Richard Bruton (Dublin North Central, Fine Gael)
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Question 530: To ask the Minister for Communications, Energy and Natural Resources if his attention has been drawn to the fact that some insulation systems for cavity blocks are not accepted for the purpose of the SEI grant; and his views on relaxing the rules in order that householders would not be forced to use the high cost systems that are being permitted under the scheme. [22065/09]

Eamon Ryan (Dublin South, Green Party)
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There are three different types of wall insulation solution grant-aided under the Home Energy Savings scheme, which is administered by Sustainable Energy Ireland (SEI). These are cavity wall insulation, internal dry-lining insulation and external wall insulation. The appropriate insulation solution will vary depending on a number of factors, such as the structure of the wall and the internal size and features of the rooms.

SEI advises that the "u-value" of a wall is the commonly used measure of the insulation properties of a wall. The lower the u-value, the less heat is lost through the wall. Injection of insulating product from the outside is an ideal method for insulating cavity walls and can reduce the u-value of such a wall by almost 70%. This is an excellent low-cost insulation solution. A grant of €400 is available under the scheme for this approach.

However, this insulation solution is not suitable for a cavity block wall, which is a fundamentally different structure from a cavity wall. Typically, cavity walls consist of two rows of brick or concrete block, with a complete cavity or space between them. Cavity block walls contain hollows inside each block. Most heat loss in such walls occurs through the cavity block ends and spine. Filling the hollows with insulation material will not address this and therefore such an insulation solution would reduce the u-value by only about 22%. This estimate assumes that the hollows can be completely filled. This is not certain, as it can be affected by mortar blockages. There is also a high risk of damp occurring on the internal walls with this solution.

For cavity block walls, SEI recommends either internal dry-lining insulation or external wall insulation. These solutions will reduce the u-value of the wall by approximately 80%. Grants of €2,500 and €4,000 respectively are available for these solutions, reflecting their higher installation cost. The internal dry-lining option is to be preferred, because of its considerably lower cost, compared to external insulation and for this reason the grant available for this represents a higher percentage of the installation cost, to encourage homeowners to favour this option.