|
Imagine a home so energy efficent that you can cut heating bills out of your household budget... for Touchwood Home owners, this is a reality.
“Our Touchwood home has remained above 18 degrees all of winter 2008 without
our heating system ever being turned on” Chris and Sharon Brown, Norfolk
The Touchwood homes team have been in the construction industry for three generations and realised many years ago that traditional building methods were not delivering energy efficient houses suitable for modern living.
Sixteen years ago we built our first Ecohome, and our methods and techniques have been improving continually since. We have evolved our design and build process to allow us to supply a complete pre-cut timber frame with all components (windows, doors, cladding etc.) to a very high specification.
Windows and doors can be built to the German Passivhaus standard, meaning they will meet Code 6 of CSH in terms of energy saving. For the structure we use engineered timber ‘I’ beams to create very thick walls packed with insulation. Combining these ideas, and our methods to achieve excellent air-tightness levels results in a fantastic low energy eco-home. Our walls can achieve U values down to 0.09W/m2K, with a typical wall being 0.12W/m2K.
On average a typical modern house loses a substantial amount of heat through air gaps in the structure. This means the internal space has to be constantly re-heated. We avoid this issue by constructing the house to be very air-tight using the latest internal and external vapour permeable air-tight layers. Installing these layers in such a way as to make them effective is a difficult process, one which requires the house design to be altered to ensure the membrane is effective. Over the last 16 years we have developed the required techniques and house designs to make installing the layer a simple job. All our houses are designed with the air tight layer in mind.
Once the air-tight layer is installed ventilation can be controlled by a Mechanical Ventilation with Heat Recovery (MVHR) unit, to minimise heat loss and provide the house with constant filtered fresh air.
To further the ‘flask effect’ our next heat loss enemy is through conduction (cold bridging) through the structure. Cold bridging occurs when solid elements within the walls conduct the heat within the building straight to outside. Our designs always minimise cold bridging through the use of ‘I beams’ in the structure – because I beams have very little solid material passing right through the entire wall – just the thin 12mm web.
Our air-tightness levels are improving all the time, with our most recent test achieving 0.47 m3/m2.hr @ 50Pa - the best rating the independent tester had ever recorded. Passivhaus design requires a figure below 1.0.
|
Touchwood Homes exhibited at the Home and Lifestyle 08 show held in Fort Regent, St.Helier, Jersey.
Our low energy build methods shown on the stand along with the PV, Solar panel and rain water harvesting produced a huge amount of interest, ensuring we will return next year! |
