Your one-stop shop for going green at home. Decarbonarma brings together in-depth articles, real-world case studies built on metered data, and free interactive tools — a tariff finder, heat-loss estimator and home energy optimiser — alongside impartial buyer's guides to solar, batteries, heat pumps, EVs and AI energy management. Everything you need to cut bills, cut carbon, and future-proof your home, in one place.
I decarbonised my own home — a re-roof with Superfoil and solar, an air-to-air heat pump and a Sunamp heat battery — and I write up what actually worked, what didn't, and what it really cost. No installer pays me to say any of it.
My setup has been featured twice on Skill Builder, the UK building channel that doesn't sugar-coat heat pumps. Decarbonarma gives you the same straight answers — backed by real numbers, not a sales script.
Featured ×2 on Skill BuilderReal metered homeIndependent · no installer funding
Technologies
Five ways to green your home
From harvesting sunlight to intelligent energy AI — each technology plays a role in your home's sustainable future.
Combine technologies for maximum impact. Our experts help you build the right system for your home, budget, and lifestyle.
Why Decarbonarma
We make going green simple
🎯
Impartial Advice
We're not tied to any single manufacturer. We recommend what's genuinely best for your home, your budget, and your goals.
🏠
Whole-Home Approach
We design systems where solar, battery, heat pump, EV charging and AI work together seamlessly — maximising every pound you invest.
💷
Grant & Funding Support
We navigate the Boiler Upgrade Scheme, ECO4, and other UK grants so you never miss out on money you're entitled to.
📊
Performance Monitoring
Your dashboard shows real-time generation, consumption, and savings — so you always know exactly how your system is performing.
Free Tools
Two free tools to guide your green home journey
Use our AI-powered tools before you spend a penny — find the right energy tariff and check your heat pump sizing.
⚡
AI Tariff Finder
Answer 5 quick questions and our AI matches you to the best Octopus or EDF tariff for your home — with referral links so you and Decarbonarma both earn on a switch.
Find My Tariff →
⏱ Takes 60 seconds · 🎁 £50 referral bonus
🏠
Heat Loss Estimator
Estimate your home's Heat Transfer Coefficient using Michael de Podesta's methodology. Cross-check your MCS installer's heat pump quote before you sign anything.
Estimate Heat Loss →
🔬 Based on real physics · 🤖 AI-powered analysis
📄
Case Studies
Real homes, real data, real policy. Seven in-depth pieces covering heat pumps, EVs, solar, SMR nuclear, and North Sea policy — all built from primary sources.
Read Case Studies →
📊 7 deep dives · 🏡 Real metered data
Happy Customers
Real homes, real savings
★★★★★
"Our energy bills have dropped by over £120 a month since installing solar and a battery. The whole process was smooth and the team were brilliant."
SH
Sarah H.Manchester
★★★★★
"The heat pump has transformed our old Victorian terrace. Warmer in winter, cooler in summer, and I don't miss the gas bills one bit."
JM
James M.Bristol
★★★★★
"The AI energy manager is genuinely impressive. It predicted a sunny week and shifted all our heavy usage to maximise free solar. Magical."
PL
Priya L.London
Ready to start your green home journey?
Get a personalised savings report for your home. Completely free, no commitment required — just honest advice about what's right for you.
Enjoying Decarbonarma?
Everything here is free and independent. If it helped, you can support the site with a coffee — scan the code or tap the button.
Our news agent scans solar, wind, battery, nuclear, heat pumps, hydro and wave energy every morning and brings you the stories that matter — a 60-second read with the day's biggest themes.
☀️ Solar Panels
Harvest the power of the sun
Modern solar photovoltaic (PV) panels convert sunlight into clean electricity for your home. With payback periods under 8 years and 25-year warranties, solar is the foundation of every green home.
How solar panels work
Solar panels are made up of photovoltaic cells that absorb photons from sunlight and convert them into direct current (DC) electricity. An inverter then transforms this into the alternating current (AC) your home appliances use.
A typical UK home installation of 10–12 panels (3.5–4kW system) will generate around 3,000–4,000 kWh of electricity per year — covering roughly 50–70% of a household's typical usage.
Any surplus electricity can be exported to the grid via the Smart Export Guarantee (SEG), earning you additional income on top of your savings.
Key Benefits
💰
Slash Your Bills
A typical 4kW system saves £600–£900/year on electricity. Combined with a battery, savings exceed £1,200/year.
📈
Strong ROI
Most systems pay back within 7–10 years and continue generating free energy for 25+ years.
🌿
Cut Carbon
A typical system prevents over 1.3 tonnes of CO₂ entering the atmosphere every single year.
🏡
Add Home Value
Studies show solar panels add 4–14% to property values in the UK.
🔌
Smart Export Guarantee
Get paid for every unit you export back to the grid — currently up to 15p/kWh with some tariffs.
🔧
Low Maintenance
No moving parts means minimal maintenance. A periodic clean and an annual health check is all that's needed.
Popular Solar Systems
🏠
Starter System – 3.5kW
Perfect for 1–2 bedroom homes. 8 panels, SolarEdge inverter, app monitoring.
From £5,500 installed
🏡
Family System – 6kW
Ideal for families of 3–4. 14 high-efficiency panels with export tariff optimisation.
From £8,200 installed
⚡
Power System – 10kW
Maximum generation for large homes or those with EVs and heat pumps.
From £12,500 installed
🔋
Solar + Battery Bundle
Our most popular package. 4kW solar with 10kWh battery — the perfect pairing.
From £11,000 installed
Get your solar quote today
We'll survey your roof, assess your consumption, and give you a detailed breakdown of expected savings — completely free.
🔋 Battery Storage
Store energy. Use it on your terms.
Home battery systems capture the solar energy you generate — or cheap overnight grid electricity — and make it available whenever you need it. Never waste free solar power again.
Why battery storage changes everything
Without a battery, surplus solar energy is exported to the grid for as little as 5–15p/kWh. With a battery, you store that energy and use it in the evening when grid electricity costs 28–35p/kWh — a significant difference.
Batteries also enable "time-of-use" arbitrage — charging from the grid overnight at cheap rates (as low as 7p/kWh on Octopus Agile) and discharging during peak hours. Many customers earn back £400–£600/year from this alone.
And in a power cut, a battery with islanding capability keeps your lights, fridge, and devices running — essential peace of mind.
Key Benefits
🌙
Evening Power
Use your daytime solar energy in the evening when you actually need it most.
💲
Tariff Optimisation
Charge at 7p/kWh overnight and avoid paying 30p+ during peak hours.
🏚️
Power Cut Protection
Keep essential appliances running during grid outages with islanding-capable batteries.
📱
Smart Control
App-based control lets you set charge windows, view history, and optimise automatically.
🔗
Pairs With Everything
Works with existing solar, new installations, heat pumps, and EV chargers.
🌱
Grid Support
Join virtual power plants and earn money by supporting the grid during high-demand events.
Popular Battery Systems
⚡
Tesla Powerwall 3
13.5kWh capacity, integrated inverter, 100% depth of discharge, excellent app.
From £9,500 installed
🔋
GivEnergy AIO 9.5
9.5kWh, all-in-one solar + battery hybrid. Most popular UK choice in 2024.
From £6,800 installed
🏠
SolarEdge Home Battery
10kWh modular design — expandable as your needs grow. Pairs perfectly with SolarEdge solar.
From £7,200 installed
💡
Huawei LUNA2000
Modular 5–30kWh system with best-in-class efficiency. Premium choice for larger homes.
From £5,900 installed
Find your perfect battery system
Our advisors will match the right battery to your usage patterns, solar output, and EV charging needs.
♨️ Heat Pumps
Ditch gas. Heat smarter.
Air source heat pumps extract warmth from outside air — even at -20°C — and deliver it into your home at 3–4x the energy efficiency of a gas boiler. The future of home heating is here.
How heat pumps work
A heat pump works like a refrigerator in reverse. A refrigerant fluid absorbs heat energy from the outside air, is compressed to raise its temperature, and then transfers that heat to your home's heating and hot water system.
The magic number is the Coefficient of Performance (COP). A good heat pump delivers a COP of 3–4, meaning for every 1kWh of electricity used, 3–4kWh of heat energy is produced. No gas boiler can match this.
Powered by your own solar energy, a heat pump can make your home truly zero-carbon for heating — a major step towards meeting the UK's 2050 net-zero target.
Key Benefits
🌡️
300–400% Efficient
A COP of 3–4 means heat pumps are up to 4x more efficient than even a brand new gas boiler.
💷
Boiler Upgrade Scheme
Claim £7,500 government grant towards your air source heat pump installation.
❄️
Works in All Weathers
Modern inverter-driven heat pumps work efficiently down to -25°C outside temperatures.
🚿
Heating & Hot Water
One system handles all your space heating and domestic hot water needs all year round.
🌬️
Cooling Capability
Many heat pumps can reverse to provide cooling in summer — a growing need in the UK climate.
📉
Lower Running Costs
When paired with solar, many homeowners see heating costs drop by 50–70% vs gas.
Heat Pump Solutions
🏠
Mitsubishi Ecodan 8.5kW
The UK's best-selling heat pump. Reliable, quiet, and class-leading in cold weather performance.
From £10,500 inc. grant
⚡
Samsung EHS Mono 12kW
Excellent efficiency ratings and smart controls. Ideal for larger homes or those with underfloor heating.
From £11,200 inc. grant
🌿
Vaillant aroTHERM Plus 7kW
Award-winning design, ultra-quiet operation, and best-in-class A+++ efficiency rating.
From £9,800 inc. grant
🏡
Daikin Altherma 16kW
For larger properties. Integrated cylinder option and excellent solar PV compatibility.
From £13,000 inc. grant
⚡ EV & Home Charging
Drive on sunshine. Charge at home.
Pair a smart home EV charger with your solar panels and charge your car using energy you've generated yourself. The combination of solar, battery, and EV charging is the ultimate green home package.
Why home EV charging makes sense
Public charging is getting faster but remains expensive — often 60–80p/kWh. Charging at home from solar costs effectively zero, and overnight on an Octopus Go tariff just 7.5p/kWh. Over 10,000 miles a year, the difference is over £1,000.
Smart chargers go further still. They communicate with your battery, solar inverter, and energy tariff to automatically charge your car at the optimal time — maximising solar use and minimising cost without you lifting a finger.
Vehicle-to-home (V2H) and vehicle-to-grid (V2G) technology is now also available, allowing your EV's battery to power your home during peak electricity pricing periods.
Key Benefits
☀️
Charge on Solar
Smart chargers detect surplus solar and automatically divert it to your car — fuel that costs nothing.
⏰
Smart Scheduling
Set charge windows aligned to cheap overnight tariffs. Your car is always ready by morning.
🔄
V2H Capability
With compatible vehicles, use your car's battery to power your home during expensive peak hours.
📱
Full App Control
Monitor charging sessions, set targets, review costs, and control remotely from any smartphone.
🔌
Fast 7.4kW Charging
A 7.4kW home charger adds around 25 miles of range per hour — over 200 miles overnight.
💷
OZEV Grant Available
The EV Chargepoint Grant offers up to £350 off a home charger installation for eligible properties.
Smart EV Chargers
⚡
Ohme Home Pro
The UK's most popular solar-integrated smart charger. Links to Octopus tariffs automatically.
From £799 installed (with grant)
🔌
Zappi by myenergi
The original solar diverter charger. Eco+ mode maximises solar charging with zero waste.
From £849 installed (with grant)
🏠
Indra Smart Pro
V2G-ready charger for compatible vehicles. Export from your car back to the grid and earn.
From £999 installed (with grant)
📱
Pod Point Solo 3
Reliable, smart, and app-controlled. Excellent value and compatible with all solar systems.
From £699 installed (with grant)
Add EV charging to your green home
Whether you have solar already or are starting fresh, we'll design the perfect integrated EV charging solution for your home.
🤖 AI Technology
Your home. Intelligently optimised.
AI-powered energy management systems learn your routines, predict weather patterns, and automatically orchestrate your solar, battery, heat pump, and EV to minimise your bills and maximise your green impact.
The brain of your green home
A green home with multiple technologies — solar, battery, heat pump, EV — is only as smart as the system managing them. AI energy management systems connect all of these devices and make thousands of micro-decisions every day to optimise your home's performance.
Machine learning models analyse your historical usage, live energy prices, weather forecasts, and grid carbon intensity. They then decide: should the battery charge now from solar, or wait for a cloud to pass? Should the EV charge now or in three hours when the wind picks up and prices drop?
The result is a home that continuously gets smarter, cheaper to run, and lower in carbon — without you needing to think about it.
AI Capabilities
🧠
Predictive Learning
AI learns your daily routines and anticipates your energy needs — pre-heating, pre-charging before you even wake up.
🌤️
Weather Forecasting
72-hour solar yield predictions adjust your battery strategy in real time so you're always fully charged for cloudy days.
📊
Carbon Optimisation
Algorithms track grid carbon intensity and shift flexible loads to times when the grid is greenest.
💰
Price Arbitrage
Real-time tariff data means your battery and EV charge when electricity is cheapest and discharge when it's most expensive.
📱
Unified Dashboard
One app to see all your devices, live energy flows, historical performance, savings, and carbon reduction in one place.
🔮
Anomaly Detection
AI spots unusual consumption patterns — from a faulty appliance to a leaving a window open — and alerts you instantly.
AI Energy Platforms
🤖
Homely Smart Control
UK's leading AI heat pump controller. Learns your preferences and cuts heat pump running costs by up to 25%.
From £299 + subscription
⚡
Hildebrand Glow
Smart meter data integration with AI insights. Beautiful dashboards and Octopus tariff optimisation.
Free app + hardware from £49
🏠
Loxone Smart Home
Full-home automation platform integrating lighting, heating, solar, and security with a single AI brain.
From £2,500 system cost
🌿
GivEnergy Cloud
Premium energy management for GivEnergy systems with advanced grid services and VPP participation.
Included with GivEnergy hardware
Make your home truly intelligent
Whether you have an existing system or are starting from scratch, we'll design and install the right AI platform for your home.
⚡ AI Tariff Finder
Find your perfect energy tariff
Answer 5 quick questions and our AI will match you to the best Octopus or EDF tariff for your home — and tell you exactly how much you could save.
✅ Takes 60 seconds
🎯 Personalised to your home
💷 You & us both earn on a switch
Step 1 of 5
What green technology do you have at home?
Select all that apply — this is the biggest factor in choosing your tariff.
✓ Select all that apply
Do you have a smart meter?
Smart meters unlock the best time-of-use tariffs — essential for Octopus Agile and Go.
When do you use the most electricity?
Your daily routine determines which tariff structure saves you the most money.
What's your typical monthly electricity bill?
An estimate is fine — this helps us calculate your potential savings.
£80/month
£20£150£300+
Who is your current energy supplier?
This helps us understand your switching journey and the best next step for you.
Analysing your energy profile…
Our AI is matching your home to the best available tariffs
Reviewing your green technology setup
Checking current tariff rates
Calculating potential savings
Preparing your personalised report
Your personalised tariff report
Based on your answers, here's what our AI recommends for your home.
🎁 Use our referral link — £50 credit for you when you switch.
🤖This recommendation is generated by AI based on the information you provided and current UK tariff data. Energy prices and tariff terms change regularly — always check the latest rates on the supplier's website before switching. This page contains referral links; Decarbonarma may earn a commission if you switch.
🏠 Heat Loss Estimator
How well does your home hold its heat?
Estimate your home's Heat Transfer Coefficient (HTC) — the key number that determines the right heat pump size. Cross-check your MCS installer's quote before you sign.
Methodology based on the work of Michael de Podesta — physicist and heat pump pioneer.
📊 Based on real physics🎯 MCS sanity check tool🤖 AI-powered analysis🆓 Completely free
🌡️ Household Temperature Profile
Enter the temperatures you keep different zones of your home at during winter. This lets us calculate your average daily indoor temperature — a key input for the heat loss calculation. Think about morning, daytime and sleeping temperatures.
Lounge, kitchen — when occupied
Hallways, spare rooms, daytime bedrooms
Bedrooms overnight
Typically 6–8 hrs (evenings + morning)
Typically daytime if out at work
Overnight sleeping hours
Calculated average daily temperature:
—
🚿 Hot Water Usage
We need to separate the gas used for hot water from gas used for space heating. This is important because a heat pump handles both but at different efficiencies — and getting the split right gives a more accurate HTC.
Each person uses roughly 50 litres of hot water per day
This affects hot water consumption significantly
Estimated daily hot water energy:
—
⛽ Gas Consumption & Boiler
Your annual gas consumption is the foundation of the calculation. Look at last year's gas bill for the total kWh figure — or use your smart meter data. This is the single most important number you'll enter.
5,000 = small flat · 15,000 = average house · 30,000+ = large house
Check your boiler's installation date if unsure
The coldest temperature your heat pump must handle. -3°C suits most of England; -7°C for Scotland.
🏠 Your Home Details
A few details about your home help us calculate the insulation figure of merit and give context to your heat loss result — and help our AI give you more specific advice.
Total heated floor area across all floors
Enter this if you have a quote to cross-check
Sometimes shown on MCS design documents
All data stays in your browser — nothing is sent to any server except the anonymised values used to generate your AI analysis via Claude.
—
Heat Transfer Coefficient
W/°C
—
Suggested Heat Pump Size
kW
—
Insulation Figure of Merit
kWh/m²/year
—
—
📊 Calculation Breakdown
⛽ Annual gas consumption
—
🚿 Hot water energy (estimated)
—
🔥 Space heating energy (thermal)
—
📍 Location heating degree days
—
🌡️ Average indoor temperature
—
🏠 Reference temperature (HDD basis)
—
📐 Floor area
—
🔍 MCS Quote Sanity Check
Compare our estimate against your MCS installer's figures. A well-sized heat pump should be within 20–30% of this estimate. Large discrepancies warrant a conversation with your installer.
Our estimate — Heat Pump Size
—
Based on your gas usage & location
MCS installer's figure
Not entered
From your MCS design document
Enter your MCS figures in the Home Details step to see a comparison.
🤖
AI Analysis & Recommendations
Powered by Claude — personalised to your specific home profile
Analysing your home's heat loss profile…
📱 Setup Guide
Setting up Homey Pro for your green home
The only UK-specific guide to getting Homey Pro working with your battery, solar, smart meter, and Octopus tariff — written for Decarbonarma customers, not developers.
🕐 30–60 mins to set up🇬🇧 UK-specific advice✅ No coding required🔋 Battery + solar + EV
🛒
Choose Hub
⚡
Smart Meter
🔋
Battery App
🐙
Octopus
⚡
Flows
🌿
VPP Ready
Step 1 — Choose your hub
Homey Pro is the local smart home hub that sits between your battery, solar, and Octopus tariff — acting as the brain that makes everything talk to each other. There are two current models to choose from.
💡
Both Homey Pro models are officially supported until at least June 2031 and receive identical features and updates. The only difference is RAM (4GB vs 2GB) and the inclusion of Z-Wave, Bluetooth, and Infrared in the larger model.
⭐ Recommended🏠
Homey Pro (2026)
The current flagship. 4GB RAM, quad-core processor, all 8 wireless protocols including Z-Wave and Matter. Handles large battery setups, complex Flows, and multiple battery apps simultaneously without slowing down.
Best for: homes with battery + solar + EV + heat pump. Future-proof for VPP participation.
£399 — homey.app
📦
Homey Pro Mini
Same core software as the Pro 2026, at £200 less. No Z-Wave, Bluetooth, or Infrared — but has Ethernet built-in. If your battery system uses Wi-Fi or Zigbee only, this is perfectly capable.
Best for: simpler setups with one battery brand and no legacy Z-Wave devices.
£199 — homey.app
What about Home Assistant?
Home Assistant (HA) on a Raspberry Pi or dedicated hardware is a more powerful but significantly more technical alternative. For users who are comfortable with YAML configuration files and want maximum control, HA with the Predbat plugin is the gold standard for battery optimisation on Octopus tariffs. For everyone else, Homey Pro gives 80% of the capability with a fraction of the setup time.
Feature
Homey Pro
Home Assistant
Setup time
30–60 mins
Several hours to days
Technical skill required
None
Moderate–high
Octopus Agile integration
Community app (in development)
Official integration, mature
Predbat battery optimisation
Not available
Full support
GivEnergy* support
Community app — see note
Excellent via local API
Tesla Powerwall support
Official app
Via Teslemetry/official
Huawei LUNA support
Community app
Excellent via Modbus
VPP webhook support
Built-in webhook trigger
Full webhook support
Mobile app quality
Excellent native app
Functional but complex
⚠️
GivEnergy note: GivEnergy Ltd entered administration on 9 April 2026 and has ceased trading. Existing GivEnergy systems will continue to work, but manufacturer warranties are now uncertain and software support may be affected. If you have a GivEnergy system, contact your installer. If you are choosing a new battery, we currently recommend Tesla Powerwall 3, Huawei LUNA2000, or SigenStor as alternatives.
Step 2 — Getting your smart meter data into Homey
This is the most commonly misunderstood step for UK users. Unlike European countries where smart meters have a P1 port, UK SMETS2 meters communicate differently — and the Homey Energy Dongle does not work in the UK.
🚫
The Homey Energy Dongle does NOT work in the UK. It uses a P1 port connector (RJ12) which is a European standard. UK SMETS2 smart meters do not have a P1 port — they use a proprietary Zigbee-based Home Area Network (HAN) that requires a licensed Consumer Access Device (CAD). Homey only ships the dongle to mainland European countries.
The UK solution: Hildebrand Glow CAD
The Hildebrand Glow CAD (Consumer Access Device) is currently the best option for UK homeowners wanting live smart meter data. Hildebrand are a licensed DCC Other User, meaning they can legally access your SMETS2 meter data independently of your energy supplier.
✅ UK Recommended📊
Hildebrand Glow Display + CAD
Connects to your SMETS2 meter via Zigbee, sends live data (10-second electricity, 30-min gas) to Hildebrand's servers, and makes it available via API, MQTT, and the Bright app. Compatible with Home Assistant and Homey.
Works with SMETS1 and SMETS2. Octopus Agile customers can see live tariff costs. API included free.
~£50 — glowmarkt.com
📡
Glow Zigbee CAD (no display)
Same data access as the display model but without a screen — just data. Lower cost option if you only need the API/MQTT feed for automation and are happy to view data in Homey or Home Assistant instead.
Ideal for technical users who want MQTT data flowing straight to Home Assistant.
~£35 — glowmarkt.com
1
Order your Glow CAD
Buy from glowmarkt.com. Download the free Bright app and register your account — you'll need these credentials to authorise the CAD to access your meter.
2
Register and pair to your meter
When your Glow CAD arrives, plug it in near your meter and follow the Bright app pairing process. Hildebrand will connect it to your specific meter via the DCC network — this can take 24–48 hours to activate.
3
Connect to Homey (via Bright app credentials)
Install the Glow (Hildebrand) app from the Homey App Store. Sign in with your Bright app email and password. Your electricity consumption, gas usage, and live costs will appear in the Homey Energy tab.
4
For Home Assistant users: enable MQTT
In the Glow app settings, enable the local MQTT feed. Point it at your Home Assistant MQTT broker IP. You'll get 10-second electricity readings as sensor.glow_electricity_power — ideal for Predbat and real-time Agile automation.
💡
Do you already have an Octopus account? If you're on Octopus, you can also pull your tariff and consumption data via the Octopus Energy integration (Home Assistant) or the community Octopus app (Homey) — no physical device needed. This is ideal for viewing half-hourly usage but doesn't give the live 10-second power readings that the Glow CAD provides.
Step 3 — Install your battery app
Each battery brand has its own Homey app. Most connect directly over your local Wi-Fi network — no cloud dependency needed for control, which is important for VPP dispatch reliability.
⚡
Tesla Car & Energy
Controls Powerwall 2 & 3 plus Tesla vehicles. Uses Tesla Fleet API. Requires a Tesla developer account (free). Charge/discharge modes, reserve %, SoC monitoring.
Official App
☀️
Huawei Solar
Controls Huawei SUN2000 inverter and LUNA2000 battery. Local Modbus connection — works without internet. Working mode, charge/discharge power, SoC.
Community App
🌿
SolarEdge
Monitoring and some control via SolarEdge cloud API. Generation, consumption, battery SoC. Note: control capability more limited than local-API brands.
Community App
🔋
Fox ESS
Full control via FoxCloud API. Charge/discharge schedules, working mode, SoC. Good integration, active development community.
Community App
⚡
Sigenergy / SigenStor
Local Modbus control via Home Assistant. Full charge/discharge capability. Strong UK installer network in 2026. Recommended GivEnergy alternative.
HA Recommended
🌱
GivEnergy
Community app using local network connection. Note: GivEnergy Ltd entered administration April 2026. Existing systems work but see Step 1 warning before choosing this brand.
⚠️ See Warning
Installing an app on Homey Pro
1
Open the Homey app → App Store
Search for your battery brand name. Both official and community apps appear here. Tap Install and wait for it to download to your hub (~30 seconds).
2
Add your battery as a device
Go to Devices → + → Add Device. Select your battery brand. You'll be asked for either your cloud account credentials (e.g. Tesla, FoxESS) or your inverter's local IP address (e.g. Huawei, SigenStor).
3
Find your inverter's local IP address
For local network connections, log into your home router and look for a device with your inverter's brand name. Assign it a static IP address so it doesn't change. Common addresses: 192.168.1.xxx. Your router admin page is usually at 192.168.1.1.
4
Verify in the Energy tab
Once added, open Settings → Energy in Homey. Your battery, solar generation, and consumption should all appear as live devices. This confirms everything is talking correctly before you build any Flows.
💡
Tesla Powerwall setup note: Tesla's Fleet API requires a free developer account at developer.tesla.com. You'll generate an API key and link it to your Homey app. This takes about 10 minutes and only needs doing once. The Powerwall then appears in Homey with full SoC, charge/discharge mode, and reserve percentage control.
Step 4 — Connecting Octopus Energy
The Octopus Energy integration brings your real-time tariff prices, consumption data, and Intelligent dispatch slots into Homey — enabling price-responsive automations. For UK users this is the most valuable integration you can add.
⚠️
UK status (May 2026): The official Octopus Energy Homey app is a community development — it is functional but not as mature as the Home Assistant integration. If you need the most robust Octopus + battery automation (particularly for Agile half-hourly price response), Home Assistant with the official Octopus Energy integration and Predbat is currently the stronger choice. That said, Homey + Octopus works well for simpler automations like scheduled EV charging and heat pump pre-heating.
Setting up the Octopus app on Homey
1
Install the Octopus Energy app
Search the Homey App Store for "Octopus Energy Integration". This is a community app — install it and open its settings page within Homey.
2
Get your Octopus API key
Log into your Octopus account at octopus.energy/dashboard. Go to Account → Personal Details → API Access. Generate a personal API key. This is what Homey uses to read your tariff data.
3
Enter your MPAN and API key
In the Homey Octopus app settings, enter your electricity MPAN (found on any Octopus bill or in your account) and your API key. This links Homey to your specific meter and tariff data.
4
Verify tariff data is flowing
After a few minutes, you should see your current Agile or Go rate appearing as a device in Homey. You can use this as a trigger in Flows — e.g. When electricity price drops below 10p → Start EV charging.
For Home Assistant users: Predbat + Octopus
If you're using Home Assistant, the official Octopus Energy integration is the most capable route. Combined with Predbat (free, open-source battery optimisation), it creates a fully automated system that:
✓
Reads your Octopus Agile half-hourly prices automatically
Tomorrow's prices download from Octopus every evening after 4pm — Predbat plans your battery charging schedule overnight to use the cheapest slots.
✓
Integrates Intelligent Octopus Go dispatch slots
If you're on Intelligent Go, Predbat reads Octopus's dispatch schedule and coordinates your EV charging and home battery to avoid conflict — so both charge at 7p/kWh overnight without fighting each other.
✓
Connects to Solcast for solar forecasts
Free Solcast API provides 48-hour solar generation forecasts. Predbat uses this to decide whether to charge the battery from the grid tonight, or wait for tomorrow's solar generation instead.
💡
Not on Octopus yet? Use our AI Tariff Finder to find the right Octopus tariff for your home setup. Switching takes about 3 weeks and you'll both earn £50 credit via our referral link.
Step 5 — Building your first Flows
Homey Flows are the automations that make everything work together. Each Flow has a When (trigger), optionally an And (condition), and a Then (action). Here are the four most valuable Flows for a UK green home.
Flow 1 — Charge battery from cheap overnight electricity
WHEN
→
Time is 00:30 (start of Octopus Go / Intelligent cheap window)
AND
→
Battery SoC is less than 80%
THEN
→
Set battery to Charge from Grid mode at maximum rate
Flow 2 — Switch to solar-priority mode at sunrise
WHEN
→
Time is 06:00 (or use sunrise trigger)
THEN
→
Set battery to Self-consumption / Eco mode (store solar, avoid grid import)
Flow 3 — Protect battery during peak hours (Octopus Agile)
WHEN
→
Octopus electricity price rises above 30p/kWh
AND
→
Battery SoC is above 30% (leave reserve for evening)
THEN
→
Set battery to Discharge mode — power the home from battery, avoid buying expensive grid electricity
Flow 4 — EV charging on cheap overnight rate
WHEN
→
EV is plugged in AND time is between 00:30 and 04:30
THEN
→
Enable EV charger (Zappi / Ohme / Pod Point) at full rate — charges during cheapest overnight window
💡
Advanced Flows: Homey Pro's Advanced Flow editor (available in the web app at my.homey.app) lets you create complex multi-branch automations with if/else logic, delays, and parallel actions. It's the right place to build more sophisticated energy management once you've got the basics working.
Step 6 — Get VPP-ready
Once your battery, smart meter data, and Octopus tariff are all working in Homey, you're ready to join the Decarbonarma Virtual Power Plant — earning passive income by allowing your battery to support the grid during peak demand events.
1
Set up your VPP webhook in Homey
Go to Settings → API Keys in the Homey web app and create a new API key with device control permissions. You'll provide this to Decarbonarma during VPP sign-up. Also note your Homey's external webhook URL: https://webhook.homey.app/[your-homey-id]/vpp-dispatch
2
Create the VPP dispatch Flow
In Homey Flows, create a new Flow with When: Webhook event "vpp-dispatch" received. In the Then action, set your battery to discharge at the rate specified in the webhook payload. Add a condition: Battery SoC > [your SoC floor]% as a safety check.
3
Create the VPP restore Flow
Create a second Flow with When: Webhook event "vpp-restore" received. This returns your battery to its normal operating mode (self-consumption or time-of-use) when the dispatch event ends.
4
Register for the Decarbonarma VPP
Complete the sign-up form we provide when you join the pilot. You'll need: your battery brand and capacity, your Homey webhook URL, your preferred SoC floor, and consent to the dispatch terms. We'll test the webhook before going live.
💡
Estimated setup time for all 6 steps: Allow 30–60 minutes for first-time Homey setup, plus another 30 minutes to install apps and build your first Flows. The VPP webhook setup takes about 10 minutes once everything else is working. Most customers are fully live within 2 hours of their Homey Pro arriving.
Ready to join the VPP?
Your battery is set up, Homey is running, and Octopus is connected. The last step is registering for the Decarbonarma Virtual Power Plant and starting to earn.
📄 Real-world analysis
Case studies & deep dives
Real data, real homes, real policy. Every piece here is built from primary sources — metered monitoring data, official government figures, peer-reviewed research — not green optimism.
🏡
Case study
Heat pumps · Solar · EVs · Home automation
Rose Cottage: from gas to nearly zero
177 m² stone cottage in rural Oxfordshire. Staged decarbonisation: 15.8 kWp solar, Sunamp 300e, Daikin air-to-air (SCOP 4.50 verified), SuperFOIL insulation, Homey automation. Gas down 60%. Air-to-water and gas disconnection planned next.
🚗
Case study
EVs · Running costs · Gulf conflict
Two cars, two fuels, one brutal comparison
Mercedes GLE diesel + Mini diesel → EQE 53 AMG + Mini Electric. 7p/kWh charging. £3,948/year total running cost saving. EQE bought at 18 months for £60k (48% off new). With diesel at £1.85/litre, the economics only widen.
🔬
Data analysis
HeatpumpMonitor.org · 639 systems · Brands
Does brand matter? What 600+ real heat pumps actually tell us
Vaillant vs Mitsubishi vs Samsung vs Daikin — finally answered with real data. Within-brand Carnot % variation (up to 17 points) is larger than between brands. Commissioning dominates performance. Brand is secondary.
📊
Data review
HeatpumpMonitor.org · Flow temp · SPF
HeatpumpMonitor.org — what the data actually says
A readable summary of the UK's most rigorous open heat pump dataset. 639 systems, average SPF H4 3.86, and a clear finding: flow temperature is the single strongest predictor of performance (R²=0.55). Design guidance direct from the data.
⚛️
Policy analysis
Nuclear · SMRs · Rolls-Royce · Wylfa
The 70-reactor question: can SMRs replace Britain's ageing gas fleet?
UK signed its first SMR contract April 2026 — Wylfa, 1.4 GW, mid-2030s. Replacing the full gas fleet needs 70 reactors, £175 billion, 30 years. Here's the full deployment timeline, levelised cost analysis, and investment comparison.
🛢️
Policy analysis
North Sea · Fracking · Energy policy · May 2026
Drill, baby, drill? The case for and against UK domestic fossil fuel production
The debate is settled — permanent North Sea licensing ban in the King's Speech, May 2026. Both sides examined honestly. Verdict: right decision, incomplete plan. The gas gap and worker transition remain unresolved.
🔥
Case study
Thermal storage · Sunamp Thermino 300e · Solar
The heat battery that replaced our hot water tank in four hours
When Rose Cottage's hot water cylinder failed, a Sunamp Thermino 300e went in the same day and was charging from solar by midday. Compact phase-change thermal storage in practice — and why it's been delivering near-free hot water ever since.
Decarbonarama Magazine
In-depth analysis. Real data. Real homes.
Long-form investigative journalism and data-driven analysis on the UK and global energy transition — from grid infrastructure and wasted wind to heat pumps, boilers and battery storage.
Filter:
🔋
Case studyH1 2026
Six months, four arrays, one battery — the real H1 2026 numbers
North, South, Garage and the original Sonnen array compared panel-by-panel, plus battery cycling, grid position and the real financial return for H1 2026.
Read article →
🔆
Deep diveJune 2026
Samsung EHS Quint: one box, five modes, free hot water from cooling
The first residential heat pump to do air-to-air and air-to-water from one outdoor unit — with heat recovery that makes hot water while it cools. Specs, the grant angle, and the honest caveats.
Read article →
🏠
Case studyAs seen on Skill Builder
I re-roofed with Superfoil and solar — here's what happened
Whole-home energy now a £20/month direct debit. The real cost, 6.91 MWh of metered output, the north-roof myth busted, and the free scratched panels that became my best producers.
Read article →
❄️
Case studyAs seen on Skill Builder
Air-to-air + Sunamp instead of a gas boiler
My air-to-water quote was £27,000. My A2A + Sunamp was ~£10k all-in — heating, cooling and all the hot water. The honest cost, the grant catch, and who it suits.
Read article →
🔥
Buyer's guide2026
Is a heat pump worth it in the UK? An honest 2026 answer
No sales pitch. The £7,500 grant, real running costs vs gas, the bit the adverts won't tell you, and exactly when it isn't worth it yet.
Read article →
☀️
Buyer's guide2026
Are solar panels worth it in 2026? The real numbers
The actual 2026 cost of solar and a battery, honest payback maths by region, and when it's genuinely not worth it. From someone who monitors every panel.
Read article →
♨️
OpinionJune 2026
Shhh… air-to-water heat pumps are dead
Cost, complexity and a £5,000 grant gap are the only things keeping them alive. Air-to-air now does heating and cooling — a metered 444% SCOP and £5,300 at Rose Cottage. Plus Daikin's Altherma 4 X prototype.
Read article →
🔌
Deal watchJune 2026
Can an EV pay for itself? Almost.
We run the free-car test on the Frontera: can the fuel and tax savings, plus a cheap EV tariff for the whole home, cover the monthly payment?
Read article →
🚗
Deal watchJune 2026
The cheapest new car in Britain? £138 a month
A new electric SUV for less than a city car. The true all-in cost with tax, insurance and 7p charging — and how an EV unlocks a cheap tariff for your whole home.
Read article →
⚡
Buyer's guideJune 2026
The top 5 home EV chargers for 2026
Ohme, Zappi, Hypervolt, Indra and Easee — ranked on popularity, tech and integration. Plus Intelligent Octopus Go: the good, the bad and the ugly.
Read article →
🌍
Global reviewMay 2026
Coal has been beaten. Now comes the hard part.
Renewables overtook coal globally for the first time. China 230GW. UK 98.8% zero-carbon. India 5 years early. The full H1 2026 scorecard.
Read article →
🌬️
InvestigativeMay 2026
The wind is blowing. The turbines are switched off. You're paying for it.
£1.5bn wasted in 2025. Seagreen curtailed 71% of the time. The B6 bottleneck, the EGL cables, and what fixes it — and when.
Read article →
🔋
Thermal storageMay 2026
What if Scotland's wasted wind filled a Sunamp and a ZEB too?
Three UK manufacturers. 50.7 GWh distributed storage. 86% less carbon from hot water — peer-reviewed. The triple thermal cascade.
Read article →
⚡
Grid analysisMay 2026
Can the UK grid actually handle it?
The maths of electrifying every home and car. 114GW unmanaged peak. The 100A fuse problem. £40.7bn distribution gap. Smart storage as the answer.
Read article →
☀️
Case study · Real dataMay 2026
COP 4.8 in Scotland. No borehole. No noise. 954 days of proof.
Barry Sharp's NIBE S1155 PVT: 12,542 kWh in, 59,748 kWh heat out. Ground source performance from a West Lothian rooftop.
Read article →
🔥
Pragmatic guideMay 2026
If gas is still your only option, do it properly.
Viessmann Vitodens 100-W vs Intergas Combi Compact HRE. Proper sizing, modulation, weather comp, Danfoss Dynamic Valves — the complete guide.
Read article →
🔌
Grid warningMay 2026
The Netherlands is running out of grid. The UK is next.
The Dutch electrified faster than they built the network — and hit the wall. Connection queues, frozen projects, and the warning signs Britain is already showing.
Read article →
🦫
Nature & carbonMay 2026
The animals quietly saving the climate
Reintroduce a predator, watch the carbon return to the soil. Why some of the most powerful climate interventions come from rewilding, not technology.
Read article →
📈
FinanceMay 2026
You decarbonised your home. Should you have bought the stocks instead?
A hard-nosed comparison: the return on insulating, electrifying and generating at home versus putting the same money into green equities.
Read article →
❄️
Heat pump newsMay 2026
SCOP 6 has already been broken — by a startup you've never heard of
Tyrolean manufacturer Lambda Wärmepumpen has pushed seasonal performance past SCOP 6. What it means for the efficiency ceiling of home heat pumps.
Read article →
☀️
Buyer's guide2026
Buy cheap or go premium? The real quality differences in solar
Budget vs premium panels, the brands everyone argues about, and whether SunPower, Aiko and Tesla badges are actually worth the extra money.
Read article →
🔋
Storage & strategyMay 2026
Shell bought the future of home energy — then put it in a drawer
Shell acquired sonnen, a leader in home batteries and virtual power plants — then let it stall. The corporate strategy story behind the technology.
Read article →
📩
Read the full story
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