15kW Solar Panel System UK | Output, Suitability & Install

The right fit

Why a 15kW system could be the right fit

A 15kW solar system is the largest residential configuration we install. It suits very large homes, small estates and rural properties using 10,000 to 15,000 kWh of electricity a year, typically households combining heat pumps, multiple EVs, swimming pools, outbuildings or annexes. It uses 37 panels across 90 to 110 square metres of roof, often spread across the main house, an annexe and one or more outbuildings.

A 12 to 15 kWh battery is the typical pairing, sized to evening peak loads and overnight standby on a property of this scale. Three-phase supply is standard at this scale, and all paperwork and grid approvals are handled by Solar4Good on your behalf.

The datasheet

15kW spec sheet

Indicative figures for a 15kW system on a very large UK property. Your exact output depends on your roof, orientation, shading and usage, confirmed in a site visit.

System size15 kW DC

Solar panels37 panels

Roof space90-110 m²

Suited toVery large / estate

Output · daily~35-41 kWh

Battery pairing12-15 kWh

Output · monthly~1,060-1,250 kWh

Output · yearly12,750-14,250 kWh

Self-consumption70-90% w/ battery

Panel warranty25 yrs

Indicative, not a quote · final figures after a free roof assessment.

What is included

37 tier-one panels

High-efficiency 450W panels, sized to deliver 15 kW DC.

Inverter (hybrid option)

A quality inverter, hybrid-ready for a 12 to 15 kWh battery.

Mounting, wiring & connection

All roof mounting, cabling and grid connection, done neatly and safely.

Monitoring app & walkthrough

Live generation on your phone, set up and explained before we leave.

Full MCS install + SEG setup

Fitted under our own MCS registration, with export-tariff (SEG) setup handled.

25-year panel warranty

Plus a team you can still call after switch-on. Every job certified under our own MCS registration.

Storage

15kW with or without a battery

Panels only

Good if you use power in the day

The panels power the home in daylight and export the surplus for a payment under SEG. Ideal if someone is home in the day, or you run appliances, an EV or a heat pump while the sun is up.

Panels + battery

The most common upgrade

A 12 to 15 kWh battery stores daytime solar for the evening, lifting self-consumption to 70 to 90%, sized to evening peak and overnight standby on a property of this scale.

The right size?

Is 15kW enough for your home?

For very large homes and small estates using 10,000 to 15,000 kWh a year, a 15kW system covers a large share of annual electricity, and with a 12 to 15 kWh battery, self-consumption typically reaches 70 to 90%. It is the natural choice for properties combining heat pumps, EVs, pools and outbuildings.

If your usage is lower, a 10kW system may be enough; if this is a commercial or agricultural building, our commercial team designs systems from 40kW upwards. We size to your actual usage, not a template, and three-phase supply is standard at this scale.

How it works

Go solar in three easy steps

STEP 01

Site visit & design

A local engineer visits, assesses your roof for pitch, orientation and shading, and designs a 15kW system around your actual property. No cost, no obligation.

STEP 02

Fixed-price quote

A clear, itemised proposal with no hidden costs. We handle all paperwork and grid approvals as standard.

STEP 03

Installation day

A named installer and team complete the full install in one to two days. Tested, MCS-certified and your monitoring set up before we leave.

Why Solar4Good

Engineer-led, in-house, UK-wide

You work with a UK-wide team based in Harrow, not a remote sales centre. The person who assesses your roof is directly involved in designing the system, and once it is in we handle MCS certification, SEG export-tariff setup and your monitoring app, so you are never left navigating the process alone.

3,000+UK installs

50,000+Panels installed

4.9★from 1,000+ reviews

MCSCertified, in-house

Rated 4.9/5 from 1,000+ verified reviews on Trustpilot, TrustATrader and Google

“George the sales chap was straightforward and honest, and the whole installation team were awesome, courteous and professional throughout.”

Jamie Wilson · Verified Trustpilot review

“From start to finish the whole job has been seamless. The install guys were polite, knowledgeable and efficient.”

Timothy Clarke · Verified Trustpilot review

“I wholeheartedly recommend this company for solar and battery storage installation.”

Soham Acharya · Verified Trustpilot review

Read All reviews →

Good to know

The questions homeowners actually ask about a 15kW solar system.

Is 15kW enough for a very large home or estate?

For very large homes and small estates using 10,000 to 15,000 kWh a year, a 15kW system covers a large share of annual electricity. With a 12 to 15 kWh battery, self-consumption typically reaches 70 to 90%.

How many panels are needed for 15kW?

37 panels using modern high-efficiency modules, sized to deliver 15 kW DC. They typically spread across multiple roof areas, the main house, an annexe and outbuildings, to maximise unshaded surface.

How much roof space does a 15kW system need?

90 to 110 square metres of unshaded roof, usually across several roof areas on a large property. Our engineers design the layout to maximise output across all available aspects.

Should I add a battery to a 15kW system?

Yes. A 12 to 15 kWh battery is the typical pairing at this scale, sized to evening peak loads and overnight standby on a property of this size.

Do I need three-phase power for 15kW?

Three-phase supply is standard at this scale. Our engineers confirm your supply and handle all grid approvals and paperwork as part of the installation.

Who installs it, and do you handle the paperwork?

Most installations are carried out under our own MCS registration. Further afield we use installers working under our MCS registration, and the certificate and workmanship warranty remain ours. We handle all paperwork, grid approvals, MCS certification and SEG export-tariff setup on your behalf.