A fixed solar panel installation does. RdSAP, the method behind every domestic EPC, has a photovoltaic input, and the generation it models lowers the modelled energy costs the rating is built from. Whether a plug-in balcony device gets the same treatment is a different question, and we couldn’t settle it from a primary source.
That second answer is why this page exists. Almost every guide on the subject is about rooftop solar panels signed off by a contractor. A plug-in device isn’t that. It comes in a box, hangs off a railing, goes into a socket, and from 27 August 2026 a compliant one can lawfully be sold and used in Great Britain. The EPC rulebook predates all of it.
The short answer, in three parts
Fixed solar panels wired into the property: counted. The assessor records the array and the software credits the solar energy it models.
A plug-in device: unresolved. We read the current RdSAP conventions and the RdSAP 10 specification in full. Neither mentions plug-in, portable or socket-connected generation. There’s a clause in the photovoltaics convention that a plug-in kit looks likely to fail, but the documents don’t say so, and we won’t decide it for them.
House value: don’t buy one expecting any. The research linking energy efficiency to sale price is about EPC bands and permanent work. An 800 VA appliance you can unplug and carry out of the front door isn’t in that category.
If you’re still working out where the law stands, start with whether balcony solar is legal in the UK and what changes on 27 August.
How an EPC rating is actually worked out
An EPC isn’t a survey of your home, it’s a modelled result. An assessor visits, collects a fixed list of data items and enters them into approved software running the Reduced Data Standard Assessment Procedure. The current version is RdSAP 10, worked to the RdSAP Conventions, v12.2 of which applies from 6 August 2026.
The software turns your dwelling into a modelled annual energy cost per square metre, and the EPC score and its A to G band come out of that. Which is why improving your EPC usually means the fabric and heating items: wall and loft insulation, glazing, heating controls and the heating system, a heat pump included. Renewable energy generated on site offsets part of what’s left. Your actual energy bills don’t come into it.
The consequence that matters here: nothing is credited unless the assessor can record it against a data item that exists in the specification.
What the RdSAP rules say about solar panels
The RdSAP 10 specification’s data entry table lists a "Photovoltaic array" item. Where peak power is known, the assessor enters kWp, pitch, orientation and overshading, for up to three arrays. Pitch options include vertical, so a panel hung flat against a balcony railing is representable, and nothing in the specification says an array has to sit on a roof.
Convention 9.05 governs what the assessor may record, and two parts of it matter.
Capacity first. "When photovoltaics are present the peak power (kWp) of the PV array is required," taken from system specification documents or the wiring schematic. Failing that, "the declared net capacity (DNC) stated on the MCS certificate may be used instead."
Then the clause that decides it for a balcony kit. "PV connection to the dwelling’s meter must be verified by the presence of a PV generation meter or documentary evidence. In all cases, the PV-generated electricity is included in the assessment of a dwelling only if the dwelling has a PV generation meter serving it."
Where a plug-in device runs into that
Capacity is the easy one. A compliant kit ships with a datasheet, so kWp comes from manufacturer documentation. There’s no MCS certificate for a self-connected device, but the convention offers documentation first and MCS only as a substitute.
The generation meter is the problem. A plug-in solar device has no generation meter, and the Interim Product Specification doesn’t require one. The word "meter" doesn’t appear anywhere in its 45 pages. Some microinverters report output to a phone app, and whether that counts as "a PV generation meter serving the dwelling" is the sort of question a convention exists to answer, and this one doesn’t.
Read literally, that final sentence keeps the generation out of the calculation. Read against the sentence before it, which allows documentary evidence as an alternative route to verifying connection, it’s less clear. We’re flagging the tension, not resolving it.
What we checked, and what we couldn’t establish
We searched the full text of the RdSAP Conventions v12.2 and the RdSAP 10 specification for plug-in, portable, balcony, microgenerator, free-standing and non-permanent. Nothing relating to photovoltaics comes back. RdSAP does say "include fixed systems only", but that’s convention 9.04, about cooling systems. Nor is RdSAP purely a fixed-equipment model: it runs the calculation for portable electric heaters where a dwelling has no space heating at all.
We checked both mechanisms RdSAP provides for recognising technologies its specification doesn’t cover. SAP Appendix Q lists three technologies under its RdSAP 10 heading, none of them solar generation. BRE Technical Notes are the other route, and BRE’s list wouldn’t render the day we looked, so we can’t tell you what’s on it.
We searched the Interim Product Specification v2 and the government’s July 2026 consultation response for EPC, energy performance, SAP and RdSAP. Neither mentions any of them. The closest anything official gets is the Solar Roadmap, which lists "improved Energy Performance Certificate (EPC) scores and property valuation" among the benefits of rooftop solar, then discusses plug-in solar separately without joining the two.
We couldn’t establish this, and here’s who to ask
Ask whoever owns the rulebook, not a solar retailer. Your assessor’s accreditation scheme, whose contact details are printed on the EPC itself. MHCLG, which owns the methodology in England, Wales and Northern Ireland, on mhclg.digital-services@communities.gov.uk or 020 3829 0748. Or BRE, which publishes the conventions. Ask three things: can a plug-in device be entered as a photovoltaic array in RdSAP 10; does convention 9.05’s generation meter requirement exclude it; and if it can be entered, what evidence does the assessor need?
Do you need to get a new EPC after you install solar?
Not because you fitted something. The duty bites on transactions. Gov.uk is plain: you must have an EPC when you’re selling a property, renting one out or building one, and you must order it before marketing. It’s valid for ten years, and government confirmed in its January 2026 partial response on EPC reform that it intends to keep that period. So fit a kit and stay put, and nothing happens to your certificate.
A fresh EPC assessment is voluntary, and worth it only if you expect a better figure, which takes you back to the unresolved question above. Look your address up on the free Find an Energy Certificate service first. And keep the paperwork, because MHCLG’s assessor guidance says that "without supporting information and evidence, such as receipts, the energy assessor will not be able to include that feature in the EPC".
What you have to tell a buyer
Selling is where this stops being academic, because a property information form is a document you sign. In England and Wales that’s the Law Society’s TA6, whose 6th edition replaced the 4th and 5th on 30 March 2026. Question 5.6, in the alterations section, asks whether "a solar power system for generating electricity, hot water or heating" has been installed at the property. Answer yes and you get sub-questions on the year, outright ownership, roof or airspace leases, batteries, and any Feed-in Tariff or Smart Export Guarantee.
Then comes 5.6(h), which asks for "a copy of the building regulations completion certificate or compliance certificate (e.g. MCS) for the installation of the system". A plug-in kit has neither, since putting a compliant device into an existing socket isn’t notifiable work and there’s no installer to certify it. The form allows "not available", which is the honest answer, but expect the question.
All of which argues for disclosing rather than staying quiet. Sellers are told that "buyers can rely on the information you give in the TA6 form" and that "if you give misleading information, the buyer may be able to claim compensation after completion". Whether a plug-in device is a solar power system for 5.6 purposes is a call for your conveyancer.
Planning is more comfortable. An amendment to England’s permitted development order, in force the same day as legalisation, writes "plug-in solar" into domestic solar permitted development rights. Check the exclusions: it doesn’t cover installation on "a wooden wall, balcony or enclosure", or on any part of the exterior clad in timber.
Three things to hand your conveyancer
The product documentation showing the model and its rated output. Any written consent from a landlord, freeholder or managing agent. And your network operator notification, since G98 notification is mandatory and a buyer’s solicitor may ask.
Does it stay with the house, or leave with you?
The starting position is that the device is yours and goes with you. Whether that holds depends less on the plug than on the bracket.
Objects brought onto land are either chattels, which don’t pass with a sale, or fixtures and things that are part and parcel of the land, which do. In Elitestone Ltd v Morris on 1 May 1997 the House of Lords took the test from Holland v Hodgson (1872) as turning "mainly on two factors, the degree of annexation to the land, and the object of the annexation".
On the plug, the courts have been blunt. In Botham v TSB Bank plc the Court of Appeal rejected the idea that plugging something in amounts to affixing it, holding that electrical equipment "affixed, if that is an apt word, by no more than a plug in an electric point" could not become a fixture.
The mounting is the part to think about. Holland v Hodgson presumes an article resting by its own weight stays a chattel, but presumes one "affixed to the land even slightly" is part of the land unless shown otherwise. So a ballasted frame on a balcony floor sits comfortably on the chattel side, while panels bolted through a railing are harder, with the burden on whoever says they stayed a chattel. The specification helps, describing the module as attached "semi-permanently" and requiring that "any attachment method shall be reversible and non-permanent".
None of which stops you agreeing otherwise, because contents and fixtures are contractual. The Law Society’s TA10 fittings and contents form has no row for solar, so it goes in a free-text "other items" line. Write it there rather than leave it to be argued about after exchange. And since network notification attaches to the property rather than to you, tell the operator if the device leaves. Our G98 form walkthrough covers deregistration too.
What you have to tell a freeholder or managing agent
This one isn’t optional, and it isn’t only about selling. The Interim Product Specification requires the instructions supplied with every compliant device to state that "users are responsible for obtaining any necessary permissions from the property owner, landlord, freeholder, managing agent or relevant authority prior to installation". The government’s July 2026 response says its forthcoming guidance "will also make clear that renters, leaseholders and residents in managed buildings should obtain any permissions that may be required before installing a device".
Whether your lease requires consent depends on your lease. Where the covenant is a qualified one, forbidding improvements without consent rather than outright, section 19(2) of the Landlord and Tenant Act 1927 deems it "subject to a proviso that such licence or consent is not to be unreasonably withheld". That proviso won’t rescue you from an absolute prohibition. Our page on balcony solar in leasehold flats works through the clauses to look for, and the managing agent consent guide covers how to ask.
It bites harder on a sale. The LPE1 leasehold enquiries form, which your buyer’s solicitor sends to the freeholder or managing agent, asks at 2.4 whether they are "aware of consent having been given to any alterations or additions to the Property", and at 8.13 for a copy of any permission to alter. Install without asking and that’s where it surfaces, in a reply you don’t control. And the specification’s fire safety prohibitions, covering timber balconies and several cladding types, are not a freeholder’s to waive. Saying yes doesn’t turn a prohibited surface into a permitted one.
Do solar panels add anything to what the house is worth?
Treat the honest answer as no, and treat any page telling you otherwise as talking about a different product.
The evidence people cite traces back to one piece of government research published on 17 June 2013, covering 325,950 English dwelling transactions between 1995 and 2011, which found moving up EPC bands was associated with higher sale prices. It’s thirteen years old, and it’s about bands. If a plug-in kit doesn’t move the band the mechanism never engages, and a device that leaves with the seller can’t be capitalised into the price of what the buyer is buying.
The government’s estimate of annual bill savings from a plug-in device is £70 to £110, and a balcony sits at the bottom of that range, because the upper figure models a 30 degree south-facing installation rather than a panel hanging vertically off a railing. Our balcony solar savings guide sets out the arithmetic.
If a higher EPC rating is genuinely the goal, the fastest way to improve an EPC score is the energy efficiency measures the model is most sensitive to: loft and cavity wall insulation, glazing, heating controls and the heating system. A fixed rooftop solar installation sits inside the assessment too. An 800 VA plug-in device makes its case on lower energy bills day to day, not on a better certificate.
Frequently asked questions
Do solar panels improve your EPC rating?
A fixed installation does. RdSAP has a photovoltaic array data item, and the modelled generation reduces the modelled energy costs the EPC rating is built from. How much depends on capacity, orientation, overshading and the dwelling, so no one can promise a number of points in advance.
Does a plug-in solar device count towards an EPC?
We don’t know, and neither the conventions nor the specification says. The obstacle is convention 9.05, under which PV-generated electricity counts "only if the dwelling has a PV generation meter serving it". A plug-in kit has none. Ask your assessor’s accreditation scheme rather than assuming either way.
Do I need a new EPC after installing solar panels?
No. The obligation attaches to selling, letting or building, not to making an improvement. If your energy performance certificate is still within its ten years you can sell on it. A fresh one is optional.
Does a plug-in solar kit stay with the property when I sell?
Normally it leaves with you, since the courts have held that plugging something in doesn’t make it a fixture. Bolting the mounting to a railing is a closer question. Either way, write your intention on the fittings and contents form.
Do I need freeholder permission to install solar panels on a balcony?
Very possibly, and the product instructions will say so. Compliant devices must carry a statement that users are responsible for obtaining permissions from the owner, landlord, freeholder or managing agent before installing. Whether your lease requires it turns on its alterations clauses.