Solar Energy Concepts

DIY Solar for UK Homes. Real guides from a real install.

Step-by-step practical guides, component lessons, and hard-earned fixes from a real UK DIY solar setup.

7.15kWpinstalled 6,072kWhgenerated 2025 £1,668/yrmodelled value

Latest field notes

Fundamentals

Use the calculator below to compare tilt, direction and 10-year ROI for your roof. It covers every UK region; the optimal angle barely changes across a postcode area.
The textbook optimum is 35-40° facing south, but east-west and even vertical setups beat it for many real households.
Flat roofs win summer, steep walls win winter. Match the angle to when you actually use power.

Updated 7 Nov 2026 Read Entry →

Practical and DIY

Solar on a flat garage roof is usually possible, but it is a structural job first: the ballast holding the array down, not the panels, is what loads the roof.
Panels add about 15kg per square metre, ballast adds 30 to 60kg or more: the ballast is set by a site wind calculation, not a fixed rule, and is the load that grows on exposed plots.
Wind uplift is worst at the roof edges, so a small garage roof is nearly all edge; a low 10 to 15 degree tilt cuts the ballast a flat-roof array needs.
MCS MIS 3002 requires a structural engineer to assess the load on a ballasted flat-roof array: the panel-plus-ballast load can rival the roof’s entire code-minimum allowance, so do not judge it by eye.
Protect the membrane: seal every penetration to the EPDM, felt or single-ply type, and keep ballast clear of the drainage paths so water still reaches the outlets.
The checks are cheap next to the array: the ballast calculation usually comes free with the mounting kit, and a structural engineer’s assessment is typically a few hundred pounds.

Updated 7 Nov 2026 Read Entry →

System Guides

East/west roofs lose about 19% of annual yield vs south, but the demand-curve match is often better for a typical 3-bed household.
A battery turns the midday lull into evening savings. The single biggest ROI lever on this roof.
The budget 3.6kW DIY build is £2,400 and pays back in 3.3 years on a typical 3-bed.
The premium 5kW + 16kWh build only makes sense with a heat pump or EV.

Updated 7 Nov 2026 Read Entry →

Practical and DIY

Honest verdict: a solar gazebo is expansion with garden value, not a free lunch on yield per panel.
My build: about £2,018 including tools for 3.28 kWp on a ~6° flat roof structure.
Flatter tilt means more panels and more cleaning where water ponds on the frame edge.
Compare roof and ground first if height safety and planning allow a better tilt.

Updated 7 Nov 2026 Read Entry →

System Guides

There is no legal maximum number of solar panels allowed in the UK: standard homes are limited by practical constraints, not panel count.
Nine 400W panels make 3.6kWp: ten make 4kWp DC and can still use a 3.68kW G98 inverter.
Allow roughly 1.9m² per panel: then leave room for roof edges, ridges, valleys and obstructions.
G98 limits inverter capacity, not panel capacity: above 3.68kW AC on single phase, obtain G99 approval first.

Updated 7 Nov 2026 Read Entry →

System Guides

UK solar panel output is strongly seasonal: June and July normally peak, while December produces the least.
Winter output is a small part of summer output: November to February cannot be treated like four average months.
A battery cannot move summer electricity into winter: size it around daily surplus, not annual generation.
PVGIS provides the useful estimate: enter your location, roof direction, angle and system size rather than relying on one UK average.

Updated 7 Nov 2026 Read Entry →

System Guides

North roofs yield about 63% of south per kWp (PVGIS reference). The gap is real; economics need high self-use and a battery.
Pays back for high-consumption homes (heat pump, EV). Marginal under ~3,000 kWh/year.
Budget 3.6kW + 12 panels + 5.12kWh around £3,226 DIY with G98-friendly AC.
Run the tilt calculator for your pitch and direction before you accept a quote.

Updated 7 Nov 2026 Read Entry →

Fundamentals

Plug-in solar feeds 230V AC into a socket: your appliances use it first, so self-consumption decides what you actually save.
Your breaker cannot see the solar current: a kit injects power downstream of it, so a cable can carry more than its rating while the breaker sits under its trip point. That, not shock risk, is why the law caps plug-in solar at 800 VA (3.5 A) and one device per home.
If you already have solar, adding 800W is not a plug-in job: the 3.68 kW G98 limit is cumulative across the property, so a 3 kW array plus a kit drops the whole house into G99 and a formal application.
Legal in Great Britain since 27 August 2026: the ENA register listed 120 compliant kits on 10 October 2026, the rule is one device per household, and not every home is suitable because the RCD in your consumer unit decides it.
800W covers a home’s 200-400W daytime base load: a clipped kit makes roughly 650-800 kWh a year, worth about £40-85 without a battery.
The plug pins go dead in a fraction of a second: the specification requires them below 34V within 100 milliseconds of losing the grid, which is why nothing works in a power cut.

Updated 6 Nov 2026 Read Entry →

Fundamentals

You can buy a compliant plug-in solar kit now: 129 were listed on the ENA register on 6 November 2026, and City Plumbing, Argos, Wilko, Homebase and Very range them, from £336.
The cheap Amazon look-alikes are the trap: apart from Modular Solar’s own units, none I found was listed Compliant on 22 September 2026, and battery kits sit outside the law’s own definition of a plug-in microgenerator.
Compliance is a register listing plus six limits: 800 VA and 3.5 A from the inverter, 2,000 W of panels at STC, a moulded plug with a 5 A fuse, no extension lead, and no battery.
Budget £43-84 a year and a 5 to 10 year payback on the £444 two-panel kit: 650-800 kWh at 25-40% self-consumption and 26.32p/kWh, the price cap rate to 31 December 2026. Export income is £0 unless you have the Octopus kit and Octopus supply.
A Type AC RCD rules your home out until an electrician changes it: Electrical Safety First lists Type A, F and B as suitable, and the device also has to work with power flowing both ways.
City Plumbing, Argos, Wilko, Homebase and Very range listed kits: Lidl, Aldi, B&Q and IKEA had none on 10 October 2026.

Updated 6 Nov 2026 Read Entry →