Zero energy buildings drastically reduce energy use by slashing the demand for energy, while
supplying the remaining energy needs from renewable energy sources, such as solar panels
Almost 48 percent of energy in the U.S. goes to residential and commercial buildings. Zero energy
buildings drastically reduce that energy use
by slashing the demand for energy, while
supplying the remaining energy needs from
renewable energy sources, such as solar
panels. Zero energy buildings are connected
to the grid, drawing power at night or
during sunless days and sending power
to the grid when the sun is shining. They
not only cut net energy use and net carbon
emissions to zero, but also lower cost of
ownership and enhance the quality of life of
their occupants.
The key components of a zero energy
building include simple, off the shelf
technologies beginning with energy
modeling software, such as Energyplus for
commercial buildings or REM/Rate for
homes. This technology, used during the
design phase, with the architect, engineer,
general contractor, HVAC specialist and
building energy consultant working together,
helps determine the most cost effective mix
of the following energy saving technologies
needed to get to zero energy.
Insulation: The simplest measure on the
path to zero energy involves increasing the
insulation for the floors, walls and ceilings
using standard insulation practices to meet
the R-values set by the energy modeling.
Air Sealing: One of the most cost
effective measures involves air sealing the
building envelope to eliminate air leaks
from the building structure itself and from
around windows, doors, electrical outlets,
plumbing fixtures and all other building
penetrations. Air sealing is usually done
with commonly used caulking compounds
and foam products. Blower door technology
to create a pressure differential within the
building makes it much easier to detect air
leaks, either by feeling the air flow or with a
smoke stick.
Heating and Cooling: Ground-source
and air-source heat pumps are effective
energy efficient technologies for heating and
cooling. Air-source heat pumps can now
heat a building at outside temperatures as
low as -10F. They can utilize central heating
systems or smaller units such as mini-splits
or package terminal units. New air-source
equipment based on CO2 refrigerants offer
The National Rene wable Energy Laboratory in Golden, Colorado includes several zero energy labs, including a high-speed computing center in which waste heat from a supercomputer is used
for other purposes. Credit: Zero Energy Project
