Revision Date 2/6/2015 Page 2 of 3
The HERS Index is a numerical scale, with 100 as
the relative value of a home built to the 2006 IECC
Energy Code. A HERS Index of 65, for example,
means that the home uses about 35% less energy
than a code-built, or reference home with an index
of 100. An inefficient home may have a HERS
Index well above 100.
The HERS rater will require
Scale drawings of the floor plan, including
window and door locations, ceiling heights, and
mechanical equipment locations.
Exterior wall sections
Slab insulation details
Foundation wall sections
Insulation type and R-values for walls, ceilings
and floors
Heating and air equipment
o Type, capacity, & efficiency
o Ductwork location and R-value
Window and door schedule
o U-factors
o SHGC values
Water heater
o Type, capacity, & efficiency
Other energy feature information, such as solar
hot water heaters, photovoltaic panels, passive
solar design, etc.
Projected Rating
It is strongly recommended that a rater perform
energy modeling and obtain a projected rating
BEFORE framing begins. The HERS rater
performs a pre-construction plan review and energy
modeling to determine whether the project as
proposed will meet performance requirements of the
2009 IECC. The rater analyzes energy feature
options and helps the builder select the most cost-
effective mix of options to achieve 2009 IECC
compliance plus whatever additional level of energy
performance may be desired.
Pre-Drywall Inspections
Thermal Bypass Inspection: Identifies areas
that may cause building air infiltration failure at
final test-out
Insulation Inspection: Verifies and grades wall
and floor insulation
Window/Door Inspection: Verifies installation
and specifications
HVAC Duct Testing At Rough-in: Avoids
duct leakage failure at final inspection
Final Inspection and Testing
Duct Leakage Test: A special fan unit is
attached to a return air plenum, the supply
registers are taped off, and the duct system is
then pressurized to a standard level. This test
gives the Total Duct Leakage. Duct leakage to
outside is potentially a very large loss of energy
when supply ducts leak. Leaking return ducts
are a source of indoor air pollution, pulling
unconditioned, contaminated air into the home.
Duct leakage tests can also be performed at
rough-in, prior to a framing inspection, which
will allow for easy access to correct any
deficiencies. However, if modifications are
made to the HVAC system, damage occurs, or
visual inspection indicates lack of proper sealing
at the final inspection, a second test may be
required at the final inspection.
Blower Door Test: This test measures the
leakiness of the building envelope. The house is
depressurized to a standard amount using a
powerful calibrated fan in an exterior door
opening. A digital pressure gauge measures the
volume of air being moved at that pressure. A
target level of air tightness for a home is no
more than 0.35 Natural Air Changes per Hour
(NACH).