How do I know how efficient my new green home is?

How do I know how efficient my new green home is?
Tags: Certification / LEED
July 6, 2011 - Luis Imery

As many of the readers know there has been a tremendous boom in green building programs and eco-friendly construction. Depending on the region where you live, you might have three or more programs that are administer by different organization. For example, in Georgia, you will come across the EarthCraft House program, LEED for Homes and Energy Star as well as other smaller, local programs. Although this new trend is great, it has created a lot of confusion among the consumer.

Each program has its strength and weaknesses but the fact is that they all try to reduce the impact that the construction and operation of that home has on the environment. Energy efficiency is the core of all these programs because is the most effective way to reduce our carbon footprint. It has been said that just by being mindful on our energy consumption and reducing its use you can reduce about 65-70 percent of your impact. The bottom line is that you get the most bang for your buck by focusing in energy efficiency first.

So you see a green house, and you wonder how efficient it is?

The green certification achieved does not really tell you anything unless explained to you, correct?

Well, you can find the information you are looking for in the electrical panel. Most of the green homes will have a label that displays something call a HERS index. A HERS index is the measuring stick for which all new homes are rated. A HERS index is defined by RESNET (Residential Energy Service Network) as:

"A scoring system established by RESNET in which a home built to the specifications of the HERS Reference Home (based on the 2006 International Energy Conservation Code) scores a HERS Index of 100, while a net zero energy home scores a HERS Index of 0. The lower a home's HERS Index, the more energy efficient it is in comparison to the HERS Reference Home. Each 1-point decrease in the HERS Index corresponds to a 1 percent reduction in energy consumption compared to the HERS Reference Home. Thus a home with a HERS Index of 85 is 15 percent more energy efficient than the HERS Reference Home and a home with a HERS Index of 80 is 20 percent more energy efficient."

The labels may vary; sometimes the HERS index is imbedded on the green program label such is the case with the Energy Star. In any case, the important thing is that the lower the number the better the home will perform.

RESNET (Residential Energy Service Network) which is the "mother ship" for all the rating protocols and setting up the energy reference standards have been heavily promoting the display of this label, even if the home is not being built to a particular green standard. They figure that they can improve the energy efficiency of the future stock of new home if builders embrace at least the HERS index for which the home will have to be third party verified.

The direct consequence of this is that the consumer will now have a standard of measurement so that they can make a more educated purchasing decision when comparing homes.