[P962c]

Installation Date:
May 2021.
Installation duration:
5 days
System:

• Mitsubishi Ecodan 8.5kw Ultra Quiet R32 Monobloc
• Master Controller
• System Diverter Valve(s)
• Magnetic Filter
• Hydro Connection Kit
• HP Fluid
• Generation Meter

• Electrical Connection Pack
• DN25 Pipe
• Heat Pump Mounting Kit
• External Trunking
• 250l High Gain Heat Pump Unvented Tank
• G3 Tank Connection Kit
• System Buffer
• Immersion Heater (Auxiliary Heat)
• Remote Thermostat
• Internet connection

Reasons for purchase:

• Gas Boiler at end of life
• Installation of Solar Panels the previous year – offset running cost.
• Ofgem RHI grant of £10,000 (closed March 2022)
• Good level of house insulation
• Suitable spaces for the Pump and Tank
• Environmental benefits.

Installation Pros:

• Tank was able to be fitted into the existing airing cupboard (utility room was too small).
• Remote thermostat can be sited at the best possible position for the most efficient system operation and can be left as a freestanding unit.

Installation Cons:

• Nine new radiators required. Five radiators were included in the price paid.
• Extensive pipe work changes as some of the original plumbing was micro bore so had to be replaced with 15mm pipe.
• A good deal of disruption during installation.
• Remedial decorating required.

System Pros:

• System allows different set-ups so maximum efficiency is achieved.
• System has in-built safety systems that prevent damage being caused to the pump, such as frost protection, freeze protection (glycol required for the heating side of the system)
• The system is very quiet (a noise increase when pump is working in very cold conditions)
• System has a Legionella protection system for the pipework. (runs overnight at two weekly intervals. It uses the immersion heater to do this rather than run the pump)
• System is very efficient. The pump speed automatically adjusts throughout the heating cycle to reduce power consumption.
• Mitsubishi Customer Service
• Mel Cloud App, which allows setting changes from anywhere. And has troubleshooting and error reporting available on Apple Store, Google play and Microsoft Store.
• Up to seven-year warranty

System Cons:

• System takes a little time to get set up initially.
• System takes longer to get the radiators to temperature.
• The pump itself is large.

The system has been running faultlessly for just over two years and heats the house well even during really cold spells.
System Thoughts:
I guess the main questions concerning having a system like this installed are:
Would I have had the system installed if the house was less well insulated – no
Would I have had the system installed if Solar Panels had not already been installed – no
Would I have had the system installed if the RHI grant had not been available – definitely not.
The RHI grant is paid quarterly over a period of seven years, so I still had to pay all the cost upfront. So was not ideal.
Would I have a heat pump system installed again – yes as long as the grants and costs were acceptable.
I would have preferred underfloor heating rather than radiators, unfortunately this was not possible in this house due to the costs involved.
General Thoughts:
The current grant for air source heat pumps is £5000 which is not, In my opinion, anywhere near sufficient given the price of the equipment and potential installation costs. The pumps themselves currently cost more than the grant.
The whole grant system needs to be rethought with insulation being the starting point.
I hope the cost of these systems can be reduced (I know Octopus Energy are looking to make a small low-cost heat pump for smaller properties) and grants for insulation of properties are made available otherwise these systems are not going to be viable as a solution for the replacement of gas boilers in homes.
These issues need to be addressed quickly if heat pumps are going be widely adopted and other solutions sought for those properties where there is no space for these systems.
With the current state of the country as a whole and the political games going on due to an upcoming general election this seems very unlikely.

[P962c]

Hi @LeeDQ_EONNext

The system has been performing faultlessly so far.
We have 12 PV panels on the roof and we have the heat pump system set to heat the water twice a day (6am and 4pm) which takes priority over the heating. It takes around 25 minutes to heat the water. So the heating will stop until the water reaches temperature and then switch back on.
The whole system is currently set to run between 6am and twelve midnight.
The system can be set up in so many different ways to suit what works best. We find that the set up we use is fine for us.
The only time electricity is used from the grid (with no assist from the PV panels) is for heating water is when the Legionella cycle runs overnight once every two weeks from 3am for around an hour
I have attached some usage figures of usage from the grid for July and October this year so you can get an idea of the benefits. Our normal usage is around 9kWh Our daily standing charge is currently 54p (It is a good weather indicator as well.)

We have no gas supply to the house since we installed the system

Just for information the system can be set up to have dedicated solar thermal panels (if sufficient roof space is available) to heat the water, this requires an extra valve to be fitted in the system, but would cost around £3000.

Hope this helps
Let me know if I can help with any further information

[WizzyWigg]

@P962c

Good morning. I found your thread most interesting and informative. It was very realistic. I hope that more people read it and find it as useful as I did. Thank you. 👴

[P962c]

Hi WizzyWigg
I am glad you found the thread useful. I will try and keep it updated if anything happens with the system
P

[WizzyWigg]

Originally Posted by P962c

Hi WizzyWigg
I am glad you found the thread useful. I will try and keep it updated if anything happens with the system
P

That would be absolutely brilliant if you could keep the community updated. A realistic view like yours will be I'm sure helpful to many in the future. 👍👴

[DebF_EONNext]

Thanks for sharing your experience @P962c. It's lovely to actually read someones lived experience with these things it gives a better picture of how they function and the pro's and con's!

I think you're right though the cost is most likely a contributing factor for most when considering any kind of installation. Like you say though there is the £5000 grant, also E.ON Next customers can get a further discount that can be used in conjunction with the grant too, while it's not massive in the grand scheme it all helps 🤩

[wizzo227]

Your thread was really useful to show how much stuff goes into a retrofit, and how important it is to have the space for it all and a hot water tank. Please could the newbuild housing regulations absolutely require the proper tank radiators and piping as yours, because retrofitting those resulted in your taking apart and redecorating every room of your house. Please could moderators consider lobbying for newbuild to have the rooftop photovoltaics and insulation, warm water pipework and radiator components of this system as a minimum, and absolute prohibition of new fossil gas boilers so that trades have a firm date to retrain by? Has anyone got one or more rooftop solar water heater panels series-connected in a system like this one ?

[Lee_EONNext]

@P962c This is great, I'm curious how they are performing now it's been a bit longer since install and how are the benefits?

I think this post can really help people who are looking at this type of tech.

[meldrewreborn]

Originally Posted by wizzo227

Your thread was really useful to show how much stuff goes into a retrofit, and how important it is to have the space for it all and a hot water tank. Please could the newbuild housing regulations absolutely require the proper tank radiators and piping as yours, because retrofitting those resulted in your taking apart and redecorating every room of your house. Please could moderators consider lobbying for newbuild to have the rooftop photovoltaics and insulation, warm water pipework and radiator components of this system as a minimum, and absolute prohibition of new fossil gas boilers so that trades have a firm date to retrain by? Has anyone got one or more rooftop solar water heater panels series-connected in a system like this one ?

I've got two solar thermal panels as we've discussed previously. @P962c does I think have PV panels but not solar thermal. My hot water tank has has two heating coils, one (lower) for the solar thermal connection and the upper for the boiler connection. If the boiler were replaced with a heat pump, it would utilise the lower connections. I do not see why it would be incompatible, and i expect monitoring of hours of operation, energy gained and pump energy consumed would be much improved compared to mine. The gains would be reduced energy consumption in the summer, but if the heat pump is fed by primarily solar PV, the benefit would probably be in allowing a higher level of export as the heat pump would not have to run to produce hot water, and so that energy could be exported.

Solar thermal is not cheap to install, and the savings are radically different depending on whether the fuel displaced is oil, gas or main electricity. Unless one was displacing the most expensive of these, mains electricity, solar thermal makes little financial sense (unless like mine, another agency pays the majority of the cost), or else a DIY system is put in (a la @retrotecchie).

[Lee_EONNext]

@P962c Thank you, I will have a look.

I wonder if anyone else on the community is looking into this type of technology?