What Is a HERS Rating? Home Energy Rating Score Explained (2026)

The term HERS rating shows up everywhere in the energy-efficiency world — on builder websites, federal-program rules, utility-bill rebates, and real-estate listings. If you are trying to figure out what a HERS Index is, whether you need one, and who can issue one, this page answers all of it.

HERS stands for Home Energy Rating System

A HERS Index score is produced using RESNET-accredited HERS rating software (REM/Rate or Ekotrope). The score runs on a 0–100+ scale, with a typical resale home scoring around 130 and a brand-new ENERGY STAR reference home scoring 100. The lower your HERS Index, the more energy-efficient the home. A HECS USA-built home that achieves a HERS Index of 50 uses roughly 50% less energy than the code-built reference.

HERS ratings are required for:

  • ENERGY STAR Certified Homes — must score ≤ an ENERGY STAR target index for the region.
  • 45L Tax Credit — required documentation for the federal energy-efficient home tax credit.
  • Most state utility rebates — utilities pay builders and homeowners for verified low HERS scores.
  • Energy Efficient Mortgage (EEM) programs — lenders offer better rates on homes with verified HERS ≤ 80.
  • DOE Zero Energy Ready Home — HERS score requirement by climate zone.

How a HERS Rating Is Calculated

The HERS rating process is twofold: a model-based rating plus an on-site inspection.

Step 1 — The Plan Review (Pre-Construction)

The HERS rater reviews architectural plans, mechanical design, window specs, insulation specs, and HVAC sizing. They input everything into the rating software to produce a Projected HERS Index. If the projected score is too high, the rater works with the builder to choose better assemblies, windows, or HVAC equipment.

Step 2 — The Site Inspection (Three Visits)

The rater visits the construction site at three key stages:

  1. Pre-drywall — verifies insulation, framing, sealing, window U-factors and SHGC, rough-in duct leakage, and HVAC equipment match the model.
  2. Final — verifies finished insulation, window installation, blower-door test result ≤ ENERGY STAR target, duct-leakage ≤ ENERGY STAR target, HVAC startup and combustion analysis.
  3. Quality assurance — a RESNET-accredited QA rater performs a 10% random re-inspection on a sample of homes; some builders receive an Energy Rating Index (ERI) verification.

Step 3 — The Final HERS Index

After all inspections pass, the HERS rater issues a final HERS Index certificate — a single-page PDF document with the project address, builder, HVAC designer, rater, and final index. This certificate is what third parties (IRS, utility, lender) require.

The Three Pieces of a HERS Rating

A complete HERS rating consists of three paired inspections:

  • Blower door test — measures air leakage through the building envelope. Required at both pre-drywall (rough) and final (finished).
  • Duct leakage test — measures air leakage through the forced-air duct system, both to outside and total leakage.
  • Combustion analysis + blower door test — verifies gas appliance efficiency and safety.

The rater’s report also documents window U-factor and SHGC, insulation R-values, HVAC equipment make/model/SEER/HSPF, thermostat type, and any renewable energy systems (PV, solar thermal).

What HERS Certification Does NOT Include

A HERS rating is NOT the same as:

  • An ENERGY STAR certification — ENERGY STAR requires a HERS rating PLUS meeting program-specific requirements.
  • A FORTIFIED Home designation — FORTIFIED is a separate program focusing on roof, windows, and attached structures for storm resilience.
  • An ASHRAE 62.2 indoor air quality test — that is a separate ventilation-rate calculation.

Why Choose a RESNET-Accredited HERS Rater

The Residential Energy Services Network (RESNET) is the national accreditation body. Only RESNET-accredited HERS raters can issue valid scores that count for ENERGY STAR, the 45L tax credit, and utility programs.

HECS USA is a RESNET-accredited HERS Rating Provider. Every HERS certificate we issue is registered in the national RESNET registry and carries a unique rating number recognized by the IRS, HUD, ENERGY STAR, and your local utility.

Get Your HERS Rating

If you are building a new home, developing a subdivision, or refinancing an existing home with an EEM, call HECS USA. We provide certified HERS ratings, ENERGY STAR certification, blower door testing, duct leakage testing, and combustion analysis across Kentucky, Indiana, Ohio, Tennessee, Illinois, and Missouri. Call (859) 983-7382 or request a quote online.