raise concerns. Has anyone here had their kit for more than a year or so and can comment?

The Energie solution looks beautiful but seems very expensive for what it is. Plus it is recommended to be installed on a south facing wall, whereas I need an install on a north facing wall (where I already have the HP). Any comments on this one?

* Mutsubishi multisplit + 3 room units

** Energie ECO: energie.co.uk/products/eco/

Rodders53

I'd respectfully suggest that a 1:1 immersion heater unvented HW cylinder fed on E7 via a timer  (EV tariffs perhaps) will be cheap enough, and likely much cheaper to install.  That said a neighbour has a solar-thermal HW thing on the roof to supplement his Kerosene boiler for many years.  It's not new tech...  We haven't spoken about it for ages but was happy enough.

Note it's just the solar-thermal panel that needs to be in the Sun when the sun is available -- the rest of the gubbins is inside... pipes to/from, cylinder, pumps, controls...  On a north-facing roof the benefits would be much less worthwhile.  Plus the panel heat will be less in winter and you'll have to supplement with an immersion anyway.

Someone made a ASHP-HW cylinders that vent air to/from an external wall (HP was atop the cylinder) but I believe very noisy and not especially efficient... I can't readily find who/what it was but this thing is similar EcoStore 300L All In One Exhaust Air Heat Pump Hot Water

SarahEmmm_2

Thanks, Rodders!

Yep, its the panel that will need to be fitted on a north wall. That's the side of the house where all the plumbing lives. Aircon engineer who fitted the A2A was perfectly happy with that location, and there have certainly been no problems. 

I currently have a gas combi boiler, so no HW tank. As far as I can tell, I will need a tank, come what may, which will need to feed 3 shower rooms + basins/sink. 

Have just now been looking at what seems to be called heat batteries (eg Sunamp Thermino), which may be a better solution. No info on costs yet, but the sizes of the heat units are quite small, so should fit in a kitchen cupboard okay. Also removes the legionnaire's and venting issues. Seems fairly similar to the Heat Geek idea.

NedS

SarahEmmm_2 said:

Thanks, Rodders!

Yep, its the panel that will need to be fitted on a north wall. That's the side of the house where all the plumbing lives. Aircon engineer who fitted the A2A was perfectly happy with that location, and there have certainly been no problems. 

I currently have a gas combi boiler, so no HW tank. As far as I can tell, I will need a tank, come what may, which will need to feed 3 shower rooms + basins/sink. 

Have just now been looking at what seems to be called heat batteries (eg Sunamp Thermino), which may be a better solution. No info on costs yet, but the sizes of the heat units are quite small, so should fit in a kitchen cupboard okay. Also removes the legionnaire's and venting issues. Seems fairly similar to the Heat Geek idea.

I have a friend who has a Sunamp Thermino and is happy with it, but they are only two occupants with low water usage.

Yes, they are small so ideal where space is a consideration, but you mention feeding 3 shower rooms. How many occupants and what level of usage do you have? Will the volume of hot water be sufficient for your usage?

What are your constrains here? Is it space, ruling out a large conventional cylinder. Is it cost ruling out clever solutions such as the Mixergy tank with integral heap pump built in. Do you have access to cheap rate electricity to make a simple vented cylinder with immersion cost effective and not worth spending more?

Once we have a better idea of your constrains, the best solution should be easier to identify.

SarahEmmm_2

Glad to hear that about your friend, Ned.

3 people, 3 shower rooms. One currently has an electric shower. We don't shower at the same time, so I think 

recovery time won't really be an issue. Space is definitely an issue, because what was the airing cupboard has been converted into a wardrobe. I was thinking to use the space in the kitchen where the gas boiler is currently. I had heard of the Mixergy, but I don't feel too enthusiastic about an all in one solution - some companies are good at tanks, others at heat pumps, but I suspect few are good at both.

Upfront cost is a consideration; running costs less so, really. I'm with Octopus, so it may help to move from their standard tariff. I did have a conversation with them about a PV+HP solution, but they said my roof is not suitable for PV.

matelodave

A heatpump hotwater tank is an option but quite expensive so you really need to do some sums to work out whether the costs (and space required) are worth it compared with an immersion heater on something like E7.

Although if you get through a lot of hot water then you might find that you cant heat enough during the off-peak period to keep you going all day unless you get a tariff with multiple off peak times during the day. - see here, https://www.greenmatch.co.uk/heat-pumps/water-heater

QrizB

matelodave said:

A heatpump hotwater tank is an option but quite expensive ...

A similar price to the typical preplumbed tank used with a ASHP. £1400 here and I've sent them as low as £1000:

https://www.modernheat.co.uk/product/air-source-heat-pump-hot-water-system-all-in-one-combined-aqua-thermica-200/

tacpot12

Another DHW only ASHP: Vaillant aroSTOR 200 Litre

SarahEmmm_2

Wow - a remarkable range of prices for what seem very similar systems! Thank you, Qriz, tacpot. Fun fact: I had one of the very first gas combis from Vaillant, installed in 1984. It was great and worked perfectly, though I have heard that Vaillant have had their problems more recently.

matelodave, I did do a Greenmatch form and got referrals from 2 national and 1 local business (who wants to sell me the Energie system). I will prefer a local supplier/installer to hopefully get better aftercare. 

NedS, do you think your friends would be prepared to discuss their Sunamp install? I would be very interested in talking to them.

NedS

SarahEmmm_2 said:

NedS, do you think your friends would be prepared to discuss their Sunamp install? I would be very interested in talking to them.

I've sent you a PM 

QrizB

My big reservation about thermal stores like the Sunamp products and their larger cousin the Tepeo ZEB is that you can store more energy, in less space, at least cost, using a battery.

You'd also need some sort of electrically heated HW tank to convert that stored electricity into hot water, but a 50-litre stored water heater is both compact and cheap. Meanwhile the storage battery lets you arbitrage your daytime electricity against the nighttime cheaper rate.