Improving your EPC rating should be simple—but many homeowners and landlords invest in upgrades only to find little to no improvement on their final certificate. The problem isn’t the effort; it’s the strategy. Not all upgrades affect the EPC score equally, and some work only when the right conditions are in place.
This guide explains why certain EPC upgrades fail, what usually goes wrong, and how to make sure your improvements actually increase your EPC score. If you’re preparing for an assessment and want expert help, visit our EPC Services to get accurate guidance.
1. The Biggest Reason EPC Upgrades Fail: Wrong Priorities
Many property owners invest in the wrong improvements first.
For example:
Installing expensive double glazing but ignoring loft insulation
Upgrading to smart thermostats when the boiler is outdated
Adding solar panels to a poorly insulated property
EPC scores follow a hierarchy, and insulation and heating efficiency always come before smaller add-ons.
How to Get It Right
Start with the highest-impact upgrades:
Loft insulation
Wall insulation
Floor insulation
Boiler efficiency
Heating controls
If you’re unsure what your property needs most, schedule an assessment through our Booking Page.
2. Insulation Failures: Why They Don’t Always Count
Insulation is one of the biggest EPC factors—but surprisingly, many insulation upgrades don’t get counted due to:
2.1 Missing Documentation
If cavity wall insulation, floor insulation, or roof insulation isn’t visible or accessible, the EPC assessor must assume “no insulation” unless proper documentation is provided.
2.2 Partial Coverage
Insulation must meet certain thickness and coverage standards.
2.3 Poor Installation
If insulation is patchy, damp, or incorrectly fitted, the EPC score may barely change.
How to Get It Right
Keep paperwork for all insulation work
Ensure insulation meets recommended thickness (270mm loft insulation)
Use accredited installers
For more clarity on what assessors look for, visit our About Us page.
3. Heating Upgrades That Fail: When a New Boiler Isn’t Enough
Replacing an old boiler with a modern one does not guarantee a significant EPC boost if:
Radiators are outdated
Pipework is poorly insulated
No smart controls or TRVs are installed
The boiler is oversized for the property
A boiler upgrade only works well when part of a complete heating system strategy.
How to Get It Right
Combine a new boiler with:
Thermostatic radiator valves
Smart heating controls
Pipe insulation
Or, if the boiler is still modern, focus on controls instead.
4. Double Glazing: Why It Often Fails to Raise EPC Scores
Many homeowners expect a big EPC rise from double glazing—but often see minimal improvement.
Why It Fails
Glazing upgrades offer only moderate SAP benefits
If insulation and heating are poor, window upgrades barely help
New windows don’t affect energy demand as much as expected
How to Get It Right
Double glazing is best when combined with:
Solid wall insulation
Loft insulation
Draught-proofing
Otherwise, it improves comfort more than the EPC rating.
5. Solar Panels: High Impact, But Only in the Right Scenario
Solar can dramatically raise EPC scores—but only when paired with the right heating and electrical setup.
Why Solar Fails
Homes with old electric heaters get limited benefit
Poor insulation lowers the system’s effectiveness
Incorrect installation or outdated inverters
How to Get It Right
Solar performs best when:
The home is well insulated
The boiler or heating system is modern
Energy usage is balanced
To discuss solar suitability, message our team via the Contact Page.
6. Draught-Proofing: Small Gains, Not Major Upgrades
Draught-proofing improves comfort and supports heating efficiency but doesn’t significantly shift EPC bands—unless paired with major insulation improvements.
How to Get It Right
Use draught-proofing as a supporting upgrade, not a lead improvement.
7. Lighting Upgrades: LED Bulbs Alone Won’t Move EPC Bands
Switching to LED lights is helpful, but it contributes only a tiny section of the EPC score.
Why It Fails
Lighting makes up a very small part of the SAP calculation
If larger inefficiencies exist, the impact is nearly invisible
How to Get It Right
Upgrade lighting only after:
Insulation
Heating
Hot water efficiency improvements
8. Hot Water System Upgrades: When They Do and Don’t Work
Replacing hot water tanks or heaters improves EPC scores only when paired with good insulation.
Why Hot Water Upgrades Fail
Cylinder insulation missing
Pipes uninsulated
New system undersized or poorly fitted
How to Get It Right
Add pipe insulation
Ensure cylinders have adequate insulation jackets
Upgrade systems as part of a whole-home improvement plan
9. Behaviour-Based Improvements Never Count
Many homeowners purchase:
Smart plugs
Power strips
Energy-monitoring devices
Behaviour-based energy-saving tools
These do not count in EPC assessments. EPC scores are based on fixed systems—not user behaviour.
10. How to Ensure Your EPC Upgrades Succeed
Step 1: Get the Property Assessed Before Upgrading
A pre-upgrade EPC (or consultation) lets you understand:
Current weaknesses
Best upgrade sequence
Estimated rating after improvements
Book a fast EPC visit via our
➡ EPC Booking Page
Step 2: Prioritise High-Impact Improvements
Always start with:
Insulation
Heating efficiency
Smart controls
Hot water insulation
Renewable energy (if suitable)
Step 3: Keep Receipts & Documentation
EPC assessors require evidence when upgrades aren’t visible.
Step 4: Use Accredited Installers
Poor installation reduces EPC impact—even for good improvements.
Final Thoughts
Many EPC upgrades fail not because the improvements are useless, but because they’re done:
In the wrong order
Without proper documentation
Without supporting upgrades
Or without understanding how EPC scoring works
To get upgrades right, focus on insulation, heating efficiency, hot water improvements, and renewable energy—supported by clear documentation and professional installation.
Email :info@epcrate.co.uk
Phone:020 34884142
