Renovating a property in stages is a common approach for homeowners managing budgets, time constraints, or planning permissions. However, when it comes to obtaining an Energy Performance Certificate (EPC), properties undergoing phased renovations introduce unique challenges.

Understanding how EPC assessments apply to homes that are partially renovated—or in the middle of an upgrade cycle—can help you plan better and avoid misleading EPC scores.

Do You Need an EPC During Renovations?

An EPC is legally required:

  • When selling a property.

  • When renting it out to new tenants.

  • For certain types of government funding and compliance schemes.

If your property is on the market or about to be let during phased renovations, an EPC must reflect its current state at the time of the assessment—even if planned upgrades are scheduled for the near future.

Challenges of EPC Assessments in Phased Renovation Properties

1. Incomplete Insulation Works

If insulation upgrades (loft, walls, floors) are only partially completed, EPC software will calculate energy efficiency based on the areas still uninsulated, dragging down the overall rating until the work is fully finished and re-assessed.

2. Temporary or Legacy Heating Systems

If new heating systems (like a heat pump) are not yet operational and old systems (e.g., storage heaters or boilers) are still in use, the EPC assessment must base calculations on the existing, less efficient setup.

3. Windows & Glazing Midway Through Replacement

If only a portion of windows has been upgraded to double or triple glazing, EPC inputs will average out the existing and new installations, which may dilute the efficiency benefits until all units are replaced.

4. Air Tightness Assumptions

During renovations, properties may have temporarily compromised air permeability due to works in progress. Unless airtightness testing is done post-completion, default (often penalizing) leakage rates will be applied in EPC software.

5. Delayed Renewable Energy Installations

Planned solar PV systems, solar thermal panels, or heat recovery units won’t be accounted for in the EPC if they’re not fully installed and operational at the time of assessment.

Can You Update Your EPC After Renovation Completion?

Yes. Once renovations are complete, you can commission a new EPC assessment to reflect the upgraded energy performance. There is no limit to how often you can renew your EPC, but it’s only a legal requirement for sale/rental transactions or compliance purposes.

Strategies for Homeowners Undergoing Phased Renovations

  • Time the EPC Assessment Strategically: If possible, wait until key efficiency upgrades are complete before commissioning the EPC.

  • Provide Detailed Plans & Specifications: While EPC software only reflects the current state, providing upgrade documentation helps assessors understand the property’s trajectory.

  • Consider a Pre-Renovation & Post-Renovation EPC Strategy: Get an EPC pre-renovation for current compliance and plan a follow-up assessment post-renovation to update the rating.

  • Communicate With Your EPC Assessor: An assessor experienced with renovation properties can help navigate EPC software inputs more precisely and avoid default penalties.

EPCrate: EPC Services Tailored for Renovating Homes

At EPCrate, we understand the nuances of assessing properties during phased renovations. Our EPC assessment services ensure you get accurate advice on when and how to time your EPC for the best outcome.

Check our pricing and book a consultation through our online booking system.

Need an EPC Mid-Renovation? We Can Help.

Contact EPCrate to discuss your renovation timeline and book an assessment that aligns with your upgrade plans.