Backup power is shifting fast. See whats changing with batteries, generators, compliance and client expectations — and how to turn it into profitable work.
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Power cuts used to mean a torch and a takeaway. Now clients want silent backup, app control, and a clean handover that just works. You’re being asked for batteries, generators, hybrid inverters, and sometimes to "make the whole house run as normal". This guide breaks down what’s changing, why it matters to your business, and how to prepare. We’ll cover the current landscape, the big shifts for 2025, the compliance pieces (G98/G99, BS 7671, siting), the impact on delivery, and a practical 30‑day action plan you can put to work immediately.
Many contractors find clients default to what they’ve seen online: a shiny battery on the wall or a big green generator in the garden. The problem is matching expectations to the right solution, budget, and local rules.
A client in a semi‑detached asks for "whole‑home, no cuts". After a quick load review, you find essentials sit around 4 kW continuous (fridge/freezer, lighting, sockets, boiler controls, internet), with a 6–7 kW peak on kettle plus microwave. A 10 kWh battery with 5 kW inverter and a smart load panel covers 90% of what they care about. They skip the electric shower during outages and they’re happy — without paying for a 20 kW generator.
The market is shifting towards quieter, cleverer systems. Clients want seamless changeover and minimal hassle.
Backup jobs touch electrics, sometimes gas, and always client expectations. That means tighter scoping, paperwork, and neat commissioning.
Many contractors report the first few battery jobs add 2–3 extra admin hours just on documentation and DNO comms. Standardise your template set and it gets faster.
Oversizing kills budget. Undersizing kills confidence. A structured load review keeps you on target.
| Option | Transfer Speed | Runtime | Noise | Maintenance | Typical Install Time | Best Fit |
|---|---|---|---|---|---|---|
| Portable Generator (2–7 kW) | Manual | Hours (fuel‑limited) | High | High | Half day | Budget, short outages, manual use |
| Standby Generator + ATS (8–24 kW) | 10–30 seconds | Days (with gas/LPG) | Medium | Medium/High | 2–3 days | Whole‑home, long outages |
Use Donizo to narrate the scope on site, attach photos, and produce a clean, branded PDF (paid plans). Send via email, capture a legal e‑signature, and convert to invoice in one click when accepted.
If outages run for hours or days and loads are heavy (e.g., electric showers, cookers), a standby generator with ATS is the safer bet. If clients want silent, sub‑second switchover for essentials (lighting, sockets, IT, boiler controls) and like the idea of bill savings, a 5–10 kW hybrid inverter with 10–15 kWh of storage is ideal. Many contractors combine both on high‑end homes: battery for instant cover, generator for long runs.
Commonly, yes. Up to 3.68 kW per phase is generally under G98 (install then notify within 28 days). Above that, expect G99 prior approval before you install. If you’re offering V2H or any export‑capable system over the G98 threshold, plan the paperwork early and keep the client informed about timelines.
Follow the manufacturer’s siting guidance and local rules. In general: keep clearances, avoid escape routes and sleeping areas, allow ventilation if specified, and protect from water ingress and direct sun. A tidy, accessible location near the consumer unit and service head makes cable runs shorter and neater. Mount on suitable substrates and use approved fixings.
Never install or operate portable generators indoors. For standby units, site outdoors with correct clearances, secure the slab, use proper exhaust routing, and consider acoustic enclosures if neighbours are close. Local authorities often set tight night‑time noise limits, so discuss run schedules with the client.
Some vehicles and bidirectional chargers support V2H, but it’s early‑stage. Expect G99 approval, specific hardware, and careful integration to ensure safe islanding. If the client’s car or charger isn’t on a supported list, set expectations and offer a proven battery system instead.
Backup power is moving fast: quieter systems, smarter load control, and clients expecting instant switchover. Get the compliance right, right‑size the spec, and package clear options. The work itself is solid, but the winners are speeding up scoping and sign‑off. Use Donizo to capture site details by voice with photos, send a professional proposal, collect a legal e‑signature, and convert to invoice without re‑typing. That’s how you turn today’s backup demand into smooth, profitable jobs.
| Battery + Hybrid Inverter (5–15 kWh, 3–10 kW) | Sub‑second | Hours (capacity‑limited) | Low | Low | 1–2 days | Essentials, quiet, bill optimisation |