The upfront cost of a solar panel system is the single biggest barrier for most UK households. A typical 4kW system with battery storage runs £8,000—£14,000 installed, and even without storage you’re looking at £5,000—£8,000. That’s a significant lump sum for most families, which is why the solar finance market has expanded considerably over the past couple of years.
The good news is that you now have four realistic routes to solar: pay cash, take a loan, sign a power purchase agreement, or lease the panels. The bad news is that each option has a different cost profile, risk structure, and impact on things like property sales and Smart Export Guarantee eligibility. Here’s what you actually need to know.
Option 1: Paying Cash (Outright Purchase)
If you have the funds available, this is straightforwardly the best long-term financial option. You own the system outright, you get the full Smart Export Guarantee payments, your electricity savings are yours, and there’s no interest or monthly repayment eating into your return.
The numbers typically look like this: a 4kW system costing £7,000 saves around £900—£1,200 per year in electricity bills depending on your consumption patterns and how much electricity you use during the day. Add SEG payments of roughly £200—£400 per year and you’re looking at a payback period of around 5—7 years. Over a 25-year panel lifetime, the total return is often £15,000—£25,000 above the initial cost.
The obvious limitation is that not everyone has £7,000+ sitting in a savings account they’re willing to deploy. And if that money is in a savings account earning 4—5%, you need to factor in the opportunity cost. For most households, the solar return still beats current savings rates, but it’s worth doing the maths for your specific situation.
Option 2: Solar Loan
A solar loan lets you spread the cost over 5—15 years while still owning the system. Interest rates vary: specialist green energy lenders like Ecology Building Society and Triodos Bank offer rates in the 5—8% range for home improvement loans specifically for solar and energy efficiency. Some mainstream banks offer similar rates. Government-backed loans through the Great British Insulation Scheme and local authority retrofit programmes can be lower, though eligibility is means-tested.
Here’s the thing to check: does your monthly electricity saving plus SEG payment exceed your monthly loan repayment? If yes, the system is essentially paying for itself from day one. On a £7,000 system with a 10-year loan at 6%, monthly repayments are around £78. If your electricity saving plus SEG is £90—£110 per month, you’re cash-positive immediately.
The loan route gives you full ownership — SEG payments go to you, savings are yours, and you can take advantage of any future government grant schemes (grants typically go to the owner of the installed system, not to a lender or landlord). When you sell the property, the system adds value rather than complicating the sale with a third-party lease agreement.
Option 3: Power Purchase Agreement (PPA)
A power purchase agreement is structurally different from buying or borrowing. Under a PPA, a third-party company installs and owns the solar panels on your roof. You pay them a fixed rate per kilowatt-hour for the electricity the panels generate — typically 8—14p/kWh, compared to 24—30p/kWh you’d pay your supplier for grid electricity.
The appeal is zero upfront cost and immediate savings. The PPA provider handles installation, maintenance, insurance, and inverter replacement. You just pay a lower rate for electricity.
The complications are worth understanding. You don’t own the system, so SEG export payments go to the PPA provider, not you. The PPA agreement typically runs 20—25 years, and if you sell your house during that period, you need to either transfer the agreement to the buyer (which may or may not suit them) or pay an early termination fee. Some mortgage lenders have concerns about PPA agreements on properties, so it’s worth checking with your lender before signing.
Legitimate PPA providers include Eon Solar and Octopus Energy’s solar division, but the space has historically attracted some less-scrupulous operators, so check that any PPA provider uses MCS-certified installers, provides a clear written contract, and has clear terms for property sale scenarios.
Option 4: Solar Lease
A solar lease is similar to a PPA in structure — a third party owns the panels — but instead of paying per kilowatt-hour for solar electricity, you pay a fixed monthly lease fee regardless of how much electricity the panels generate. Typical lease fees are £30—£80 per month for a standard residential system.
This structure is simpler to understand than a PPA and gives you predictable fixed monthly costs. The trade-off is that you take on weather risk: in a sunny year, you get more electricity (and save more on your bill); in a cloudy year, you get less but still pay the same lease.
Solar leases are less common in the UK than in the US, where they’re an established product. Some UK companies offer hybrid arrangements that combine elements of both. If you’re being offered a lease, scrutinise the contract terms carefully: what happens at the end of the lease period? Does the company remove the panels, transfer ownership, or extend the lease?
Which Option Is Right for You?
To be honest, cash or loan ownership beats PPA and lease on long-term financial terms for most households. The SEG payment alone adds up to £5,000—£10,000 over 20 years that goes to the PPA provider rather than you under a third-party ownership model.
Where PPAs and leases genuinely win is the no-hassle, no-upfront-cost angle. If you can’t access finance or don’t want to take on debt, a PPA with a reputable provider delivers real savings from day one with no financial risk. For households who move frequently or who aren’t planning to stay in their current home for the long term, the shorter-term savings without long-term ownership commitment can also make sense.
A few practical points regardless of which route you choose:
Use an MCS-certified installer. This isn’t optional if you want to claim the Smart Export Guarantee or access any government grant schemes. The MCS mark is your guarantee that the installer meets technical competence and code of practice requirements. Check the MCS installer database at mcscertified.com before signing anything.
Get multiple quotes. Solar installation prices vary significantly. Three quotes from MCS-certified installers gives you a market sense and negotiating leverage. Don’t assume the cheapest quote is the best — check what’s included (scaffolding, monitoring systems, inverter warranty, aftercare).
Factor in battery storage. Adding a battery to a solar installation typically adds £3,000—£6,000 to the cost but significantly improves self-consumption (using more of the electricity you generate rather than exporting it at low SEG rates). The payback calculation changes substantially with storage.
The finance structure you choose matters less than getting the installation right. A good system on a suitable roof with a reputable installer will pay back under any reasonable finance scenario. A bad installation won’t pay back regardless of whether you own or lease the panels.