Helios. Is plug-in solar worth it?

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South
London
Scientific

Is plug-in solar worth it
for your home?

Plug-in solar panels will be available in the UK soon, letting you
generate electricity from your balcony without expensive
installation fees or planning permission.

Enter your postcode and house or flat number to see how much energy
you could generate, and whether it’s likely to be worth it.

Start with my postcode

How it works

We resolve your postcode against Ordnance Survey data, ray-trace
the surrounding buildings from Environment Agency LIDAR, then ask
PVGIS for an annual yield given the shading we found. We have no
database — your address isn't stored.

Where do you live?

Postcode is required. House number or flat is optional — we use
it to pinpoint your building for this calculation, not to store
your address.
Privacy.

Postcode

House number or flat

Next

What floor are you on?

Ground floor is 0. Higher floors clear more obstructions but also
shift the solar peak season.

−

0
Ground

+

Back
Next

Which way does your balcony face?

Pick the compass direction the panel will point. South is typically
best in the UK; east and west still produce well.

NW

N

NE

W

E

SW

S

SE

Back
Next

About your bill.

Roughly how much electricity do you use a year? Pick the closest band — the
medium default works for most UK homes.

Low
1,800 kWh / year
Flat or studio, electric efficient

Medium
2,700 kWh / year
Typical UK home

High
4,100 kWh / year
House, electric heating

Skip — use the medium default

Back
Next

Your kit and your tariff.

UK rules cap plug-in kits at 800 W inverter output, so most
kits sold here are around 0.8 kWp — two panels and a microinverter.

0.4 kWp
One panel

0.8 kWp
Two panels

Your electricity tariff

Standard variable (EDF / British Gas / similar)
Octopus Agile
Octopus Cosy
Octopus Go
Octopus Tracker
British Gas standard variable
Other fixed rate

Advanced. Kit cost and self-consumption

Kit cost (£)

Install cost (£)

£0 assumes a DIY socket install. Until the plug-in safety
standard lands (expected mid-2026), the compliant route is a
quick hardwire by a registered electrician — add their cost
here if that applies.

Self-consumption fraction (0 to 1)

SEG export rate (p / kWh)

Defaults to 0. The Smart Export Guarantee needs an
MCS-certified install, which DIY plug-in kits can't get — so
most owners earn nothing for exported power, and the value is
in what you use yourself. Set a rate only if you have an MCS
install.

Back
Calculate

Modelling shading and yield.

Something went wrong.

Start over

Here's what we found.

We don't have detailed building data for this address.
This estimate assumes a clear horizon — actual yield will be lower
if nearby buildings or trees shade your panel.

Net earner

£
kWh

Kit cost
.
incl. VAT

Annual generation
.
kWh / year

Payback
.
years

These are estimates to help you weigh it up — not financial advice.
Real yield and savings vary with the weather, your day-to-day
electricity use, and how the kit is installed.

Where the panel is

Show map

What the sun sees from your balcony

Grey is the sky blocked by nearby buildings (LIDAR-derived).
Gold arcs trace the sun on midsummer, the equinox, and midwinter.
Where a gold arc dips into the grey, the sun is hidden then.

Midsummer
Equinox
Midwinter
Panel faces

Generation by month

How we worked this out

Panel orientation
.
Panel tilt
.
Approximate observer height
.
Building height (LIDAR)
.
Address precision
.
System size
.

Tariff and savings

Tariff
.
Solar-weighted import rate
.
Annual savings
.
Lifetime savings (20 years, net of capex)
.

Savings come from the power you use yourself: most plug-in kits
can't claim the Smart Export Guarantee (it needs an MCS install),
so exported energy is assumed to earn nothing. Self-consumption
defaults to 60% (spec §3.7). Time-of-use tariffs use a
typical-day model. Refresh quarterly.

Tell me when kits arrive in the UK.

Plug-in solar is in regulatory limbo here — the kits available
elsewhere in Europe aren't legally for sale in Britain yet. We're
tracking the market. Leave your email and we'll let you know when
things change.

Email address

I agree to be emailed when UK plug-in solar kits hit the market.
Stored with Brevo;
unsubscribe any time.
Privacy.

Notify me

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Built by
South London Scientific.
·
Privacy

Plug-in solar panels are anticipated to become available in the United Kingdom, offering a method for generating electricity from a balcony without requiring expensive installation fees or planning permission. The process for assessing the viability of such a system is based on an analytical framework that incorporates geographical and environmental data to estimate potential energy generation and savings for a specific residence.

The methodology involves resolving the user's postcode against Ordnance Survey data and ray-tracing surrounding buildings using Environment Agency LIDAR data to map shading. This environmental assessment is then used in conjunction with PVGIS to determine an annual energy yield based on the calculated shading. To perform this calculation, the user inputs details regarding their location, including floor level, the orientation of the balcony, and their estimated annual electricity consumption band (Low, Medium, or High).

The system accounts for physical constraints and temporal variations, noting that higher floors clear more obstructions but also shift the solar peak season. The direction the panel faces is determined by a compass orientation, noting that south-facing orientation is typically optimal in the UK, although east, west, and other directions still yield energy. Annual generation is further modeled by considering the sun's path through the year, distinguishing between midsummer, the equinox, and midwinter, and assessing how these periods interact with the shading derived from nearby structures.

The analysis also incorporates specifics regarding the existing electricity tariff, factoring in solar-weighted import rates. A crucial consideration in the financial evaluation is self-consumption, which defaults to a 60 percent fraction, as most DIY plug-in kits lack the necessary MCS certification required to claim the Smart Export Guarantee (SEG) export rate, meaning exported energy is generally not monetized. The system also considers the constraints of current UK regulations, noting that plug-in kits are capped at an 800 W inverter output, resulting in typical system sizes around 0.8 kWp, consisting of two panels and a microinverter.

The calculation ultimately estimates potential financial outcomes, including net energy generation, estimated payback periods, and lifetime savings over twenty years, net of capital expenditure. It is essential to recognize that these figures are estimations intended to help weigh the potential benefits, as actual yield and savings are highly dependent on unpredictable variables such as specific weather conditions, the user's daily electricity usage patterns, and the precise installation method. Furthermore, the text cautions that the system lacks detailed building data for specific addresses, meaning the estimates assume a clear horizon, and actual yield may be lower due to unmodeled shading from nearby trees or buildings. The availability of these kits in the UK remains subject to regulatory changes, necessitating tracking of market developments.