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Major Changes from HERS to Energy Star

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.

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