Almost 15 years ago I designed my own resource efficient home, which is still ahead of its time even today. When we give tours of our home I’m often asked “what would you do differently?” Much has changed in the last 15 years. If I were designing a new resource efficient home right now here are the things I would focus on:
Size
Space efficiency has a favorable impact on so many areas. An appropriately sized home uses less land, less resources to build, less energy to operate, and is less work to maintain. All those things make it much more affordable and you can invest in quality systems and appliances. Go for QUALITY over QUANTITY.
Passive Systems
Climate appropriate design is a must. Proper orientation with respect to the local climate conditions is a no cost item with eternal payback. If you are in a dry climate with cold nights and warm sunny days, then thermal mass is a must. If you are in the hot, humid southeast then you focus on reflective roofs and good insulation. In the cold, cloudy climates extra insulation and high quality windows are a must. The right quantity and location of windows is different for every climate. Reduced air infiltration is critical in almost all climates. Better design tools can assist in better designed homes – appropriate for their local climate.
Technology to Solve the Balance
If you do the first two things well, your need for mechanical systems is significantly reduced and sometimes eliminated. Solar hot water should make the list is most climates. High absorption panels, heat exchangers, differential controllers, and small/efficient pumps (solar powered) are the technologies that make this work well. For backup, heat-pump water heaters are now on the market.
In well sealed homes, mechanical ventilation with a heat exchanger is appropriate. I have an enthalpy wheel exchanger that recovers over 70% of the energy, yet provides a steady supply of fresh air.
For cooling/heating I have a geothermal system for its high efficiency. Ideally a good passive design could even eliminate the need for some mechanical systems. Solar powered absorption cooling is a promising technology as the need for cooling is usually the highest during peak sunshine. Thermal storage can carry the cooling through the evening. Solar can also provide space heating.
Natural daylighting should be the primary illumination source during the day. Lighting technology can continue to improve on efficiency – either from super efficient ballasts/fluorescents, or solid state lighting such as LED’s.
Appliances have to eliminate standby power losses and continue to improve in efficiency.
Homes should all strive to become more self sufficient with efficiency first. Then they should provide power generation – through solar, wind, or other renewable energy technologies. The grid can act as a giant “battery” as homes feed excess energy back in or draw centrally produced power out. Energy storage technology is very important – either with batteries, flywheels, or chemical storage systems. These storage technologies are also key to integrating transportation into the “smart garage.” Electric vehicles can be charged from the home power or the grid. The vehicle storage can also be the home’s energy buffer system – either storing or generating power.
Paul Westbrook
Sustainable Development Manager, SMTS, LEED AP
Original publication date: 02/04/2009
