Automating your appliances to use solar power removes the daily effort of manual load shifting and ensures you capture as much free solar electricity as possible. Instead of remembering to run the dishwasher at noon or checking whether there’s enough generation to charge your EV, automated systems monitor your solar output and control appliances in real time – turning them on when you have surplus power and off when you don’t.
The most popular automation for solar homes is the immersion heater diverter, which sends excess solar to your hot water tank instead of exporting it to the grid. Smart EV chargers can match your charging rate to available solar, and home automation systems can orchestrate multiple appliances based on generation, battery state, and electricity prices.
This guide covers the main automation options for solar homes, from simple solar diverters to sophisticated whole-home systems, what they cost, how they work, and how much they can save.
Solar Automation at a Glance
| Purpose | Automatically use solar instead of exporting |
| Most common | Immersion diverter; smart EV charger |
| Cost range | £20 (smart plug) to £1,000+ (full system) |
| Typical savings | £100-£500+ per year |
| Self-consumption boost | +15-40% |
| Complexity | Varies from simple to advanced |
Why Automate
The Problem with Manual Control
| Issue | Impact |
|---|---|
| Forgetting to run appliances | Miss solar window |
| Away from home | Can’t respond to generation |
| Variable weather | Hard to predict best times |
| Daily effort | Gets tedious over time |
| Imprecise timing | Run too early/late |
What Automation Solves
| Benefit | How |
|---|---|
| Always captures surplus | Real-time monitoring |
| No daily effort | Set and forget |
| Optimises continuously | Adjusts to conditions |
| Works when away | Runs automatically |
| Precise matching | Matches generation exactly |
Self-Consumption Impact
| Setup | Without Automation | With Automation |
|---|---|---|
| Solar only | 25-35% | 45-60% |
| Solar + manual shifting | 40-50% | 55-70% |
| Solar + battery | 65-75% | 80-95% |
Self-consumption economics are directly tied to the gap between what you pay for import (typically 24-30p/kWh) and what you receive for export (4-15p/kWh under SEG). Use our Smart Export Guarantee calculator to see what your current export tariff is worth – the smaller your export payment, the more automation pays off.
Types of Automation
Overview
| Type | Cost | Complexity | Best For |
|---|---|---|---|
| Smart plugs | £15-£40 | Low | Simple scheduling |
| Solar diverters | £300-£600 | Medium | Hot water heating |
| Smart EV chargers | £300-£900 | Medium | EV solar charging |
| Smart appliances | Varies | Low | Individual devices |
| Home automation | £100-£500+ | High | Full system control |
| Inverter integration | Often included | Medium | Battery + loads |
Choosing the Right Approach
| Situation | Recommended |
|---|---|
| Have immersion heater | Solar diverter first |
| Have EV | Smart charger essential |
| Tech-savvy | Home automation system |
| Simple preference | Diverter + smart plugs |
| Have battery | Inverter scheduling + extras |
Solar Diverters
What They Do
| Function | Details |
|---|---|
| Monitor export | CT clamp on mains measures export |
| Divert surplus | Send excess to immersion heater |
| Proportional control | Varies power to match surplus |
| Priority to home | Only uses true excess |
| Zero export | Minimises grid export |
Popular Models
| Device | Price | Features |
|---|---|---|
| myenergi Eddi | £400-£500 | Two heater outputs; app; scheduling |
| iBoost+ | £350-£450 | Simple; reliable; sender unit |
| Catch Power | £300-£400 | Budget option; basic features |
| Solic 200 | £200-£300 | Entry level; single heater |
| Immersun | £400-£500 | Multi-output; display |
Installation
| Aspect | Details |
|---|---|
| Electrician required | Yes – mains connection |
| Installation cost | £100-£200 |
| Total cost | £400-£700 installed |
| Time | 2-3 hours typically |
| Disruption | Minimal |
Savings Potential
| Scenario | Annual Saving |
|---|---|
| Replace gas heating of water | £150-£300 |
| Replace electric immersion | £200-£400 |
| Payback period | 2-3 years typically |
Smart EV Charging
EV charging transforms solar economics – see our solar panels for EV charging guide for sizing, charger options, and how to maximise the free-solar-miles opportunity.
Solar-Aware Chargers
| Feature | Benefit |
|---|---|
| Solar matching | Charge rate follows generation |
| Surplus only mode | Only uses excess solar |
| Boost option | Add grid power if needed |
| Scheduled charging | Overnight cheap rate backup |
| App control | Monitor and adjust remotely |
Popular Smart Chargers
| Charger | Price | Solar Features |
|---|---|---|
| myenergi Zappi | £700-£900 | Best solar integration; CT clamp |
| Ohme | £450-£600 | Tariff integration; solar option |
| Wallbox Pulsar Plus | £500-£700 | Solar integration via app |
| Andersen A2 | £800-£1,100 | Premium; solar aware |
| Pod Point | £500-£700 | Basic solar mode |
Zappi Modes
| Mode | How It Works |
|---|---|
| Eco | Solar only – minimum 1.4kW surplus needed |
| Eco+ | Solar priority with grid top-up if needed |
| Fast | Maximum speed regardless of solar |
| Scheduled | Set times (e.g., overnight cheap rate) |
EV Charging Savings
| Charging Source | Cost per kWh | Annual (8,000 miles) |
|---|---|---|
| Public rapid | 50-80p | £1,200-£1,920 |
| Home standard rate | 24p | £576 |
| Home overnight rate | 7-10p | £168-£240 |
| Solar (free) | 0p | £0 |
| Mix (50% solar) | ~5p average | £120 |
Smart Plugs and Switches
What They Do
| Function | Details |
|---|---|
| Remote on/off | Control via app |
| Scheduling | Set times to run |
| Power monitoring | See consumption |
| Automation rules | Trigger based on conditions |
Popular Options
| Brand | Price | Features |
|---|---|---|
| TP-Link Kasa | £15-£25 | Reliable; energy monitoring |
| Tapo | £10-£20 | Budget; good app |
| Hive | £30-£40 | UK brand; integration |
| Eve Energy | £35-£45 | HomeKit; no cloud needed |
| Shelly Plug | £20-£30 | Home Assistant friendly |
Limitations for Solar
| Limitation | Impact |
|---|---|
| No solar awareness | Can’t respond to generation |
| Timer-based only | Fixed schedule; not dynamic |
| Need automation hub | For solar-responsive rules |
| On/off only | No proportional control |
Making Plugs Solar-Responsive
| Method | How |
|---|---|
| Home Assistant | Rules based on inverter data |
| IFTTT | Limited solar triggers |
| Inverter integration | Some inverters control plugs |
| Manufacturer apps | If they support solar input |
myenergi Ecosystem
UK-based myenergi makes an integrated family of solar-aware devices that talk to each other through a central hub. The Eddi diverter and Zappi EV charger are the two most popular products in UK solar homes, and once you add the Harvi wireless sender and (optionally) the Libbi battery, you have a complete solar automation ecosystem with a single app.
Overview
| Product | Function | Price |
|---|---|---|
| Zappi | Smart EV charger | £700-£900 |
| Eddi | Solar diverter | £400-£500 |
| Harvi | Wireless CT clamp sender | £80-£100 |
| Libbi | Home battery | £5,000-£8,000 |
| Hub | Connects all devices | £50-£70 |
How They Work Together
| Scenario | System Response |
|---|---|
| Surplus available | Priority: EV, Immersion, Battery |
| EV plugged in | Zappi takes priority if set |
| EV full | Eddi takes surplus for hot water |
| Water hot | Libbi charges battery |
| All satisfied | Export remainder |
Priority Settings
| Configuration | Best For |
|---|---|
| EV first | Need car charged reliably |
| Hot water first | Daily hot water essential |
| Battery first | Maximise evening self-use |
| Dynamic | Changes based on conditions |
If you’re retrofitting a battery to an existing solar array (common route into the myenergi ecosystem), our retrofitting batteries to existing solar guide covers AC-coupled vs DC-coupled options and how they interact with diverters.
Home Automation Systems
Popular Platforms
| Platform | Cost | Complexity | Solar Support |
|---|---|---|---|
| Home Assistant | Free (+ hardware) | High | Excellent |
| Node-RED | Free | High | Good |
| Hubitat | £100-£150 | Medium | Moderate |
| SmartThings | £50-£100 | Low-Medium | Limited |
| Apple HomeKit | Varies | Low | Limited |
Home Assistant for Solar
Home Assistant is the open-source home automation platform that sits behind most sophisticated UK solar setups. It’s free, runs on a Raspberry Pi, and integrates with virtually every mainstream inverter, battery, smart plug, and tariff. Once set up, it becomes the central brain that reads your solar data and decides what to switch on and when.
| Capability | How |
|---|---|
| Read inverter data | Integration with most brands |
| Control devices | Smart plugs; switches; chargers |
| Create automations | If solar > X, then turn on Y |
| Tariff integration | Octopus; Agile; others |
| Dashboard | Visualise generation and usage |
Example Automations
| Automation | Trigger | Action |
|---|---|---|
| Excess solar | Export > 1kW for 5 mins | Turn on smart plug |
| Low solar | Export drops to 0 | Turn off smart plug |
| Cheap rate | Agile price < 10p | Charge battery |
| High rate | Agile price > 30p | Discharge battery |
| Battery full + excess | SoC 100% + export | Turn on immersion |
Hardware Requirements
| Component | Options | Cost |
|---|---|---|
| Server | Raspberry Pi; NUC; old PC | £50-£200 |
| Smart devices | Plugs; switches; sensors | £10-£50 each |
| Network | Reliable WiFi or Zigbee/Z-Wave | Varies |
| Time investment | Setup and learning | Hours to days |
Inverter-Based Automation
Your inverter choice strongly affects what automation is possible out of the box – see our best solar inverters guide for brand-by-brand capability, or our GivEnergy review specifically if you’re interested in the most Home Assistant-friendly ecosystem.
Built-In Features
| Brand | Automation Capability |
|---|---|
| GivEnergy | Scheduled charging; tariff integration |
| Solax | Time-of-use settings; forced charge |
| Solis | Basic scheduling |
| Growatt | Time periods; charge/discharge |
| SolarEdge | Smart energy management |
| Sunsynk | Flexible time-of-use settings |
What Inverters Can Control
| Function | Details |
|---|---|
| Battery charging | When to charge from grid |
| Battery discharge | When to use battery |
| Export limiting | Reduce grid export |
| Backup mode | Reserve for outages |
| Third-party devices | Some support dry contacts |
GivEnergy Example
| Feature | Capability |
|---|---|
| Tariff support | Octopus Agile; Flux; Go |
| Scheduled charge | Set overnight charge window |
| Export control | Force discharge at peak |
| API access | Home Assistant integration |
| Predbat | Advanced automation add-on (see Predbat on GitHub) |
Automating Specific Appliances
Hot Water
| Method | Device | Cost |
|---|---|---|
| Solar diverter | Eddi; iBoost | £400-£600 |
| Smart switch | Shelly; Sonoff | £30-£50 |
| Timer + boost | Existing timer | Free |
| Heat pump integration | Built-in scheduling | Included |
Washing Machine/Dishwasher
| Method | How It Works |
|---|---|
| Delay timer | Built-in timer to solar hours |
| Smart plug | Turn on when solar available |
| Smart appliance | App scheduling |
| Limitation | Many need button press to start |
Pool/Hot Tub
| Device | Application |
|---|---|
| Pump timer | Run filtration during solar |
| Smart relay | Solar-responsive control |
| Diverter output 2 | Eddi second output to heater |
| Heat pump | Schedule for solar hours |
Heating (Heat Pump/Storage)
| Method | Implementation |
|---|---|
| Time-of-use mode | Pre-heat during solar/cheap periods |
| Weather compensation | Adjust to conditions |
| Smart thermostat | Schedule aligned with solar |
| Thermal mass | Heat home when generating |
Costs and Savings
Equipment Costs
| Solution | Cost | Installation | Total |
|---|---|---|---|
| Solar diverter | £350-£500 | £100-£200 | £450-£700 |
| Smart EV charger | £500-£900 | £200-£400 | £700-£1,300 |
| Smart plugs (5) | £75-£150 | DIY | £75-£150 |
| Home automation | £100-£300 | DIY time | £100-£300 |
| Full myenergi | £1,200-£1,600 | £300-£500 | £1,500-£2,100 |
Annual Savings
| Solution | Typical Saving | Payback |
|---|---|---|
| Solar diverter | £150-£300 | 2-4 years |
| Smart EV charger | £200-£500 | 2-4 years |
| Smart plugs | £30-£100 | 1-2 years |
| Home automation | £100-£200 | 1-2 years |
| Combined system | £400-£800 | 2-4 years |
Savings Calculation Example
| Component | Before | After | Saving |
|---|---|---|---|
| Hot water (solar) | £300/year | £50/year | £250 |
| EV charging | £500/year | £150/year | £350 |
| Appliance shifting | £100/year | £20/year | £80 |
| Total | £900/year | £220/year | £680 |
Battery storage adds another dimension to these calculations – see our best solar batteries guide for how batteries interact with diverters and smart chargers, and which brands give best automation support.
Installation Considerations
DIY vs Professional
| Item | DIY Suitable? | Notes |
|---|---|---|
| Smart plugs | Yes | Plug and play |
| Home automation | Yes | Software setup |
| Solar diverter | No | Mains wiring – electrician required |
| EV charger | No | Requires Part P certification |
| CT clamps | Sometimes | May require consumer unit access |
Compatibility Checks
| Check | Why |
|---|---|
| Inverter compatibility | Data access for automation |
| CT clamp space | Room in consumer unit |
| WiFi coverage | Devices need connectivity |
| Immersion heater type | For diverter compatibility |
| EV charging cable | Charger compatibility |
Getting Started
Recommended Order
| Priority | Item | Why First |
|---|---|---|
| 1 | Solar diverter | Best payback; daily use |
| 2 | Smart EV charger | Big load; high savings |
| 3 | Smart plugs | Low cost; easy wins |
| 4 | Home automation | Tie everything together |
Quick Wins
| Action | Cost | Time |
|---|---|---|
| Set appliance timers | Free | 10 minutes |
| Add smart plug to immersion | £20 | 5 minutes |
| Schedule EV charging | Free | 10 minutes |
| Download monitoring app | Free | 5 minutes |
Summary
| Aspect | Key Points |
|---|---|
| Purpose | Automatically use solar power |
| Best first step | Solar diverter for hot water |
| For EV owners | Zappi or smart charger essential |
| For tech enthusiasts | Home Assistant offers full control |
| Typical investment | £500-£1,500 |
| Typical savings | £200-£600 per year |
Automating your appliances to use solar power transforms your self-consumption without daily effort. A solar diverter like the Eddi or iBoost automatically sends surplus generation to your immersion heater, heating your water for free instead of exporting at 10p per kWh. This alone can save £150-£300 per year with a payback of 2-3 years.
For EV owners, a smart charger like the Zappi is almost essential. It can match your charging rate to available solar, ensuring you use free power whenever possible while seamlessly topping up overnight on cheap rates when needed. The savings on EV charging can exceed £300 per year compared to standard rate charging.
Smart plugs offer a low-cost entry point, and when combined with home automation systems like Home Assistant, you can create sophisticated rules that respond to solar generation, battery state, and electricity prices. This level of automation can boost self-consumption from 35% to 60% or higher without any daily intervention.
Start with the highest-impact automation for your situation – diverter if you have an immersion heater, smart charger if you have an EV – and build from there. The combined effect of multiple automation devices working together maximises the value of every kilowatt-hour your panels produce.
If you buy only one automation device, make it a solar diverter (Eddi £450-£500 installed). It’s the most reliable financial win: payback in 2-3 years, works the moment you plug it in, and requires no ongoing attention. Everything else in this guide is a refinement around that core.
If you’re tech-curious, install Home Assistant on a £80 Raspberry Pi alongside your diverter. You’ll get an inverter dashboard, per-appliance monitoring, tariff integration (Octopus Agile support is excellent), and the ability to build automations like “charge battery if tomorrow’s price forecast > 30p” or “turn on pool pump when export exceeds 2kW”. It’s a weekend project that pays back indefinitely. Avoid paying for proprietary home automation platforms – Home Assistant is free, open-source, and better-supported than any commercial alternative.
