Stommel Haus has a track record of building energy efficient timber eco friendly luxury houses and long before the tighter energy saving requirements were introduced in the UK or Germany. With the right plot and a few extras we can also achieve 'Passivhaus'-standards (please note, that Passivhaus does not only stand for energy efficient homes but also for a certification process).
Stommel Haus clients can select the energy efficiency rating they wish to achieve for their new build dream timber houses. Owners of a Stommel house
need little energy to heat their home. The house is heated typically with an air source heat pump. Stommel Haus installs under-floor heating on ALL storeys of the house, installed in a thick
screed (between 25 and 40 tons of screed in a house). The screed acts as a heat sink and the heat is distributed evenly throughout the energy efficient eco friendly house. Together with the
well insulated walls and roof and the excellent triple glazing windows (to passivhaus standard), only little energy is required to heat a Stommel eco friendly home.
Besides the well insulated house and excellent heating, clients can decide to optionally install photovoltaic panels, solar thermal panels as well as to link up with a "clean" electricity provider, or to collect rain water to flush toilets and feed the washing machine.
Stommel Haus energy efficient eco friendly homes ensure comfortable living in all seasons due to the property of solid timber which evens out temperature variations. The house stays cool in summer and warm in winter.
During the heating period, it is important to keep the energy loss to a minimum: heat loss happens through transmission of heat (measured in u-value), by opening windows and doors (simply going in an out the house) and through air gaps (measured as air-tightness, here Stommel Haus over-excels with air-tightness values of 0.7 to 1.1 m³/hm² at 50 Pa.)
The thermal transmission coefficient, so called u-value indicates the heat loss through a surface. The coefficient rises with increasing thermal conductivity (timber ~0,1 – 0,2, concrete ~2,4). The thickness of a wall also helps reducing the heat flow. Within the same time period, if you take an amount of heat of 1, the amount of 2 to 5 flows through wood and about 60 through concrete. This is due to the low thermal conductivity of timber. The low thermal conductivity and the slow storage capacity of wood also reduce thermal bridges to an absolute minimum (i.e. less heat loss and no mould).
Furthermore, in Stommel Haus energy efficient eco friendly homes, we use a big mass of concrete in the screed: both on the ground and the first floor there is about 6 to 7 cm thick screed over the entire surface in which the under-floor heating pipes are installed. With the under-floor heating, the heat is distributed in the screed, i.e. directly where it is stored in the huge mass of screed ->About 30 tons of screed are installed in a typical 3 to 4 bedroom house.
When looking at heating energy consider both storing and insulation. Once the heat is in the house (through sun light and heating) it takes much longer in a timber house for the heat to escape through the wall. Furthermore, due to the thermal transmission the surface of a timber house feels much warmer than for instance a stone or concrete wall. Due to this a timber surface feels warmer than stone or concrete, the temperature in timber houses can be lowered by 2°C in comparison to a stone house in order to generate the same feeling of wellbeing.