Scheme Summary
The scheme consists of the refurbishment of four inner terraced houses built about 1900. The refurbishment was carried out to a very high standard of energy efficiency, and involved the use of environmentally friendly materials. The properties were purchased in 1999, and work was completed in August 2000.


Scheme Details

Arches Housing Association bought four terraced houses in the Meersbrook and Heeley areas of Sheffield. Three were improved to very high standards of energy efficiency. The fourth was improved to the minimum energy efficiency required by the Housing Corporation as a 'control' house, enabling comparison of monitoring results from gas, electricity and water bills. The aim was to reduce residents' bills by around 300.

The original houses had a basic central heating system, single glazed windows and no roof insulation. They were heated effectively, but without insulation the heat escaped very effectively too. The houses had an average SAP of 46 and NHER 4.4.

The environmental refurbishment aimed to provide healthier and more comfortable homes, but not at the expense of the environment. Budget constraints meant that 'passive' energy saving measures and low cost approaches were considered over complicated and/or expensive technology.

The value of comprehensive insulation and the use of energy efficient appliances was crucial to the scheme's success. By keeping the approach simple, Arches has proved that the impact on the environment can be reduced and significant fuel cost savings made.


Environmental Features

In each house the windows needed replacing. New, sustainable sourced timber windows were installed with double glazed low-emissivity Pilkington K glass. This glass provides a similar energy performance to triple glazing but is much more cost effective. It cost around 10 extra per m2; an extra 70 - 100 for a typical terraced house (Low emissivity windows have a coating applied to the inner surface of the outer pain of glass. This allows the warmth of sunlight through, but reduces heat lost through the glazing).

Insulation was needed throughout the buildings' fabric. 200mm of cellulose insulation (recycled newspaper) was introduced to the roof, improving energy efficiency significantly.

The 9" solid brick external walls were dry-lined with liner board encapsulating 52mm of mineral wool insulation. This reduced the heat loss (U value) to a rate similar to a standard cavity wall and gave a SAP as good as some newly built homes.

The properties were built with cellars, and access could be gained to install 150mm of mineral wool under-floor insulation. Once the issues of the building envelope were addressed, other areas were considered. Thermostatic radiator valves were added and low energy light bulbs installed. Energy efficiency could have been further improved with the removal of existing gas fires, however residents wanted to retain them.

Gas condensing boilers were installed with simple heating controls rather than state of the art programmers and controllers. Although it was recognised that when properly programmed they can improve energy efficiency, they can also be difficult to understand and use correctly. One house was fitted with a condensing boiler and solar water panel to pre-heat hot water. This improved its SAP to 97, which is far in excess of the energy efficiency achieved in a typical standard built home. One home was fitted with a grey water recycling system. The bath water is pumped back to flush the toilet and reduce mains water use.

Water based paints and stains and linoleum flooring to kitchens and bathrooms added to the environmental and healthy quality of the houses.

The refurbished houses achieved a final SAP of 94 and annual savings in the region of 420. The 'control' house had a SAP of 68 and achieved annual savings in the region of 300.


Costs

The total cost to refurbish the control house was 10,500. This includes a condensing combination boiler that proved necessary to achieve the minimum SAP rating. The average cost to refurbish the more energy efficient and sustainable houses was 17,500.


Developer's Comments

The Green Scheme was funded by the Housing Corporation. It is energy efficient and acts as a test bed for green materials and ideas to show the compromises necessary when existing stock and limited works budgets come together. Great results are easy to enhance stock, save residents 8 a week and benefit the environment.

Summary of energy efficiency improvements, costs and resident savings:

Feature
SAP
NHER
Cost
Saving p.a.
Double glazed low E
48
4.7
70-100*
33.00
Condensing boiler
60
5.8
200-300*
30.00
Insulation
94
9.4
1,600*
310.00
Thermostatic radiator valves
-
-
50.00**
7.00
Low energy light bulbs
-
-
24-40
13.00

* Additional costs ** DIY costs

Contact: Karen Wormald,
Arches Housing Limited,
242 Burngreave Road,
Sheffield S3 9DE
Tel: 0114 228 8100
Fax: 0114 228 8150
E-mail: info@archeshousing.org.uk