The hypermile house: Saving energy is easier than you think

You’ve probably read stories about “hypermilers” getting 80 miles per gallon in regular cars and thought, “Wow, can how you drive really matter that much?” It can, and it also turns out that how you live in your house can produce the same kind of savings.

My journey as a “house hypermiler” began when my husband and I moved into our new net-zero energy home in June 2011. As energy-efficiency professionals, we had a lot invested in the design and construction of our highly efficient home, and we also had a lot of personal credibility on the line if the home didn’t live up to our expectations for efficiency. We also knew that every kilowatt-hour we saved meant one less pound of coal that had to be burned at the power plant.

We installed a circuit-by-circuit energy monitor and began watching our energy use carefully. The HVAC and hot-water systems were all working as designed. The rooftop photovoltaic system was producing the amount of electricity that we expected. That left two big question marks: lighting and appliances.

For most people lights and appliances account for 30-40 percent of their overall home energy use. Energy codes and heating/cooling equipment efficiencies are getting better. But at the same time, we have more “devices” that need to be plugged in. It’s still important to weatherize your home, but after you’ve done that, there’s still work to do on lights and appliances. This was especially crucial for us — we had made our home so efficient that lights and appliances accounted for 70 percent of our expected energy use.

Hypermiling your home works the same as it does for your car: Don’t do unnecessary things, and do the necessary things as efficiently as possible. In your car, you avoid situations where the car needs to idle (like sitting at stoplights), and you’d empty out all the “junk in the trunk” that you’re hauling around, causing you to waste gas.

The analogy in homes is “vampire” power that creates no useful benefit to you whatsoever. Chargers for cell phones use power even when nothing is plugged into them. If you feel the box on the cord, you’ll notice that it’s warm — that’s energy that you’re paying for, unless you unplug the charger when not in use. Even better, charge it using USB when you’re driving (this doesn’t reduce fuel efficiency) or using your computer. Computers, TVs, AV equipment and gaming systems in “sleep” mode can use a lot of power. It varies, so it’s worth getting a handheld power meter (like the Kill-a-Watt meter, available at home improvement stores for about $20) and testing them. Or rent one from the WNCGBC. In general, you should turn these things off with a power strip when you’re not using them. Walk around your house and fully appreciate the number of appliances with a digital display. Check each of them to see how much “vampire power” they’re using.

Our home office was the biggest power vampire we found in our home. We found that we were able to save 1,400 kWh per year by turning all of our computers off at the end of the day instead of just letting them sleep. We experienced a 16-percent reduction in our annual energy use, just from doing that!

Homes also have a lot of what I call “almost vampire loads.” These are things that provide really small benefits in proportion to how much power they use. Lighting waste falls into this category — lights left on, that are brighter than they need to be, or that use incandescent light bulbs. Don’t get your energy or health advice from chain emails. CFL bulbs are perfectly safe and actually better for the environment — if you dispose of them properly. Fortunately, this is really easy to do in Asheville: Take them to most big-box home improvement stores for recycling. What about the outdoor light that you leave on all the time? Could that be on a motion or photo sensor? Or, can it be turned off entirely if you have street lights in your neighborhood?

The extra refrigerator in your garage is another big power user that provides little benefit to you most of the time. Call Progress Energy and they’ll give you $50 to take it away. If you run your furnace fan on constant “on” instead of the “auto” setting, you’re wasting a ton of energy and you’re only getting a modest increase in air filtering. Most people would be better off changing to a clean filter and setting the fan back to “auto.” Certain TVs and gaming systems use a substantial amount of power — sometimes more than a refrigerator. Do you need to run the TV 24/7 in the background? Could you buy an LED TV instead of a plasma TV next time you replace yours? Don’t let the cable company give you an old cable box. If it heats up the cabinet it’s in, it’s wasting a lot of energy.

Pumps use a lot of energy, and are frequently used as examples of big savings in the marketing for home-energy monitors. If you have a well pump, that is a necessity you can’t do much about. But a lot of people have landscaping pumps for water features. Yes, they look pretty … but they can cost hundreds of dollars per year to operate. Is it really worth it? Hot-water recirculation pumps can also waste both pump energy and hot-water heating energy if not designed and installed properly. It’s always better to design a house so that fixtures are close to the water heater so that recirculation isn’t needed. When this can’t be achieved, using multiple tankless water heaters may be a better approach than a recirculating system.

Finally, there are big energy users that you can sometimes avoid through mild sacrifice or behavior alteration. Clothes dryers are one of the biggest energy users in your house. It took me a while to motivate myself, but a clothesline is really not very hard or time-consuming to use. Just try it sometime.

My grandmother wouldn’t “light her oven” in the summer because it would heat up her house and she did not have the luxury of air conditioning. She had summertime recipes for no-bake cookies and salads. You don’t have to make it an all-the-time rule and suck all the joy out of life, but try to bake and boil more in the winter. In the summer, you use energy to cook, and more energy to cool the house back down. Instead, try to make quick meals and cold foods in the summer. It’s nice to be in tune with the seasons.

A low-flow showerhead is a great way to save energy on hot water. It’s probably one of the fastest payback changes you can make to your home. If your showerhead uses more than 1.75 gallons per minute (it should be printed in tiny lettering on the showerhead), change it. If I can rinse my 3-foot-long hair with a low-flow showerhead, anyone can.

Hypermiling your house is really just about having a little bit more awareness of what it means when you press that button, flip that switch or plug in that power cord. It’s about understanding your house like you understand you car, and “driving” it with the intention of using power for things that matter to you, rather than wasting it on things that don’t.

Amy Musser is a founder/principal of Vandemusser Design PLLC, an Asheville-based home energy efficiency company. A licensed mechanical engineer, she provides design assistance, certification and audits to support high-performance homes.