Balcony Solar + Battery Storage: Is It Worth It in a UK Flat?

If you live in a flat in the UK, you’ve probably seen glossy photos of roof-fulls of solar panels and wondered: What about me? Balcony solar has started to change that – and the next question many people ask is:

“Should I add a battery as well, or is that overkill for a flat?”

This guide walks through what balcony solar with battery storage really looks like in a UK flat, how it fits with the rules, and when it’s likely to be worth it.

At SaveOnWatts, our belief is simple: solar should be for everyone, including people in flats, rentals and homes without big roofs. The aim here is straight answers, not hype.

What do we mean by “balcony solar with battery” in the UK?

When we talk about balcony solar with a battery, we’re usually describing a small system that includes:

• One or more solar panels mounted on a balcony rail or wall.
  
• A micro-inverter that turns the panel’s direct current (DC) into grid-style alternating current (AC).
  
• A way to connect into your flat’s electrics, often via a dedicated socket or circuit.
  
• Battery storage, which could be:
  
• A portable power station that you move around, or
• A small fixed battery unit managed by an inverter.

The idea is simple:

• Use sunlight to power part of your flat in real time and
  
• Store surplus energy in a battery to use later, when the sun isn’t shining.
  

In the UK context, that can also work alongside smart tariffs that have cheaper off-peak electricity at night. Some batteries can top up from the grid when prices are low, then cover some of your usage when prices rise.

Can you actually have balcony solar and a battery in a UK flat?

In most cases, yes... but it has to be done safely, legally and with the right permissions.

For many flats there are three layers to think about:

1. Your tenancy or lease

• As a renter, you almost always need your landlord’s written permission for any kit that affects the building fabric, railings or wiring.
  
• Leaseholders in blocks of flats may also need approval from the freeholder or managing agent, especially for anything visible from the outside.
  

2. Building and fire safety

• Panels and batteries must not obstruct escape routes or create trip hazards on balconies or stairwells.
  
• Batteries should be sited in dry, well-ventilated areas, away from direct heat sources, following manufacturer guidance.
  
• Some buildings already have specific rules about energy devices on balconies, always check.
  

3. Electrical and grid rules

• Many balcony solar kits are designed to keep within certain power limits and connection methods.
  
• For anything that exports to the grid, your installer or supplier may need to notify the local DNO (Distribution Network Operator) under standards such as G98 or G99 (technical rules for connecting generators and storage).
  
• Even with very small systems, you must use compliant equipment and follow UK wiring regulations.
  

The short version: balcony solar and batteries can fit in flats, but not every flat or landlord will say yes to every set-up. A big part of SaveOnWatts’ work is helping you find solutions that fit your building’s reality.

How balcony solar + battery works in practice (in plain English)

Here’s what happens on a sunny lunchtime in a typical set-up:

1. Sun hits the panels on your balcony, generating DC electricity.

2. The micro-inverter converts that to AC, matching your flat’s electricity.

3. That power flows into your flat and is used by whatever is running at the time: fridge, router, laptop, lights.

4. If you’re generating more than you’re using, the surplus can:

• Charge a battery, or
  
• In some designs, flow back towards the grid (subject to how it’s wired and what’s allowed).
  

Later on, in the evening:

• Your battery discharges, covering some of your usage when your panels aren’t producing.
  
• If your battery can also charge from the grid, you may top it up overnight on an off-peak tariff and then use that stored energy during higher-priced hours.
  

You don’t need to become an engineer to benefit. Just keep two ideas in mind:

• Power (watts, W) – how quickly energy is used (like speed).
  
• Energy (kilowatt-hours, kWh) – how much total energy you have (like distance).
  

A 1 kWh battery, for example, could roughly run a 100 W device for about 10 hours (100 W × 10 h = 1 kWh), allowing for some losses.

Types of batteries that pair with balcony solar in flats

Not all batteries are the same, and the best match depends on your flat, permissions and goals.

1. Portable power stations

These are self-contained battery units, often used for camping and containing:

• Built-in battery management
  
• UK 3-pin sockets and USB outputs
  
• A charger to top up from the mains
  
• Sometimes a way to plug in solar panels

Some balcony solar kits can feed these units via dedicated connectors; others require a compatible set-up. They may not require DNO notification, this will depend whether they are hard-wired into the grid or used as a standalone off-grid device. Either way, you still need to follow the manufacturer’s limits and safety guidance.

2. Micro wall-mounted batteries

These are compact batteries that may:

• Mount on a wall or floor
  
• Charge from a dedicated outlet or small inverter
  
• Store enough energy to cover a chunk of daily usage
  

They sit between portable units and full home batteries. In a flat, they may still be treated as equipment in your dwelling, but installation and location need to respect:

• UK wiring regulations
  
• Fire safety and escape routes
  
• Your landlord or freeholder’s rules
  

3. Larger fixed storage systems (mainly for small houses & maisonettes)

If you’re in a small house or maisonette with more control over the wiring, you might look at a fixed home battery tied into your consumer unit (fuse box). These systems:

• Must be installed by a qualified electrician
  
• Typically require DNO notification under G98/G99
  
• Often pair well with both rooftop or balcony solar and smart tariffs
  

They can be excellent for self-consumption and bill control, but are usually a step beyond what most flat-dwellers can install without significant permissions.

Safety, permissions and UK rules you must respect

Whatever mix of balcony panels and batteries you consider, keep these guardrails in mind:

• Any energy generating device cannot be plugged into a 3 pin plug. This means for any on-grid activity such as using the battery during peak tariff times, the battery will need to be installed on a dedicated line. 
• Follow electrical rules. Any work on fixed wiring must comply with BS 7671 (UK wiring regulations) and be done by a competent person.
• Ask before you mount. For renters and leaseholders, get written approval from your landlord, freeholder or managing agent before fixing panels or batteries to walls, rails or fabric of the building.
  
• Use certified kit. Look for UK and EU conformity markings and choose suppliers who can explain how their kits align with UK requirements.
  
• Respect escape routes. Don’t run cables across walkways or block balcony doors and stairways.
• Check DNO requirements. For systems that export to the grid, your installer or supplier should handle any DNO notification and explain whether G98 or G99 applies.
  

Always check the latest guidance from your DNO, landlord or building management before installing any balcony solar kit, and follow manufacturer instructions for batteries and inverters.

Is balcony solar with battery actually worth it in a flat?

This is the big question... and the honest answer is: it can be, but it depends what you’re expecting.

Where it can be “worth it”:

• You’re at home during the day and can use a good chunk of what you generate.
  
• You want resilience, keeping your router, lights and small appliances running during power cuts.
  
• You can use smart tariffs to top up a battery cheaply and offset some peak-time usage.
  
• You value the environmental benefit of producing some of your own low-carbon electricity.
  
• You see it as a long-term, movable asset (especially for portable systems you can take when you relocate).
  

Where expectations need to be realistic:

• Small balcony systems generate much less than a full roof array. You’re trimming bills, not wiping them out.
  
• Batteries add cost. Their financial “payback” depends on:
  
• How much energy they cycle each day
• The difference between your off-peak and peak prices
• Future energy costs and usage habits
• Not every flat has the perfect orientation, shading or permissions for panels or wall-mounted units.
  

For many flat-dwellers, balcony solar plus a modest battery is best seen as a practical step into solar, a tool to shift some usage to cheaper or self-generated power, rather than a full replacement of grid electricity, and a way to protect key devices during outages.

Who balcony solar + battery suits best (and who it doesn’t)

You’re likely a good fit if:

• You have a balcony with some direct sun and space for one or two panels.
  
• You’re comfortable getting permissions sorted and following building rules.
  
• You care about bill control and resilience, not just headline savings.
  
• You like the idea of a portable or modular system that can move with you.
  

It may not be the right move if:

• Your balcony is heavily shaded or north-facing with very limited sun.
  
• Your landlord or freeholder is firmly against any visible kit.
  
• You’re looking for a very short payback period and every pound must be justified purely in financial terms.
  
• You have nowhere safe, dry and ventilated to store a battery.
  

If you’re unsure, SaveOnWatts can help you map your balcony, consumption patterns and landlord position to realistic options.

FAQ: Balcony solar with battery in UK flats

Do I need a battery for balcony solar to be worthwhile?

Not always. If you’re home during the day and can use most of what the panels produce, you may start without a battery. A battery adds flexibility, backup and the option to shift more usage into the evening, but it also adds cost.

Is balcony solar with battery legal in the UK?

Balcony solar and batteries are allowed in principle, but you must follow UK electrical rules, building and fire safety guidance, product standards, and your building’s own policies. For certain grid-connected systems, your installer or supplier may need to notify the local DNO under G98 or G99 standards.

Can renters install balcony solar with a battery?

Often, yes, but only with landlord permission, and usually with solutions that don’t permanently alter the building. Portable batteries are particularly renter-friendly because you can remove them when you move.

Will a balcony solar + battery system cover all my electricity use?

Very unlikely in a typical flat. Expect it to cover a portion of your consumption and provide useful backup, especially for low-power devices and efficient appliances.

Can I take the battery with me when I move?

Portable power stations and some micro batteries are designed to move with you. Fixed systems tied into the wiring are harder to relocate and may be sold with the property instead.