5 times solar panels might not be worth it yet
Five situations where UK solar panels may not make financial sense yet, and what to check before ruling them out completely.
Key takeaways
- Poor roof suitability can outweigh attractive headline savings.
- Very low electricity use can make payback longer.
- An expensive battery can weaken the financial case if the extra annual benefit is small.
1. The roof is heavily shaded or awkward
Shade doesn't have to kill a solar project, but heavy or badly timed shade can make the numbers hard. Chimneys, dormers, nearby buildings and trees all need to be factored into the generation estimate.
An awkward roof can still work if the design is careful, but it may need extra equipment, a smaller array or a more modest generation forecast. If the quote assumes perfect output from a compromised roof, be sceptical.
2. Your electricity use is very low
A household with low electricity use has fewer kWh to replace. That doesn't make solar impossible, but it can make the payback slower unless the system cost is low and export income is strong.
This is where system sizing matters. A smaller, simpler system may make more sense than chasing a large array that exports most of its generation at a lower rate.
3. The quote hides the assumptions
A solar quote should make the core assumptions easy to find. You want system size, annual generation, installed cost, battery cost, self-consumption, export rate, warranties and any DNO export limit.
If those details are missing, the payback claim is not ready to trust. Ask for a clearer breakdown or get another quote from an MCS-certified installer.
4. The battery is doing too much work in the payback
Battery storage can be useful, but Energy Saving Trust's battery cost guidance shows why it needs careful modelling. A 5kWh system around £4,600 is a serious add-on cost.
If the solar-only system looks reasonable but the battery pushes the total cost up sharply, judge the battery separately. It may still be worth it for tariff flexibility or backup, but the pure financial case has to earn its place.
5. The paperwork or grid connection is unclear
DNO, MCS and SEG paperwork can sound dull, but it affects whether the system is connected correctly and whether export payments are straightforward.
If the installer can't explain the DNO route, export limit, certification route and handover pack, pause. A cheap system with messy paperwork can create avoidable problems later.
What to do before you walk away
A weak first quote doesn't always mean solar is wrong for the home. It might mean the system is oversized, the battery is unnecessary, the export tariff is badly chosen, or the generation estimate needs correcting.
Run a careful solar-only scenario, then test a smaller system, a different export rate and a no-battery option. If the numbers still don't work, walking away is a perfectly sensible decision.
- Ask for roof-specific annual generation in kWh.
- Compare at least three quotes where possible.
- Use the export tariff you can actually apply for.
- Separate solar-only and battery payback.
- Check MCS, DNO and warranty paperwork before paying a deposit.
Sources checked
- Energy Saving Trust solar panel guideConsumer guidance on costs, payback, savings and maintenance.
- Energy Saving Trust battery storage guideConsumer guidance on home battery costs, storage limits and tariff use.
- Ofgem SEG guidance for generatorsOfficial SEG eligibility, certification, metering and payment guidance.
- Energy Networks Association Distributed Generation GuideG98 and G99 connection process guidance.