Buying a Home? Look for the HERS Rating

What Is HERS? 

The acronym stands for the “home energy rating system.” Developed by the California-based Residential Energy Services Network (RESNET), HERS is generally applied to new homes, although existing homeowners could pay to have their homes rated.

Understanding a HERS rating is not all that difficult. Homes get rated on a 0 to 150 basis, with a net-zero home having the highest energy efficiency and energy production through solar panels. 

The US Department of Energy estimates a typical resale home carries a rating of 130. A home constructed to meet the 2006 International Energy Conservation Code scores 100.

Of course, new homes with a rating of 60 or below would be considered very efficient. A 60 rating would save homeowners, on average, $718 annually on energy costs. The number jumps to $898 for a 50 home rating, according to the HERS website.

How Is the HERS Rating Determined? 

First, a builder or homeowner must hire a HERS rater. These individuals are trained in the system and have access to software that helps develop ratings for their clients. They carry certifications and charge roughly $500 to $3,000 for their services. A search engine is available to locate raters in every state. 

The raters look at a variety of issues where leaks are causing problems. A process called thermographic imaging shows precisely which areas of homes are leaking energy. These areas include gaps in the wall and ceiling insulation and heating, ventilating, and air conditioning (HVAC) distribution systems. 

Leaks, of course, lead to higher energy bills. Even newly constructed homes can have poorly sealed doors, windows, and vents that bleed energy. A modest investment fixes leaks. 

Raters capture lots of details, including the condition of foundations, attics, and crawl spaces. Homes receive points for having sophisticated thermostats, heating, and cooling equipment. And appliances with high ENERGY STAR ratings from the EPA help lower HERS scores. 

HERS raters often work closely with builders and homeowners to create strategies for improving scores. They can suggest vulnerable areas in a home and how to make affordable improvements. The HERS score can be adjusted upward by tweaking different parts of a home to reflect energy efficiency improvements. Many state or municipal codes require similar home ratings after construction when it is too late to change anything. Why not hire the rater before construction to ensure you have the best-performing home for the most cost-effective way to do it.

How Can A High HERS Score Be Achieved?

To get the highest score possible new home buyers should consider an “energy smart builder.” The HERS website lists dozens of them. But the list is hardly inclusive. Buyers speaking to builders must express their desire for an energy-efficient home. Any builder can build a low HERS rated home with little effort - they can even attain net-zero!

How Does HERS Relate To Appliances?

Retailers display ENERGY STAR ratings of appliances prominently on yellow tags. Consumers can easily compare energy consumption between different models.

Refrigerators and dishwashers with ENERGY STAR ratings are 20% and 10% more efficient than the federal minimum energy efficiency standard, respectively. Washing machines with the ENERGY STAR rating consume 50% less water and 30% less energy than standard washing machines.

Higher efficiency can come with higher price tags, yet the higher cost can pay for itself in savings over the life of the appliances. The investment will be worth it since studies show heating and cooling represents 56 percent of the cost of operating a home.

How Do Windows Affect the HERS Rating?

The choice of windows is essential, whether buying for a new home or selecting replacements for an existing one. Windows today come double or triple-paned. Dual-pane windows have two panes of glass with airspace in the middle. Triple pane windows are even better, adding an extra pane of glass and additional airspace that increases efficiency and blocks noise.

Look for the different gas components that improve thermal efficiency. Argon gas fills dual pane windows, generally the standard window in today’s market. Krypton gas is even better. Denser than air or argon gas, the odorless krypton offers the highest level of efficiency.

Windows also have sophisticated glazing. Coating with low-E values reduces heat transfer from outside to inside a home. In winter, the coating allows the sun to stream into rooms.

How Does Insulation Affect the HERS Rating?

Insulation should also be a top priority for new or existing homeowners. Study the R-value of insulation, which measures resistance to heat flow. The higher the R-value, the better the insulation. A talented contractor can help with determining which type of insulation performs best in different areas of a home.

Along with insulation, homeowners should check the exterior of homes for damage. Mold, mildew, termites, and structural rot all conspire to allow heat to escape and drive up energy costs. Fixing exteriors with proper roofing, sheathing, insulation, and cladding will help seal a home’s envelope while protecting it from the elements.

Does An HVAC System Affect the HERS Rating?

An efficient heating system and a proper mechanical ventilation system go a long way in lowering your energy usage. Insulating and sealing the home should be tackled first and typically provide for more significant gains. Insulating and air sealing at the outset and very liberally will also allow you to spec a smaller heating and cooling system for your home. Look for electric alternatives over gas, like air or ground source heat pumps - all-electric space and water heat pumps now give dwellings lower (better) HERS ratings.

How Does Lighting Affect the HERS Rating?

Finally, lighting represents about twenty percent of a typical energy bill. An easy way to drop the cost is to use LEDs throughout a home. They last for years and consume a fraction of fluorescent or even compact fluorescent bulbs. LED prices have dropped considerably over the past five years, making their payback period typically below six months. They can even come with motion sensors built in them to save even more energy.