With an increasing focus on green home building there is also a greater interest in knowing just how energy efficient an already-built home is. The HERS score is a way of quantifying that information.
Like it or not HERS scores will be entering our mainstream home sales market and you will start seeing more and more of them, but just what is a HERS score? The Home Energy Rating System or HERS, is a numerical value for the efficiency of a home. A HERS score takes into account the home’s insulation levels, orientation (with North-South exposure being more efficient), the number and kind of windows, the efficiency of the HVAC unit(s), leaks in the home envelope (your home’s barriers to outside elements), leaks in ducts, and electricity generation such as solar panels.
A RESNET (Residential Energy Services Network)-certified professional uses performance testing such as a blower door test in addition to energy-modeling software to give you a numeric score. The lower the score the better.
A new home built to standard 2006 international codes would have a score of about 100. ENERGY STAR homes have HERS scores of 85 or lower, meaning they are built 15% more efficiently than required by code. Average existing homes may be around 130, though some homes score well over 200.
Net-zero energy homes score zero or lower. A Habitat for Humanity “Legacy Home” in 2010, had a -16 HERS because the home produced more energy than it used.
The rating shown here is from a 1954 block-construction home, renovated in 2005. Apparently, the previous owners did a pretty good job when retrofitting and didn’t skimp on insulation. This this rating was done, the owner has installed PV solar panels.
HERS scores may be required to be posted in future home sales as a good indicator of how much it may cost to operate the home. The cost to conduct a HERS rating varies, so it’s important to shop around. Quotes may run between $250-$450. Qualified professionals can be found at: resnet.us/trade/find-raters-auditors.
Realtor Melisa Camp, Phoenix, AZ