Home Energy Rating System (HERS) Index is the standard that is used in the industry to measure a home’s energy efficiency. This system is nationally recognized and is used across the country when inspecting and calculating a home’s energy performance. Homebuilders today are finding ways to make sure the homes they are building have low HERS scores.
HERS Index standard scores are determined using energy modeling software. The most common HERS Index score in 2019 was 58 (the standard ranged was between 45 and 80). When building a home, the lower the score, the more energy-efficient the home is. Here are some useful tools builders are using to make sure their new construction homes are energy efficient.
Builders are using specific heating equipment. In recent studies, ground source heat pumps had the lowest score ranges. Air source heat pumps had the best scores overall which ranged between -20 and 5. Traditional furnaces had high scores ranging from 25 to 70 and electric resistance heating scored the highest ranging 75 or higher.
Heating and cooling efficiency also plays a part. Seasonal Energy Ratios (SEERS), as well as the Annual Fuel Utilization Efficiency (AFUE), play a big part. Homes that scored lower on the HERS index from 25 to 40 had SEER ratings of 17-24. Homes with a SEER around 14 scored a high HERS index score of 45 and above. For an Annual Fuel Utilization Efficiency in the mid-80s, the HERS score ranged from 70 – 75. For a lower HERS score (below 55) the AFUE will need to be 90 and above.
Another tool to look at is the mechanical ventilation type. To achieve a HERS score of 40 and below, most homes must only have Energy Recovery Ventilators (ERVs) and Heat Recovery Ventilators (HRVs). Homes with HERS scores that range between 40 and 50 had exhaust only and those with HERS scores between 56 and 80 had air cyclers only.
Solar photovoltaics (PV) is a specific technology that changes sunlight into direct current electricity by using semiconductors. How it works is when the sun hits the semiconductor (within the PV cell) electrons are freed and the form an electric current. Homes with PV had a HERS score of 30 and below. Homes without the solar photovoltaics had a Home Energy Rating System Index score of 40 and higher.
Homebuilders have vast resources when it comes to building an energy-efficient home. When a builder combines multiple efficient products with sound building science principles they will have a greater potential for building a great energy-efficient home.
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