What insulation adds in SM4

62.2 → 80.4

Rating, now → potential

+18.2

Average uplift

£233

Avg saving / yr

13954

Certificates

The realistic uplift

Each energy certificate lists the improvements an assessor recommends and the rating the home would reach if they were done. Averaged across 13954 certificates in SM4, the current rating of 62.2 could rise to about 80.4 out of 100. The estimated annual heating cost averages £703 now, and about £470 after the recommended work – an estimated saving of roughly £233 a year.

These are the register's own estimates, averaged across many homes; the figure for any one property depends on its fabric and how it is heated.

What the certificates say about the fabric

The most common construction descriptions recorded across these certificates. Percentages are of certificates where the field was recorded.

Walls

Solid brick, as built, no insulation (assumed) – 37.5%
Cavity wall, as built, no insulation (assumed) – 30.0%
Cavity wall, filled cavity – 10.0%

Recorded as having no wall insulation: 67.5%.

Roofs

Pitched, no insulation (assumed) – 17.5%
Pitched, 250 mm loft insulation – 12.5%
Pitched, 200 mm loft insulation – 10.0%

Recorded as having no roof insulation: 25.0%.

Glazing

Fully double glazed – 85.2%
Partial double glazing – 7.4%
Mostly double glazing – 3.7%

Main heating

Boiler and radiators, mains gas – 92.5%
Room heaters, electric – 2.5%
Portable electric heating assumed for most rooms – 2.5%

Which streets need it most

See the streets in SM4 with the highest share of homes rated band D or below.

Leakiest streets in SM4

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