Powerwall 3 specifications in context
Tesla’s UK support comparison lists Powerwall 3 at 13.5 kWh, with on-grid power up to 11.04 kW depending on local conditions and an integrated solar inverter. Capacity is energy; power describes delivery rate. Neither guarantees that a particular home may export at that power.
The same UK material lists a 10-year warranty headline. Read the contract for the supplied UK model, applications, retained capacity, exclusions and installation responsibilities. A headline term is not a promise from this website.
What to include in the price
Ask whether the proposal includes the necessary gateway or other system-control equipment, backup circuits, electrical upgrades, monitoring, commissioning and tax. Confirm the inverter arrangement for an existing array. Replacing or retaining an old solar inverter can materially alter the work.
A promotional hardware price without this scope cannot be compared with a complete installed quote. We do not publish a price-per-kWh ranking using incomplete totals. Check the full proposal and ask for exclusions in writing.
Backup is an installation design
Ask which loads are supported in an outage, any reserve setting and how long they can run under your assumed use. The maximum equipment rating does not imply every load or circuit is backed up. Network and site constraints can also change the configuration.
Keep backup preference separate from savings. You may choose resilience even when the additional cost does not recover through bill reduction. The annual tool does not value outage avoidance or forecast dynamic tariff trading.
Compare the additional battery return
For a new system, ask for the same solar design without storage. For a retrofit, treat the installed solar as sunk and verify existing payments and metering. Use the battery scenario comparison, with your actual additional installed price and explicit shifted-energy assumption. Read the retrofit checks before assuming remote compatibility.
Sources and review dates
Research-based guidance. Source checks do not imply product testing or verification of an individual installer.
- Energy Saving Trust: Battery storage. Storage losses, scope of cost estimates and possibility that savings do not justify battery cost. Scope: UK. Checked .
- Ofgem: FIT generators. Existing FIT arrangements require agreement-specific checks before storage or export changes. Scope: Great Britain. Checked .
- Tesla: How Powerwall works - UK. Powerwall 3 13.5 kWh; up to 11.04 kW depending on local conditions; headline 10-year warranty subject to contract. Scope: UK. Checked .
Registry sources-2026-11-01. Tariffs have a 30-day internal review interval. Methodology and assumptions.