Warm Homes Loan Calculator UK

Not automatically. The Warm Homes Loan Scheme is not a single government-issued loan, but a £300m government subsidy to private lenders that reduces contractual interest rates by up to 5 percentage points, down to a floor of 0.0%. Select lenders—such as Sunsave (3-year term for solar & battery) and HomeServe Finance via E.ON Next (up to 5 years for solar, 6 years for heat pumps)—offer 0% APR on shorter terms. Longer repayment terms (7 to 30 years) carry interest, typically ranging from 2.7% to 4.6% APR.

Borrowing limits apply per technology: up to £15,000 for solar PV panels, up to £15,000 for battery storage, up to £20,000 for air-to-water heat pumps, up to £35,000 for ground source heat pumps, up to £20,000 for biomass boilers, and up to £7,500 for low-carbon heat network connections. Measures can be combined in a single project (for example, up to £30,000 for solar plus battery). Maximum project borrowing is ultimately subject to individual lender credit limits (e.g. Selina Finance caps aggregate borrowing at £65,000).

Yes. In England and Wales, you can combine a Warm Homes loan with the £7,500 Boiler Upgrade Scheme grant (or £9,000 for off-gas oil/LPG properties until 31 March 2027). The statutory technology cap (£20,000 for air-to-water heat pumps) applies prior to grant deduction, and the loan finances the remaining net installation balance. You cannot use both schemes to double-fund the exact same portion of the cost.

The initial ten lenders approved by DESNZ in October 2026 are: HomeServe Finance (partnering with E.ON Next and BOXT), Sunsave Energy, The Money Co-op, South Manchester Credit Union, Selina Finance, Tandem Bank (partnering with British Gas and OVO), Hometree Finance, Propensio Finance, Secure Trust Bank (via V12 Retail Finance), and This Bank (thisbank). A second onboarding window for additional high-street banks and building societies opens in late 2026 / early 2027.

It depends on your lender. Direct credit unions like The Money Co-op and South Manchester Credit Union allow you to use any MCS-certified installer with a valid written quotation dated within the last 6 months. Conversely, lenders like Sunsave, HomeServe (E.ON Next / BOXT), and Tandem Bank operate closed networks requiring you to use their approved installation partners. Selina Finance operates through installers using the OpenSolar platform.

No. The scheme strictly excludes building fabric improvements (loft, cavity, or solid wall insulation, windows, doors) and roof repairs. If your roof requires structural timber strengthening before solar panels are installed, that work cannot be funded through the Warm Homes loan and must be financed separately or paid out of pocket.

Yes, provided they apply as personal borrowers. Section 4.4 of the DESNZ Scheme Rules permits private rented sector (PRS) landlords to take out a separate Warm Homes loan for each domestic property they own in their personal name. However, corporate entities, limited companies, and Special Purpose Vehicles (SPVs) are strictly excluded from the scheme.

Stretching your loan over 10, 15, or 20 years reduces your monthly cash payment, but because interest compounds over twice or four times as many years, the total lifetime cost can be drastically higher. Furthermore, the government’s 20% subsidy cap means the interest rate discount shrinks on terms over 10 years (from a 5-point cut down to ~2.8 points at 20 years). A 10-year subsidised loan often costs thousands more in total interest than a shorter 5-year loan.