Is it worth adding a battery to existing solar panels? The honest answer for West Yorkshire

The short answer: yes, if your house is empty during the day; probably not if someone is home all day using the solar as it is made. A typical 3.5 kW system in West Yorkshire makes about 2,678 kWh a year, and a working household exports more than half of it. That exported electricity earns around 8p a unit on a Smart Export Guarantee tariff. The same unit bought back at six in the evening costs 26.32p on the current price cap (Ofgem, 1 October to 31 December 2026). A battery is the difference between those two numbers, multiplied by every evening of the year.

The sums for a 3.5 kW system

Take a semi-detached house in Leeds with 3.5 kW of panels on a south-west roof. At 850 kWh per kWp a year for this part of the country (PVGIS) and a typical roof factor of 0.9, the system generates about 2,678 kWh a year. If the house is empty between nine and five on weekdays, roughly 1,500 kWh of that goes to the grid.

• Without a battery: 1,500 kWh exported at 8p earns about £120 a year.
• With a battery: the same 1,500 kWh stored and used in the evening replaces electricity you would have bought at 26.32p, so it is worth about £395 a year to you.
• The difference: around £275 a year, before any gain from charging the battery on a cheap overnight tariff in winter.

That £275 is the number to hold against the installed price of the battery. In practice a battery never captures every exported unit (summer days make more than it can hold, and round-trip losses take a few per cent), so treat it as the upper end and let the survey put a real figure on it from your own export readings. Our calculator shows the same effect for your bill with the battery switch on and off.

When it is not worth it

A battery makes money by moving electricity from the middle of the day to the evening. If that move is small, so is the saving. Three situations where we tell people to hold off:

• Someone is home all day. Retired, working from home, young children: if the washing machine, dishwasher and kettle run while the sun is out, you may already be using 60% or more of your solar. The battery only captures the remainder and the sums rarely work.
• Your export is tiny. A 2 kW system on a north-east roof in Halifax might export 500 kWh a year. Stored and used, that is worth about £132 a year instead of £40. The gap is real but small against the cost of a battery.
• Your inverter is on its last legs. A string inverter from 2011 or 2012 is near the end of its life. If it needs replacing anyway, a hybrid inverter plus a DC-coupled battery is often the better route than bolting an AC battery onto old kit. The survey will say which, and it changes the price.

AC-coupled or DC-coupled: what goes on your wall

AC-coupled batteries have their own built-in inverter and connect to your consumer unit. Your existing panels and inverter stay exactly as they are. This is the usual route for a system fitted under the Feed-in Tariff, because nothing on the generation side is touched and your generation meter keeps reading as before.

DC-coupled batteries connect to a hybrid inverter that handles both the panels and the battery. It is slightly more efficient (one fewer conversion) and tidier, but it only applies if you already have a hybrid inverter with a free battery port, or if you are replacing the inverter anyway. Either way the installer needs to be MCS-certified for battery storage, and the installation is notified to your network operator, Northern Powergrid in West Yorkshire.

0% VAT until 31 March 2027

Since February 2024 a home battery has been zero-rated for VAT in Great Britain whether it is fitted with new panels, added to existing panels or installed on its own. That ends on 31 March 2027; from 1 April 2027 the rate is 5%, confirmed in the Budget on 28 October 2026. The rate is decided by the tax point, which is normally the invoice date, so a battery has to be installed and invoiced before 31 March 2027 to get 0%. A deposit paid before the deadline does not fix the rate on the balance. The VAT deadline page has the detail.

The January price cap makes the gap wider

The current cap, 1 October to 31 December 2026, puts electricity at 26.32p a unit with a 54.83p daily standing charge (Ofgem, GB average, direct debit). Ofgem announces the January to March 2027 cap on 25 November 2026; Cornwall Insightforecasts a typical annual bill of about £1,999, up from £1,723 (forecast, updated 14 October 2026). Export rates do not move with the cap, so every rise in the unit rate widens the gap a battery earns on. Figures as of 3 November 2026.

What the survey checks

A battery quote from a web form is a guess. The free survey from a local MCS-certified installer looks at six things before a price is fixed:

• Your inverter: make, age, and whether it is hybrid or string.
• Your export: from your Smart Export Guarantee statements or your smart meter, not an estimate.
• Your evening usage, which sets the battery size.
• The consumer unit and whether it has space, or needs upgrading.
• Where the battery goes: garage, utility room or an outside wall, never a bedroom or an escape route.
• Whether you want backup circuits for a power cut, which have to be wired on the day.

The quote that follows is fixed, in writing, with 0% VAT already off, and names the installer and its MCS number.

Get a number for your house

Run the calculator with the battery switch on and off, then book a free survey. We call back to check your set-up, and a local installer measures up and sends a fixed quote. If the numbers do not work for your house, we say so. Thinking about a full system instead? Solar panels and a battery covers what a new install includes, and the Leeds page covers what we see on roofs across the city.

Questions people ask about this