How many solar panels do I need for a 3-bed house?

It depends more on your electricity use and roof than on the number of bedrooms. Most homes we fitted in 2026 had between 11 and 16 panels.

Is a 6 kWp system enough?

For many homes, yes. In 2026, homes using 3,000–4,499 kWh a year typically had about 6.3 kWp.

What size battery do most people get?

10 kWh, chosen by 48% of Spark homes in 2026.

What if I'm getting an electric car or heat pump?

Tell us. Your future use matters more than last year's bill, and it often means a bigger system and battery.

What Size Solar System and Battery Do I Need?

It depends on how much electricity you use and how much roof you have. You don't have to guess, though: here's what the 525 homes we fitted in 2026 chose, and how that changed with their electricity use.

Updated November 2026·6 min read·Written by the Spark team from SparkOS data

Key takeaways

The most common Spark system in 2026 was 14 panels (about 6.7 kWp). Half of homes had between 11 and 16 panels.
10 kWh was the most popular battery, chosen by 48% of homes. Smaller users more often chose 5 kWh.
Your annual electricity use, from your bill, is the best starting point. Homes using more had bigger systems.
Inverters above 3.68 kW need the network operator's approval first, which adds time to the install.

Start With Your Electricity Use

Your annual use in kWh is on your electricity bill or in your supplier's app, usually as "annual consumption" or "estimated annual usage". It's the most useful single number for sizing.

The homes we quote use more than most. Of the customers who have shown us a bill since 2024, the median used about 4,560 kWh a year, and a quarter used more than 6,400 kWh. Electric cars, heat pumps and working from home all push it up.

If you can't find a bill, you're not alone: about a third of our customers couldn't get one from their supplier. We'll estimate from your home and how you live, then check it.

What Homes Like Yours Chose

This is what homes that showed us a bill chose in 2026, grouped by how much electricity they use.

Annual electricity use	Homes	Typical system	Typical battery
Under 3,000 kWh	67	5.8 kWp (about 12 panels)	5 kWh
3,000–4,499 kWh	113	6.3 kWp (about 13 panels)	10 kWh
4,500–5,999 kWh	71	7.2 kWp (about 15 panels)	10 kWh
6,000 kWh and over	93	7.8 kWp (about 16 panels)	10 kWh

"Typical" is the median for each group. Bigger users usually want more panels, but roof space often sets the limit before electricity use does.

How Many Panels Is That?

We fit AIKO Neostar 3S 490W panels as standard, so each panel adds about 0.5 kWp.

Panels	System size
10	4.9 kWp
12	5.9 kWp
14	6.9 kWp
16	7.8 kWp
18	8.8 kWp
20	9.8 kWp

Not sure what you use?

Send us a bill, or we'll estimate it with you. Your quote is sized to your home.

Get My Free Quote

What Size Battery?

A battery stores daytime solar so you can use it in the evening and overnight, when you would otherwise buy from the grid. As a rough rule, size it to cover your evening and overnight use, not your whole day.

In 2026, 34% of Spark homes chose 5 kWh, 48% chose 10 kWh and 18% went for 15 kWh or more. We fit the EcoFlow OCEAN 2, which is built from 5 kWh or 8 kWh modules, so it can be sized to your home. See what each size cost in our cost guide.

What Size Inverter?

The inverter turns your panels' power into electricity your home can use.

Up to 3.68 kW, the network operator paperwork is usually quick. Above that, the operator has to approve the system before we connect it, which takes longer; see how long installation takes. In 2026, 43% of our systems used a 3.68 kW inverter, 28% used 5 kW and 24% used 6 kW. A larger inverter makes sense for bigger systems and batteries, and your quote will explain the trade-off.

Does My Roof Matter?

Yes, mostly because of how much space it has and which way it faces.

Most of the roofs we fit are standard pitched roofs. In a sample of 578 recent quotes, 88% were gable roofs and 80% had concrete tiles, with slate the next most common. Detached houses made up 43% of that sample, semis 31%, terraces 21% and bungalows 4%, so you don't need a big house to make solar work. Our roof suitability guide covers the details.

How We Worked Out These Figures

These figures come from SparkOS, our own sales system.

System and battery sizes come from all 525 Spark orders signed between 1 January and 5 November 2026, leaving out cancelled orders. The electricity-use table includes only the 344 of those homes that gave us a bill. Electricity use across all customers covers 1,347 bill-backed quotes since 2024, and roof and property types come from 578 quotes where they were recorded. We update these figures every quarter.

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