A Tesla Powerwall 2 remains the common model in the UK in 2025. It has 13.5 kWh usable capacity and about 5 kW continuous power. Most installs include a Tesla Gateway for control and backup switching.
Typical installed prices in Great Britain in 2025:
Single Powerwall 2 with Gateway: £7,500–£9,500 installed
Second Powerwall added at same time: +£6,000–£7,500
Retrofit to an existing solar system: £8,000–£10,000 (extra work and testing can push cost up)
Prices vary by cable runs, wall type, and whether you need a DNO application for higher export limits. Some quotes sit below or above the ranges, but the mid-point is a fair planning figure.
UK averages in 2025 for standard black mono panels, all-in and installed:
3 kWp (about 7–8 panels): £4,500–£5,800
4 kWp (about 10 panels): £5,200–£6,800
5 kWp (about 12 panels): £6,200–£8,000
6 kWp (about 14–16 panels): £7,000–£9,500
8 kWp (larger roof): £9,000–£12,000
These prices include scaffolding, standard mounting, a single MPPT inverter, testing, and paperwork. Add £400–£1,000 if you need a bird guard, optimisers for shade, or an extended inverter warranty.
Answer a few quick questions, and we will send you a bespoke solar panel quote.
Here are typical real-world bundles to frame your budget:
4 kWp solar only: £5,800 with a 3.6 kW inverter, generation meter, and app monitoring
4 kWp + Powerwall: £13,500–£15,500 depending on layout and switchgear
6 kWp solar only: £8,200 with a 5 kW inverter and DC isolators
6 kWp + Powerwall: £15,500–£18,000
8 kWp + 2× Powerwall: £24,000–£27,000 for high-use homes
These examples assume a simple two-storey house, standard roof access, and no major electrical upgrades.
Domestic solar and batteries qualify for 0% VAT in Great Britain until March 2027. This covers supply and install when done together. Standalone battery installs also sit at 0% VAT.
Large national grants are not active in England and Wales in 2025. Support exists in specific cases:
Scotland: Home Energy Scotland offers grants and interest-free loans at times. Amounts change by funding round. Check current terms before you buy.
Low income or hard-to-heat homes: ECO4 and the Great British Insulation Scheme can help in select cases. Solar is rare under these schemes but can appear when tied to wider upgrades.
You can get paid for exports under the Smart Export Guarantee (SEG). You need an MCS install and a smart meter.
Rates change often. Typical SEG rates in late 2024 and early 2025:
Basic SEG: 2p–8p per kWh from large suppliers
Better fixed export: 12p–20p per kWh from agile or green suppliers
Time-of-use export: higher in peak windows, lower off-peak
Examples that have been on the market include 15p fixed export and time-of-use deals that pay more in the evening peak. Your import tariff and export tariff can be different products. Check standing charges and contract rules. Some suppliers require you to take their import tariff to get the better export rate.
You can estimate payback with five inputs:
Annual generation from your system (kWh)
Share you use in the home vs what you export
Import price (p/kWh) and standing charge
Export rate (p/kWh)
System cost after VAT (here it is 0%)
Useful UK averages for 2025 planning:
4 kWp south-facing roof in southern England: ~3,800 kWh/year
6 kWp mixed east/west roof: ~5,200–5,800 kWh/year
Import price on a standard cap tariff: ~28–32p/kWh
Good fixed SEG: ~12–15p/kWh
Self-consumption rates:
Solar only: 35%–55% (lower if you are out during the day)
With a Powerwall: 70%–90% in spring/summer, 50%–70% over a full year
Method:
On-site use saves import at your unit price.
Exports earn revenue at your SEG rate.
Annual benefit = import savings + export revenue.
Simple payback = system cost / annual benefit.
Case A: 4 kWp solar only
Cost: £6,000
Generation: 3,800 kWh
Self-use: 45% (1,710 kWh at 30p) = £513
Export: 2,090 kWh at 12p = £251
Annual benefit: ~£764
Simple payback: ~7.9 years
Case B: 4 kWp + Powerwall
Extra cost for Powerwall package over solar only: ~£8,500
Self-use rises to 80% on average
Self-use: 3,040 kWh at 30p = £912
Export: 760 kWh at 12p = £91
Annual solar benefit: ~£1,003
Battery-specific benefit over solar only: £1,003 − £764 = £239/year
Battery-only payback on those solar shifting gains: £8,500 / £239 ≈ 35+ years
Case C: 6 kWp + Powerwall with time-of-use import and export
Cost: £16,500
Generation: 5,500 kWh
Self-use with battery: 75% = 4,125 kWh
Import price off-peak: 8–10p/kWh: peak: ~30p/kWh
Export rate (good fixed): 15p/kWh
Strategy: charge the battery from solar and cheap night rates in winter, export some at peak if your tariff allows.
Blended annual benefit can reach £1,400–£1,900 depending on your load shape and tariff.
Indicative payback: 9–12 years
Key takeaways:
Solar alone often gives the fastest payback.
A Powerwall adds comfort and backup and can boost savings if you use time-of-use tariffs well.
Your profile matters. High evening use or an EV can lift battery value.
Answer a few quick questions, and we will send you a bespoke solar panel quote.
Roof size and pitch: bigger arrays need more rails and labour.
Orientation: south is best. East/west is fine and spreads output through the day.
Shading: chimneys, trees, and dormers reduce yield and may need optimisers.
Height and access: three-storey or tricky access adds scaffold cost.
Panel choice: premium black panels cost more but look cleaner.
Inverter type: microinverters or power optimisers cost more but can help with shade and string mismatch.
Main fuse and tails: older 60A supplies may need an upgrade. Your DNO can upgrade the fuse.
Consumer unit: you may need RCBOs, SPD, or a new board for compliance.
G98 vs G99: up to 3.68 kW per phase export is G98 (fit and notify). Above that requires G99 prior approval.
Export limits: the DNO can set a cap. A power control device may be needed.
Earthing and bonding: older homes may need remedial work.
Backup circuits: if you want backup, agree which circuits go on the backed-up board.
A Powerwall makes sense if you:
Use most of your energy in the evening or early morning
Have high annual use (4,500–8,000 kWh) or an EV or heat pump
Can get a cheap night import rate and a fair export rate
Value backup during outages
It adds less value if you are at home in the day and already use most solar as you make it. It also adds less value if your supplier pays a very low export rate and you cannot get a better plan.
Start with a larger array if your roof allows. Extra panels are cheap relative to batteries per kWh saved.
Try load shifting first. Run washing, dishwasher, and hot water on timers.
Consider a smaller battery. A 5–10 kWh unit may cover your night load at lower cost.
Use time-of-use import. Night rates of 7–12p/kWh can slash winter bills.
Look at time-of-use export. Evening export bonuses can be strong in summer.
If you have an EV, use a smart EV tariff first. This can deliver big savings without a battery.
Gather your last 12 months of bills. Note kWh used and your day/night split if you have it.
Check your roof area. A modern 400 W panel is about 1.7 m². Ten panels need about 17–20 m².
Pick a target array size from your roof and use. 4–6 kWp suits many homes.
Decide on a battery size. Aim to cover your typical night use. Many homes sit well with 10–14 kWh.
Choose priorities: lowest cost, highest output, or best look. This guides panel and inverter choices.
Plan for future loads. An EV or heat pump raises the case for a battery and a bigger array.
Get at least three like-for-like quotes. Ask for panel make and model, inverter model, and battery brand.
Request a yield estimate (SAP or PV*Sol) and a savings model. Check the inputs match your home and tariff.
Confirm MCS certification and membership of a consumer code such as HIES or RECC.
Ask about DNO applications, scaffold, bird proofing, and any roof work.
Check warranties: panels often 25-year performance, inverters 5–12 years, Powerwall 10-year warranty.
Review monitoring: ensure you get app access and clear circuit labelling.
Agree on backup scope if you want it. Critical circuits only keeps cost down.
Avoid pressure sales. Good firms explain limits, export caps, and timeframes.
Lead time in 2025 is often 2–8 weeks from order to install, longer if you need G99 approval.
In 2025, a Tesla Powerwall 2 with Gateway typically costs £7,500–£9,500 installed. Adding a second unit at the same time is usually £6,000–£7,500 extra. Retrofitting to an existing solar setup tends to be £8,000–£10,000 due to extra testing. Cable runs, wall type and DNO requirements affect quotes.
Typical 2025 installed prices for black mono panels are: 3 kWp £4,500–£5,800; 4 kWp £5,200–£6,800; 5 kWp £6,200–£8,000; 6 kWp £7,000–£9,500; 8 kWp £9,000–£12,000. These usually include scaffolding, standard mounting, inverter, testing and paperwork. Allow £400–£1,000 extra for bird guards, optimisers or extended warranties.
Yes. In Great Britain, domestic solar and batteries benefit from 0% VAT on supply and installation until March 2027, including standalone batteries. Large national grants aren’t active in England and Wales. Scotland periodically offers grants/interest-free loans via Home Energy Scotland. ECO4/GBIS may help some homes, though solar support is limited.
A 4 kWp solar-only system costing ~£6,000 can save ~£764/year, giving ~7.9-year simple payback. Adding a Powerwall lifts self-use but its solar-shifting gains alone can push battery payback beyond 35 years. However, a 6 kWp + Powerwall on time-of-use tariffs can achieve ~9–12 years, depending on usage and rates.
For grid connection, exports up to 3.68 kW per phase are G98 (fit-and-notify); higher exports usually need G99 approval and may have limits. Planning-wise, roof-mounted solar and wall-mounted batteries are typically permitted development, but listed buildings, flats or conservation areas may need consent. Always confirm with your DNO and local authority.
