Bearing in mind the energy efficiency mantra: The cheapest energy is the energy you don’t use (where “cheapest” refers to both finance and environment). The most efficient way to keep your spaces warm in winter and cool in summer is to design and build them with energy efficiency in mind in the first place. Insist that your architect consults with an energy consultant to help him/her achieve the best possible energy efficiency in the design phase as well as in the materials and equipment specifications.
Passive Solar is the technique used to design and build energy efficient buildings. There is a lot of information on the web (just Google “Passive Solar Design”) and libraries of books have been written on the subject. It’s not a new concept either, I remember as a child, my parents talking about the benefits of the south facing aspect of a house or garden (I grew up in the UK). In South Africa we are south of the equator so we want our houses and offices to be facing north to make the best use of the winter sun and to help shade us from the worst of the summer heat.
The basic principle of passive solar design is to enable as much heat from the winter sun as possible to enter the space and warm the floors and walls so that they can re-radiate that stored heat after the sun has gone down. At the same time, the building needs to be able to protect itself from the heat of the summer sun. Roof overhangs, awnings, balconies, strategically planted deciduous trees and cross ventilation are just some of the techniques available to control summer temperatures and year-round airflow through the building. Another aspect of passive solar design is to maximise the amount of natural light entering the building thereby minimising the amount of artificial lighting needed during the day.
If your building is properly designed it will be well insulated, preferably with an environmentally friendly system such as Eco-Insulation in the walls and ceilings. Floors are a bit more tricky to insulate because the insulation has to be integrated into the slab to be of any real use and this means you have to go with one of the less environmentally friendly options. Ask your energy consultant for advice on this.
The very best and most efficient way of heating and cooling any space, however large or small, is to design in a ground sourced heat system. It is by far the most energy efficient means of artificially controlling temperature inside a building; it has a life expectancy 3 or 4 times greater than the equivalent air-sourced systems AND you get free domestic hot water as a by-product!
In our climate it is possible to design and build a building which requires no electro-mechanical heating, ventilation or air conditioning (HVAC) at all, and this is what we should be striving for in the design and planning stage of any building or group of buildings. Download a copy of Energy 101: part 8.
Next month we will be looking at what materials to use in your new building, bearing in mind issues such as:
- Embedded energy – how much energy was used in making the product and delivering it to your site.
- The expected useful lifetime of the product in its current form and how much maintenance it will require in its current application.
- What will happen to it at the end of its life – how easy will it be to re-assimilate the material into the natural cycle or to recycle it into something else useful?
*This is part 8 in Eric’s Energy 101 series