With the current hype on carbon emission and sustainable housing I have been fooled to believe that the government and local authorities are doing everything they can (money permitting) to encourage us to live in 'greener' homes. Far from it, as I found out the a few days ago. With a recent planning approval the local authority has set certain conditions. One of the most confusing ones was the insistance on single glazing in a new garden room (large windows with well insulated roof) , which is an extension to a house built in the 80s. The fact that the property is in a conservation area seems to override environmental concerns. After questioning the condition we have been told that it is standard policy to request single glazing on any property in a conservation area. It does beg the question wether the council got their priorities right.
Certainly on the continent a lot of historic buildings receive the double-glazing treatment when they are being refurbished or renovated. Perhaps the difference is the quality of the actual window system. I do agree that there are few worse things than bad PVC double-glazed windows.
29 March 2007
19 March 2007
Energy efficiency measures - Walls
The indicative savings described below are for a typical heated semi-detached dwelling. These figures are provided to aid comparison of the different energy efficiency measures available.
Cavity insulation is one of the most cost-effective insulation measures available to our homes, reducing heat loss through walls by up to 60%. Insulation can be added to most cavity walls. Dwellings built after the early 1980s normally incorporate wall insulation as standard. Installing wall insulation when replacing the heating system is a good opportunity to specify a smaller and cheaper system. It usually takes less than half a day to blow insulation into the cavity through holes cut into the outer skin and the occupant can remain in the dwelling. Prior to installation there should be a pre-installation inspection to assess the wall's suitability - including exposure of wall to driving rain, masonry material used and pointing of the masonry. It is recommended that cavities of less than 50mm should not be filled.
Annual saving £130-160
Installed cost approx. £260
Installed payback less than 2 years
Solid walls typically loose double the heat of an uninsulated cavity wall. However it can be insulated either internally or externally, which will increase comfort and reduce heating costs. Internal insulation can be applied either by dry lining in the form of a laminated insulating plasterboard or by a built-up system using insulation between a studwork frame.
Annual saving £270-340
Installed cost from £40/sqm
External insulation systems are made up of and insulation layer fixed to the existing wall. This can be achieved by using a wet-render system (either thick sand/cement render applied over wire mesh or a thinner, lighter polymer cement render applied over a 'GRP scim') or a dry-cladding system. The latter is a popular option as the cladding material can be variety of materials such as timber panels, stone or clay tiles, brick slip or aluminium panels.
Annual saving £290-350
Installed cost from. £1800
Installed payback 5-6 years
Insulation in timber-framed dwellings can be equally improved (buildings built after 1976 are insulated to a reasonable standard), however professional guidance is required to avoid problems.
Cavity insulation is one of the most cost-effective insulation measures available to our homes, reducing heat loss through walls by up to 60%. Insulation can be added to most cavity walls. Dwellings built after the early 1980s normally incorporate wall insulation as standard. Installing wall insulation when replacing the heating system is a good opportunity to specify a smaller and cheaper system. It usually takes less than half a day to blow insulation into the cavity through holes cut into the outer skin and the occupant can remain in the dwelling. Prior to installation there should be a pre-installation inspection to assess the wall's suitability - including exposure of wall to driving rain, masonry material used and pointing of the masonry. It is recommended that cavities of less than 50mm should not be filled.
Annual saving £130-160
Installed cost approx. £260
Installed payback less than 2 years
Solid walls typically loose double the heat of an uninsulated cavity wall. However it can be insulated either internally or externally, which will increase comfort and reduce heating costs. Internal insulation can be applied either by dry lining in the form of a laminated insulating plasterboard or by a built-up system using insulation between a studwork frame.
Annual saving £270-340
Installed cost from £40/sqm
External insulation systems are made up of and insulation layer fixed to the existing wall. This can be achieved by using a wet-render system (either thick sand/cement render applied over wire mesh or a thinner, lighter polymer cement render applied over a 'GRP scim') or a dry-cladding system. The latter is a popular option as the cladding material can be variety of materials such as timber panels, stone or clay tiles, brick slip or aluminium panels.
Annual saving £290-350
Installed cost from. £1800
Installed payback 5-6 years
Insulation in timber-framed dwellings can be equally improved (buildings built after 1976 are insulated to a reasonable standard), however professional guidance is required to avoid problems.
Insulate or generate?
Since B&Q has brought out their windturbines for less than £2000 it seems to have become increasingly easy to generate our own electricity. Afterall, who doesn't want to 'go green' for an affordable price?
However questions have been raised if we are spending our money wisely by investing into microgeneration. Shouldn't we rather spend the money on highly insulating our homes?
The government has set out the following targets for housing in its recent zero-carbon announcement:
25% lower carbon emission by 2010 (3 star rating)
44% lower carbon emission by 2013 (4 star rating)
Zero carbon emission overall by 2016 (6 star rating)
To achieve these targets we need to improve the performance of our homes as space heating counts for 57% of carbon emission of our homes and water heating for 20% of carbon emission. Alongside tough insulation and good airtightness, buildings need to run on efficient heating and ventilation systems. There needs to be an appropriate balance of thermal storage, solar gain, shading and ventilation. With all the above, we can think about the addition of microgeneration without blowing the gained energy straight out again. Insulate before generate!
However questions have been raised if we are spending our money wisely by investing into microgeneration. Shouldn't we rather spend the money on highly insulating our homes?
The government has set out the following targets for housing in its recent zero-carbon announcement:
25% lower carbon emission by 2010 (3 star rating)
44% lower carbon emission by 2013 (4 star rating)
Zero carbon emission overall by 2016 (6 star rating)
To achieve these targets we need to improve the performance of our homes as space heating counts for 57% of carbon emission of our homes and water heating for 20% of carbon emission. Alongside tough insulation and good airtightness, buildings need to run on efficient heating and ventilation systems. There needs to be an appropriate balance of thermal storage, solar gain, shading and ventilation. With all the above, we can think about the addition of microgeneration without blowing the gained energy straight out again. Insulate before generate!
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