More new homes are being handed over with solar panels already on the roof. That is a good thing. It also means the system was chosen by the builder, not by you.
This guide explains why the panels are there, what you should have been given with them, and what to check if you want to add a battery or more panels later.
Key Points
- The energy rules for a new home are set by Part L of the Building Regulations. The 2021 edition of Approved Document L, Volume 1: Dwellings came into force on 15 June 2022.
- A new legal requirement for renewable electricity generation on new dwellings comes into force on 24 March 2027, followed by a 12 month transition period.
- The guidance benchmark is solar panels equal in area to 40% of each dwelling's ground floor area, and other methods are allowed.
- The requirement is for generation. It does not require a battery.
- You should be handed the installation certificate, evidence that the network operator was notified, and the equipment warranties.
- To be paid for export you need certification, an export meter that can take half hourly readings, and an export meter point number.
- A new build is not on the Feed-in Tariff. That scheme closed to new applicants on 31 March 2019.
Common Misconceptions
"The panels are free because the builder fitted them." They were part of the price of the house.
"A new build system must include a battery." It does not. The new requirement is for renewable electricity generation.
"Export payments start automatically." They do not. You apply to a supplier yourself.
"My solar is covered by the builder's warranty." The structural warranty and the equipment warranties are different documents with different lengths.
Real-World Advice
None of our published case studies is recorded as a new build, so there is no example of ours to show here. See our work for the jobs we do publish.
Two things come up again and again on the new build homes we visit. The developer fits the minimum number of panels needed to meet the target, and no more. And the panels are often fitted in-roof, set into the tiles rather than mounted on top of them, which makes adding more panels later harder than it should be.
UK-Specific Considerations
Why new homes come with panels
Part L of the Building Regulations covers the conservation of fuel and power. The current guidance is Approved Document L, Volume 1: Dwellings, 2021 edition incorporating 2023 amendments, which came into force on 15 June 2022. It sets a target the design of the home has to hit. It does not name solar panels as compulsory.
That changes. In its response to the Future Homes and Buildings Standards consultation, published in March 2026, the government said it has "created a new functional requirement for the provision of renewable electricity generation" for new dwellings. The requirement is "to install a system for renewable electricity generation when a building, which is or contains a dwelling, is erected", and the system "can be installed on the building or within its curtilage". The response says "The regulations and amended guidance will come into force on 24 March 2027, subject to transitional provisions", followed by "a 12 month transition period". Guidance will say the requirement is met "if solar panels to the equivalent area of 40% of each dwelling's ground floor area are installed (though it will be possible for other methods to be used)".
An earlier government announcement, published on 6 June 2025, put it plainly: "new build homes will have solar panels by default".
What the developer's system usually includes
Two things follow from that wording. The benchmark is a share of the ground floor area, so on a small house the array is small. And the requirement is for generation, not storage, so a battery is not part of it. A new build system is built to meet a target, not to match your electricity use.
The paperwork you should have
Ask for three things, in writing.
| Document | Why it matters |
|---|---|
| The certificate for the installation | Export tariffs ask you to show the installation and installer are certified. See what an MCS certificate is |
| Evidence the network operator was notified | Engineering Recommendation G98 requires the installer to give the network operator the information "no later than 28 days after the Micro-generating Plant has been commissioned". See the G98 route |
| The equipment warranties | Panels, inverter and any battery are covered by the manufacturers, on their own terms and dates |
Getting paid for what you export
Export payments come through the Smart Export Guarantee. Ofgem's guidance for generators says an eligible installation must "Demonstrate that the installation and/or installer are suitably certified", "Have an export meter" and "Have an export meter point administration number (MPAN)". For solar up to 50 kW, both the installation and the installer need certification, which "may be a Microgeneration Certification Scheme (MCS) certificate, but the SEG also recognises that other schemes may be equivalent to MCS". The meter "must be capable of taking half-hourly measurements", and suppliers set their own rates.
Signing up is your job, not the builder's. The steps are in the SEG application process.
Adding a battery or more panels
A battery is the usual first addition, because a small array often makes more in the middle of the day than the house uses. Whether it goes in on the DC side or the AC side depends on the inverter already fitted, which is explained in AC coupled and DC coupled batteries. See also battery storage.
Adding panels is a bigger change, because it alters the capacity the network operator was told about. G98 covers micro-generators up to and including 16 A per phase, and says the operator "shall have the right to request that the Customer arrange to have compliance tests undertaken after any failure, modification or replacement of any equipment that may have an impact on the Micro-generator's compliance". Above 16 A per phase the G99 process applies instead. This work goes through solar installation.
One thing you can ignore. A new build is not on the Feed-in Tariff, because that scheme "closed on 31 March 2019", so adding panels to a Feed-in Tariff system does not apply to you.
Inverter sizing on a small array
Every inverter has a range of array sizes it works well with and a maximum output. A small developer array may sit near the bottom of that range, which matters if you later want to add panels, so check the inverter model and its published limits first. The general rules are in inverter sizing and selection in the UK.
The builder warranty question
A new home usually comes with a structural warranty as well as the equipment warranties. NHBC describes its Buildmark as "our 10-year warranty and insurance cover for new-build or newly converted homes", made up of "A two year builder warranty period, during which the builder is liable to put right defects which are reported to them" followed by "Insurance cover of eight years". For those first two years "the builder, not NHBC, is responsible for rectifying problems arising from the builder's failure to meet NHBC requirements".
Buildmark is not a solar warranty. Read your own policy for what it covers, and keep the equipment warranties separate in your files.
When This Isn't Right For You
Storage is not the right first step if the array is very small and the household already uses most of what it makes during the day. There may be little spare power to store.
Adding panels is not straightforward where the roof has no more usable area, or where the existing inverter has no headroom left.
Nothing should be added while you are in a dispute with the builder over the existing installation. Sort that out first.
Before You Spend Money
Collect the handover pack first: the installation certificate, the network notification and the warranties.
Check whether you have an export meter and an export tariff. If not, sign up.
Find out the inverter model, its maximum output and whether it is a hybrid, because that decides how a battery is added.
Get a full year of half hourly electricity data if you can, then ask any installer quoting for an addition to confirm in writing who notifies the network operator and when.
Frequently Asked Questions
Q: Do all new build homes have to have solar panels?
A: Not yet. The new legal requirement for renewable electricity generation on new dwellings comes into force on 24 March 2027, followed by a 12 month transition period.
Q: I bought the house second hand. Whose certificate is it?
A: Ask the seller or the developer for the original installation certificate and the network notification. An export supplier will ask you to show the installation and installer were certified.
Q: Can I add a battery to a developer fitted system?
A: Usually yes. Which type fits depends on the inverter already installed, which is the subject of AC coupled and DC coupled batteries.
Q: Is my new build on the Feed-in Tariff?
A: No. That scheme closed to new applicants on 31 March 2019. Export payments now come through the Smart Export Guarantee.
Summary
New homes come with panels because the Building Regulations are pushing that way, and from 24 March 2027 a new legal requirement for renewable electricity generation applies to new dwellings, with a 12 month transition. The guidance benchmark is panels equal to 40% of the ground floor area, so the array is often small, and no battery is required. What you do next starts with paperwork. Get the installation certificate, the network notification and the warranties, sign up for an export tariff, then look at whether a battery or more panels suit how your household actually uses electricity.