Strategies for net zero energy vary by household, climate, region and housing type.
Passive House Institute
The passive house standards in Germany and Austria have demonstrated that performance and cost savings can result when peak heating loads are reduced significantly.
Building Sciences Corporation completed a comprehensive renovation of a 100 year old home that resulted in a 60% energy savings while increasing the living space by 80%. (Pettit 2008)
Energy Efficiency Strategies That Work
A deep reduction approach with comprehensive insulation and air sealing can make a conventional furnace and air circulation system unnecessary, thus using simpler technical solutions to combustion safety distribution systems, durability and indoor air quality.
A deep energy retrofit could eliminate a conventional chimney, furnace and attic ductwork and replace these building elements with a mechanical ventilation system that manages indoor air quality and moisture control.
The Canadian Mortgage Housing Corporation (CMHC) recently published a study, "Approaching Net Zero Energy in Existing Housing" and concluded that climate, housing stock, energy loads, solar gain and occupant behavior all contribute to the feasibility of reaching net zero energy use in existing homes. With no incentive available, it is not cost effective to achieve net zero energy in most Canadian housing.
Energy Efficiency Justification
Solving problems with wet basements, radon, outdated mechanical equiment and inadequate indoor air quality can help justify energy efficiency choices.
Reducing heating loads is relatively easy. It is more challenging to achieve deep reductions in baseloads and cooling loads which are more dependent on occupant behavior and lifestyle. Motivated occupants are essential.
The California energy crisis of 2000-2001 resulted in a 15% reduction in electrical energy use that was primarily the result of occupant behavior, not technology. The actions of a small number of supersavers and modest efforts by many residents were deemed responsible for the reduction.
Utility programs can substantially reduce energy use with energy efficient features such as low-e windows and building enclosure improvements that focus on reducing air infiltration and upgrading insulation performance. Also helpful are replacement of heating nd cooling systems, duct leakage reduction, and use of other controls for electrical and cooling loads.
Community Solutions
Homeowner choices sometimes affect lifestyle choices significantly. Possible strategies can include use of renewable energy supply or a change in the use of space or the number of people in a home. Highly effective choices can include co-housing with efficient shared cooking, water heating, clothes washing and entertainment facilities.
Reduce the Load First
Marc Rosenbaum suggests a simple maxim, "Invest as much as you can afford to reduce the load, even if it means completing a project in phases." These load-reducing options that can help achive optimum results are major systems such as siding and roofing.
Choices for Thermal Comfort
Thermal comfort accounts for 25 - 80% of residential energy use. Some of the options available include:
Community Solutions
Technical Solutions with Higher Cost
Technical Solutions with Lower Cost
Passive House Institute
The passive house standards in Germany and Austria have demonstrated that performance and cost savings can result when peak heating loads are reduced significantly.
Building Sciences Corporation completed a comprehensive renovation of a 100 year old home that resulted in a 60% energy savings while increasing the living space by 80%. (Pettit 2008)
Energy Efficiency Strategies That Work
A deep reduction approach with comprehensive insulation and air sealing can make a conventional furnace and air circulation system unnecessary, thus using simpler technical solutions to combustion safety distribution systems, durability and indoor air quality.
A deep energy retrofit could eliminate a conventional chimney, furnace and attic ductwork and replace these building elements with a mechanical ventilation system that manages indoor air quality and moisture control.
The Canadian Mortgage Housing Corporation (CMHC) recently published a study, "Approaching Net Zero Energy in Existing Housing" and concluded that climate, housing stock, energy loads, solar gain and occupant behavior all contribute to the feasibility of reaching net zero energy use in existing homes. With no incentive available, it is not cost effective to achieve net zero energy in most Canadian housing.
Energy Efficiency Justification
Solving problems with wet basements, radon, outdated mechanical equiment and inadequate indoor air quality can help justify energy efficiency choices.
Reducing heating loads is relatively easy. It is more challenging to achieve deep reductions in baseloads and cooling loads which are more dependent on occupant behavior and lifestyle. Motivated occupants are essential.
The California energy crisis of 2000-2001 resulted in a 15% reduction in electrical energy use that was primarily the result of occupant behavior, not technology. The actions of a small number of supersavers and modest efforts by many residents were deemed responsible for the reduction.
Utility programs can substantially reduce energy use with energy efficient features such as low-e windows and building enclosure improvements that focus on reducing air infiltration and upgrading insulation performance. Also helpful are replacement of heating nd cooling systems, duct leakage reduction, and use of other controls for electrical and cooling loads.
Community Solutions
Homeowner choices sometimes affect lifestyle choices significantly. Possible strategies can include use of renewable energy supply or a change in the use of space or the number of people in a home. Highly effective choices can include co-housing with efficient shared cooking, water heating, clothes washing and entertainment facilities.
Reduce the Load First
Marc Rosenbaum suggests a simple maxim, "Invest as much as you can afford to reduce the load, even if it means completing a project in phases." These load-reducing options that can help achive optimum results are major systems such as siding and roofing.
Choices for Thermal Comfort
Thermal comfort accounts for 25 - 80% of residential energy use. Some of the options available include:
Community Solutions
- Comfort centers
- Cogeneration or micro-cogen
- Community thermal storage
- Community-based renewable energy supply
- Use of waste heat from industrial processes
- GHG reduction campaigns
- Feedback, benchmarking, aggregation
- Competitions and challenges
- Technical, financial and regulatory support
- 24/7 set point adjustment or setback
- Apply comfort zone
- Change use of space with new thermal boundaries
- Adaptive comfort (clothing, surface temperature, air movement)
- Increase occupancy
- Reduce internal gains with behavioral cooling loads
- Decrease occupancy size with relocation or demolishing space
Technical Solutions with Higher Cost
- Superinsulation (walls, ceiling, floor, foundation - climate specific for R25-R80)
- Efficient windows (U 0.1 to 0.3)
- Super air tightening (0.2 CFM/ftx2 floor space)
- High efficiency mechanical ventilation
- Ultra high efficiency HVAC system
- Automatic movable window insulation
- Highly insulated doors
Technical Solutions with Lower Cost
- Fill cavities with insulation
- Air sealing
- Do-it-yourself superinsulation
- Seal / insulate attic ducts or eliminate ducts
- Point heat or cooling source
- High performance storm windows
- Manually controlled movable window insulation
- Reduce internal gains with technical fix of cooling loads
- Control systems to optimize comfort, indoor air quality and humidity
- Increase solar gain through windows
- Sunspace or solar buffer to reduce heat loss
- Active solar thermal
- Solar PV
- Wood heat
- Trees vegetation or other shading to reduce cooling loads