On his smart metre, Kumi Thiruchelvam looks satisfied at the "0 watts" showing up under electricity. It's about 10 am, and he's not using any electricity from the grid.
Cost of installation? Between £12,000 and £13,000 (€13,500-€14,500), a fair chunk of savings, even for Thiruchelvam, who lives on a private avenue in Luton.
The investment was common sense for him following the surge in energy prices caused by the Russian invasion of Ukraine.
According to the Office of National Statistics, electricity prices in the UK had increased by 67 per cent in January 2023 compared to January 2022.
Solar power installations doubled in 2022 compared to 2021, according to MCS, the standards organisation in charge of solar installations.
"We've had a combination of soaring energy prices around the world, and then also we've increased our electricity consumption in the home through a number of reasons, including electric vehicles," says Thiruchelvam.
His family owns a big house and no less than three electric vehicles, so their electricity consumption is higher than the normal household, about 12,000 kWh per year.
Around two-thirds should now be provided by solar panels.
"We originally sought the configuration to be rear, which is where the sun comes up, but we went for the front because it spends more time in the front throughout most of the year than in the rear. Also, there's more shade in the rear with trees," he says.
To get a quote for the installation, Thiruchelvam used Otovo, a Norwegian company which recently launched in the UK.
Using their app, he can monitor the electricity generated by his photovoltaic (PV) installation from his phone. The data comes from the inverters installed in the attic.
Their role is to change the direct current generated by the solar panels into alternating current to power appliances in the house safely.
They also communicate with the grid and monitor the electricity generated.
"We went for two hybrid inverters allowing for me to use a battery in the future," says Thiruchelvam.
"But because battery technology is still evolving, I chose not to. And also I viewed at that time that we would be consuming everything we'd be generating. So we didn't. But most likely I will upgrade the system as we approach summer with batteries."