Home battery storage without solar in the UK

Battery storage is often associated with solar panels, but it does not rely on them. In the UK, a home battery can operate independently by charging from the grid overnight and supplying your home during the day.

For some households, this can reduce electricity bills noticeably. For others, the impact is smaller. The difference usually comes down to usage, tariff structure and system design.

This guide explains how battery-only systems work, what determines grid approval, where installer responsibility ends, and what sits with the homeowner.

Can you have a home battery without solar? 

Yes.

A home battery does not need solar panels to function. Instead of storing excess solar generation, it stores electricity from the grid when it is cheapest.

Most battery-only systems in the UK are paired with a smart time-of-use tariff. These tariffs offer lower rates during certain hours, usually overnight. The battery charges during that window, then powers your home during peak-rate periods.

The system is not generating energy. It is shifting it.

To run a battery-only setup, you will usually need:

• A smart meter
  

• A compatible smart tariff
  

• A correctly sized battery and inverter
  

• DNO notification or approval

When installed correctly, charging and discharging happen automatically. Ongoing performance depends on how the tariff is managed.

How does home battery storage without solar work?

Electricity prices vary throughout the day. Many smart tariffs offer reduced pricing between midnight and early morning.

During those hours, the battery charges from the grid. When peak rates begin, the battery discharges and supplies the home.

The more of your daily usage the battery can cover, the less electricity you buy at higher daytime rates.

Battery capacity is measured in kilowatt hours. A 10 kWh battery can store 10 kilowatt hours of electricity. Larger homes may require 15 kWh, 20 kWh or more depending on annual consumption.

Most modern systems use lithium iron phosphate chemistry. This is widely used in domestic energy storage because it is stable and designed for frequent daily cycling over many years.

Some batteries can be installed indoors or outdoors, depending on the model and site conditions.

What determines G98 or G99 approval?

This is often misunderstood.

Grid approval is determined by inverter size, not battery capacity.

Under current UK engineering standards:

• Systems with an inverter rated up to 3.68 kW per phase typically fall under G98.
  

• Systems with an inverter rated above 3.68 kW and up to 50 kW fall under G99.
  

Battery size does not decide the route. The inverter does.

For example:

• A system with three 5 kWh batteries and a 3.6 kW inverter would normally fall under G98.
  

• A single integrated battery unit with an 11 kW inverter would usually fall under G99, even if the battery capacity is smaller.

This distinction affects both export capability and installation times.

What is G98?

G98 applies to smaller inverter systems.

It is a notification process rather than a pre-approval process. Installation can usually proceed without waiting for formal approval from the DNO.

However, a smaller inverter limits the maximum power that can flow between your home and the grid. A 3.6 kW inverter cannot export more than 3.6 kW at any one time, even if the battery holds more stored energy.

This does not limit storage capacity. It limits the rate of flow.

What is G99?

G99 applies to larger inverter systems.

This requires formal DNO approval before installation can proceed. Approval times vary depending on your local network and current capacity. In some areas this can add several weeks to the process.

The advantage of a larger inverter is greater power capability. This may allow faster charging, higher export limits or better support for high-demand homes.

At iHeat, the correct route is assessed before installation and all DNO paperwork is handled on your behalf.

Who is responsible after installation?

This is where expectations matter.

Once installation is complete:

• The system is commissioned.
  

• DNO approval or notification is confirmed.
  

• MCS certification is issued to the customer.

After this point, some responsibilities sit with the homeowner.

Setting up an export tariff is the customer’s responsibility. The installer does not enrol you onto an export agreement.

A compliant smart meter must be installed and functioning correctly. Without one, export payments cannot be recorded.

Tariffs change frequently. It is up to the customer to review available import and export options and switch suppliers if needed.

If you are on a dynamic tariff, such as an agile structure, you may need to monitor pricing windows through your supplier’s app and adjust charging schedules accordingly.

A battery system provides flexibility. Optimisation depends on how it is used.

Is home battery storage without solar worth it?

It depends largely on usage and tariff spread.

A battery-only system works best when:

• Your household uses a high amount of electricity
  

• You are on a smart time-of-use tariff
  

• There is a clear price gap between cheap and expensive periods
  

• You are willing to review tariffs periodically
  

If you use a small amount of electricity, savings are usually modest.

If you use an average amount, savings can be meaningful.

If you use a lot of electricity, particularly with electric vehicles or high-demand appliances, savings can be stronger.

In one recent UK installation, a high-usage household consuming between 15,000 and 20,000 kWh per year reduced daily electricity costs significantly by charging a large battery overnight and using that energy during peak hours.

That property had unusually high demand, which amplified the results.

This illustrates how usage influences outcomes. It does not represent every home.

What affects savings with a battery-only system?

Several variables matter.

Annual electricity consumption

Higher usage creates more opportunity to replace peak-rate electricity with cheaper stored energy.

Tariff structure

The wider the gap between cheap and expensive periods, the stronger the case.

Inverter size

A smaller inverter limits flow rate. A larger inverter allows higher charge and discharge power but may require G99 approval.

Battery capacity

Capacity should reflect real demand. Oversizing does not automatically improve payback.

Customer engagement

Monitoring tariffs and adjusting settings can influence performance, especially on dynamic pricing structures.

How much does home battery storage cost in the UK without solar?

Pricing depends on battery capacity, inverter size and installation complexity.

As a general guide based on recent UK installations:

• Around 10 kWh capacity may cost approximately £5,000 to £6,000 for battery-only.
  

• Around 15 kWh may cost approximately £6,500 to £7,000.
  

• Around 20 kWh may cost approximately £8,000.
  

• Larger 25 kWh systems may cost from approximately £9,000 and above.
  

These figures are indicative and vary by property and specification.

Correct sizing should always be based on actual annual kWh usage.

Who is home battery storage without solar suitable for?

Battery-only systems may suit:

• High electricity users
  

• Homes with electric vehicles
  

• Properties with limited roof space
  

• Households wanting minimal installation disruption
  

• Those prepared to review tariffs periodically
  

They may be less suitable for:

• Low-usage properties
  

• Homes without access to smart tariffs
  

• Households unwilling to engage with tariff management
  

Usage is the starting point. Tariff structure is the next filter.

How to decide if a battery-only system makes financial sense

Home battery storage without solar is entirely possible in the UK.

It shifts electricity from cheaper overnight periods to more expensive daytime hours. It does not generate power, but it can reduce how much high-rate electricity you purchase.

Grid classification depends on inverter size, not battery capacity. Installer responsibility ends at commissioning and certification. Ongoing optimisation depends on tariff choice and smart meter setup.

For high-usage households on suitable tariffs, it can provide meaningful savings. For lower-usage homes, returns may be slower.

The most reliable way to assess suitability is to review your annual kWh usage, your tariff structure and your willingness to manage it.

If you want to see what a battery-only system would look like based on your usage, you can explore your options here: