Energy Efficiency Standard for Social Housing: peer review

Appendix 1 - Group A: Validation of Impact of varying hot water tank insulation and open chimneys

Ventilation - Chimney

Case studies 1E and 1G - pre 1919 solid wall dwelling - ground floor were re-run to include open chimneys and compared against the baseline which assumed there were no chimneys present.

It was found that for electrically heated property, the inclusion of one open chimney:

• reduces the SAP by 2 points, from 52 to 50, both remaining within the "E" band.
• reduces the EI by 2 points, from 33 to 31, both remaining within the "F" band.
• increases the running costs by 5%
• increases the CO ₂ emissions by 5%
• increases energy consumption by 5%

Increasing the amount of open chimneys to two for the electrically heated property:

• reduces the SAP by 4 points, from 52 to 48, both remaining within the "E" band.
• reduces the EI by 5 points, from 33 to 28, both remaining within the "F" band
• increases the running costs by 10%
• increases the CO ₂ emissions by 11%
• increases energy consumption by 11%

It was found that for gas heated property, the inclusion of one open chimney:

• reduces the SAP by 2 points, from 51 to 49, both remaining within the "E" band.
• reduces the EI by 2 points, from 49 to 47, both remaining within the "E" band.
• increases the running costs by 3%
• increases the CO ₂ emissions by 4%
• increases energy consumption by 4%

Increasing the amount of open chimneys to two for the gas heated property:

• reduces the SAP by 3 points, from 51 to 48, both remaining within the "E" band.
• reduces the EI by 5 points, from 49 to 45, both remaining within the "E" band
• increases the running costs by 7%
• increases the CO ₂ emissions by 8%
• increases energy consumption by 8%

Space and water heating - hot water cylinder insulation

Case studies 1E and 1G - pre 1919 solid wall dwelling - ground floor were re-run to assume a loose hot water tank jacket of 12mm and compared against the baseline which assumed there 25mm of spray foam insulation was assumed.

It was found that for electrically heated property, downgrading the hot water tank insulation as above:

• reduces the SAP by 2 points, from 52 to 50, both remaining within the "E" band.
• reduces the EI by 3 points, from 33 to 30, both remaining within the "F" band.
• increases the running costs by 6%
• increases the CO ₂ emissions by 7%
• increases energy consumption by 7%

It was found that for gas heated property, downgrading the hot water tank insulation as above:

• reduces the SAP by 3 points, from 51 to 48, both remaining within the "E" band.
• reduces the EI by 4 points, from 49 to 45, both remaining within the "E" band.
• increases the running costs by 7%
• increases the CO ₂ emissions by 8%
• increases energy consumption by 8%

Chimney and hot water cylinder insulation combined

Case studies 1E and 1G - pre 1919 solid wall dwelling - ground floor were re-run to include open chimneys and a loose hot water tank jacket of 12mm. This was compared against the baseline which assumed there were no chimneys present and 25mm of spray foam insulation on the hot water tank.

It was found that for electrically heated property, the inclusion of one open chimney downgrading the hot water tank insulation:

• reduces the SAP by 5 points, from 52 to 47, both remaining within the "E" band.
• reduces the EI by 5 points, from 33 to 28, both remaining within the "F" band.
• increases the running costs by 11%
• increases the CO ₂ emissions by 11%
• increases energy consumption by 12%

Increasing the amount of open chimneys to two and downgrading the hot water tank insulation for the electrically heated property:

• reduces the SAP by 7 points, from 52 to 45, both remaining within the "E" band.
• reduces the EI by 7 points, from 33 to 26, both remaining within the "F" band
• increases the running costs by 16%
• increases the CO ₂ emissions by 17%
• increases energy consumption by 18%

It was found that for gas heated property, the inclusion of one open chimney and downgrading the hot water tank insulation:

• reduces the SAP by 5 points, from 51 to 46, both remaining within the "E" band.
• reduces the EI by 5 points, from 49 to 44, both remaining within the "E" band.
• increases the running costs by 11%
• increases the CO ₂ emissions by 13%
• increases energy consumption by 13%

Increasing the amount of open chimneys to two and downgrading the hot water tank insulation for the gas heated property:

• reduces the SAP by 7 points, from 51 to 44, both remaining within the "E" band.
• reduces the EI by 7 points, from 49 to 42, both remaining within the "E" band
• increases the running costs by 14%
• increases the CO ₂ emissions by 17%
• increases energy consumption by 17%