Finance is rarely the obstacle on new-build solar — 0% VAT relief, self-build mortgage staged drawdowns, green-mortgage cashback, and the £39bn Social and Affordable Homes Programme (SAHP 2026–2036) funding envelope all work in the homeowner\'s and developer\'s favour. The challenge is knowing which of the available routes applies to your specific procurement scenario. This page breaks down the four main finance pathways and how to optimise across them.
1. 0% VAT on new-build solar PV
Two distinct VAT mechanisms apply, and it pays to know which is which. Solar fitted as part of constructing a new dwelling is zero-rated under VAT Notice 708 — the long-standing zero-rating of new residential construction, which has no end date. This covers the PV panels, in-roof mounting, inverter, battery and labour when supplied as part of the build, plus developer plot sales (zero-rated, so the relief is baked into the purchase price).
Separately, the energy-saving materials relief (VAT Notice 708/6) zero-rates solar, batteries and heat pumps retrofitted to existing homes. That relief is legislated to run until 31 March 2027, after which it reverts to 5% VAT. This is the deadline quoted across the industry — but it bites on retrofit, not on solar fitted during new-build construction. The VAT on solar panels guide covers both reliefs in full, including batteries and self-build refunds. The two reliefs together mean:
- •New-build self-build dwellings — zero-rated under Notice 708 (construction), no end date
- •Conversion of non-residential to residential — zero-rated construction
- •Retrofit to existing dwellings — 0% under the ESM relief until 31 March 2027, then 5%
- •Plot sales by volume housebuilders — zero-rated; the developer recovers input VAT
On a typical 5 kWp + 13 kWh battery + 8 kW ASHP self-build package (gross cost ~£17,000 inclusive of labour), zero-rating saves ~£3,400 versus the 20% rate. For developers the relief is baked into the per-plot price as plot sales are zero-rated. See our new-build solar incentives guide for the full incentives picture including SEG export payments.
2. Self-build mortgage staged drawdowns
Self-build mortgages release funds in stages against build progress rather than as a single advance. The typical drawdown schedule:
| Stage | Cumulative % | Solar PV cost trigger |
|---|---|---|
| Land purchase | ~25% | — |
| Foundations + ground floor | ~35% | — |
| Wall plate / weatherproof | ~50% | Panel order deposit (10%) |
| First fix | ~65% | Solar PV install (50%) |
| Second fix | ~85% | Battery + ASHP (30%) |
| Completion / final fix | 100% | Commissioning & handover (10%) |
Self-build lenders comfortable with this aligned schedule include Ecology Building Society, Hanley Economic, Buildstore, BuildLoan and Newbury Building Society. Ask the installer to format their invoicing schedule for the lender’s monitoring surveyor.
3. Green mortgage cashback for EPC A/B new builds
FHS-compliant new builds are designed to reach a high EPC band, and a band A or B rating is what most green-mortgage products at UK lenders ask for:
| Lender | Product | Benefit |
|---|---|---|
| Nationwide | Green Additional Borrowing | 0% interest on £5k-£15k for energy-saving works |
| Halifax | Green Living Reward | £250 cashback for EPC A/B properties |
| Barclays | Greener Home Mortgage | Rate reduction ~10bps for EPC A/B |
| NatWest | Green Mortgage | Rate reduction + cashback for EPC A/B |
| Santander | Greener Home Reward | £500 cashback for EPC A/B new build |
| HSBC | Energy Efficient Mortgage | Rate reduction for EPC A/B properties |
On a £400k mortgage, a 10-basis-point rate reduction saves approximately £400/year. Combined with a £250-£500 cashback at completion, the total green-mortgage benefit on an FHS-compliant new build is typically £650-£900 in year 1 and £400/year ongoing — material against the FHS price premium.
4. Developer credit lines and procurement terms
Two procurement models are common for volume housebuilders:
- Per-plot fixed price with staged payment: Total per-plot cost agreed at procurement (for example, about £4,080 for a 3.4 kWp array at around £1,200/kWp). Payment schedule: 10% deposit on bulk order placement, 30% on first plot delivery to site, 50% on completion of each plot installation (paid weekly in arrears against MCS certificates issued), 10% post-handover.
- Schedule of rates with monthly account: Day-rate and unit-rate pricing applied to actual installations completed in the period. Monthly invoicing with 30-day payment terms. Suits developers with variable plot release programmes where exact volume is not pre-committed.
Agree payment terms, retention and how variations are priced before the first plot is released.
5. Social and Affordable Homes Programme funding
The £39bn Social and Affordable Homes Programme runs from 2026 to 2036, funding new affordable homes through Homes England and, in London, the GLA. Homes it funds must meet the Building Regulations in force when they are built, including the Future Homes Standard, so the PV and heat pump costs sit inside the scheme budget. Check the programme’s current capital funding guide for any additional specification requirements and for how grant rates are set.
For how solar fits social-housing procurement, see the social housing guide. For Welsh schemes, the equivalent Welsh Government Social Housing Grant route applies. For Scottish schemes, the Affordable Housing Supply Programme.
Need a fixed-price quote with our standard staged invoicing schedule? Use the contact form with your plot details. For a 30-second indicative cost based on your ground floor area, use the FHS PV calculator.