Should you install solar now or wait? Cost curves vs lost generation
A UK-focused guide to the real install-now vs wait decision. Learn the break-even logic (price drops versus lost savings), the few scenarios where waiting is rational, and the traps that keep homeowners stuck.
Should you install solar now or wait? Cost curves vs lost generation
“Solar prices might fall.”
“Electricity prices might fall.”
“Maybe a better battery is coming.”
“Maybe there will be subsidies.”
These thoughts are normal. They can also keep people stuck for years.
The useful way to decide is not “do I feel like now is a good time”.
It is:
- what you might gain by waiting (a cheaper system)
- what you lose by waiting (a year of generation and savings you could have earned)
If you want a quick postcode-level baseline for output and savings where you live, start here: Find your postcode
This guide gives you a clean UK-specific framework that stays honest, even when you do not know the future.
If you have not read these two yet, they are the foundation:
- Solar payback periods in the UK: why averages mislead homeowners
- Is solar still worth it without generous subsidies? A UK-specific answer
Quick answer: should you install now or wait?
- Waiting has a cost: you lose the self-use savings and SEG export income you would have earned.
- Price falls are not guaranteed: installers, labour, scaffolding, and demand drive quotes as much as panel prices.
- Use a break-even test: “Will the expected price drop be bigger than one year of savings?”
- The best “timing” lever is often boring: get good quotes, right-size the system, and avoid expensive extras.
Assumptions and variability
- We talk about system size in kWp, power in kW, and energy in kWh, and we reference SEG export payments (see Glossary).
- We assume a typical UK grid-connected home solar system, not off-grid setups.
- We assume you are deciding mainly on household economics and practical value, not trying to time a market perfectly.
- What varies most between real homes: your self-use share (daytime usage), your install price and roof complexity, shading, and your import and export rates.
- If you want the modelling assumptions behind SolarByPostcode pages (yields, rates, and savings calculations), see: Data sources and methodology
The decision in one sentence
Waiting is only rational if the expected price drop over the waiting period is larger than the savings you would have earned during that period.
That is it.
Everything else is just guessing about inputs.
The friendly version of the break-even test
You do not need a perfect model. You need a reality check.
Ask:
1) If I wait one year, what is the most plausible price drop?
2) If I install now, roughly how much would I save over the next year?
If (1) is clearly bigger than (2), waiting can be rational.
If not, waiting is usually just delay.
The “how much would I save” part is exactly what the postcode baseline helps with:
- use Find your postcode to anchor expected output and a typical savings range
- then adjust for your household pattern (daytime vs evening use)
If you want the clearest intuition for why daytime usage matters, read:
And for the two-price model behind savings:
Table 1: Install now vs wait (the real trade-offs)
The key point: “wait” is not free. It has an opportunity cost.
What actually drives solar prices in the UK
People assume solar price is mainly “panel prices”.
In reality, a quote is often dominated by things that do not follow a neat global cost curve:
- labour and installer availability
- scaffolding and roof access
- roof complexity (valleys, dormers, awkward cable runs)
- demand cycles (busy seasons, regional installer backlogs)
- design choices and padding (over-specified inverters, “premium” add-ons)
That is why “solar prices will fall next year” is not a safe assumption for any specific home.
If you want to focus on what you can actually control, start here:
- How to compare solar quotes in the UK: a numbers-first checklist
- Solar panel cost in the UK: the honest 2026 price range and what actually drives it
The hidden cost of waiting: lost generation is not theoretical
When you wait, you do not just “pause”.
You lose real kWh that your roof would have produced.
And in the UK, those kWh have two money outcomes:
- self-used kWh avoids buying at your import rate
- exported kWh earns your SEG rate
Even if your export rate is modest, export is still value. It is not “wasted”.
If you want the cleanest explanation of this “two prices” model:
Table 2: A practical break-even test you can do in 10 minutes
This table is not trying to be precise. It is trying to stop you getting stuck.
If you want a more structured payback band approach (which helps with this decision), read:
The few cases where waiting is genuinely rational
Most “wait” arguments are vague. These ones are concrete.
1) You have a near-term roof constraint
Examples:
- roof needs replacement
- structural work is planned
- you are about to do a loft conversion, extension, or dormer
- the roof is being re-tiled soon
If your roof is changing anyway, waiting can be rational because:
- a re-roof later can force removal and reinstall costs
- you may end up with a better layout after the works
2) Your house move is a real probability, not a thought
If you are likely to move soon, the best question is not “is solar worth it”.
It is:
- will I personally recoup meaningful savings before I move?
In that case, waiting may be rational simply because you will not be around to capture the benefits.
3) Your quote is clearly inflated and you have time to shop properly
Sometimes the “wait” decision is really:
- “I should not accept a bad quote.”
That is not waiting for the market. That is avoiding overpaying.
If this is you, do not delay blindly. Use the time to get like-for-like quotes and compare properly:
- How to compare solar quotes in the UK: a numbers-first checklist
- Inverters explained (UK): what matters, what doesn’t, and what gets oversold
4) You expect a big change in your own usage pattern
If you expect a change that will materially increase self-use soon (for example, sustained work-from-home, or an EV with daytime charging), waiting can make sense.
But notice: this is still not “waiting for subsidies”.
It is aligning the install to your household pattern.
Common traps that keep people stuck
Trap 1: Waiting for a perfect subsidy or policy change
The UK solar case today is not built on big subsidies. It is built on self-use savings plus SEG export value.
This is the clearest explanation of that:
Trap 2: Waiting for a perfect battery
Batteries can be rational for some households, but solar does not require a battery to make sense.
If someone implies “it only works with a battery”, read:
Trap 3: Oversizing now “because future me will use it”
Oversizing can be sensible, but it can also push lots of low-value export and weaken the economics.
If you are tempted to size for a hypothetical future, read:
- Oversizing your solar system in the UK: when it pays off and when it does not
- Solar system sizing in the UK: choosing the right kWp without wasting money
Trap 4: Ignoring shading and assuming payback will be “average”
If you have repeatable shading, waiting does not solve it.
It just delays dealing with the real constraint.
Start here:
A practical “do this next” plan
If you feel stuck on timing, do these in order:
1) Use your postcode baseline to anchor expected output: Find your postcode
2) Decide whether you are more daytime-heavy or evening-heavy (self-use is the main lever)
3) Get 2 to 3 like-for-like quotes
4) Apply the break-even test: “Is a likely price drop bigger than one year of savings?”
5) If you install, right-size the system rather than chasing a perfect future
If you want the “regrets” guide that captures the mistakes people most often wish they avoided:
FAQs
Do solar prices always fall over time?
Not in a way you can rely on for a specific quote. Labour, scaffolding, roof complexity, and local demand move prices as much as panel costs.
What if electricity prices fall?
If import prices fall, self-use value falls, which can lengthen payback. That is why you should avoid overpaying and aim for a robust payback band rather than a fragile best-case.
Should I wait until I can afford a battery too?
Not necessarily. Many households do better by getting the solar system right first. Batteries should be a separate decision with its own justification.
How do I know my likely “one year of savings”?
Use your postcode baseline first, then adjust based on your usage timing and tariff. That is more honest than a generic UK average.
Next reads
- Is solar still worth it without generous subsidies? A UK-specific answer
- Solar payback periods in the UK: what actually drives the number
- Solar panel cost in the UK: what you actually pay and why quotes vary
- How to compare solar quotes in the UK: a numbers-first checklist
- The most common solar regrets (and how to avoid them before you install)