Importance of the HERS Rating

If you’re in the market to build or buy an energy efficient home, how do you know that the home you want is actually going to be energy efficient?  The key is the Home Energy Rating Systems rating.  You can think of it as the equivalent of the mile per gallon sticker on a new car.

What exactly is a HERS rating?

A HERS rating is a score between 0 and 100, with 80 being the baseline score that the same home would be given if built to the minimum requirements of the Model Energy Code (MEC).  Each point above or below 80, represents a 5% increase or decrease in the energy efficiency of the home.  As an example, an ENERGY STAR qualified home must have a HERS rating of at least 86, meaning the minimum standard for ENERGY STAR qualification is a 30% increase in energy efficiency. 

How is the HERS rating calculated?

A HERS rating utilizes computer simulations to generate an evaluation of the energy efficiency of a home.  In order to receive a HERS rating, you will need to employ the services of a certified HERS rater.  Typically, a HERS rater will evaluate construction plans and conduct a home inspection.  During the inspection the rater will evaluate the home’s structure, insulation, air flow, windows, heating ventilation and air conditioning, geographical orientation, shading and appliances.  In addition, they will conduct two tests, a duct blaster test to verify the seal of the ducts and a blower door test to verify the overall tightness of the house.  All of this information will be input into the rating program and used to generate the official HERS rating as well as the home’s projected annual energy use.

Why get a HERS rating?

Well for one, if you are building or buying an ENERGY STAR home, a HERS rating is required in order to obtain qualification.  However, there are many other advantages as well.  Even if your home is not currently energy efficient, a HERS rating can provide you with recommendations for improving your energy efficiency.  Not only that, recommendations generated by a HERS rating qualify you for energy efficient mortgages , allowing you to get cash to improve the efficiency of your home.  Using the projected savings from recommended improvements report from your HERS rating equips you to make informed decisions about which upgrades will provide the most value. 

In some areas of the country, utility costs can make up a significant percentage of the total monthly ownership costs of a home.   Whether you buy a new or preexisting home, you owe it to yourself to get a clear idea of the true ownership costs.  Just as a typical home inspection is a standard part of the buying process in order to prevent any nasty structural or functional surprises down the road, a HERS energy rating should be done to prevent surprises when you open your utility bills each month.

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