Understanding and Improving Your HERS Score

What is the HERS Index?

The Home Energy Rating System (HERS) Index is the industry standard for measuring a home’s energy efficiency. Developed by the Residential Energy Services Network (RESNET), this nationally recognized system provides homeowners, buyers, and builders with a standardized measurement of a home’s energy performance.

The HERS Index works on a scale where:

• 100 represents the energy usage of a standard new home built to code
• 0 represents a net-zero energy home (one that produces as much energy as it consumes)
• >100 indicates less efficiency than the reference home

For perspective, the average existing home in the United States scores around 130 on the HERS Index, meaning it’s 30% less energy-efficient than a standard new home.

How the HERS Index is Calculated

A certified HERS Rater conducts a comprehensive evaluation of your home, analyzing various components that impact energy efficiency:

1. Thermal Envelope Assessment

   • Insulation levels in walls, ceilings, and floors
   • Window specifications and performance
   • Air leakage rates throughout the structure

2. Mechanical Systems Evaluation

   • Heating and cooling equipment efficiency
   • Ductwork design and leakage testing
   • Water heating system efficiency

3. Additional Energy Factors

   • Lighting efficiency
   • Appliance energy usage
   • On-site renewable energy systems (if present)

The rater inputs this data into specialized software that compares your home’s energy consumption against a reference home of similar size and shape built to meet the minimum requirements of the International Energy Conservation Code. The resulting score indicates how much more or less energy-efficient your home is compared to this reference home.

Benefits of a Lower HERS Score

A lower HERS score translates to multiple advantages:

• Reduced Energy Bills: On average, a home with a HERS score of 70 can save 30% on energy costs compared to a standard new home.
• Improved Comfort: Better insulation and efficient systems typically result in more consistent temperatures and reduced drafts.
• Enhanced Resale Value: Energy-efficient homes often command higher prices in the real estate market.
• Environmental Impact: Lower energy consumption means reduced greenhouse gas emissions.
• Qualification for Incentives: Many utility companies and government programs offer rebates and incentives for energy-efficient homes.

Strategies to Improve Your HERS Score

1. Enhance the Building Envelope

• Upgrade Insulation: Increase R-values in attics, walls, and floors.
• Seal Air Leaks: Address gaps around windows, doors, plumbing penetrations, and electrical outlets.
• Improve Windows: Install ENERGY STAR-rated windows with appropriate U-factors and Solar Heat Gain Coefficients for your climate zone.
• Reduce Thermal Bridging: Use continuous insulation to minimize heat transfer through framing members.

2. Upgrade Mechanical Systems

• Install High-Efficiency HVAC: Replace older systems with models that have higher SEER, EER, HSPF, or AFUE ratings.
• Optimize Ductwork: Seal and insulate ducts, particularly in unconditioned spaces, and consider duct design improvements.
• Upgrade Water Heating: Install ENERGY STAR tankless, heat pump, or high-efficiency conventional water heaters.
• Implement Smart Thermostats: Add programmable or smart thermostats to optimize heating and cooling usage.

3. Improve Electrical Systems and Appliances

• Transition to LED Lighting: Replace incandescent and CFL bulbs with energy-efficient LEDs throughout the home.
• Upgrade Appliances: Install ENERGY STAR-rated refrigerators, dishwashers, washing machines, and dryers.
• Address Plug Loads: Use smart power strips to reduce phantom energy use from electronics.
• Install Ceiling Fans: Supplement HVAC systems with energy-efficient ceiling fans to improve air circulation.

4. Consider Renewable Energy

• Solar Photovoltaic Systems: Installing solar panels can significantly reduce or eliminate electricity purchases.
• Solar Thermal Systems: Consider solar water heating to reduce water heating energy costs.
• Geothermal Heat Pumps: Though initially expensive, geothermal systems offer exceptional energy efficiency for heating and cooling.

The HERS Rating Process

To obtain an official HERS rating:

1. Hire a Certified Rater: Contact a RESNET-certified HERS Rater in your area.
2. Home Assessment: The rater will conduct a thorough inspection, including diagnostic testing such as blower door tests to measure air leakage and duct blaster tests to assess duct system efficiency.
3. Energy Modeling: Using specialized software, the rater will model your home’s energy consumption based on the collected data.
4. Score Calculation: The software calculates your HERS Index score compared to the reference home.
5. Recommendations: The rater provides a detailed report with prioritized recommendations for improvements.

Cost Considerations

Improving your HERS score requires investment, but many improvements offer excellent returns:

• Low-Cost Measures: Air sealing, programmable thermostats, and LED lighting typically pay back quickly.
• Moderate Investments: Insulation upgrades and ENERGY STAR appliances generally offer payback periods of 2-7 years.
• Major Investments: HVAC system replacements and renewable energy systems have longer payback periods but provide significant long-term savings.

When planning improvements, consider available incentives:

• Federal tax credits for energy-efficient improvements
• Utility company rebates and incentives
• State and local energy efficiency programs
• Special energy-efficient mortgage products

Conclusion

The HERS Index provides a valuable metric for understanding your home’s energy performance. By systematically addressing the various components that influence your score, you can create a more comfortable, cost-effective, and environmentally friendly living environment. Whether you’re building a new home, purchasing an existing property, or improving your current residence, understanding and optimizing your HERS Index can lead to substantial benefits over the life of your home.

For maximum impact, consult with a certified HERS Rater at Eco Three who can provide personalized recommendations based on your specific home characteristics and regional climate factors. Eco Three is a home energy efficiency company that offers HERS ratings in Alabama and Florida. We are a qualified and experienced company that can help you improve your home or business’s energy efficiency and save money on your energy bills. Contact us today to learn more about our services.