How EPC C upgrades work: our process from enquiry to evidence pack
How EPC C upgrades work is simple to describe and easy to get wrong in practice. This page sets out our steps, from your first enquiry to the final evidence pack. Compliant Lets is a trading name of LAMTANS Holdings Ltd. The work is delivered by LAMTANS Engineering Ltd. Checked 21 October 2026.
Law status, checked 21 October 2026: the EPC C by 1 October 2030 rule for rented homes is confirmed government policy, not yet law. Legislation is targeted for 2027. The current legal minimum is still EPC E.
How EPC C upgrades work, step by step
The table shows each stage, who leads it and what you receive. Later sections explain each one.
| Step | Who leads | What you receive |
|---|---|---|
| 1. Enquiry and consent | Our team | A clear list of what we need and who receives your details |
| 2. Starting point | Domestic Energy Assessor | Your current EPC rating, or a plan to get a new one |
| 3. PAS 2035 retrofit assessment | Retrofit Assessor and Retrofit Coordinator | A written assessment of the building |
| 4. Design | Retrofit Designer and Retrofit Coordinator | A set of measures in a sensible order |
| 5. Funding check | Retrofit Coordinator | A list of grants you may qualify for, with dates |
| 6. Installation | LAMTANS Engineering Ltd installers | The measures fitted under PAS 2030 |
| 7. Quality checks and records | Retrofit Coordinator | Certificates, test results and photographs |
| 8. Post-works EPC | Accredited assessor | A new EPC lodged on the national register |
Step 1: enquiry and consent
You send an enquiry through our contact page or the assessment form. We ask which homes you own or manage and which tenancies are in place.
Every form tells you who receives your details and why. Marketing messages are a separate choice, and the box is never ticked for you. Tenants must agree access before any survey or work starts.
Step 2: find your starting point
Work starts with the current EPC for each home. A Domestic Energy Assessor can produce a new one if the old one is out of date. Only an accredited assessor can lodge an EPC.
If you think your rating is wrong, our independent EPC check gathers the evidence. A new EPC can come out lower than the old one, so we tell you this before you commission one.
Step 3: the PAS 2035 retrofit assessment
PAS 2035 is the British standard for assessing and designing retrofit work. A PAS 2035 retrofit assessment looks at the whole building, not one measure at a time.
The assessment covers the condition of the building, the existing ventilation, how the home is used and any constraints. It also records the risks, such as damp, that new measures could cause.
A Retrofit Coordinator leads this stage. The standard names the coordinator as the project manager of a retrofit. Our specialists page explains each role.
Step 4: design and the order of work
The designer chooses a package of measures and sets the order they go in. Insulation and draught-proofing usually come first. Heating and controls follow, because a heat pump cannot make up for a leaking building.
The plan also covers ventilation and moisture. Poorly planned insulation can trap damp, so this part matters. For the cost side, see our cost of reaching EPC C guide.
What is a medium-term improvement plan?
It is a staged plan of improvements for the home over many years, in a sensible order. The coordinator prepares it with the designer. You can follow it at your own pace.
Step 5: the funding check
Before you commit, we check which schemes may apply. These include Warm Homes: Local Grant in Greater Manchester, ECO4 and the Boiler Upgrade Scheme. Each has its own rules and end date.
ECO4 ends on 31 December 2026. Our grants for landlords guide gives scheme names, who qualifies and the dates we last checked.
Third-party funding such as ECO4 counts towards the proposed £10,000 cost cap. That cap is confirmed policy, not yet law. Our cost cap and exemptions guide explains it.
Step 6: installation
LAMTANS Engineering Ltd carries out the installation. It holds PAS 2030, which sets the standard for installing energy efficiency measures in existing homes. Check the registers yourself: TrustMark, RECC, ICO, Gas Safe Register and Simply Certification.
The coordinator oversees the installers and arranges testing. Where your project includes new windows, the window installers provide their own FENSA warranties.
Step 7: quality checks and records
At handover the coordinator collects the certificates, consents, test results and manuals. These go into one folder for you. Outcomes are also recorded as TrustMark requires.
Our adviser tip, from a Retrofit Coordinator: keep every invoice, certificate and dated photograph from day one. Spend since 1 October 2025 may count towards the proposed cap, and a complete record is far easier to build as you go than to rebuild in 2030.
Step 8: the post-works EPC and your evidence pack
After the work, an accredited assessor produces a post-works EPC. The coordinator recommends this step. The result may not match what you expected, so we explain any gap.
The evidence pack is the folder you can show a letting agent, lender or council. It holds the documents listed below.
What goes in the evidence pack?
- Your starting EPC and the retrofit assessment.
- The design and the improvement plan.
- Funding applications and approvals.
- Invoices, installer certificates and test results.
- The post-works EPC.
What we cannot promise
We cannot promise an EPC band before an assessment. We cannot promise a grant. Grants depend on the scheme rules on the day you apply.
We also cannot say the rule is law today. When the position changes, we update this page and the EPC C 2030 guide.
Sources
- TrustMark: Retrofit Coordinator scheme requirements, checked 21 October 2026
- BSI: PAS 2030:2023 overview, checked 21 October 2026
- GOV.UK: Improving the energy performance of privately rented homes, government response, checked 21 October 2026
- GOV.UK: Find an energy certificate, checked 21 October 2026
Designed & developed by LAMTANS Technologies LLC, USA — part of the LAMTANS Group
Frequently asked questions
Do I need an EPC before you start?
Usually yes. Your current EPC shows the starting point. If it is out of date or looks wrong, an accredited assessor can produce a new one first.
Who carries out the work?
LAMTANS Engineering Ltd delivers the work. Compliant Lets is a trading name of LAMTANS Holdings Ltd. We say this plainly on every page that mentions delivery or accreditation.
Is the rule to reach EPC C already law?
No. The government has confirmed EPC C by 1 October 2030 as policy. Legislation is targeted for 2027. The current legal minimum for rented homes remains EPC E.
Will my tenants be disturbed?
Some measures need access to the home. Tenants must agree access before surveys or work begin. We explain what each measure involves so you can plan around the tenancy.
Can finance spread the cost?
Finance may be available through Ideal4Finance, subject to status. LAMTANS ENGINEERING LTD is an Introducer Appointed Representative of Ideal Sales Solutions Ltd, t/a Ideal4Finance, which is a credit broker and not a lender. Rates are provisional.
How much will it cost?
Each home needs a visit before we can price it, so we do not quote fixed prices online. Our cost guide shows researched starting prices where we have them.