There are many reasons to switch from Energy Code to HERS and many more reasons to switch from HERS to Energy Star - some of the biggest reasons being 1) marketability and 2) the 45L Tax Credit of $2,500 per qualifying home. But a change of energy compliance doesn't come easily and requires a lot of preparation. To help, we've compiled a cheat sheet of the major changes you'll need to consider when switching from HERS to Energy Star.
Frame Stage Changes
Reduced thermal bridging at above grade walls
Using continuous insulation of R-3 OR
Using structurally insulated panels, concrete forms OR double wall framing OR
Advanced Framing, including:
Corners insulated to R-6
Headers above windows and doors insulated to R-3
Framing limited at all windows & doors to one pair of king studs, plus one pair of jack studs per window opening to support the header and sill
Interior / exterior wall intersections insulated to same R-value as rest of exterior wall (Ladder blocking)
Minimum stud spacing of 16” OC for 2x4
Air Sealing
Attic access panels, drop-down stairs, & whole-house fans equipped with durable ≥ R-10 cover that is gasketed (i.e., not caulked).
HVAC System
Ductwork installed without kinks, sharp bends, compressions, or excessive coiled flexible ductwork.
Rough-in Duct Leakage: The greater of ≤ 4 CFM25 per 100 sq. ft. of CFA or ≤ 40 CFM25, with air handler & all ducts, building cavities used as ducts, & duct boots installed.
Mechanical Ventilation
Inlet is ≥ 2 ft. above grade or roof deck; ≥ 10 ft. of stretched-string distance from known contamination sources not exiting the roof, and ≥ 3 ft. distance from dryer exhausts and sources exiting the roof.
Final Stage Changes
HVAC System
National HVAC Design Report
Provided by the mechanical designer to the rater
Compared to the as-built rating file in the following categories:
Ventilation airflow design
Ventilation system type
Override controls
Number of occupants
Conditioned Floor Area
Window area
Infiltration rate
Total Heat Gain/Los
Equipment Selection
Duct design
HVAC System - Testing
External Static Pressure Testing
Requires holes in supply and return plenum provided by contractor
Bedroom pressure balancing
Bedrooms pressure-balanced (e.g., using transfer grilles, jump ducts, dedicated return ducts, undercut doors) to achieve a Rater-measured pressure differential ≥ -3 Pa and ≤ +3 Pa with respect to the main body of the house when all air handlers are operating.
Furnaces, boilers, & water heaters are mechanically drafted or direct-vented.
MERV 6+ filter(s) installed in each ducted mech. system, located to facilitate occupant access & regular service.
Filter access panel includes gasket and fits snugly against exposed edge of filter when closed to prevent bypass.
Mechanical Ventilation Systems
Rater-measured ventilation rate is within either ± 15 CFM or ±15% of design report value.
Design value is allowed to be adjusted based on our field-tested results
Controls automatically restrict airflow using a motorized damper during vent. off-cycle and occupant override
Inlet is provided with rodent / insect screen with ≤ 0.5 inch mesh.
Local Mechanical Exhaust
Bathroom fans required to move at least 50CFM
If you have any questions about the information above or would like the Burgess Team to assist you relative to your current building specs, please contact us.