For self-builders & custom build

Self-build solar PV — without the volume-builder compromises

Designing PV in with your architect, your roof and your building control body, and how 0% VAT on new-dwelling construction applies.

Request a quote Self-build cost guide

40%

PV area / ground floor area

Part L 2026 notional dwelling

RIBA 2–3

Best stage to design PV in

0% VAT

New-dwelling construction

HMRC Notice 708

24 Mar 2027

FHS in force

Self-build solar deserves more than a volume-house spec

Volume housebuilders often fit the array the SAP file needs and stop there. Self-builders may want more. Three things are different on a custom plot:

→Extra panels cost less at build stage. Adding them while the roof is being built avoids a second scaffold and roof visit later.
→A larger array gives design headroom. Extra PV helps the SAP calculation meet its targets, which can give your architect more room elsewhere in the design.
→You live with the result for decades. Panels commonly carry 25-year performance warranties, so size the array for the household you expect, including an EV and possibly a battery.

See typical self-build costs →

Architect-designed self-build home with integrated solar PV array

Your self-build PV journey

From plot purchase to handover: where solar fits a custom build programme.

Plot acquisition

Pre-purchase solar assessment of orientation, shading and roof potential. Useful when comparing two plots.

RIBA Stage 2–3

Form, roof geometry and array placement settled with your architect. Drawings and SAP modelling.

Tender & Stage 4

Fully specified PV package costed and tied to your main contractor's programme.

Build & sign-off

In-roof installation during roofing stage. Commissioning, MCS, EPC and Building Control completion.

Self-build resources

Plot design →

Roof pitch, orientation, shading: how plot choice and form decide the PV array.

Architect coordination →

How to integrate PV from RIBA Stage 2 onwards so the building works as a system.

Building Control sign-off →

Full plans, building notice, SAP/HEM compliance pack and the inspection schedule.

Finance options →

Custom build mortgages, 0% VAT, the Smart Export Guarantee and ECO4 interactions.

Frequently asked questions

Do I have to install solar panels on my self-build?

In England, a self-build without transitional protection must meet Part L 2026. Its notional dwelling carries PV with an area equal to 40% of the ground floor area, so in practice an array of about that size, with a heat pump, is how most new homes will comply. Transitional protection applies only where a building notice, initial notice or full-plans application is in before 24 March 2027 and work starts before 24 March 2028.

Can I exceed the FHS minimum?

Yes. Part L sets no upper limit, and on a one-off build a larger array and a battery can be worth considering, subject to roof space and the network operator’s connection rules (G98 up to 16 A per phase, G99 above that).

How does solar PV affect my build cost?

See the cost guide for indicative ranges by house size. PV installed as part of constructing a new dwelling is zero-rated for VAT under HMRC Notice 708, and fitting it during the build avoids a second scaffold and roof visit later.

When should my architect get involved with the PV?

Ideally from RIBA Stage 2, so the roof form, pitch and orientation can suit the array rather than the array being fitted to whatever roof is left. Ask the installer for roof layout drawings, structural loadings and electrical details for the architect and building control.

In-roof solar or BIPV solar tiles?

In-roof solar (panels set into the roof in place of tiles) is the usual choice: lower cost per kWp and a clean finish. BIPV solar tiles and slates, such as Marley SolarTile or GB-Sol PV Slate, come into play in conservation areas, within the curtilage of listed buildings and on design-led custom builds where a panel array would not be accepted.

How long does installation take?

A typical in-roof system is fitted over a few days during the roofing stage: the mounting goes in before tiling or slating, then the panels and inverter follow. Make sure the installer and the roofer are working to the same programme.

FHS in force from 24 March 2027

Request a self-build solar quote

Share your plot details, architect drawings if you have them, and your target start on site, and a solar installer can size and price an array. There is no obligation to go ahead.

✓ Sized to the 40% ground-floor-area rule
✓ For developer programmes and one-off self-builds
✓ Check any installer against the MCS register before you sign

Try the FHS calculator

Request a quote

A few details about the plot help an installer price it accurately.