The answer first
Check every firm on the MCS register, confirm it belongs to a consumer code carrying Chartered Trading Standards Institute approval, and read its Companies House record. Get two or three written quotes after a survey of the actual roof. For a listed or conservation-area house, ask what kinds of consent the firm has worked under and who will apply.
Three public checks
Before any firm visits, three registers can be searched in a few minutes, and together they rule out a good share of problems.
1. The MCS register
The MCS installer search lists the firms certified to install small-scale renewables. Search for the firm’s name and check that solar PV appears among its technologies, along with battery storage if a battery is being quoted. Note the certification number and compare it with the one printed on the quote and the firm’s paperwork. After installation the firm registers the system and an MCS certificate is issued; that certificate is what an export tariff under the SEG scheme requires, and what a buyer of the house will later ask to see.
2. A consumer code
Firms selling to households often sign up to a consumer code that the Chartered Trading Standards Institute has approved; in renewables the usual ones are RECC and HIES. A code sets standards for sales, contracts, deposits and complaints, and gives the customer a route to independent dispute resolution. Ask which code the firm follows, and look the firm up in the code’s own member search; a logo on a van or leaflet proves nothing.
3. Companies House
A limited company’s record on Companies House shows whether it is active, when it was incorporated, who its directors are, its registered address and whether its accounts are filed on time. Check that the company named on the quote is the one on the register, since trading names can differ from legal names. A very recent company is not necessarily a problem, but it is worth asking about, as is a history of directors running companies that later closed.
What a sound quote contains
- How many panels, the total kWp, and which panel and inverter models are proposed.
- A roof layout, ideally with the projection above the slope shown, and an output estimate that allows for shade.
- Access: scaffold, towers or other equipment, and any licence needed.
- Electrical work: consumer unit, isolators, cable routes and meter changes.
- Any battery, diverter or monitoring, each as its own line.
- Who handles the G98 notification or G99 application.
- Any planning or consent work, and who prepares and submits it.
- Warranties on panels, inverter and workmanship, and what happens if the firm ceases trading.
- The VAT rate assumed, the payment stages and the size of any deposit.
Two or three quotes on this basis allow a proper comparison. The per-kW method for checking the price against national figures is explained on solar costs.
The survey
A quote produced from satellite images alone can be a starting point, but it cannot see the condition of the roof timbers, the age of the consumer unit, the route a cable must take, or the shade cast by a neighbour’s chimney in December. Ask whether someone will inspect the roof and the electrics in person before the price is final, and what happens to the price if the survey finds something unexpected. For an older or timber-framed house, ask what the surveyor will look for in the loft; the points are listed on timber-framed homes.
Listed and conservation-area work
The Nantwich Conservation Area holds 125 list entries, according to the 2012 appraisal, and a listed house outside it is bound by the same consent rules. Work on these houses tests a different set of skills from a standard roof. In general terms, ask each firm:
- What kinds of consent it has worked under before: a prior-approval decision in a conservation area, full planning permission, Listed Building Consent, or none.
- Who prepares the drawings and supporting statements, and whether it works with an architect or heritage adviser when needed.
- How it fixes rails to handmade tiles, stone slates or other old coverings, and how it replaces any that break.
- Whether it will wait for a decision before ordering equipment or taking a large deposit.
- How it would deal with conditions the council might attach, such as panel colour, frame finish or position.
Answers in general terms are enough; the point is to hear whether the firm understands the process, not to collect names of past customers. Check the listing yourself on the National Heritage List, and read listed buildings and solar and the conservation-area page before the firm visits, so that the answers can be weighed.
Who will actually be on the roof
Many solar firms use subcontractors for parts of the job, most often scaffolding, roofing repairs or electrical work. That is normal, but the contract should make clear that the firm you sign with remains responsible for all of it. Ask who will be on site, who supervises, and who carries the insurance. Electrical work in a home has to meet building regulations, and firms registered with a competent person scheme can certify their own work rather than involving building control separately; ask which scheme covers the electrician and make sure the certificate appears in the handover pack.
Comparing the equipment
Quotes often name different panels and inverters, which makes them hard to compare. Ask for the datasheets and the warranty documents rather than relying on a summary. Look at the panel’s rated output, its product and performance warranties, and the inverter’s warranty length and whether it can be extended. For a battery, compare usable capacity and the conditions in its warranty. A higher-rated panel is not automatically better for a given roof; the layout, shading and inverter matter as much.
Village houses and long cable runs
For an oil- or LPG-heated house in the villages, ask whether the firm has fitted hot-water diverters and how it would wire one to the existing cylinder. For panels on an outbuilding or a garden array, ask for the trench route, cable size and depth on a drawing, and for trenching and reinstatement as separate prices. The background is on off-gas villages.
The contract and the money
Read the contract before signing, not on the day of the visit. It should name the company, the price, the equipment, the start and completion dates, the payment stages and the warranties. Contracts agreed at home normally carry a fourteen-day cooling-off period, which the firm should explain in writing. Keep deposits modest and ask how they are protected. If the job depends on planning permission or consent, the contract should say what happens to the deposit if permission is refused. Credit agreements have their own rules; check that any lender is authorised by the Financial Conduct Authority.
Warning signs
- Pressure to sign on the day, often with a discount that expires that evening.
- A price given before anyone has looked at the roof or the electrics.
- Talk of grants that turn out to be a discount, or that the firm cannot name.
- Promises of exact running costs or income, which no firm can know in advance.
- Reluctance to put the specification, the warranties or the cancellation rights in writing.
Grant offers are covered on grants and schemes.
Aftercare
A solar system should run for many years with little attention, but faults happen, most often with inverters. Ask how faults are reported, how quickly the firm aims to respond, whether monitoring alerts it as well as you, and who would honour the warranties if the firm stopped trading. An insurance-backed workmanship warranty, offered through some consumer codes, is designed for that last case; ask whether one is included and get the policy document.
At handover
On completion, expect a handover pack: the grid notification or G99 approval, the MCS certificate, the warranty documents, a building regulations compliance certificate, the electrical installation certificate, the layout drawing and the manuals. Keep them together; a buyer will ask for all of them, as buying a home with solar explains. The network operator for the address can be confirmed through the Energy Networks Association, and the connection rules are on grid connection. Questions about a quote in hand can be sent through the question form, and quick answers to common worries are on the FAQs.