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 that require MCS certification and Boiler Upgrade Scheme applications take three to four months from first contact to completion, meaning the planning needs to start well before the intended installation 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 dependency conflicts (insulation must come before a heat pump to meet BUS eligibility), timing risks (improvements that cannot realistically be completed before an event on current lead times), 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 take ten to sixteen weeks from first contact with an installer to completed commissioning, so planning needs to start four to five 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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Insulation must come before a heat pump for Boiler Upgrade Scheme eligibility, because the scheme requires a valid EPC with no outstanding insulation recommendations before a grant application can be submitted.
If loft or cavity wall insulation is shown as an outstanding recommendation on the current EPC, it must be installed and a new EPC issued before the BUS application can proceed; otherwise the £7,500 voucher is unavailable and the heat pump becomes substantially more expensive. The planner places insulation in the earliest phase whenever a heat pump is also selected to reflect this dependency. There is also a technical case for insulating first: reducing heat loss allows a smaller and less expensive heat pump to be specified, which improves both upfront cost and ongoing running efficiency.
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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.
Retrofit timeline planner
Enter your upcoming financial events and the improvements you are planning to see a recommended schedule and visual timeline. All recommendations are illustrative planning guidance.
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 ten to sixteen weeks, sometimes longer in busy periods. To complete a heat pump installation before a specific deadline, planning should start at least four to five 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 regardless of tenant preference.
How to Use This Planner
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 and construction era determine which improvements are time-sensitive for MEES compliance, what the BUS eligibility position is, and which dependencies apply. Pre-1920 properties with no cavity walls have a different improvement profile from post-1960s cavity-wall properties, and the timeline reflects this.
Tick the improvements you are planning
Tick any improvement you are seriously considering. The planner sequences them with dependency rules applied (walls before heat pump, solar before battery) and assigns each to a phase based on optimal timing relative to your events. You do not need to know the order yourself: the planner works it out.
Read the phase cards, timeline, and warnings
The phase cards show which improvements to start in each time window. The visual timeline shows all events and improvements together so you can see the full picture at once. Warnings flag where an improvement cannot realistically be completed before an event on typical lead times, so you can either start earlier or accept that it will not be achievable before the deadline.
Related Tools and Guides
Tool
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.
Tool
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.
Tool
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.
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 one to two hours on site, 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 sequence based purely on financial return 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.
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 five months before a BUS grant deadline and one that starts three months before it is the difference between qualifying and missing the application 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 toolsThis 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. 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.
