For self-builders

Financing self-build solar — mortgages, 0% VAT and grants

How self-builders finance the solar PV component of an FHS-compliant new build — custom build mortgages, 0% VAT, Smart Export Guarantee and the interaction with ECO4 and grants.

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Finance Options for Self-Build Solar PV — UK self-build solar PV guidance

The good news for self-builders is that solar PV on a new dwelling attracts 0% VAT and integrates cleanly with most custom-build mortgages. This page walks through the financial mechanics.

0% VAT on solar PV materials and labour

Under VAT Notice 708, construction of a new dwelling is zero-rated. This includes the solar PV, the in-roof mounting, the inverter and the installation labour. Self-builders save ~£1,400 on a typical 5 kWp installation versus retrofit pricing.

Custom build mortgage integration

Most custom build mortgage products (BuildLoan, Ecology, BuildStore, Buildloan Direct) advance funds stage-by-stage. The solar PV invoice is usually paid out of the "roofing/wind & water tight" or "second fix" stage advance. We invoice in two stages — 50% on in-roof mounting installed, 50% on commissioning — to align with most lenders.

Smart Export Guarantee (SEG) payments

Once your home is occupied and the PV system is MCS-certified, you register with a SEG supplier (Octopus, EDF, Bulb successor, etc.). Export tariffs range from 4p to 24p per kWh — Octopus Outgoing and OVO's smart export rates are typically the best for self-consumption-aware homes.

ECO4 and grant interactions

ECO4 is a retrofit funding scheme and does not apply to new dwellings. Self-builders who hit FHS spec do not qualify for ECO4 grants for their solar PV (which is the correct outcome — the FHS already mandates the equipment). The Smart Export Guarantee remains the primary income source.

Insurance and warranty

Buildmark for Self-Build (NHBC), Self-Build Zone, LABC Warranty Self-Build, and Premier Guarantee are the four main self-build warranty providers. All accept MCS-certified PV installations with insurance-backed workmanship warranty.

40% of ground floor area

PV / ground floor area

Mar 2027

FHS in force

75%

CO₂ vs 2013 baseline

£4,350 per dwelling

Per-plot premium

For self-builders and architects

Finance options for self-build solar pv for one-off custom builds

Engagement from RIBA Stage 2. PV sizing collaborative with the architect. SAP/HEM modelling that gives the architect freedom on glazing ratios and roof geometry. Building Control submission pack ready for the Approved Inspector. 0% VAT on new-build dwellings. Staged invoicing aligned to your self-build mortgage drawdowns. We work with custom-build buyers across England, Wales and Scotland.

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How this fits into the FHS compliance pathway

Every FHS-compliant new build must pass three regulatory gates. Finance options for self-build solar pv fits primarily into the second gate — design-stage Part L compliance — but has knock-on implications for Building Control sign-off and post-completion warranty:

1
Planning permission Most solar PV on new dwellings is consented within the dwelling\'s primary planning consent. Conservation Areas, Article 4 directions and listed-curtilage plots require additional planning consideration — we handle the planning evidence required for these.
2
Building Control — Part L compliance SAP 10.3 or HEM compliance modelling demonstrating Dwelling Emission Rate ≤ Target Emission Rate. PV specification, ASHP capacity, fabric U-values and air permeability all entered into the modelling. We provide the full compliance file ready for the Approved Inspector.
3
Post-completion — warranty & EPC MCS certificate, EPC, monitoring app onboarding and 20-year insurance-backed workmanship warranty. NHBC, LABC, Premier and Buildmark all accept our installation specification without query — important if you\'re relying on a structural warranty for buyer mortgageability.

For a fuller walkthrough of the compliance process, see our Part L 2026 page and the FHS PV calculator which sizes a compliant system from your ground floor area in 30 seconds.

Frequently asked

Self-build questions

Answers to the questions we get most often when discussing finance options for self-build solar pv with new clients.

Can I self-build a home that exceeds FHS specifications?

Yes — and the marginal cost of exceeding FHS is small relative to the long-term running cost benefit. A typical "FHS-plus" self-build specification: 6 kWp array (vs 3.4 kWp minimum on a 3-bed), 13 kWh battery, air permeability target 1.5 (vs FHS 3), PassivHaus-style thermal bridging detail. Capital premium over FHS minimum: £8,000–£12,000 on a £400k build budget. Running cost saving: ~£500/year, plus a clear EPC band A rating that adds 4–6% to resale value at 2026 prices.

Will my Approved Inspector understand FHS — or will Building Control sign-off be slow?

Approved Inspectors and LABC officers across England have been training to the FHS dual-route (SAP and HEM) compliance pathway since the consultation response in Q4 2025. Most are now confident on Part L 2026. The slowest area is HEM modelling — the new dynamic simulation engine has a steeper learning curve than legacy SAP. Most submissions in 2026 are being filed under the SAP 10.3 route during the transitional period, with HEM adoption growing through 2027.

When does the Future Homes Standard come into force?

24 March 2027 in England, with a 12-month transitional period running to 24 March 2028 for projects already under construction. The Approved Documents L and F were published on 24 March 2026 (Government statement HCWS1445), giving the industry exactly 12 months of certainty before regulatory commencement. Scotland, Wales and Northern Ireland are following with broadly equivalent regulations on roughly aligned timetables, although devolved nuances apply — Welsh regulations are typically 6 months ahead.

What does FHS-compliant solar PV actually cost per plot?

The Government Impact Assessment puts the total FHS premium at ~£4,350 per dwelling per dwelling (2025 prices, weighted average across heat pump, solar PV, MVHR and enhanced fabric). Of that, solar PV is roughly £4,200 — covering ~3.4 kWp for a typical 3-bed semi (panels, in-roof mounting, inverter, monitoring, MCS certification and 20-year insurance-backed warranty). Larger dwellings cost proportionately more; volume procurement reduces per-plot cost by 20–25%.

FHS 2027 deadline approaching

Book a free self-build consultation

Tell us your plot details — ground floor area, location and target start-on-site date. We return a fully-costed system sized to Part L 2026 (40% PV rule), with the SAP/HEM compliance pack included.

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