Some of My Window Seals Are Blown – Does It Matter for My EPC?
Many homeowners notice condensation or misting between the panes of their double-glazed windows and ask:
"Will blown window seals affect my EPC rating?"
In most cases, the simple answer is:
Blown window seals are not specifically assessed as part of an EPC inspection.
What Is a Blown Window Seal?
Most modern double-glazed windows consist of two panes of glass separated by a sealed cavity.
Over time, the seal around the glass unit may fail, allowing moisture to enter between the panes.
Common signs include:
Condensation between the panes
Misting inside the glass unit
A cloudy appearance that cannot be cleaned from either side
This is commonly referred to as a blown double-glazed unit or failed window seal.
Are Blown Window Seals Assessed During an EPC Inspection?
No.
An EPC assessment is not a condition survey and does not involve testing the performance of individual window units.
The assessor records the type of glazing present within the property, such as:
Single glazing
Double glazing
Secondary glazing
Triple glazing
The condition of individual sealed units is not specifically assessed as part of the EPC methodology.
How Are Windows Recorded on an EPC?
The EPC methodology requires the assessor to record the glazing type and the proportion of glazed areas within the property.
For example, a property fitted with double-glazed windows will generally be recorded as having double glazing.
The assessment does not normally involve determining whether individual glazing units have failed seals or measuring their thermal performance.
Will Replacing Blown Window Units Improve My EPC Rating?
Not necessarily.
Because blown seals are not specifically assessed during an EPC inspection, replacing an individual failed glazing unit may not affect the information recorded within the assessment.
It is therefore important not to assume that replacing misted or failed glazing units will automatically improve an EPC rating.
What Improvements Are More Likely to Affect an EPC Rating?
Measures that often have a greater impact on an EPC rating include:
Loft insulation
Cavity wall insulation
Heating system upgrades
Renewable energy technologies
Improved heating controls
Hot water system improvements
These measures are more likely to influence the energy performance characteristics used within the EPC calculation.
Check the "Steps You Could Take to Save Energy" Section
If you are considering energy efficiency improvements, it is worth reviewing the:
"Steps you could take to save energy"
section of your EPC.
This provides recommendations specific to the property and may identify improvements that could have a positive effect on energy efficiency and running costs.
How A1 Home Inspectors Can Help
At A1 Home Inspectors, we are often asked whether condensation between double-glazed panes or failed window seals will affect an EPC rating.
As EPC assessments are not condition surveys, the condition of individual glazing units is not normally recorded as part of the assessment process.
If you would like advice on your EPC, the recommendations contained within it, or energy efficiency improvements that may influence your rating, we will be happy to help.
Need advice about your EPC rating? Contact A1 Home Inspectors today and speak with one of our assessors.
Disclaimer
The information provided on this page is for general guidance only. EPC assessments are carried out using approved methodologies and are not condition surveys. The condition or performance of individual glazing units is not normally assessed as part of an EPC inspection.
