Boiler Upgrade Scheme (BUS)

Introduction

The Boiler Upgrade Scheme (BUS) is a UK Government-backed grant designed to reduce the upfront cost of switching away from fossil-fuel heating and towards low-carbon alternatives. If you currently rely on gas, oil, LPG or certain electric heating systems, BUS can make the jump to a heat pump (and, in limited cases, a biomass boiler) significantly more affordable. The key thing to know from the outset is that the scheme is installer-led: you don’t apply directly as a homeowner or business owner—your chosen certified installer applies on your behalf.

What BUS is (and what it isn’t)

BUS is not a rebate you claim after the fact, and it’s not a general home-improvement fund. It is a targeted scheme intended to support specific heating technologies that can reduce emissions from buildings over time. In practical terms, it works like a discount against the cost of supply and installation, delivered via a voucher system administered by Ofgem.

You will usually experience BUS as a reduction in the quote you accept from your installer (with the installer later redeeming the voucher). This matters because it changes how you should compare quotes: you’ll want to check whether the grant is clearly shown and whether the final price includes everything you expect (more on this later).

BUS at a glance

Why this guide exists

BUS can feel deceptively simple at first (“get £7,500 off a heat pump”), but the detail matters. Eligibility turns on property status, existing heating, EPC rules, location (for biomass), and the way the installation is designed and commissioned. This guide walks you through each moving part in a way that lets you:

• understand whether you’re likely to qualify before you invest time in quotes

• budget realistically (including common costs beyond the grant)

• avoid the most common pitfalls that lead to delays or ineligibility

• plan for running costs and long-term value, not just the upfront price

A note on “expanded BUS”

You may see references to an “expanded Boiler Upgrade Scheme”. This typically refers to the Government’s stated intention to broaden what’s supported (for example, additional technologies and changes to eligibility and certification requirements). In this guide, I’ll clearly separate what is currently in the published Ofgem guidance from what has been announced or proposed so you can make decisions with confidence.

Why the scheme was introduced

Heating is one of the UK’s biggest decarbonisation challenges because it touches nearly every home and many workplaces. For decades, the default option has been burning fossil fuels on-site—mostly gas, but also oil and LPG—through boilers that are familiar, compact, and relatively cheap to replace. BUS exists to tackle the two biggest barriers that stop people switching to cleaner heating: upfront cost and market readiness.

The problem BUS is trying to solve

Even though low-carbon heating options have matured technically, the UK market historically lagged behind comparable European countries in deployment. There are several reasons, but the main ones are:

• High upfront costs compared with like-for-like boiler replacement

• A need for better building readiness, such as insulation and heat emitter suitability

• Consumer uncertainty, including concern about comfort, noise, disruption, and running costs

• Installer capacity and supply chain scaling, including design skills and product availability

BUS targets this by providing a straightforward capital grant to reduce the financial “gap” at the point of purchase and by encouraging installers and manufacturers to scale up.

Heating, emissions, and the net zero direction of travel

The UK’s legal commitment to net zero means the way we heat buildings must change over time. Public bodies and watchdogs have repeatedly highlighted that emissions from home heating are material and that a shift away from fossil-fuel boilers is unavoidable in any credible pathway.

• Heating the UK’s homes has been reported as a significant share of national greenhouse gas emissions, with parliamentary scrutiny emphasising the scale of the challenge and the need to transition away from burning natural gas for heat.

• Government strategy has also pointed to a rapid expansion in heat pump deployment capacity by the late 2020s.

These points are not abstract—they are the reason BUS exists at all. It’s designed as a market mechanism: nudge uptake, build confidence, lower costs through scale, and normalise low-carbon heating as a mainstream choice.

How BUS supports low-carbon heating in practice

BUS supports low-carbon heating in three very practical ways:

1) It reduces the “decision friction” at quote stage

People rarely replace a boiler because they want to—they replace it because they have to. BUS helps installers present a financially credible alternative at the exact moment a property owner is already prepared to invest.

2) It supports better design and consumer protection through certification

Because BUS is tied to certification requirements (notably MCS), it encourages proper heat loss assessment, commissioning, and documentation. This improves outcomes: comfort, efficiency, and fewer “bad installs” that damage consumer confidence.

3) It aims to create long-term cost reductions through market scaling

As installation volumes rise, costs typically fall due to:

• increased installer competition

• improved installer productivity and standardisation

• better supply chains and shorter lead times

• product innovation and more UK-focused models

Why this matters to you as a homeowner or business owner

Even if your motivation is mainly financial (and that’s completely reasonable), BUS is part of a broader shift. Choosing a low-carbon system today can:

• reduce exposure to volatile fossil-fuel prices over time

• improve your EPC and potentially your property’s marketability

• future-proof your heating as policy and pricing signals evolve

The key is to make the decision on the right facts—including the limitations and the real-world running cost picture, not marketing headlines.

Who is eligible

Eligibility under BUS is straightforward in principle but strict in execution. That’s a good thing: it protects public funds and reduces the risk of consumers being mis-sold. Your installer will usually do the formal checks, but you can save time by understanding the main eligibility rules before you request quotes.

The two core eligibility tests

In everyday terms, you are broadly eligible for a BUS grant if:

1. You own the property you’re applying for (including second homes and some rental properties), and

2. You are replacing an eligible existing heating system, typically fossil fuel heating (and in some cases electric heating without a heat pump).

This is not an income-tested benefit. BUS is about the heating system and the property status.

Property requirements you should check early

A valid EPC is normally required

Most properties must have a valid Energy Performance Certificate (EPC). EPCs typically last 10 years, so many homeowners already have one from a purchase or remortgage.

If you don’t have a valid EPC, this is one of the first things to arrange—because an installer cannot safely proceed with a voucher application without confidence that the property meets scheme rules.

Most new builds are not eligible

BUS is not intended to subsidise new build compliance (new builds are generally expected to meet modern standards without grant support). There is, however, nuance: if you buy a finished new build that already has a fossil-fuel boiler installed, you may be eligible in some cases.

Social housing is excluded

Properties that meet the definition of social housing are generally not eligible for BUS. Other public programmes exist to decarbonise social housing stock.

Previous public funding for the same technology can exclude you

If the property has already received government funding/support for a heat pump or biomass boiler, it’s not eligible again under BUS. This prevents “double funding” for the same decarbonisation measure at the same address.

Special cases: self-build properties

Self-build is one of the most misunderstood areas. BUS can apply to self-build properties, but the definition is narrow and evidence-based. You may need to show proof of ownership and that the property has not been owned by a business or organisation, depending on the scenario.

The practical guidance is: raise self-build status upfront with the installer and expect some paperwork. Done early, this is manageable. Done late, it can delay installation and risk voucher expiry.

Biomass boilers: additional location and fuel constraints

Biomass support is deliberately limited because biomass can create air quality impacts and is not considered the default solution for most homes. For BUS, biomass is typically only supported when:

• the property is off the gas grid, and

• the property is in a rural location, and

• the appliance meets emissions requirements.

Quick “sense check” list before you request quotes

You’re likely in a good starting position if:

• you own the property (owner-occupier, landlord, or small business owner)

• you currently heat with gas/oil/LPG (or qualifying electric heating)

• you can provide a valid EPC (or are willing to obtain one)

• you’re open to system changes (for example, a hot water cylinder for many heat pump installs)

• you understand the grant supports a technology switch, not a simple boiler swap

If any of these points are uncertain, that doesn’t mean “no”—it means you’ll benefit from a more careful installer assessment before spending money on design work or upgrades.

Eligible heating systems explained

Choosing the right low-carbon heating system is less about chasing the “best technology” and more about matching a system to your building, your space, and your comfort expectations. BUS focuses on technologies that can deliver reliable, scalable emissions reductions across the housing stock—provided they are properly designed and commissioned.

The three technologies currently set out in BUS guidance

Under the published Ofgem installer guidance, BUS supports:

• Air source heat pumps (ASHPs)

• Ground source heat pumps (GSHPs) (including water source heat pumps and shared ground loops)

• Biomass boilers (in limited, rural/off-gas circumstances)

How heat pumps work (without the jargon)

A heat pump moves heat rather than generating it by burning fuel. It uses electricity to transfer heat from:

• the air (ASHP),

• the ground (GSHP), or

• a water source (a type of GSHP/water source heat pump).

The main practical implications are:

• Heat pumps work best with low-temperature heating, delivering steady warmth rather than short, high-temperature “bursts”.

• Many homes need radiator upgrades or improved heat distribution to get the best performance.

• Most hydronic heat pump systems need a hot water cylinder (unlike many combi boilers).

Air source heat pumps (ASHPs)

ASHPs are the most common type of heat pump in the UK because they suit a wide range of homes. You’ll typically have an outdoor unit and internal components that connect to your heating system.

ASHPs tend to be a strong fit if:

• you have some outdoor space (even modest)

• you want a system that can provide both space heating and hot water

• you can accommodate (or already have) a hot water cylinder

Ground source heat pumps (GSHPs) and water source heat pumps

GSHPs typically offer very stable performance because ground temperatures are steadier than air temperatures. The trade-off is complexity and cost: you need land for trenches or boreholes, or access to a suitable water source.

GSHPs tend to be a strong fit if:

• you have sufficient outdoor space or the property is part of a communal solution

• you want high seasonal efficiency and long-term stability

• you can handle more significant groundwork

Biomass boilers (limited circumstances)

A biomass boiler burns organic material (often pellets) to produce heat. In BUS it’s restricted to rural, off-gas properties and appliances that meet emissions requirements.

Biomass may be considered if:

• you are off the gas grid and heat demand is high

• you have space for fuel storage and deliveries

• local air quality considerations are manageable

Where “expanded BUS” fits in

The Government has signalled its intention to expand the scheme to support additional technologies and to adjust some requirements. It’s important to treat this as announced policy direction unless and until Ofgem guidance and the formal application routes reflect it.

Technology comparison table

Grant amounts and what is covered

BUS grant values are easy to state but easy to misunderstand. The scheme is not “£7,500 for everyone”; it is a defined voucher amount for eligible installations under strict rules about commissioning, evidence, capacity, and what counts as an eligible plant.

Current grant values and voucher validity periods

BUS grant values have changed over time (notably with increases that took effect in October 2023). The property owner guidance sets out both the current levels and the earlier levels.

What this means for you:

• If you are comparing installer quotes, you should expect the grant value to be clearly reflected.

• Voucher expiry is not a technicality—it can be decisive. Groundworks, stock delays, or scheduling issues can put a project at risk if timelines are tight.

• GSHP projects often need more time; that’s reflected in the longer voucher validity period.

The maximum size rule (why it exists)

BUS is designed for typical homes and small non-domestic buildings, not large commercial or industrial heat projects. The scheme therefore sets a maximum permitted capacity.

For most homes, this is not a problem—the cap is intended to cover the vast majority of residential installations. But if you have:

• a very large home

• a multi-building setup

• unusually high heat demand (for example, high hot water usage with poor insulation)

…your installer may need to discuss whether BUS applies and whether the design can remain within scheme limits.

What counts as “covered” by BUS?

The grant supports the cost and installation of the eligible low-carbon technology, but the scheme definition is wider than just the “box on the wall”. Ofgem guidance treats an eligible plant as including required ancillary equipment.

That said, “covered” doesn’t mean “free”. It means the installer can include eligible components within the scope of the BUS-funded installation—while you still pay any balance after the voucher is applied.

What the grant typically covers vs what you should budget for

Funding rules you must not ignore

A few rules trip people up repeatedly:

• You cannot “stack” BUS on top of another grant for the same heat pump/biomass boiler at the same property.

• You can usually have had separate funding for energy efficiency measures (like insulation) and still qualify.

• The installation must be properly commissioned and supported by the required documentation.

Scheme budgets and voucher availability

BUS is a funded programme with annual budgets. This doesn’t typically affect an individual application day-to-day, but it matters for timing in high-demand periods.

The application process

The BUS process is designed to feel simple for the property owner: you choose an installer, agree a quote, and the installer handles most of the administration. But “simple” doesn’t mean “hands-off”. The smoothest projects are the ones where the homeowner understands what evidence is needed, what timelines apply, and what to check before signing.

Step 1: Confirm your starting point

Before you contact installers, gather:

• your property address details (as recorded officially)

• your current heating system details (fuel type, boiler type, age if known)

• your EPC (if you have it) or readiness to obtain one

• any property status factors (new build, self-build, listed building, flats)

This helps installers quickly rule in/out any obvious issues.

Step 2: Choose an installer who can actually deliver BUS

You need an installer who is:

• appropriately certified (typically via MCS requirements for BUS-funded installs)

• able to apply for vouchers through the BUS portal

• willing to provide clear documentation and a properly scoped quote

Practical tip: if a quote is vague, the project risk is higher. Clarity early prevents disputes later.

Step 3: A survey and heat loss assessment

A credible installer will assess:

• heat loss (rooms, building fabric, ventilation assumptions)

• emitter suitability (radiators/underfloor heating)

• hot water requirements (cylinder sizing and location)

• controls strategy (weather compensation, zoning where appropriate)

• electrical requirements

• location for external units (ASHP), including noise and airflow considerations

This is where good outcomes are made. If an installer tries to skip detailed assessment, treat that as a warning sign.

Step 4: Receive and compare quotes (properly)

When comparing quotes, check:

• the model/spec and capacity of the proposed system

• what’s included for radiators/emitters

• whether hot water cylinder is included (if needed)

• how commissioning and handover are handled

• whether the BUS discount is clearly shown

• warranty terms and ongoing servicing expectations

Step 5: Installer applies for the voucher and you give consent

BUS is an installer-led, two-stage process. You will be contacted (typically by email) to provide consent for the voucher application.

Step 6: Voucher issued (if successful) and installation scheduled

Once issued:

• ASHP and biomass vouchers are valid for 3 months

• GSHP vouchers are valid for 6 months

Treat this as a real project deadline. If you’re planning other works (insulation upgrades, electrical upgrades), coordinate them immediately.

Step 7: Installation, commissioning, and documentation

Commissioning is not just turning the system on. It includes setup and verification that the system is operating as intended.

You should receive documentation such as:

• MCS certificate (for heat pumps/biomass under relevant requirements)

• commissioning records / handover pack

• user guidance (controls, heating curves, maintenance schedule)

• emissions certification (for biomass where required)

Step 8: Voucher redemption and installer payment

After commissioning, the installer redeems the voucher and receives the grant payment. Your role here is mostly to ensure you have the paperwork and that the final invoice reflects the agreed discount and scope.

A key timing rule to take seriously

This is one reason reputable installers manage their pipeline carefully. If a contractor is overbooked, your project can become time-risky.

The role of installers

Your installer is not just a contractor under BUS—they are effectively your gateway into the scheme. They assess eligibility, apply for vouchers, design the system, commission it, and carry compliance responsibility. That’s why BUS places heavy emphasis on installer certification and consumer protection.

What installers are responsible for under BUS

From a property owner’s perspective, the installer is responsible for:

• confirming your eligibility and the property’s eligibility

• applying for the voucher on your behalf

• installing and commissioning the system correctly

• providing the correct post-install documentation

• keeping evidence and cooperating with audits/compliance checks

• ensuring the grant benefit is passed to you

Why MCS matters (even if you don’t love bureaucracy)

MCS certification is not a mere “badge”. It is intended to demonstrate:

• technical competence and adherence to installation standards

• a structured approach to system design and performance evidence

• consumer protection expectations (complaints processes, standards oversight)

For you, the practical benefit is reduced risk: you’re less likely to end up with a poorly designed system that costs more to run or fails to deliver comfort.

Consumer codes: your fallback if something goes wrong

Installers operating under recognised consumer codes are typically expected to offer:

• clearer contract standards

• dispute resolution routes

• protections around mis-selling and workmanship issues

This doesn’t remove all risk, but it creates a framework that is stronger than a standalone private contract.

Regulatory requirements beyond BUS (what’s commonly involved)

Depending on your property and chosen technology, compliance may involve:

• Building Regulations compliance/notification (common for heating system changes)

• electrical safety requirements and certification

• planning considerations (particularly for external ASHP units in constrained locations)

• biomass-specific air quality and smoke-control zone requirements (local authority-dependent)

A competent installer will guide you here. If you feel you’re being asked to “figure it out yourself,” pause and reassess.

Audits and compliance checks (what to expect)

BUS-funded installations can be audited. This is normal and does not mean you’ve done anything wrong. It typically means Ofgem and/or certification bodies are verifying that public money is funding compliant installations.

As a homeowner, your main responsibility is to:

• keep your paperwork

• respond promptly if contacted for verification

• raise issues early with the installer if documentation looks incomplete

How certification requirements may evolve under expanded BUS

The Government has consulted on how certification and consumer protection should work across clean heat schemes and has published outcomes indicating changes it intends to pursue.

The key message is not “rules are changing so wait”. It’s this: choose an installer who already works transparently, documents properly, and treats compliance as part of quality. Those installers are best placed to keep your project smooth even as policy evolves.

Costs and budgeting considerations

The BUS grant can make low-carbon heating feel suddenly achievable—but it’s not the full financial picture. A sensible budget accounts for the grant and the property-specific work that often determines whether the system performs well and remains affordable to run.

Typical upfront cost benchmarks (what reputable sources say)

Costs vary by property, but credible benchmarks can help you sanity-check quotes.

If you subtract the BUS grant, you can see why some households end up with a net cost that feels reasonable—while others still face a large gap. The difference is usually the building and the system complexity, not “installer greed”.

The most common additional costs homeowners overlook

Heat emitter upgrades (radiators/underfloor compatibility)

Many homes need larger radiators or additional emitters to deliver comfort at lower flow temperatures. This can be minor (a few radiators) or substantial (multiple rooms).

Hot water cylinder and associated works

If you currently have a combi boiler, a cylinder may be new to you. The cost is not just the cylinder—it can include:

• reconfiguring cupboards

• pipework changes

• relocation of other utilities

Electrical upgrades

Heat pumps are electrical systems. Sometimes the existing electrical infrastructure needs improvement, such as:

• consumer unit (fuse board) upgrades

• cabling upgrades

• outdoor isolators and safety devices

Insulation and draft proofing

BUS does not require you to insulate first, but performance and running cost outcomes often improve dramatically when basic insulation measures are addressed.

Groundworks and reinstatement (GSHP)

For GSHPs, the ground loop work can drive cost variability. Reinstatement (lawns, paving, access routes) should be clearly specified.

Biomass fuel storage and compliance

Biomass systems can require:

• fuel store construction or adaptation

• delivery access arrangements

• ash handling and cleaning space

• local air quality considerations

Budgeting method that reduces surprises

A practical way to budget is to break your project into three layers:

1. Core system cost (after grant)

2. Readiness upgrades (emitters, cylinder space, electrics, insulation)

3. Contingency (10–15% is common for retrofit uncertainty)

Then insist your installer quote is explicit about what is and isn’t included.

How to compare quotes without getting misled

When you compare quotes, don’t just compare the headline “after grant” price. Compare:

• system sizing approach (does it align with heat loss?)

• emitter scope and assumptions

• hot water design and cylinder size

• control strategy and commissioning commitment

• warranty and aftercare

• realistic timeline relative to voucher validity

A lower quote is not a bargain if it leaves you with:

• cold rooms

• high running costs

• expensive “fixes” a year later

Financing and cashflow considerations

Even with BUS, many households still need to finance part of the cost. Common routes include:

• savings (with a clear contingency buffer)

• personal loans (compare total cost, not monthly payments)

• green home improvement finance products (where available)

• staged payments agreed with installer (ensure grant handling is transparent)

If cashflow is tight, consider prioritising insulation first (especially if other funding supports it) so that when you do install a heat pump, it can be smaller and cheaper to run.

Running costs

Running cost is where low-carbon heating decisions either feel brilliant—or frustrating. The truth is reassuring: heat pumps can be highly efficient and comfortable. But the financial outcome depends on design quality, insulation, how you control the system, and the electricity-to-gas price relationship.

What heat pumps do well (efficiency)

Heat pumps are fundamentally different from boilers. A boiler converts fuel into heat; a heat pump moves heat using electricity. That’s why heat pumps can deliver multiple units of heat per unit of electricity used.

Why some households see higher bills (and how to prevent it)

Running costs can be comparable to existing systems when the system is designed well and installed in a well-insulated property, but not always.

This is where good advice matters. The “prevention” toolkit usually includes:

• right-sizing radiators so flow temperature can be lower

• improving insulation/draught-proofing so heat demand falls

• using weather compensation and consistent heating patterns

• choosing tariffs that reward off-peak usage where appropriate

The electricity vs gas price relationship

Even when a heat pump is very efficient, electricity pricing can dominate the bill outcome.

The long-term financial story (beyond monthly bills)

Reduced exposure to fossil fuel volatility

Switching from gas or oil to electricity-based heating can reduce your exposure to oil delivery price spikes and some forms of fossil fuel volatility—particularly relevant for off-gas homes.

Property value and EPC improvements

Energy efficiency can influence property desirability. Government strategy documents have cited evidence that more energy-efficient ratings can correlate with higher property values (while acknowledging property markets are complex).

Maintenance and lifespan considerations

• Heat pumps can have long service lives when maintained properly.

• Maintenance costs vary, but you should budget for servicing, filters, inhibitor checks (where relevant), and occasional component replacement.

• Biomass boilers typically require more hands-on maintenance and fuel management than heat pumps.

A realistic way to think about savings

Rather than asking “Will this be cheaper than gas?”, ask three better questions:

1. Will this reduce my home’s heat demand over time? (insulation and draughts)

2. Will this system run efficiently at low temperatures? (emitters + controls)

3. Can I access an electricity tariff that suits heat pump operation?

If you can answer “yes” to at least two, the odds of a good long-term outcome rise sharply.

Benefits and key considerations

A well-designed BUS-funded installation can transform comfort and future-proof a home. But you deserve a balanced view: low-carbon heating isn’t magic, and it isn’t “plug-and-play” in every building. The best outcomes come from matching expectations to reality.

Benefits that matter day-to-day

Comfort and consistency

Heat pumps tend to provide steady, even warmth—particularly when run continuously at lower flow temperatures. Many households find this more comfortable than the on/off cycling of boilers.

Reduced direct fossil fuel use

You’re no longer burning gas, oil or LPG on-site for space heating (and often hot water). That supports emissions reduction and can reduce local combustion-related risks.

Efficiency advantages

As credible consumer guidance sources emphasise, heat pumps can be substantially more efficient than fossil boilers.

Limitations you should plan for (not fear)

Upfront disruption

Even a “straightforward” ASHP install can involve:

• pipework changes

• controls upgrades

• radiator resizing

• cylinder installation

Disruption is usually manageable, but it should be planned.

Space requirements

• External space for ASHP outdoor unit (airflow matters).

• Internal space for a hot water cylinder (in many cases).

• GSHP needs land access or shared loop arrangements.

Noise and placement

Modern ASHPs are generally quiet, but placement matters. A good installer will consider boundaries, neighbours, vibration isolation, and airflow paths.

Running cost uncertainty

As discussed earlier, running costs depend on price ratios, insulation, and design quality. The limitation is not “heat pumps are expensive”—the limitation is bad design and high heat loss.

Biomass-specific considerations

Biomass can be a valid rural/off-gas solution, but it’s not a default choice because:

• wood burning produces some pollution

• fuel supply and storage are ongoing responsibilities

• maintenance tends to be more involved

BUS reflects this by restricting biomass support to rural settings and off-gas properties.

Key considerations checklist before you commit

• Are you choosing the installer based on design competence, not just price?

• Does the quote clearly specify emitter upgrades, cylinder needs, and controls?

• Is the timeline realistic against voucher validity and the 120-day commissioning rule?

• Have you discussed insulation and heat loss honestly, without pressure or shame?

• Do you understand what your home will feel like (steady warmth) and how you’ll control it?

If you can tick these off, BUS becomes a genuinely powerful lever—not just a headline discount.

Combining with other grants

BUS doesn’t exist in a vacuum. Many households improve outcomes by combining BUS-funded heating with separate support for insulation and efficiency. And because energy policy is partly devolved, the UK has regional differences that matter if you own property across nations.

Combining BUS with other support (what’s usually possible)

A useful rule of thumb is:

• You can often combine BUS with funding for energy efficiency measures (like insulation), because those measures reduce heat demand and improve system performance.

• You generally cannot combine BUS with another public grant for the same heat pump or biomass boiler at the same property, because that would be double-funding the same technology.

In practice, this means households often sequence projects like this:

1. insulation and draft-proofing (sometimes via supplier/local schemes)

2. heating system upgrade via BUS

3. controls optimisation and tariff review

Regional differences across the UK

BUS is explicitly described as open to England and Wales, with other pathways referenced for Scotland and Northern Ireland.

UK-wide comparison (high level)

How “expanded BUS” may affect combinations

Government announcements about expanding BUS (for example, to include air-to-air heat pumps and heat batteries) suggest the scheme may increasingly cover a broader set of household situations—including homes where hydronic heat pumps are harder.

If and when expanded BUS becomes fully operational in Ofgem guidance and application processes, it may:

• open up new technology choices for flats and small homes

• change how certification and consumer protection is structured

• shift the “best sequencing” of insulation vs heating measures

For now, the practical advice remains: treat BUS rules as those in current Ofgem guidance, and treat expansion announcements as direction-of-travel until fully implemented.

Conclusion

A boiler replacement is one of the most consequential home energy decisions you’ll make—not because it’s fashionable, but because it shapes comfort, bills, and resilience for years. The Boiler Upgrade Scheme exists to make that decision easier: by lowering upfront cost barriers and building confidence in low-carbon heating.

The most important takeaways are simple:

• BUS is installer-led—choose your installer with care, because they control both quality and compliance.

• Eligibility depends on property ownership, existing heating, EPC status, and (for biomass) rural/off-gas restrictions.

• The grant is meaningful, but it’s not the entire budget—you still need to plan for emitters, hot water storage, electrics, and (ideally) insulation.

• Running costs can be very reasonable when the system is designed properly and the home is heat-loss-ready—but expectations should be grounded in how your building behaves.

• “Expanded BUS” is a real policy direction, but decisions today should be based on the current published Ofgem guidance and GOV.UK eligibility rules.

If you approach BUS as a whole-home upgrade rather than a simple product purchase, it becomes far more likely you’ll end up with:

• a warm, comfortable home

• stable heating costs over time

• a system that feels “quietly reliable” rather than complicated

• a property that is more future-proof as heating policy evolves

Frequently Asked Questions

Eligibility and property questions

Grant values and technology choices

Application and process

Installation and compliance

Running costs and financial impact

Landlords, tenants and shared properties

Biomass and rural heating

Expanded BUS and future changes

Troubleshooting and consumer protection

Glossary

Useful Organisations

Ofgem

Ofgem is the UK’s energy regulator and the administrator of the Boiler Upgrade Scheme (BUS) on behalf of the Department for Energy Security and Net Zero. If you need help with the scheme — including questions about eligibility, vouchers, applications, or complaints — Ofgem’s BUS support team can assist. They also publish official guidance for property owners and installers and monitor compliance with scheme rules.

• 0330 053 2006
• www.ofgem.gov.uk

GOV.UK

The GOV.UK website is the central official UK Government platform for information on public services and schemes, including the Boiler Upgrade Scheme. It provides authoritative guidance on eligibility rules, how the installer‑led application process works, property requirements (such as EPCs) and what funding you can expect. GOV.UK also links to the latest forms and updates to BUS policy.

• 0330 053 2006
• www.gov.uk

Energy Saving Trust

The Energy Saving Trust is a trusted independent UK organisation offering free advice to households and businesses on energy efficiency, low‑carbon technologies and funding options. While it does not administer BUS itself, it provides practical guidance on heat pumps, energy savings, insulation measures and how to prepare your home for upgrades, helping you make informed choices before speaking to an installer.

• 020 7222 0101
• www.energysavingtrust.org.uk

Microgeneration Certification Scheme (MCS)

The Microgeneration Certification Scheme (MCS) is an industry certification body that sets technical and install quality standards for renewable and low‑carbon technologies. Under BUS rules, your installer must be MCS certified to install a heat pump or biomass boiler eligible for the grant. MCS also helps you find certified installers and understand required documentation.

• Contact details vary by region
• mcscertified.com

References

Still have questions?

If you’ve read this guide and you’re still unsure—about eligibility, suitable technologies, what a fair quote looks like, or how to avoid running cost surprises—that’s completely normal. Low-carbon heating is a big decision, and the “right” answer depends on the details of your property and priorities.

Speaking with an expert can help you:

• sense-check whether you’re likely to qualify for BUS before you invest time and money

• understand what upgrades (radiators, cylinder space, electrics, insulation) are truly necessary

• compare quotes on the things that matter (design quality, scope clarity, commissioning, aftercare)

• make a confident plan for budgeting and long-term running costs

If you’d like personalised guidance for your situation, consider arranging a conversation with an expert—your first consultation is free.