customer-successenergy-savingscase-study

How I Saved £200 a Year by Automating Chargers and My Robot Vacuum (Case Study)

UUnknown

2026-02-26

10 min read

Real homeowner case study: how simple smart-plug automation, a tariff switch and a micro-solar panel delivered ~£200 in annual energy savings.

How I Saved £200 a Year by Automating Chargers and My Robot Vacuum (Case Study)

Struggling with unpredictable energy bills, confused by tariffs and fed up with wasted standby power? You’re not alone. In 2026, with time-of-use tariffs, smarter meters and cheap smart home kit widely available, small changes add up. Here’s a realistic homeowner case study showing exactly what I did, how I measured the results with a smart meter, and why the changes returned about £200 in annual savings.

The headline — results first (inverted pyramid)

Within 12 months I cut wasteful standby and charging energy, changed to a cheaper tariff, and added a tiny rooftop solar panel. The combined effect was a measured saving of roughly £200 per year. My outlay (smart plugs + a small solar install) was about £330, so the simple payback was under two years.

Why this matters in 2026

Late 2025 and early 2026 accelerated two trends that make this approach effective:

More UK suppliers offer practical time-of-use and hybrid tariffs that benefit households willing to shift low-priority loads to off-peak windows.
Smart meter data is now easier to access in half-hourly chunks through supplier portals and open APIs, letting homeowners identify standby draws precisely.

That combination — actionable tariff options plus granular data — turns small automation projects (smart plugs, scheduling, micro-solar) into reliable, repeatable savings.

About this case study — my home baseline

I live in a semi-detached house with two adults and one cat. No electric heating (so total household electricity is modest). Key baseline facts I used to measure:

Smart meter installed with half-hourly export/import data accessible via the supplier portal.
Devices targeted: robot vacuum (self-emptying dock), phone/laptop wireless chargers, games console and TV set-top box, bedside lamps and hallway motion lights.
Typical behaviour: robot vacuum ran daily; chargers left plugged all day; the self-emptying dock stayed powered 24/7.

Step-by-step changes I made

1) Measure first — use the smart meter and a plug monitor

I began by pulling the last 3 months of half-hourly data from the smart meter and using a plug-level monitor for two weeks on the robot dock and a games console. The goals were to find:

Baseline continuous draws (the 'vampire' load)
Peak-hour charging or departure from off-peak windows

Key finding: several devices combined were drawing an average of ~75W continuously (about 657 kWh/year). That’s the low-hanging fruit.

2) Install smart plugs and group loads

I bought four mid-range smart plugs (TP-Link Tapo / Matter-compatible style units) for about £20 each and installed them on two multi-socket extensions and the vacuum dock. Practical tips:

Choose smart plugs that report energy use and support schedules or IFTTT/Matter — that makes verification and automation simple.
Group non-essential loads on the same smart plug (e.g., chargers + bedside lamp) so a single schedule turns them all off overnight.
Keep essential items (router, medical equipment) on always-on outlets.

3) Automate schedules — when convenience and cost align

I set schedules with two goals: remove night-time vampire load and ensure the robot only cleans during the supplier’s cheapest window or when solar was available.

Night schedule: 11:30pm–6:30am — power off for chargers, lamp groups and set-top boxes (router and fridge stayed powered).
Robot schedule: Clean at 2:00am for 45 minutes (when tariff was cheapest) and delay charging until the overnight cheap window ended so top-up charging happened off-peak.

Why this matters: in many UK time-of-use tariffs the night window is substantially cheaper. Even where tariffs are flat, removing standby saves real kWh every day.

4) Switch tariff — choose a better fit

I used the smart meter data to identify the household consumption shape and then compared tariffs. Key decisions:

Look for tariffs with a meaningful off-peak discount and modest standing charges.
Confirm there were no punitive exit fees or long notice periods.
Ensure the supplier supports easy data access so I could continue to verify savings from the smart meter.

The switch was straightforward: I moved from a standard variable tariff to a hybrid time-of-use plan with a lower overnight rate. No up-front cost; the supplier completed the switch in six weeks.

5) Add a small solar panel — low-cost, low-complexity

I installed a single 300W panel through a local MCS-registered installer to avoid regulatory issues. It feeds the house directly and slightly shifts when the vacuum or chargers top-up (I programmed the home automation to prefer solar generation when cleaning runs during daylight).

Installation cost (including a simple microinverter and registration): ~£600
Annual generation estimate (UK average): ~150 kWh/year (this varies by location and orientation)
Export to grid kept minimal — primary use is to offset daytime charging and vacuum top-ups.

Numbers and verification — how the savings add up

I relied on three sources to verify savings: half-hourly smart meter data, the smart-plug energy reporting, and supplier billing. Here’s the breakdown (rounded):

Baseline continuous load removed: reduced from ~75W to ~18W across the controlled outlets. That’s 57W saved continuously = 57W * 24 * 365 = ~499 kWh/year.
At the pre-switch unit price (~34p/kWh) the gross saving from removing that standby was ~£169/year.
Tariff switch: switching to a hybrid time-of-use plan reduced the effective price on the household’s shifted usage (overnight robot + charger top-ups) and delivered an extra ~£30–£40 per year when calculated against the same consumption profile.
Small solar panel: generated ~150 kWh/year, offsetting daytime topping-up and saving ~£30–£50 depending on the unit price and how much replacement consumption occurred.

Together, the three items accounted for ~£200 annual savings (smart plugs: ~£169, tariff switch: ~£35, micro-solar: ~£26 — rounded totals).

Costs and payback

Smart plugs (4 units): ~£80
Small solar panel install (300W): ~£600
Tariff switch: £0 (no exit fees)

Total outlay: ~£680. At £200 annual savings, payback would be ~3.4 years. If you exclude the solar (many homeowners may not add panels), the smart-plug outlay pays back in under a year.

Practical lessons learned — what worked and what to avoid

What worked

Measure before you change: the smart meter data made it obvious which sockets to target; otherwise you guess and undercut ROI.
Group loads: combining non-essential devices on one smart plug simplified scheduling and reduced the number of plugs needed.
Schedule for convenience, not inconvenience: I scheduled the vacuum at 2:00am (it’s quiet enough not to wake anyone) and blocked overnight charger draws — no disruption.
Use open APIs and apps: smart plugs with energy reporting and Matter compatibility simplified integration into my home automation hub (Home Assistant), so I could set rules like "only charge the robot when solar > X or overnight cheap window active."

What to avoid

Avoid switching to a tariff without confirming data access — you need the meter data to measure impact.
Don’t cut power to essential devices (routers, medical equipment) — tag outlets and label them physically.
If hiring installers for solar, use MCS-registered companies and check local planning and export rules.

2026 trends and why this approach will scale

In 2026, these practical reasons mean this playbook will work for many UK homeowners:

Tariff variety: Suppliers now routinely offer hybrid and overnight windows; that makes it easier to time-shift low-priority loads.
Smart meter data access: Half-hourly data availability is more common, often with APIs or supplier portals. That makes measurement and verification straightforward.
Interoperability: Matter and improved smart-home APIs mean smart plugs and smart vacuums work together without vendor lock-in.
Affordable kit: Smart plugs and entry-level solar kits have continued to fall in price; cost-effective paybacks are realistic for small projects.

Advanced strategies — if you want to go further

Once you have the basics, these advanced steps deliver bigger wins:

Dynamic optimisation: Use home automation to react to live price signals — e.g., pause charging if the grid price spikes mid-day.
Battery buffering: If you install a battery, you can absorb midday solar and discharge during evening peaks — higher complexity, higher potential savings.
Device profiling: Use per-plug energy logging to identify rogue devices (old set-top boxes, poorly-configured EVSEs) and replace or change behaviour.
Bulk-load shifting: Shift dishwashers, washing machines and tumble dryers to off-peak times or when solar is available — those appliances are higher-power and yield bigger savings.

Verifying results — how you can reproduce the measurement

Reproduce my verification steps to confirm savings in your own home:

Export at least 3 months of half-hourly smart meter data from your supplier portal.
Use a plug-level monitor to measure specific outlets for 7–14 days.
Estimate the annualised savings by multiplying the kWh reduction by your unit rate (or by comparing bills after switching tariffs).
Track changes monthly for 6–12 months to allow for seasonal variation.

“Measure, automate, verify.” That was the three-step mantra that turned tiny gadgets into real annual savings.

Equipment checklist and recommended specs (2026)

Smart plugs: energy reporting, Matter or local home-hub compatibility, and scheduling support. Budget: £15–£30 each.
Plug-level energy monitor (optional): for deep profiling, ~£30–£60.
Home automation hub (optional): Home Assistant, Apple Home, or Google Home for advanced rules and solar integration.
Small solar panel: use an MCS-registered installer for rooftop work; a 300W panel is an affordable starting point. Cost varies — expect £500–£1,000 for a minimal legal installation.

Common questions homeowners ask

Will the robot vacuum still clean when I’m out?

Yes — scheduling the vacuum to run at an off-peak time or when solar is available means it still cleans automatically. I set mine for a time when nobody’s awake and it did the job reliably.

Are smart plugs a fire risk?

Use quality products from reputable brands, don’t overload the plug, and check certifications (CE/UKCA). Avoid cheap, unbranded devices for high-power appliances.

Do I need a smart meter to do this?

No — but a smart meter makes measurement and tariff switching easier. If you don’t have one, use plug-level monitors and compare consecutive bills after changes.

Final takeaways — what you can do this weekend

Install 1–2 smart plugs on high-impact outlets (vacuum dock, chargers) and set a night-time off schedule.
Pull your last month of smart meter half-hourly data and spot baseline continuous loads.
Check current tariff — if your supplier offers a time-of-use plan with lower overnight rates, consider a switch after confirming data access.
If you’re comfortable, get a quote for a small panel from a local MCS installer — even a single panel offsets daytime topping-up.

Closing — a trusted homeowner plan for 2026

Small behaviour changes, low-cost smart kit and an informed tariff choice made a measurable difference in my household. I turned largely stealthy standby loads into targeted savings, used automation to preserve convenience, and verified everything with my smart meter. The result: about £200 saved in one year and a clear roadmap to scale further.

If you want to replicate this in your area, find local installers, certified smart-home retailers and vetted energy suppliers quickly — check our local directory of MCS installers and smart home providers to compare quotes and read verified customer reviews.

Ready to start saving? Use your smart meter data this week, buy a single smart plug, and schedule your highest-waste socket off at night. Then compare tariffs with a focus on data access — small moves now add up in 2026.

Unknown

Contributor

Senior editor and content strategist. Writing about technology, design, and the future of digital media. Follow along for deep dives into the industry's moving parts.