Martin Lewis, founder of MoneySavingExpert, recommends solar panels as a long-term investment for many UK homeowners - but only if you pick the right installer, understand the numbers, and avoid the financing traps.
His Core Position
Lewis is broadly positive on solar for the right homes. His consistent message: generate your own electricity, reduce what you buy from the grid, earn from exporting surplus through the Smart Export Guarantee (SEG), and avoid any deal you don't fully understand.
In early 2026 he welcomed the government's Warm Homes Plan - which offers interest-free loans for solar, batteries, and heat pumps - but warned it must be "done right" to actually cut bills.
2026 Key Figures
| Metric | 2026 figures |
| Typical system cost (3.5-4kW) | £6,000-£8,000 installed |
| Battery storage (add-on) | £2,500-£6,500 depending on size |
| Annual bill savings | £500-£800 (with SEG income) |
| SEG export earnings | £100-£250/year (best fixed rates: 12-15p/kWh) |
| Payback period | 7-11 years |
| CO2 saving | ~1 tonne/year |
| Best for | South-facing, unshaded roofs; high daytime usage |
The Smart Export Guarantee (SEG)
The Feed-in Tariff closed to new applicants years ago. The SEG replaced it. Your energy supplier pays you per unit of electricity you export to the grid; rates vary significantly by supplier. Fixed-rate tariffs currently pay 12-15p/kWh at the top end, while some variable tariffs pay as little as 4.5p. Shopping around for a competitive SEG tariff is worth doing before you commit to an installer.
A 4kW system typically exports around 1,700 kWh per year if you have no battery, earning roughly £100-£250 annually. Add a battery and self-consumption rises from around 50% to 70-80%, reducing exports but significantly increasing the electricity you avoid buying at 24.5p.
Government Support in 2026
- Warm Homes Plan: Replaces ECO4 (which ended March 2026). Provides 0% interest loans for eligible homeowners and fully funded packages worth up to £30,000 for low-income households. Lewis has endorsed the scheme in principle but stresses it needs careful implementation.
- 0% VAT: All residential solar panels and batteries remain VAT-free through March 2027.
- Warm Homes Local Grant / Warm Homes Nest / Home Energy Scotland: Nation-specific equivalents for England, Wales, and Scotland respectively.
Funded grants still require low EPC ratings, low household income, or specific postcode eligibility. Most homeowners pay upfront or use a green loan.
Lewis's Warnings
Avoid "free" panel and lease deals. Companies that offer no-upfront-cost solar in exchange for roof access typically keep the SEG payments and most of the bill savings. These arrangements can complicate selling your home and may be treated as a liability by mortgage lenders.
Avoid debt-based financing you don't fully understand. Lewis says pay upfront if you can. If you need to borrow, use a reputable low-interest green loan - not a complex arrangement tied to the system itself.
Use MCS-certified installers. MCS certification is a requirement for SEG registration and most grant schemes. Don't compromise on this. Verify credentials and read contracts before signing anything.
DNO approval takes time. Your installer notifies the Distribution Network Operator before the system goes live. This can cause delays - your panels won't generate SEG income until approval comes through.
Is Your Home Suitable?
| Roof type | Verdict |
| South-facing, unshaded | Best results |
| East or west-facing | Still viable, ~15-20% lower output |
| North-facing | Not recommended |
| Flat roof | Can work with correct panel angle |
Payback in 2026
Lewis's historical payback estimate of 13-21 years no longer reflects current conditions. Higher electricity prices and better SEG tariffs have shortened paybacks considerably. Most households now see 7-11 years, and adding battery storage - while increasing upfront cost - pushes self-consumption high enough to improve the long-term return.
After payback, panels typically generate free electricity for another 15-20 years. Most systems carry 25-year performance warranties.
His Final Word
Lewis's position hasn't changed: solar is a viable long-term investment for suitable homes, but it is not a quick win. Do the maths on your own usage, get at least three quotes from MCS-certified installers, use an online calculator to model your savings, and walk away from any deal that seems too good or too complicated.
Contact us for a free, no-obligation quote from our MCS-certified team. We'll respond within one working day.