Balcony Solar Tools & Calculators
Free tools and reusable data: check a kit, estimate monthly generation and savings, compare UK locations, and prepare a landlord permission request.
The plug-in route opened in Great Britain on 27 August 2026 under SI 2026 No. 848, but only for kits that meet the Interim Product Specification. These tools cover the two questions that follow from that (whether a particular kit qualifies, and whether it is worth buying), plus the permission letter most renters need before either matters.
UK Monthly Solar Generation Data
Download PVGIS-modelled monthly output for twelve UK cities, six panel directions and three mounting angles. Includes the full method and limitations.
Modelled climate averages, rather than measured installations.
Explore and download the data →Plug-In Solar Compliance Checker
Work through every rule in the UK's Interim Product Specification (800 VA output, 3.5 A current, 2,000 W of panels, the DC array and 120 V limits, a factory-fitted BS 1363 plug, no battery, a verified ENA register listing, socket-circuit and connection restrictions, and prohibited mounting surfaces) and see exactly which ones a kit fails.
Says "we can't tell" rather than guessing.
Check a kit →Balcony Solar Savings Calculator
Estimate monthly and annual generation, bill savings and payback. Adjust panel angle, direction, shade, self-use, unit rate and total fitted cost.
Assumptions and formula shown in full.
Calculate your savings →Landlord Permission Letter Template
A drafted letter you can adapt and send to a landlord or managing agent requesting permission to install balcony solar, framed around the portable, non-structural nature of the system.
Written for private renters and leaseholders.
Get the template →A note on what these tools can and can't do