Energy Efficient Buildings
E/3 Houses and Simulation
E/3 House Design/Retrofit Process
1) Ensure that entire design team of owner, architect, engineer and builder is
committed to energy efficiency before pre-design phase. Designate energy consultant
within team to coordinate energy efficiency efforts.
2a) For new building, design a “base-case building” with same floor area as proposed
building, equal glazing area on all sides, standard efficiency HVAC equipment and
appliances, and constructed so that it meets applicable codes such as ASHRAE 90.1.
Simulate annual energy use of building using energy simulation program.
2b) For existing building, collect energy billing data and information about building.
Simulate annual energy use of building using energy simulation program. Calibrate
simulated energy use to existing energy use.
3) Complete a parametric analysis of base case or existing building to determine
sensitivity of annual energy use to specific load components, appliances and HVAC
equipment.
4) Using parametric analysis as guide, develop preliminary design solutions to eliminate
or reduce loads from base case or existing building and incorporate high efficiency
appliances and HVAC equipment.
5) Incorporate preliminary design solutions into computer model to estimate energy use
of low-energy building. Iterate as needed to produce final design. Use computer model
to estimated energy use of low-energy building. Compare energy use of base-case and
energy-efficient building.
5) Rerun simulations before changes are made during construction to verify that
changes will not adversely affect energy performance.
6) Commission construction, equipment and controls to ensure proper functioning.
Educate building operators how to operate building to maximize energy performance.
E/3 House Checklist
Orientation
Long axis of house runs east-west to maximize solar exposure in winter and minimize
solar exposure in summer
Landscaping
Berm or conifers on north side to block wind
Deciduous trees and vines on south, east and west to shade in summer and allow sun in
winter
Shade air conditioner condensing unit
Native plants for evaporative cooling, shade and low ground reflectivity with minimal
extra watering requirements
Walls
Minimize wall area
Minimize framing and avoid metal studs
Thick, high-R insulation: R-15 minimum
Polyisocyanurate or EPS sheathing
Tyvek over sheathing to minimize moisture and air penetration
High thermal mass on inside to reduce peak loads and store solar energy
Use sustainable materials: wood, cast earth, straw bales, cellulose, etc.
Ceilings and Roofs
Light colored roof to reduce cooling load
Adequate attic ventilation to reduce cooling load
Thick, high-R insulation: R38 minimum
Radiant barrier on underside of attic
Windows
Casement or awning style to minimize infiltration
Double glazed, low-e, argon-filled, vinyl frame for low U
Increase window area on south exposure for solar heating
Reduce window area on east-west exposure to reduce cooling load
South windows have high SHGF and overhangs
East-west windows have low SHGF
All windows have high visible solar transmittance daylighting.
Insulating shades at night
Infiltration
Tight construction: max 0.5 ACH
Forced ventilation with air-to-air heat exchanger
Double or shielded entry on lee side
Ground
High-R perimeter insulation
High thermal mass floor
Basement or earth-coupled living space, especially in very hot or very cold climates
Electrical Equipment
Maximize daylighting to reduce use of electric lights
Fluorescent and compact-fluorescent instead of incandescent lights
Energy efficient appliances (refrigerator, TV, computer, dishwasher, clothes dryer)
Hot Water
Low-flow showerheads
Water-efficient washer and dishwasher
High-efficiency hot-water heater: minimum EF = 60%
Heating and Air Conditioning
Return air in every room
Night set-back thermostat
High efficiency condensing furnace or boiler: minimum efficiency 90%
High efficiency air conditioner: minimum SEER = 16
GSHP or evaporative cooling for appropriate climates
Renewable Energy
Solar thermal hot-water heater
Solar photovoltaic electricity
Purchase wind electricity
Occupants
Energy conscious