Each energy improvement has an optimal window relative to financial events in a homeowner or landlord’s calendar. EPC improvements need to be completed, assessed, and certified before the remortgage application to unlock a green mortgage rate from day one of the new deal. Heat pump installations typically take eight to fourteen weeks from first contact with an installer to completed commissioning, meaning planning needs to start at least three to four months before the intended completion date. Improvements carried out just after a fixed rate renewal are not wrong, but they defer the mortgage rate benefit by the full length of the new deal.
This planner takes your upcoming financial events (remortgage date, planned sale, tenancy end) alongside the improvements you are planning and your current property profile, and produces a recommended phased schedule showing when each improvement is optimally timed. It also flags timing risks (improvements that cannot realistically be completed before an event on current lead times), dependency recommendations (insulating before a heat pump for better sizing and efficiency), and opportunities to align improvements with windows that maximise their financial return. All recommendations are illustrative planning guidance, not financial advice; for the borrowing routes typically used to fund these improvements, see our guide to home improvement loans.
At a Glance
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EPC improvements need to be completed, assessed, and certified before the remortgage application is submitted, not after, because the green mortgage rate applies from the start of the new deal.
Improvements completed after remortgaging onto a standard rate do not unlock the lower green rate until the next deal end, typically two to five years later, and the total deferred saving can be several thousand pounds on a typical mortgage. A new EPC certificate takes two to four weeks to issue once works are complete, and lenders need to see it during the application. To be confident of a green rate from day one of a new deal, EPC works should complete at least six to eight weeks before the planned remortgage date.
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Heat pump installations typically take eight to fourteen weeks from first contact with an installer to completed commissioning, so planning should start at least three to four months before the desired completion date.
The full process involves an MCS-certified installer site survey, a heat loss calculation and quote, an available installation slot (often the longest single delay in busy periods), the Boiler Upgrade Scheme grant application submitted by the installer, any required pipework or radiator upgrades, the installation itself, and commissioning. Each stage is sequential rather than parallel, and any one of them taking longer than expected pushes the completion date back. The planner uses typical lead times to flag whether a heat pump can realistically complete before a deadline you have entered.
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Insulating before installing a heat pump is recommended for technical and financial reasons, even though it is no longer a Boiler Upgrade Scheme eligibility requirement.
Since April 2026, the BUS no longer requires a valid EPC or that outstanding insulation recommendations be addressed before a grant application can be submitted. However, insulating first remains strongly recommended: reducing heat loss allows a smaller, less expensive heat pump to be specified, which lowers both the upfront cost and long-term running costs. There is also a practical sequencing benefit — disturbing pipework and radiators for insulation after a heat pump is installed can affect system performance. The planner flags this as a recommended sequence when both insulation and a heat pump are selected.
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The Boiler Upgrade Scheme now covers more heat pump types and offers a higher grant for oil and LPG homes.
As of April 2026, the BUS provides £7,500 towards air-to-water and ground-source heat pumps, £2,500 towards air-to-air heat pumps (newly eligible), and a temporary uplift to £9,000 for homes currently heated by oil or LPG (21 July 2026 to 31 March 2027). The scheme has been extended to 2030 and the EPC eligibility requirement has been removed entirely. The planner adjusts its recommendations based on your current heating fuel.
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Improvements intended to appear in a property listing must be completed (and a new EPC registered) before the property is marketed, because the EPC shown on a portal is the most recent one on the government register at the time of listing.
An improvement carried out after the property goes on the market has no effect on the listing EPC unless a new assessment is commissioned, registered, and the listing updated. Allow four to six weeks between works completion and the planned listing date for the new EPC to be issued and registered. The planner sequences improvements with the listing date as a deadline so the rated improvement is the one buyers see.
Interactive tool
Retrofit timeline planner
Enter your upcoming financial events alongside the improvements you are planning. Get a phased schedule showing when each improvement is optimally timed, with warnings where deadlines are tight.
Your data stays private — nothing you enter is stored, transmitted, or accessible to anyone. All calculations run entirely in your browser.
About you
Your upcoming financial events
Toggle on any events that apply. Use the slider to set roughly when each event is (months from today).
Your property
Improvements you are planning
Tick all that apply. The planner will sequence them optimally.
Why Timing Matters
Remortgage timing
Why EPC improvements must come before remortgaging, not after
A green mortgage rate reduction applies from the date the mortgage starts. Improvements completed after remortgaging onto a standard rate do not unlock the lower rate until the next deal end, typically two to five years later. The total deferred saving can be several thousand pounds. To benefit from day one, EPC improvements need to be complete, assessed, and the certificate issued before the mortgage application is submitted. Allow six to eight weeks between works completion and remortgage application to give time for the new EPC to be issued and for lenders to process it.
Heat pump lead times
Why heat pump installations need to start earlier than most assume
The heat pump process involves: finding an MCS-certified installer, obtaining a heat loss calculation and quote, waiting for an available installation slot, the BUS grant application (which the installer submits), any required pipework or radiator upgrades, the installation itself, and commissioning. From first contact with an installer to completed installation, the process typically takes eight to fourteen weeks, sometimes longer in busy periods. To complete a heat pump installation before a specific deadline, planning should start at least three to four months in advance.
Sale preparation
What EPC rating appears in a property listing
The EPC certificate used in a property listing is the most recent one registered on the government’s EPC register at the time of marketing. An improvement completed after the property is listed has no effect on the rating shown to buyers unless a new EPC is commissioned and registered. For EPC improvements to appear in the listing, they need to be complete, a new EPC assessment carried out, and the certificate registered before the estate agent instructs the listing. Allow four to six weeks between works completion and planned listing date.
Tenancy transitions
Why void periods are the best window for major improvements
Insulation works and heat pump installations are disruptive: they require access to multiple rooms, involve contractors, and may temporarily remove heating from part of the property. Carrying them out with a sitting tenant creates disruption and may require the tenant’s consent for certain works. The void period between tenancies, even if only two to four weeks, provides an ideal window for completing works that would be difficult around an occupied tenancy. For landlords with a MEES compliance issue at EPC F or G, works must be completed before re-letting — though the current cost cap of £3,500 (proposed to rise to £10,000 under the Warm Homes Plan) means landlords are not required to spend more than the cap, and can register an exemption if improvements would cost more than this threshold.
How to Use This Planner
Tell the planner whether you are a homeowner or landlord
Landlords see tenancy event scheduling and MEES compliance notes. Select your current heating fuel — oil and LPG homes qualify for an enhanced BUS grant, and the planner adjusts its recommendations accordingly.
Toggle on your upcoming financial events
Enable each event that applies and set the approximate timing using the slider. Use months from today rather than specific dates: an accuracy of plus or minus one month is sufficient for planning purposes. If you have no upcoming events, leave all events off and the planner will produce a sequence based on financial return order with no deadline constraints.
Enter your current EPC and construction era
The EPC rating determines whether MEES compliance is urgent (for landlords) and how much benefit a green mortgage switch would deliver. The construction era determines the wall insulation type — pre-1920 properties typically need solid wall insulation, which takes longer and costs more than cavity fill for later properties.
Tick the improvements and read the results
Tick any improvement you are seriously considering. The planner sequences them with dependency recommendations applied and assigns each to a phase based on optimal timing relative to your events. The visual timeline shows all events and improvements together, and warnings flag where an improvement cannot realistically be completed before your deadline.
Related Tools and Guides
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Shows the recommended order of improvements by financial return per pound spent for your property profile. Use this to confirm which improvements are highest priority before entering them in the timeline planner.
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Green mortgage EPC saving calculator
Models the total mortgage interest saving from reaching EPC B before a remortgage. Use this alongside the timeline planner to quantify the financial benefit of completing EPC improvements before your remortgage date.
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Boiler vs heat pump cost comparison
Models the 15-year total cost of replacing a boiler versus installing a heat pump. If the timeline planner shows a heat pump in Phase 2 or 3, use this to confirm whether the financial case is strong enough to justify the longer lead time.
Guide
Government grants vs home improvement loans
Covers the Boiler Upgrade Scheme, ECO4, and GBIS in full. Relevant for understanding which improvements have grant support that affects the timing priority.
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EPC improvement before selling calculator
Models whether EPC improvements before a sale are likely to pay for themselves through a higher sale price. Use this alongside the timeline planner if you have entered a planned sale event.
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Landlord MEES portfolio planner
For landlords with multiple properties, this tool helps prioritise which properties to improve first for MEES compliance. Use it alongside the timeline planner when scheduling improvements across a portfolio.
Not sure what to look at next?
All of our home improvement loan guides and tools in one placeFrequently Asked Questions
How long does it take to get a new EPC certificate after works are complete?
An EPC assessment typically takes 30 minutes to an hour on site for a standard domestic property, and the certificate is usually issued within two to five working days of the assessment. The assessor registers the certificate on the government’s EPC register, which is where lenders and portal systems pull the data. The total time from works completion to having a usable EPC certificate is typically one to three weeks if an assessor is booked in advance, and two to four weeks if the assessor is booked after works complete.
For properties where the EPC improvement is intended to unlock a green mortgage rate, it is worth commissioning the new EPC assessment before works are fully complete where the assessor can confirm the works were carried out: some assessors will visit during the final stages of installation rather than after sign-off. This can save one to two weeks in the timeline. Always confirm with the assessor that this approach is acceptable before booking.
Can I do EPC improvements during an active fixed rate deal and still access a green mortgage rate?
Yes, if your current lender offers a product transfer to a green rate for existing customers. Some lenders allow borrowers to switch to a green mortgage product mid-term without paying an early repayment charge, if the property reaches the qualifying EPC band during the current deal. This is not universal: many lenders only allow product transfers at the point of deal renewal, or only allow transfers between products at the same rate level. Check your lender’s current policy before assuming a mid-term switch is available.
If a mid-term product transfer is not available, completing EPC improvements during the current deal still has value: the property will be ready to remortgage onto a green rate when the current deal ends, and you will benefit from any energy bill savings in the interim. The timeline planner accounts for this by scheduling EPC works to complete before the remortgage date even if the current deal is active.
What if I have multiple financial events close together?
When multiple events are within a few months of each other, the planner prioritises the earliest event as the primary deadline for EPC-critical improvements. For example, if a tenancy ends in six months and a remortgage is in nine months, insulation improvements should be completed before the tenancy ends (which also satisfies the remortgage requirement, since six months before the remortgage is plenty of time for a new EPC to be issued and accepted). The visual timeline shows all events simultaneously so you can assess whether the recommended schedule is realistic given your specific combination of events.
For landlords with both a tenancy event and a remortgage, the combination is often advantageous: the void period between tenancies provides a natural window to complete insulation works, and if the remortgage follows within six to twelve months, the improved EPC is ready in time. The planner identifies this alignment and reflects it in the recommended phases.
I have no upcoming financial events. Should I still use this planner?
Yes. With no events entered, the planner produces a staggered sequence based on financial return priority order and dependency rules: loft insulation first (highest ROI, short lead time), then walls and heat pump in the appropriate sequence based on your construction era and current EPC, then solar, battery, and other improvements. This is a useful starting point for households planning improvements without a specific deadline driving the timing.
It is also worth entering a hypothetical remortgage date even if you do not have one imminently, to see how a near-term EPC improvement would position you for a future green mortgage. If the mortgage interest saving is material, it may make sense to accelerate improvements to be ready for the next deal renewal even if that is two or three years away. The green mortgage EPC saving calculator can quantify that benefit once you have the improvement timing in mind.
Has the Boiler Upgrade Scheme changed recently?
Yes, significantly. In April 2026, the BUS was amended with several major changes: the scheme was extended from 2028 to 2030, the EPC eligibility requirement was removed entirely (properties no longer need a valid EPC or need to have addressed insulation recommendations before applying), and air-to-air heat pumps became eligible for a £2,500 grant. The standard grant remains £7,500 for air-to-water and ground-source heat pumps.
Additionally, from 21 July 2026 to 31 March 2027, homes currently heated by oil or LPG qualify for an enhanced grant of £9,000. This temporary uplift is designed to accelerate heat pump adoption in off-grid areas where the economics have historically been weaker. The planner takes your current heating fuel into account and adjusts its recommendations accordingly.
Is the EPC system itself changing?
Yes. The government has announced that the current A–G EPC rating system will be replaced by a new four-metric framework (based on the Home Energy Model rather than SAP) from the second half of 2027, with the new system becoming mandatory by October 2029. The new framework will separately report energy efficiency, heating costs, heat retention, and smart readiness, giving a more nuanced picture than the current single-band rating.
For planning purposes, properties that obtain a current-system EPC before October 2029 will retain that rating until it expires (EPCs are valid for ten years). This means improvements completed and certified under the current system provide a decade of compliance certainty. If MEES compliance or a green mortgage is part of your planning, achieving the target EPC band under the current system — before the methodology changes — reduces the risk that a future reassessment under different criteria produces a different result.
Squaring Up
The timing of energy improvements is not a minor detail. Done in the right sequence at the right time relative to a remortgage, sale, or tenancy change, the same improvements produce measurably better financial outcomes than done in the wrong order or at the wrong moment. The difference between completing EPC works before versus after a fixed rate renewal can be several thousand pounds in deferred mortgage interest savings. The difference between a heat pump installation that starts four months before a deadline and one that starts two months before it is the difference between completing comfortably and missing the window.
This planner produces a first draft schedule based on the events and improvements you enter. The recommendations are illustrative planning guidance and should be refined with specific installer quotes, lender confirmation of green mortgage criteria, and professional advice where the decisions are large. Use it as the starting point for the conversation with installers and brokers, not as the final answer.
Continue your research
Guides, calculators, and comparators covering every aspect of home improvement finance Explore guides and toolsUpdate log: July 2026
What changed in this update
Updated to reflect the April 2026 Boiler Upgrade Scheme amendments: the EPC eligibility requirement has been removed, air-to-air heat pumps are now eligible (£2,500), the scheme has been extended to 2030, and an enhanced £9,000 grant is available for oil and LPG homes from July 2026 to March 2027. Heat pump lead time data refreshed using Ofgem and industry sources from late 2025 and early 2026. Added a new FAQ covering the upcoming EPC system reform (four-metric framework from H2 2027). MEES guidance now includes the cost cap and exemption system.
The planner tool has been significantly improved: the property profile inputs (EPC rating and construction era) now affect the output, with pre-1920 properties correctly shown as needing solid wall insulation rather than cavity fill. A homeowner/landlord toggle and current heating fuel selector have been added. The insulation-to-heat-pump dependency has been changed from a hard scheduling constraint to a soft recommendation, reflecting the BUS rule change. The deadline calculation and timing-risk warning system have been recalibrated. Accessibility improvements include WCAG 2.1 AA colour contrast, ARIA labels, keyboard focus indicators, screen reader support, and reduced motion support. Context-sensitive tool cross-links now appear in the results based on the user’s selections.
This tool is for illustrative planning purposes only and does not constitute financial, mortgage, legal, or energy advice. Lead times shown are illustrative estimates based on typical UK installer and lender timescales and will vary by region, season, and current demand. Green mortgage availability, EPC eligibility criteria, and Boiler Upgrade Scheme terms are subject to change — the BUS data in this article reflects the position as of July 2026. Always confirm current requirements with your lender or mortgage broker before relying on timing recommendations in this planner. Your home may be at risk if you do not keep up repayments on a secured loan.
