What powering a whole house actually means

The following points summarise the most important takeaways:

• Fully off grid

  You rely on oversized solar and batteries, and often a generator, which is uncommon in UK towns and suburbs.

• Whole house every day

  Your home can run on solar and storage most days, but still needs the grid in winter and at night.

• Whole house on an annual basis

  Your solar system generates about as many kWh over a year as your home uses.

Typical UK electricity use to compare against

The following points summarise the most important takeaways:

• Higher use homes

  Often 5,000 to 8,000 kWh per year if you have an EV, more occupants, or higher daily use.

• Average household use

  Around 2,700 to 3,500 kWh per year for electricity.

• Electric heating impact

  Electric heating loads can exceed 10,000 kWh per year, which is hard to cover with typical roof space.

Typical UK solar output ranges

For more context on how output varies by roof and location, see how many solar panels a UK home needs.

• 4 kWp Scotland

  Roughly 2,800 to 3,500 kWh per year.

• Larger roof systems

  6 kWp to 8 kWp can generate about 5,000 to 7,500 kWh per year in good southern locations.

• 4 kWp southern England

  Roughly 3,400 to 4,200 kWh per year.

• Typical domestic system size

  3.5 kWp to 5 kWp is common for UK homes.

Roof and site factors that decide whether it works

The following points summarise the most important takeaways:

• Shading

  Chimneys, trees, and nearby buildings can reduce performance by 5 to 30 percent or more.

• East west roofs

  Lower peak output but generation is spread more evenly across the day.

• Regional daylight

  The same system can produce materially different annual kWh between southern England and Scotland.

• North facing roofs

  Usually poor output unless the roof is very shallow and unshaded.

• Orientation and tilt

  South facing at around 30 to 40 degrees usually produces the best yield in the UK.

How battery storage changes the answer

If you are focused on resilience and using stored energy in the evening, see residential backup systems.

• Typical battery sizes

  5 kWh to 15 kWh usable is common for homes.

• Higher self sufficiency

  Larger homes with EVs or heat pumps may need 15 kWh to 30 kWh for more coverage.

• What batteries do not do

  They do not increase annual solar generation, only how much is used on site.

• Self consumption with a battery

  A 5 kWh to 10 kWh battery can push self use to roughly 60 to 80 percent.

• Self consumption without a battery

  Many UK homes use about 30 to 50 percent of their solar directly.

Why most UK homes still need the grid in winter

UK solar output in December and January can be 70 to 90 percent lower than peak summer months. Even large systems may not cover winter demand without oversizing the array and storage. This is why most households use the grid as seasonal backup rather than trying to eliminate it entirely.

Practical design details homeowners often do not hear early

The following points summarise the most important takeaways:

• Inverter sizing

  Inverters are sometimes sized slightly below panel capacity to improve real world efficiency.

• Export limitation

  Export can be capped to meet network limits without reducing generation.

• Shading mitigation

  Microinverters or optimisers can reduce shading losses compared to a single string inverter.

• DC to AC oversizing

  Ratios around 1.1 to 1.3 are common in system design.

• Electrical constraints

  Consumer unit capacity, earthing, and cable runs can affect what is practical.

UK permissions and grid rules that can affect system size

Planning permission is not usually required for typical roof mounted solar under permitted development. Listed buildings and conservation areas may have additional restrictions. DNO notification is required for most installations. Systems above 3.68 kW per phase typically require a G99 application approval before installation. Export may be limited depending on local network capacity. Three phase properties can make larger system designs easier than single phase in some cases.

Who this is suitable for

The following points summarise the most important takeaways:

• Best fit households

  Homes with predictable electricity use and enough unshaded roof area.

• Harder to cover fully

  Homes with high electric heating loads or limited roof space.

• Strong fit with a battery

  Homes that are empty during the day and use more energy in the evening.

• Strong fit without a battery

  Homes that use more electricity during the day.

Common UK misconceptions that affect decisions

The following points summarise the most important takeaways:

• Going off grid is normal

  Most UK systems remain grid connected due to winter shortfall and reliability needs.

• A battery makes more solar

  A battery increases self consumption but does not increase generation.

• Solar does not work in cloud

  Solar generates from daylight, not heat, but output is lower in winter.

• You need to match peak demand

  Annual generation vs annual usage is usually the key comparison for grid connected homes.

How to compare installers and quotes like for like

If you want to shortlist providers, you can browse the electrical company and electrician directory and filter for solar and battery experience.

• Battery scope

  Confirm usable kWh, warranty terms, and whether the battery is sized for your evening load.

• System size basis

  Confirm the quoted kWp and expected annual kWh are based on your roof and location.

• Export constraints

  Ask whether export will be limited and how that impacts the proposed design.

• Shading assumptions

  Check whether shading has been assessed and how it is handled in the design.

• Access and scaffolding

  Confirm whether scaffolding, roof works, and cable routes are included in the price.