Decarbonarma

I didn't research decarbonising a home.
I did it.

I'm Gareth, the founder of Decarbonarma. Everything on this site comes from one place: my own house, my own invoices, and my own meter readings. No installer pays me to say any of it.

£20/month
My whole-home Octopus direct debit — heating, hot water and electricity
~14 kWp
Solar across two arrays, with 15 kWh of battery storage
£10k vs £27k
What my heating route cost vs the air-to-water quote I was given

What I actually installed

This isn't a demo home or a manufacturer showcase. It's a lived-in UK house, decarbonised step by step over four years. Here's the full list, with real prices:

InstallKitCost
Solar + battery (2022)
First array
12× Viridian 405W (~4.9 kWp), Sonnen 15 kWh battery with 3 kW backup circuit~£20,000
Re-roof + insulation (Oct 2025)SuperFOIL SF40BB breather membrane over rafters, SF60 on the loft joistsPart of re-roof
Solar, second array (Oct 2025)
+4 garage panels, May 2026
18× Aiko 510W (~9.2 kWp), 9 north / 9 south, Enphase IQ8HC microinverters~£10,000
Air-to-air heat pump (Nov 2025)Daikin 3MXM52A9 multi-split, 3 indoor units heating and cooling the main living areas£5,300
0% VAT
Hot water (Feb 2026)Sunamp Thermino 300e heat battery (~12 kWh), replacing a limescale-killed cylinder£4,774
inc. VAT
Honest footnote: I got things wrong too. My 2022 inverter is only 3.6 kW — too small for whole-house loads. If I were doing it again I'd go bigger on both inverter and battery. That kind of lesson is exactly what this site exists to pass on.

Why the numbers here are different

Most UK energy content is written by people who have never bought the kit. Installers' blogs want to sell you a survey. The big consumer sites write from press releases. I was quoted £27,000 before the grant for a conventional air-to-water heat pump system; I heated my home a different way for around £10,000 all-in — and I publish the running data to show how it's working out.

On a good June day my panels generate over 64 kWh. The north-facing half of my roof produces about 70% of what the south side does — a number almost nobody publishes, because almost nobody metres it panel by panel. That's the standard this site aims for: numbers you can check, from a house that exists.

As seen on Skill Builder

My install has been featured twice on Skill Builder, Roger Bisby's UK building channel — not known for going easy on heat-pump hype.

Read the case studies

The full write-ups, with costs and data:

The Superfoil re-roof and solar install · Air-to-air heat pump + Sunamp: the £10k route · Sunamp Thermino 300e: six months in · Rose Cottage: the live data, half-year report

Or start with the free tools: Home Energy Adviser, Solar Generation Calculator, Heat Loss Estimator and Tariff Finder.

If the site saves you from an expensive mistake, you can buy me a coffee.