Are Plug-In Solar Panels Worth It for Renters?

A south-facing 800W kit generates in the region of 700-900 kWh a year in the UK, with a typical figure closer to 800 kWh in southern England. At the current energy price cap of roughly 27p per kWh, that is worth around £110-£150 a year if you use most of what you generate - and less if you do not. Realistic ranges land somewhere between £80 and £200 a year depending on your home and habits. These are estimates, not guarantees; your own saving turns on the section below.

Without a battery, a plug-in panel only saves you money for the electricity you actually use while the sun is on it. Power you generate and do not use is effectively given away. That makes your daily routine the single biggest factor:

• Home during the day (retired, working from home, on parental leave): you might use 60-80% of what you generate, and the savings land at the top of the range.
• Out from nine to five: you may only use 30-40%, and the same panel saves far less.

So before you buy, be honest about when you are actually home and drawing power.

A mid-range compliant plug-in kit is expected to cost roughly £500-£700 once certified kits are on sale in the UK. Set that against a saving of, say, £130 a year and you are looking at a payback of around three to five years - sooner if you self-consume well, longer if you do not. There are no installation costs of the kind rooftop solar carries, which keeps the upfront figure low and renter-friendly.

This is the point that changes the whole calculation for renters. A plug-in system is portable - it unclips, unplugs and moves house with you. That means a three-to-five-year payback is achievable even if you move after two years, because you simply reinstall the same kit at your next home and carry on saving. Unlike rooftop solar, which you leave behind, plug-in solar is an asset you keep. For anyone who does not know how long they will stay put, that portability is worth as much as the annual saving itself.

Be realistic about the cases where the maths does not stack up: a flat that is genuinely empty through the working day and stays that way; no south-ish, unshaded spot for the panel; a heavily shaded balcony; or a situation where you cannot get landlord consent. In those cases the panel either generates too little or saves too little of what it makes, and the money is better spent elsewhere. If you can fix the self-consumption problem - by shifting some daytime usage or, later, adding storage - the picture improves.