Are solar panels worth it? Compare your home, quote and tariff

Start with the property and your plans

Ask the installer to explain usable roof area, shading, orientation and roof condition. Check who owns the roof and whether permissions are needed. If repairs are due, ask how doing them before installation changes the total cost.

Write down how long you expect to remain at the property and what you want the system to do. Lower daytime bills, electric-car charging and future electric heating are different design briefs. A larger system is not automatically the right purchase.

Separate electricity you use from electricity you export

Ask for annual generation and a separate estimate of how much you can use at home. Self-used generation avoids an import cost; exported generation earns the applicable export payment. Do not count both benefits for the same unit.

For a worksheet, annual bill benefit is self-used generation × avoided import unit price, plus exported generation × export unit price. Use pounds per kWh consistently. This is a simplified scenario: account for maintenance, replacements, finance and changing tariffs separately.

A worked example you can change

Fictional inputs: 3,000 kWh annual generation, 1,200 kWh used at home, 1,800 kWh exported, 25p avoided import price and 10p export payment. The calculation is £300 + £180 = £480 a year before other costs. At an assumed £6,000 installed price, simple payback is 12.5 years.

These figures are not a quote or market benchmark. Test lower generation and export payments too. Simple payback ignores finance, tariff changes, degradation and future spending. It is not a guaranteed return.

Price the battery separately

Request comparable quotes with and without storage. Ask for usable capacity, power limits, operating mode, warranty conditions and additional electrical work. Storage moves energy between times; it does not create energy.

Account for storage losses and the export payment given up when solar charges the battery. If grid charging is proposed, use the tariff’s actual terms. Avoid adding a battery saving to a solar saving when the same electricity is already counted in both.

Give each installer the same brief

Share the same electricity consumption, roof information and future plans. Request panel and inverter models, system size, generation assumptions, scaffolding and electrical work, commissioning documents, warranty responsibility and the payment schedule.

Compare exclusions and aftercare as carefully as headline price. Keep the written proposal. An initial price with unspecified extras is difficult to compare with an inclusive quote. Ask for written clarification before deciding.

Common questions