Homeowners often improve their homes in stages. You might have insulated a loft several years ago, had cavity-wall insulation installed through an energy supplier, and only now be considering a heat pump. Does that previous assistance prevent you from using the Gov Boiler Upgrade Scheme?

Usually, earlier funding for insulation alone is not a barrier to a Boiler Upgrade Scheme application. The important distinction is what the previous support actually paid for. A grant towards insulation is not treated in the same way as public funding towards purchasing or installing the heat pump itself.

What Does the Boiler Upgrade Scheme Fund?

The Boiler Upgrade Scheme (BUS) is a government-backed installation grant for qualifying low-carbon heating at eligible properties in England and Wales. It is administered by Ofgem and works through MCS-certified installers.

In November 2026, standard support is £7,500 towards an eligible air-to-water or ground source heat pump, £2,500 for an eligible residential air-to-air heat pump and £5,000 for qualifying biomass boilers.

Some off-gas-grid properties replacing oil or LPG heating with qualifying water-based heat pumps may receive £9,000 until 31 March 2027. The grant applies to the eligible heating installation, not to general home refurbishment.

If You Previously Received Loft Insulation Support

GOV.UK explicitly explains that earlier assistance to make a home more energy-efficient, such as funding for insulation, does not automatically disqualify the property from BUS. This can be reassuring if you have already improved your loft or walls using government or supplier-backed help.

Still, tell your installer what work was completed and how it was funded. Keep relevant invoices, certificates and grant paperwork. Clear records make it easier to identify whether any earlier support was strictly for insulation or included heating equipment as well.

What Previous Funding Can Cause a Problem?

Ofgem's rules exclude certain properties where the heat pump or biomass boiler itself has already received a government or Energy Company Obligation contribution towards purchase or installation costs.

This means you should not assume two schemes can both pay for the same eligible heating installation. If a past project included an installer-funded heating system, your chosen MCS installer must investigate the details before submitting a BUS voucher request.

The restrictions also generally prevent using BUS simply to replace an existing heat pump. It is aimed at eligible conversions from fossil-fuel or conventional electric heating.

Is the Great British Insulation Scheme Still Open?

The Great British Insulation Scheme (GBIS) ran from April 2023 until 31 March 2026 and is now closed to new installations, according to Ofgem. Older articles promoting it as a currently open route to free insulation may therefore be out of date.

That closure does not erase work already completed or prevent a separate BUS application where the property qualifies. If you need funding for additional improvements, check the current schemes available through official government channels rather than assuming every historic programme is active.

Does Insulation Still Matter if It Is Not Mandatory for BUS?

Yes. Since 28 April 2026, a valid Energy Performance Certificate (EPC) is no longer a universal BUS application prerequisite. But reducing heat loss remains important for comfort and for designing an appropriately sized heat pump.

A professional assessment should look at loft insulation, walls, windows, draughts, radiators and intended room temperatures. A more efficient building may need less heating energy, but the installer should calculate the effect rather than promise a fixed percentage saving.

How to Prepare for Your Application

Gather a brief list of previous energy improvements, available completion certificates and details of your current heating system. Ask an MCS-certified installer to check property eligibility and provide an itemised quote clearly deducting the appropriate grant.

The installer submits the voucher application to Ofgem. You confirm owner consent when contacted; you do not receive the grant as a personal cashback payment.

If you want to understand the Gov Boiler Upgrade Scheme before arranging a survey, Berks Insulation's guide is a useful starting point alongside Ofgem's official rules.

Frequently Asked Questions

I already received free loft insulation. Can I use BUS?

Potentially yes. Previous support for insulation alone does not automatically exclude a qualifying heating installation.

Can an ECO-funded heat pump also receive a BUS grant?

Generally no. Public or ECO funding already used towards the heat pump or biomass boiler can create a scheme exclusion.

Do I need a new EPC because I previously had insulation work?

A valid EPC is no longer universally required for BUS applications properly made from 28 April 2026, though the installer must submit appropriate evidence.

Conclusion

Earlier insulation improvements can be an advantage when designing a heat pump, not necessarily a funding obstacle. The essential step is to separate insulation support from previous heating-equipment funding and give your installer accurate records before the voucher application.