Interior & Exterior insulation
Exterior insulation (R-10 value) thermally encases the Zero Energy Home.
This allows the masonry to be precooled during daytime hours when the
sun is shining brightly and the PV system output is at maximum power. The
precooled concrete walls help maintain indoor comfort
into the late afternoon and evening. Interior insulation
(R-30 value) lines the attic
Infiltration Prevention Mechanisms
Low Friction Duct System
Interior-mounted, oversized ducts - positioned within the
air-conditioned space as opposed to the hot attic - are
used in the Zero Energy Home to great advantage.
Oversizing the ducts allows high air flow and low friction
loss (previously shown to provide as much as 12%
improvement in cooling efficiency at essentially no extra cost)
Efficient Pumping Systems
Backup Photovoltaic System
Efficient Appliances & Lighting
High-efficiency appliances and lighting further minimize
the Zero Energy Home's electrical load. These appliances
and lighting also release less heat into the home while
operating, which decreases the cooling load that must be
met by the air-conditioning system and results in less PV
capacity required to meet the home's total electrical load.
Light Exterior Color
The reflective white-tile roof on the Zero Energy Home
serves to replace the locally popular gray/brown asphalt
shingles on the control home. Both homes have R-30
fiberglass insulation in the attic, but the Zero Energy
Home's attic remains significantly cooler during peak
Efficient High SEER AC System
As told, the combination of efficiency features reduces the
cooling loads so that a downsized air conditioner suffices.
The small size of this system (half that of the control
home) is highly unusual for such a large home (2,425
square feet) in Lakeland, Florida, but it is performing to
Solar Water Heater System
The solar water heating system supplies most of the hot
water for occupant needs. Its energy output is equivalent
to that of a 2-kW PV system.
High Performance Windows
The Zero Energy Home's windows account for almost
one-fifth of the energy savings (for cooling). The advanced
solar control windows are spectrally selective, which
means that they transmit much of the light transmission in the
infrared and ultraviolet portions (which causes
overheating and fading of interior materials).
A programmable thermostat - set so that the indoor
temperature is allowed to increase overnight and while
the house is unoccupied - decreases the number of hours
per day the air conditioner operates. Running the air
conditioner less reduces the total electricity consumption
and lowers utility costs.
Cross Ventilation and Ceiling Fans
Full Size Photovoltaic System
4-kW utility-interactive PV system.
Improved Indoor Air Quality