Solar is a significant purchase. The market includes excellent installers and companies that cut corners on quality, certification or aftercare. Use this checklist before signing anything.
The most important thing: Quality standards
High-quality solar installations are defined by their warranties and the experience of the installers. For your home, this means:
- The installer uses experienced teams for every project
- Your installation comes with a 25-year performance warranty
- You receive a full workmanship guarantee
- Your installer is fully insured for residential work
The check that matters most
Key warranties and protections that matter
Electrical safety
Solar involves significant electrical work. Your installer should use experienced electricians for all solar work. Every installation must be safe, compliant, and properly documented for your home insurance.
(Home Insulation & Energy Systems)
Crucial consumer protection: deposit protection up to £2,500 if the installer goes out of business before completing your install. Solar deposits are paid months in advance, so this matters.
Consumer Code for Renewable Energy ()
Governs sales and marketing practices: pre-contract information, sales practices, after-sales support.
Questions to ask before signing
A reputable installer answers all of these directly and without hesitation:
- Can you provide a 25-year performance warranty?
- Are your installers experienced and fully insured?
- Do you provide a written workmanship guarantee?
- What panel and inverter brands will you install?
- What warranties cover the panels, inverter and workmanship?
- Who do I call if something goes wrong after install?
- Will you handle the DNO notification for the grid connection?
- What happens if there is a delay between signing and installation?
- Can you provide references from recent similar installations?
If an installer is vague, dismissive or pressures you to decide quickly — take that as a signal.
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Ten red flags when getting a solar quote
- No Quality standards — walk away. There's no legitimate reason for an installer to lack it.
- Unsolicited door-knocking — reputable companies don't cold-call.
- Same-day pressure to sign — a sales tactic, not a sign of a good deal.
- No written quote — verbal quotes aren't enough.
- Vague warranty terms — 'manufacturer's warranty applies' is not sufficient.
- No site survey — shading, roof condition and electrics must be assessed in person.
- Unusually low price — quality components cost money.
- No deposit protection — always check registration before paying.
- Claims of 'free' solar that aren't grants — sometimes a lease where you don't own the panels.
- No aftercare or monitoring support — unclear answers now mean no aftercare later.
The Alliant Energy standard
| Certification | What it means for you |
|---|---|
| Performance | 25-year performance warranty on solar panels as standard. |
| Experienced | Experienced installation teams for every residential project. |
| Insured | Fully insured installations for your peace of mind. |
| Quotes | Free, no-obligation quotes delivered within 24 hours. |
| Local | A local business focused on quality and long-term support. |
| Warranties | Comprehensive product and workmanship warranties. |
Frequently asked questions
What warranties should I look for?
A reputable installer should offer a 25-year performance warranty on panels, at least 10 years on the inverter and battery, and a clear workmanship guarantee of 2–10 years.
What is a reasonable deposit?
Industry standard is 10–25% at order, balance on completion. Be cautious of any installer asking for more than 25% upfront — especially if they're not -registered.
Should I get multiple quotes?
Yes — two or three quotes from experienced installers gives you a clear picture of market pricing and design options. Compare system specs (brand, wattage, inverter, warranties), not just price.
How long should the warranty last?
Minimum: 25-year performance, 12-year product warranty on panels, 5-year on the inverter, 2-year workmanship. Alliant provides a 30-year panel warranty on all domestic installs.