Your home’s energy efficiency plays an important role in your comfort, peace of mind and monthly expenses, especially in a place like Minnesota.
But, beyond the size of your utility bills, you might not know how to tell how efficient your home really is. Luckily, there are a variety of questions you can ask and tools you can use to find out.
1. Does your home have a HERS rating?
One of the simplest ways to gauge your home's energy efficiency is to see if it has a HERS rating. A HERS rating is a comprehensive home energy efficiency score that takes into account variables such as a home’s airtightness, level of insulation and type of heating and cooling system.
The typical U.S resale home has a HERS rating of 130, while a home built to the standards of the 2004 International Conservation Energy Code has a rating of 100. A home with a HERS rating of 70 is 30% more efficient than a home with a score of 100, a score of 50 is 50% more efficient and so on.
Older homes are unlikely to have a HERS rating. Newer homes built since 2006 are more likely to have one, as the HERS system is an increasingly popular assessment tool. In 2014-15, 8,493 newly constructed Minnesota homes received a HERS rating.
2. Does your home have an energy efficiency certification?
Certifications like ENERGY STAR, LEED and our own Energy Fit Homes are another way to tell if a home is energy efficient. These certifications are different, but they all take into account your home’s heating system and insulation levels.
You can read more about home energy efficiency certifications in our guest post on the Star Tribune's Home Inspector blog.
3. Was your home built before the first Minnesota energy code?
Minnesota’s first energy code was implemented in 1976. Homes built before that time didn’t have to follow specific standards for insulation, heating and cooling system efficiency.
If your home was built before 1976, it’s worth doing a little digging to learn more about its efficiency. While many older homes have had energy-saving improvements made, others haven’t kept up with the times—our home energy experts still occasionally encounter homes with virtually no attic insulation.
4. What's your attic R-Value?
Speaking of insulation, R-Value is the measure used to describe the amount of insulation in a home. Homes built to the current 2015 Minnesota energy code have an attic R-Value of 49 (this is about 14-16 inches of typical attic insulation materials like fiberglass and cellulose). Many older homes have lower attic insulation R-Value, often between 0 (no insulation) and 40.
If you have your home professionally inspected, your inspector can provide more information on the home’s R-Value.
5. If your furnace was a person, would it be of legal drinking age?
Heating systems are constantly improving. If your furnace or boiler is more than 20 years old, there may be better, more efficient options out there.
For example, if your new home has an 80% efficient furnace, that means you’re wasting 20% of the energy you’re paying for. Compare that to a modern 96% efficient furnace, which only wastes 4% of the energy it uses.
Here are some things to look for: If the furnace or boiler has two plastic pipes for venting, it’s likely a high efficiency unit. If it has a metal chimney, it’s probably lower efficiency.
6. What’s your window and natural lighting situation?
Look for double paned windows, or single-paned windows with good storm windows in older homes.
If your home is orientated towards the south, you’ll have some solar heat gain in the winter. This will help keep your house slightly warmer in the colder months. However, if you don’t have the right kind of shading, you can experience overheated indoor temperatures during the summer. Shoot for good balance by letting the sunlight into the home in the winter and shading with landscaping and/or window shades in the summer.
7. What does your bill history or My Energy report tell you?
Xcel Energy customers have access to My Energy, an online tool that compares the energy use of a particular home against a subset of the 100 most efficient neighbors and a broader All Neighbors category. Taking a look at this comparison can help you understand how efficient your home is relative to the others around it. If your home uses less energy than the others in your neighborhood, congratulations!