Net zero or not zero?
What we are trying to do
We designed Reflections to not only be our family holiday home and somewhere to share with guests, but also to demonstrate that net zero energy homes could be easy to use, a delight to be in and fun.
We also committed to sharing the real life performance of the house, warts and all. Remember we are trying to export more kWh of electricity than the number of kWhs of gas and electricity that we import from the grid (other than car charging). If you want to know more about the house then do get in touch via the website email system and we will try to answer your questions.
Comparing the years
The main difference in 2025 compared to 2024 was the much improved PV performance. Some of this was due to weather but also due to the local electricity company sorting out the sub station so it kept the voltage within limits, thus stopping the PV cutting out.
Comparative PV monthly generation totals are shown in the figure to the right.
January 2026 has started well!
Final Year Table 2025
Into 2025 with a dismal and cloudy January, and February started that way but ended with a glorious week that continued through March. This resulted in a positive energy balance for Q1 even with the gas boiler. The ASHP switch is definitely on the agenda - just a question of what make, when and where to find a careful installer who wants to do a neat job plus possibly heat batteries rather than a bigger hot water tank. The SunAmp chap was visiting in July but family issues for me scuppered that.
We continued to see positive monthly balances up to October when we had just over 3,228 kWh in the bank. November and December were negative balance months, 461 kWh and 717 kWh respectively, taking the final balance for 2025 to a positive 2,050 kWh.
So success this year!
Final Year Table 2024
After some gremlins crept into my arithmetic I decided that an Excel spreadsheet would be a better way to set out the energy use. Each month will still have figures but it is all summarised and cross checked in the spreadsheet.
What is also becoming clear is that the gas usage, particularly for hot water (and possibly towel rails), is far higher than envisaged. Net zero in kWh with gas is unlikely to work.
At the end of 2024 we can see that if we had an Air Source Heat Pump (ASHP) rather than the gas boiler, we would probably be well in credit assuming average ASHP performance. Probably a local installer who is happier to do a slightly non-standard install with pipes in the ceiling void. And a heat pump with a half decent app so it is not an EcoDan ASHP with the MELCloud app which I suffer with at home.