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HERS rating in Victorville - AC Plus Heating & Air

HERS Rating. Formally known as the Home Energy Rating System score and sometimes called the Energy Efficiency Score. Is a standardized numerical index that measures how energy-efficient a home is relative to a defined reference home. It covers heating and cooling systems, duct leakage, insulation levels, window performance, air infiltration, and water heating in a single comparable number. It is a type of Residential Energy Rating System. The system was developed to give homeowners, builders, and lenders one objective measure of a home’s energy performance rather than a collection of disconnected test results. The scale runs from 0 to 150 and above, with lower numbers indicating better efficiency. A score of 100 represents the energy consumption baseline of the reference home. A score of 50 means the rated home uses roughly half the energy of that baseline.

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What the HERS Index score measures

The HERS Index score is a single integer. It places a home on a 0-to-150-plus scale, where every point below 100 represents a percentage improvement over the reference home’s energy consumption. A home scoring 70, for example, is approximately 30 percent more efficient than the reference baseline. The score is calculated from field measurements taken by a certified HERS rater after construction or a major retrofit is complete. The numerical score draws from several physical tests. A blower door test quantifies air infiltration by depressurizing the home and measuring how much air leaks through the envelope. A duct leakage test pressurizes the duct system to find how much conditioned air escapes before reaching the living space. Those two results, combined with software modeling of insulation R-values, window U-factors and the efficiency ratings of installed equipment, produce the final HERS Rating energy efficiency score. A central air conditioning system with a high SEER rating contributes meaningfully to a lower HERS Index when the duct system is tight and the building envelope is well-sealed.

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How the HERS Rating certification process works

HERS Rating certification is a two-stage process. The first stage is a rough-in inspection conducted during construction; the second is a final inspection after all systems are installed and the home is complete. The rough-in stage checks insulation placement and duct installation before walls are closed. The final stage performs the blower door test, the HERS Rating duct leakage test, and a full system verification to confirm that installed equipment matches the modeled specifications. A certified HERS rater. A third-party professional trained and accredited through a RESNET-approved provider. Conducts both stages independently of the builder or contractor. The rater enters all field measurements into accredited rating software, which calculates the HERS Index and generates a formal certificate. That certificate carries the testing date, the final numerical score, the compliance level relative to applicable energy codes and the rater’s accreditation number. Builders in California must meet Title 24 energy code requirements, and a HERS Rating is often the mechanism used to demonstrate compliance. A ductless mini split system installed in a retrofit project may require a HERS verification to confirm that the new equipment meets the efficiency threshold required for a utility rebate or permit sign-off.

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HERS Rating attributes and what each one means

The HERS Rating carries several distinct measurable attributes, each of which tells a different part of the efficiency story. The attributes are listed below.
  • HERS Index score: HERS Index score is the final integer on the 0-to-150-plus scale. The single number that summarizes the home’s energy performance relative to the reference home.
  • Energy efficiency percentage: Energy efficiency percentage expresses how much more or less energy the rated home uses compared to the reference baseline; a score of 60 equals a 40 percent efficiency gain.
  • Energy consumption baseline: Energy consumption baseline is the reference home at score 100, defined by the 2006 International Energy Conservation Code with specific adjustments, against which every rated home is measured.
  • Compliance level: Compliance level indicates whether the home meets, exceeds or falls short of the applicable energy code. In California, that is Title 24. And is printed on the rating certificate alongside the score.
  • Blower door test result: Blower door test result is the measured air infiltration rate in ACH50 (air changes per hour at 50 pascals), a component input that directly affects the final HERS Index.
  • Duct leakage test result: Duct leakage test result is the measured percentage of conditioned air lost through duct joints and connections before it reaches the living space, expressed as a percentage of total system airflow.
  • Testing date: Testing date is the calendar date on which the rater performed the final field inspections, establishing when the rating was valid and which code cycle applied.

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How HERS Rating relates to AC installation and equipment selection

HERS Rating sits at the intersection of building science and HVAC performance. Both equipment selection and installation quality affect the final score. A high-efficiency air conditioner installed with leaky ducts will produce a worse HERS Index than a moderately efficient unit installed with tight, properly sealed ductwork. Duct leakage is weighted heavily in the rating software because conditioned air lost in an unconditioned attic represents direct energy waste with no benefit to the occupant. A heat pump often produces a lower HERS Index than a conventional split system because it moves heat rather than generating it, reducing the energy consumption attributed to both heating and cooling in the model. In the Victorville climate, where summer cooling loads are high and winter temperatures drop enough to require heating, a heat pump’s dual-mode efficiency can shift the HERS score by 10 or more points compared to a gas furnace and air conditioner combination. An air conditioning contractor who understands HERS modeling can select equipment and specify duct sealing targets before installation begins, so the final rating reflects the intended design rather than a surprise after the rater arrives. AC Plus HVAC is a California licensed HVAC contractor (CSLB License #805216) serving Victorville and surrounding communities.

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What a poor HERS Rating indicates and how to contrast it

A HERS Index above 100 signals energy inefficiency. The home uses more energy than the reference baseline, not less. High energy waste at this level typically traces to one or more of the same root causes: excessive duct leakage, poor envelope air sealing, under-insulated walls or attic, or equipment that is oversized or operating below its rated efficiency due to a refrigerant charge problem or restricted airflow. A non-rated installation. A home or retrofit where no HERS rater was involved. Carries no documented compliance level and no verified duct leakage test result. That absence matters when a homeowner applies for a utility rebate, refinances under an energy-efficient mortgage program, or sells to a buyer who requests energy documentation. The code-minimum baseline, a home that barely passes Title 24 with no margin, typically scores in the mid-80s to low 90s on the HERS Index. A well-designed installation with sealed ducts, proper Manual J load calculations and a high-SEER unit can reach the 50s or 60s in a climate like Victorville’s. Targeted improvements to duct sealing and insulation alone can move a score by 15 to 25 points before any equipment is replaced. AC Plus Heating & Air serves the Victorville area and works on the HVAC components that directly influence where a home lands on the HERS Index.
AC Plus Heating & Air · Victorville, CA · (760) 474-5776 · acplushvac.com