fshr
The musings of a grumpy hairless ape
Heat Pump
Introduction
To come…
The System
In June 2025 we had a heat pump installed as part of our efforts to modernise the house and go a but more “eco”.
It took a little while to decide on a solution.
I think the main difficulty we faced wasn’t so much about the products available (they’re pretty much the same), but actually trying to work out what is the right sized solution for us. There’s a lot of information out there on heat pumps, some of which can be conflicting, and there seems to be both a lot of very house specific parts to designing a heat pump and experience based tuning on the part of the designer.
Anyway, we took the option to get 3 separate quotes to compare prices, and we pretty much ended up with 3 different solution designs. Now I’m not someone who can let that be, any OCD I may have means I absolutely need to know the whys and wherefores of not only what’s offered but why? So to get 3 different solutions to (apparently) the same problem was like the proverbial red rag to a bull.
So it took some time…
Two heat loss surveys, numerous emails, visits, and fact checking later, and we’re now at the point where I’m reasonably confident that we’re going for the right system. As a solution, it’s slightly oversized for our needs, but both heat loss surveys put us borderline for the next heat pump size down, and the installer we chose made some good cases for the size we went with.
So what did we go for?
We ended up going with:
- A 10kW Vaillant AroTherm Plus ASHP, and
- A 250ltr Vaillant DHW HP Cylinder, plus
- All the other bits and pieces
That’s spec’d to the MCS standards for our house, which should meet all our heating and DHW needs. By choice we’re also swapping out a couple of radiators with a different model and a towel rail, but that wasn’t a requirement of the install.
Home Assistant Integration
For Home Assistant there’s a HACS Integration myPyllant which uses Vaillant’s cloud service to monitor and control the heat pump. I initially used this to monitor the heat pump, but after some issues with Vaillant (apparently) changing connection quotas around Nov 2025 I removed that particular integration.
I’m now using ebusd with a wired adapter for monitoring. While likely a quite unsupported option from Vaillant’s point of view, the eBusd option gives a near real-time/instantaneous update from the heat pump into Home Assistant.
Both the heat pump and heating control circuits are also on Shelly Pro 3EM energy monitors so I can monitor their power and energy usage.
© Paul Fisher 2026 / CC BY-NC-SA 4.0
/ Disclaimer