1. About these terms
These terms of use ("terms") govern your use of the website uksolarcalc.co.uk ("the site"), operated by SolarWatt UK ("we", "us", "our"). By accessing or using the site, you agree to these terms. If you do not agree, please do not use the site.
2. Who we are and what we do
SolarWatt UK is a free, independent reference website providing online solar energy calculators and related informational content for UK homeowners. We are not an installer, a supplier, a broker, or a financial services firm. We do not install solar panels, sell equipment, or provide investment advice.
3. Estimates only — not advice
3.1 No financial, tax or engineering advice
All figures produced by the calculators on this site — including savings, payback periods, return on investment (ROI), internal rate of return (IRR), system sizes, panel counts, costs, and battery payback — are approximate estimates based on publicly available UK data and simplified assumptions. They are provided for general information and planning purposes only.
Specifically, our calculators are not:
- Financial advice under the Financial Services and Markets Act 2000 (FSMA) or any successor regulation;
- Tax advice, including advice on VAT, stamp duty, or any tax relief;
- Engineering, structural, or electrical advice;
- A formal quote, estimate, or offer to supply goods or services;
- A guarantee of any actual saving, return, or system performance.
You should always consult an independent, qualified professional — an MCS-certified installer for technical matters, an FCA-authorised financial adviser for investment decisions, and a tax adviser for tax issues — before making any decision based on information from this site.
3.2 Assumptions and limitations
Each calculator's methodology is described on its page. The assumptions include, but are not limited to:
- Regional sun hours from NREL PVWatts / Solar Energy UK;
- Ofgem default-tariff price cap (reviewed quarterly);
- Typical Smart Export Guarantee (SEG) rates, which are supplier-set and variable;
- 0.5% annual panel degradation and 3% annual electricity rate inflation;
- A 0.7 derate factor covering inverter losses, shading, temperature and degradation;
- £1,600/kW installed system cost (Great Britain mid-range, 2026).
Real-world results vary significantly with roof orientation, pitch, shading, panel model, inverter type, battery chemistry, installer quality, local microclimate, your usage patterns, your electricity tariff, and future energy prices. Do not rely on our figures as a prediction of your actual outcomes.
4. 0% VAT — important geographic differences
Our calculators apply 0% VAT to displayed costs by default. This default reflects the GB position. Users in Northern Ireland should treat any "0% VAT" figure as not necessarily applicable to them.
VAT rules can change. We are not HMRC; for authoritative guidance see gov.uk: VAT on energy-saving materials.
5. Affiliate disclosure
SolarWatt UK is reader-supported. We may earn a commission when you request installer quotes through links on this site. This is an affiliate relationship: we are paid a referral fee by installer partners when a quote request is submitted via our CTAs.
This disclosure is made in line with:
- UK Consumer Protection from Unfair Trading Regulations 2008 (CPRs) and the ASA/CAP Code (Committee of Advertising Practice), which require commercial relationships to be disclosed clearly and prominently;
- US FTC Endorsement Guides (16 CFR Part 255), in case the site is accessed from the United States.
The commission we receive never changes the numbers shown in any calculator. Calculators use the same formulas and data regardless of whether you click an affiliate link. Our editorial methodology is independent of commercial relationships, as set out on the homepage and each calculator page.
6. Third-party links and installers
This site contains links to third-party websites, including installer partners, government sources (Ofgem, HMRC, GOV.UK), and data providers (NREL, Solar Energy UK, Energy Saving Trust). We are not responsible for:
- The content, accuracy, or availability of any third-party website;
- The conduct, workmanship, pricing, or warranty of any installer we refer you to;
- Any contract, warranty, or guarantee between you and an installer;
- Any loss or damage arising from your dealings with third parties.
Any quote, contract, or installation arranged through a third-party installer is solely between you and that installer. We strongly recommend you verify that any installer is MCS-certified (Microgeneration Certification Scheme) and carries adequate insurance before signing any contract.
7. Use of the site
You agree to use the site lawfully and not to:
- Use the site in any way that breaches UK or international law;
- Attempt to gain unauthorised access to the site, its servers, or any data;
- Scrape, mirror, or republish substantial portions of the site without our written permission;
- Introduce viruses, trojans, worms, or any malicious code;
- Use automated scripts to overload or disrupt the site.
We may withdraw or restrict access at any time without notice.
8. Intellectual property
All site content — text, calculator code, design, layout, and graphics — is owned by SolarWatt UK or used under licence, and is protected by UK and international copyright law. You may view and use the site for personal, non-commercial purposes. You may not reproduce, redistribute, or commercially exploit any part of the site without our written permission.
Calculator formulas that reflect publicly documented methodologies (e.g. standard solar yield calculations) are not proprietary; the specific implementation on this site is.
9. Limitation of liability
To the maximum extent permitted by law, SolarWatt UK, its operators, and its affiliates accept no liability for:
- Any loss or damage arising from your use of, or reliance on, the site, its calculators, or its content;
- Any inaccuracy in estimates, including but not limited to savings, payback, ROI, cost, or system sizing;
- Any decisions you make based on the site, including purchasing, installing, financing, or not purchasing a solar or battery system;
- Any loss of profit, income, savings, or opportunity;
- Any indirect, incidental, special, or consequential damages;
- Any acts or omissions of third-party installers or other service providers.
Nothing in these terms limits liability for death or personal injury caused by negligence, or for any other liability that cannot be excluded under UK law.
10. No warranties
The site is provided "as is" and "as available", without any warranty of any kind, express or implied, including warranties of accuracy, completeness, fitness for a particular purpose, or non-infringement. We do not warrant that the site will be uninterrupted, error-free, or free of viruses.
11. Privacy and cookies
Your use of the site is also governed by our privacy policy and cookie policy. Please review them to understand how we handle any personal data.
12. Changes to these terms
We may update these terms from time to time. The "last updated" date at the top of this page will reflect any change. Continued use of the site after a change constitutes acceptance of the new terms.
13. Governing law and jurisdiction
These terms are governed by the laws of England and Wales. Any dispute arising out of or in connection with these terms or your use of the site is subject to the exclusive jurisdiction of the courts of England and Wales, save where you are a consumer habitually resident in Scotland or Northern Ireland, in which case the courts of your jurisdiction shall have jurisdiction.
14. Contact
Email: hello@uksolarcalc.co.uk
Postal: SolarWatt UK, [registered address to be inserted before launch].