The short version
DESNZ figures for 2025/26 put the UK median at £1,595 per kW for systems up to 4 kW and £1,546 per kW for 4 to 10 kW, with higher North West means. On those numbers a 4 kWp array lands roughly between £6,400 and £7,200. Scaffolding, older roofs and slate can move a Northwich quote.
Where the price figures come from
The Department for Energy Security and Net Zero (DESNZ) publishes solar PV cost data every year, based on the total installed costs recorded on the MCS database. Two figures matter for a house. For systems up to 4 kW, the UK median in 2025/26 was £1,595 per kW of capacity; for systems of 4 to 10 kW it was £1,546 per kW. The median is the middle value, so half of households paid more and half paid less.
For the North West, the figures given are means drawn from a regional sample: £1,800 per kW up to 4 kW and £1,627 per kW for 4 to 10 kW. A mean is the plain average, and a minority of expensive jobs pulls it upwards, so it usually sits above the median. Setting a regional mean against a UK median therefore exaggerates the regional gap. The sensible reading is to treat the two as the lower and upper edges of a range for an ordinary roof.
| System size band | UK median | North West mean |
|---|---|---|
| Up to 4 kW | £1,595 | £1,800 |
| 4 to 10 kW | £1,546 | £1,627 |
A rough guide by system size
Multiplying the per-kW figures by some common system sizes gives a ballpark for an uncomplicated roof. This is arithmetic on published averages, rounded to the nearest £100. It is not a quote, and it does not include a battery.
| System size | At UK median | At North West mean |
|---|---|---|
| 3 kWp | £4,800 | £5,400 |
| 4 kWp | £6,400 | £7,200 |
| 5 kWp | £7,700 | £8,100 |
| 6 kWp | £9,300 | £9,800 |
Two things stand out. First, the cost per kW falls as systems get bigger, because scaffolding, the inverter, design time and much of the labour are fixed costs spread across more panels. Second, part of the jump between the 4 and 5 kWp rows comes from the change of band in the statistics; real prices move more smoothly than a two-band table can show. Use the table to spot a quote that is wildly out of line, not to judge one that is a few hundred pounds either way.
Turning a quote into a per-kW figure
When a quote arrives, divide the total price for the panels and inverter by the system size in kWp. For a 3.6 kWp quote, for example, divide the price by 3.6; if the answer falls between the UK median and the North West mean for its band, it is within the published range. Take any battery out of the total first, because the DESNZ figures are for solar alone, and note separately anything unusual the quote includes, such as roof strengthening or a new consumer unit. A per-kW figure well outside the published range is a prompt for questions, not proof of a problem.
What size suits a Northwich house?
System size is set by the usable roof, not by the type of house, but house type is a fair first clue to how much roof there is. The 2021 Census shows how different the wards in and around the town are:
- Witton: 44.7% of households live in terraced houses. A terrace usually offers one front and one rear slope, each limited by the width of the house, and scaffold access at the back can be awkward.
- Rudheath: 60.3% live in semi-detached houses. Semis vary; some have a single wide slope, others a hipped end that trims the usable area.
- Hartford and Greenbank: 50.5% live in detached houses, which often have more roof and sometimes a garage roof as well.
- Leftwich: 21.3% of households live in flats, where the roof normally belongs to the building rather than to any one household; see renters and flats.
More detail is on Northwich homes by ward. Whatever the house, ask the installer why they chose the size they did: whether the roof is full, whether shading limits the design, and how the size relates to your own electricity use, which is the subject of export and self-use.
Extras that move a Northwich quote
The per-kW figures are averages across a very wide range of jobs. The items below are the ones most likely to push a particular quote above or below them.
Scaffolding and access
Nearly every roof installation needs scaffolding. On a mid-terrace with no side passage, materials may have to come through the house or over the front, and scaffolding that stands on the pavement may need a licence from the council as highway authority. A detached house with a clear drive is simpler. Ask whether scaffolding is included, and for how many weeks.
Structural checks on older roofs
On an older Northwich house the survey may recommend a structural engineer, and the engineer may recommend strengthening before panels go on. Both add cost and time, and both are worth paying for where the roof needs them. A quote that arrives without anyone having inspected the loft has probably allowed for neither. What a proper inspection covers is set out in the roof structure check.
Slate roofs
Natural slate takes longer to work with than concrete tiles. Slates have to be removed or slipped one at a time around each bracket, some will crack, and matching replacements for an old roof can be hard to source. Expect slate to cost more to fit, and check that the quote says who supplies replacements.
Electrical work
An older consumer unit may need upgrading or replacing to take the new circuit. Long cable runs, extra isolators or an inverter sited well away from the panels all add labour. A meter that cannot record exports may need changing, which is normally arranged through your electricity supplier.
Shading and equipment choices
Chimneys, dormers and trees can shade parts of a roof. Designs that cope with partial shade use extra electronics, which cost more. Higher-output panels, all-black panels chosen for appearance, bird mesh around the array and monitoring add-ons change the price as well.
Batteries
A battery is a substantial addition and should be priced as a separate line; when one makes sense is covered in batteries.
VAT on home solar
Solar panels and batteries supplied and installed in a home carry VAT at 0% until 31 March 2027, under HMRC’s VAT Notice 708/6. From 1 April 2027 the rate becomes 5%. Every quote should state the VAT rate it assumes. If a project might finish close to the change, ask how the installer will charge VAT and get the answer in writing; HMRC’s rules on when a supply takes place decide which rate applies.
Paying for it
Households pay for solar in different ways, and the options below are not exclusive.
- Warm Homes Loan Scheme. The government has published a factsheet on the Warm Homes Loan Scheme. It is a loan, not a grant, so it must be repaid. Read the factsheet for who it is aimed at and on what terms before you rely on it.
- Warm Homes: Local Grant. A means-tested scheme for homes rated EPC D to G that can include solar PV. Who qualifies is explained in grants and schemes.
- Group buying. Switch Together Solar, run by the council with neighbouring councils, sets prices through a reverse auction among vetted installers. Its latest registration closed on 25 September 2026.
- Installer credit. Some firms offer credit. Any credit offer should show a representative APR and the total amount repayable in writing; compare it with other borrowing before signing.
Deposits and protecting your money
Ask how much deposit is required and when the balance falls due. Firms certified under MCS must belong to a consumer code approved by the Chartered Trading Standards Institute, such as RECC or HIES, and those codes include protections for deposits and a route for complaints. A large deposit demanded before anyone has surveyed the roof is a warning sign. The full set of checks is in choosing an installer.
Comparing quotes line by line
Two quotes are only comparable if they describe the same job. Check each one for:
- system size in kWp and the number of panels;
- estimated annual generation in kWh, and how it was worked out;
- whether the roof structure was inspected from inside the loft;
- scaffolding, and how long it stays up;
- the fixing method for your covering, and who supplies replacement slates or tiles;
- electrical work, including any consumer unit changes;
- who handles the grid notification or application (see grid connection);
- the VAT rate assumed;
- deposit, payment stages and warranties.
A quote far below the DESNZ figures may be leaving something out; one far above them should explain why. Either way, ask, and if the answer still leaves you unsure, send the main lines through the question form and we will say what the quote covers and what it leaves out. Neighbours who already have panels can be a useful check on what local jobs involved, and solar take-up locally shows how many sites the borough now has.
These figures are published averages and simple arithmetic on them. They are not quotes and they exclude batteries. A price for your home can only come from someone who has surveyed it.