PASSIVE HOMES (PART 2)
Last week, we discussed the definition of a passive home and its benefits. Below are some examples of easy-to-implement technologies that employ passive home philosophy.
1) Insulation – all homes have insulation, but passive homes are designed to minimize the loss of heat, achieved through a balance of insulation thickness to cost ratio.
2) No air leakages – walls, floors and the roof are sealed to a much greater degree. A continuous envelope is installed, wrapping the interior in an airtight, but vapor diffusive membrane.
3) No thermal bridges – a thermal bridge is simply referring to any part of your home which absorbs and transfers heat to the external environment. Construction practices that minimize direct connections through walls and floors need to be carefully implemented here.
4) Triple glazed windows – reduce heat transfer between the inside and outside.
5) Orientation and window placement – to allow best use of heating from the sun in winter and shade in summer. Deciduous trees planted around the home provide the necessary shade in the summer and allow low winter sun warm the home. Constructing the roof eaves with a larger overhang also helps provide shade in the summer though not in winter.
6) Insulated thermal masses – large thermal masses such as the foundation can be utilized to regulate temperature drawing heat away from the house in summer, and storing heat during the daytime to help keep the house warm through winter nights.
7) Heat recovery ventilation (HRV) – “tight” homes need ventilation to bring in fresh air, which is best achieved through an HRV. This system simply works by using a heat exchanger to warm up the incoming air with the outgoing air and mitigate the heat loss from this process.
With these technologies implemented the need for heating can be largely met by a combination of body heat and electronics you use around the home. Light bulbs, TVs and cooking all put out a significant amount heat when considering the energy requirements of a passive home.