Alastair Graham

February 8, 2023

Retrofit #3: Choices

First published on Wordpress in January 2022.

Here are our choices and some thoughts about why we made them.

Installation Company

We came across Ecobubl on YouTube and had been watching their videos about heat pump installations for some time. They came across as professional yet easy going, and very knowledgeable about the systems they provide. Looking at their website, it was also heartening to see that they were planning to open a training centre - in my mind this demonstrates a commitment to the sector and the products they install.

Ecobubl's quotes were competitive but their willingness to answer the (many) questions that we kept coming up with (because we love this tech and just want to know more about it!) was spot on. The system that they were proposing seemed to make sense to us and was similar to some of the installs we'd watched online - so we could at least get a feel for what might be involved.

Solar and Zappi

The cost of solar panels and installation has decreased a lot since we had them installed in our previous property, and the quality and efficicency of the panels has also increased. This is good as the Feed-in Tariff subsidy scheme doesn't exist anymore. We decided on 20 x 395 watt Jinko black panels split between two arrays on East-South-East and South-South-West facing roofs. 

We had decommissioned and uninstalled our Zappi model 1 when we moved from our previous property, and brought it with us to our new home. This will be reinstalled here so that we can charge the car again from sunbeams only! Due to various quirks of our previous install we have a 6 m connected charge cable, so that gives us quite a bit of flexibility in where the unit gets placed. 

Home battery

Having looked around different batteries (there are quite a lot) and spoken to people who own home batteries, we decided on the Givenergy 8.2 kWh. It gives us the storage we want, given the size of our solar array, and has a suitable inverter that allows a good amount of charge/discharge power (this is something to be aware of when considering a battery). We were going to go with the hybrid inverter but actually ended up going with the AC coupled inverter due to the specifics of the installation in this property. The battery also works alongside tariffs from Octopus Energy and has an open API for developers - I'm no developer, but I'll be playing with this to see what I can do with it. We spoke with Givenergy at Fully Charged Live in 2021 and were really impressed: they weren't doing an aggressive sales pitch but answered our questions and just wanted to chat about what were planning for the house. EV Man on YouTube has also installed this system and I trust his opinion on these things.

Having been really happy with our slimline Mixergy cylinder in the previous property, we wanted one of these again. We decided on a 120 L cylinder again, although it's not slimline this time (not so tall, but a bit wider) and it also has a heat exchange plate to work with the heat pump.

A Myenergi Eddi will be installed to divert the heating source - either direct electric from the solar panels or grid, or via the heat pump.

Space heating

Air source heat pump we are going with is the Daikin Altherma 3 Monobloc 14 kW. It has a relatively large outside unit, but we didn't want to have too many parts spread out through the house as there isn't much room for indoor electrical units etc. We also understand that Daikin are a respected brand, and that their units run quietly - something else that we were keen to have. The Daikin service package also gets very good online reviews from customers, so this was also a positive. This is a low temperature system rather than a high flow temperature one. Initially we thought a high flow temperature one would be preferable, because we are all used to high temperature gas boiler systems, but the low flow system was recommended and our questions have been answered such that we are confident in this choice. 

We have also opted to have the majority of our radiator upgraded. The house is on microbore, which isn't optimal, and the original radiators were mainly single panel with no fins. The new radiators will be Stelrad K2 and will compensate for the fact that the flow temperature in the system will be lower than when using the gas boiler (see here for a post on the even larger K3s).



All of the choices that we have made and listed here are based on extensive research into the different companies and options. We have not been paid or sponsored for any products (I wish) and we are paying market prices for the installation. We are confident that we have made good decisions for our circumstances, but you will have to undertake your own research and seek advice based around your circumstances if you are thinking of switching to similar home energy improvement systems.


Next time, I hope to be discussing the installation!