Building an energy-efficient home is one thing, but, as any green remodeler knows, retrofitting an existing structure for optimum efficiency means a host of additional challenges.

For David Bolt, Mick Dalrymple, and Steve Rypka, speakers at the recent Greenbuild conference in Phoenix, the best way to learn about ultra-energy efficient remodeling was to experiment on their own homes. Each green building consultant used his house as a living laboratory, adding and subtracting products over time and trying new techniques to find what features and design elements made the greatest impact.

Energy-efficient remodeling, Bolt explained, can be broken down into the following categories:

  1. Light energy retrofit, 10% to 30% energy use reduction: Easy, non-structural changes, including sealing leaks, getting rid of phantom loads, upgrading lighting. 

  2. Deep energy retrofit, 70% to 90% energy reduction: All the elements of the light retrofit, plus major adjustments to the envelope (windows, siding, roof, vent, reducing crawl space; increasing insulation in hard-to-reach spaces; and replacing HVAC to match new reductions). 

  3. Net-zero, 100% reduction: All the elements of the light and the deep retrofits, plus the addition of renewable energy sources.

Each speaker achieved varying levels of energy reduction, using an array of techniques. Here is an outline of some of the changes each house underwent.
When Dalrymple, a principal at a.k.a. Green Services in Scottsdale, Ariz., conducted an energy audit on his 1975 Phoenix masonry home, the leakage was so bad that the duct blaster wouldn’t work; in fact, 2 to 5 tons of AC capacity was going straight through a hole in the roof caused by the evaporative cooler condenser. The steps he took to improve the home included:

  • Replacing the roof, which was damaged by water, and adding 3 1/2 inches of foam. 

  • Sealing attic venting. 

  • Putting ducts inside conditioned space. 

  • Adding a radiant barrier. 

  • Adding natural lighting via tubular skylights. 

  • Replacing an inefficient bank of first-floor windows with low-E fiberglass patio doors 

  • Replacing the pool pump with a more efficient model.

After all other elements had been fixed, Dalrymple installed solar thermal and photovoltaic systems. The result was a 70% reduction in the home’s energy bill. His next goal is to reach 85%, in part by incorporating ICFs. 
From his project, Dalrymple learned to:

  • Assess the entire situation before jumping in. 

  • Approach the house as a system, remembering that every action has a reaction. 

  • Recognize the potential savings from even the lowest hanging fruit; for example, the $75 spent to fix the hole in the roof brought a 20% energy improvement. 

  • Never underestimate the power of shade and plants, passive solar, modifying human behavior, working with nature instead of against it, and experimentation.

Most important, Dalrymple said, is that he had fun with his experiment. By using his home as a laboratory for off-the-shelf products and techniques, he’s able to apply what he’s learned to clients’ homes.
Rypka, president of GreenDream Enterprises, began his journey before he even purchased his Pulte home in Henderson, Nev. He intentionally looked for a house with glazing largely on the south-facing side to maximize passive design, which he boosted further with a tubular skylight, strategic shading with plants and trees, and tile flooring to absorb excess heat. Once these features were in place, he began to tackle other areas:

  • Installing CFLs. 

  • Selecting Energy Star-rated appliances. 

  • Installing ceiling fans and turning them off when not in use. 

  • Purchasing programmable thermostats.

But even more so, he and his wife have embraced behavioral changes, such as becoming avid bikers and trying out new things like a solar oven, which cooks food via the sun while offering a unique conversation piece.
“We need to look at this as the largest opportunity we’ve had to envision a new way of living that’s better than we’ve had before,” he said.

In renovating his 2,400-square-foot lake house, Bolt, the owner of Sustainable Future in Knoxville, Tenn., saw firsthand the difference in the energy needs of a single resident—himself—then the increased demands when his family joined him after the initial renovations were complete.

He installed solar thermal and photovoltaics, but couldn’t achieve net zero once his family came. To address the increased demands of four, Bolt:

  • Replaced his evacuated tube solar thermal system with flat plate collectors. 

  • Adjusted the tilt on the solar panels to a more optimum angle. 

  • Improved attic ventilation and added a whole-house fan. 

  • Replaced the asphalt roof with a standing-seam metal roof. 

  • Downsized to a smaller, more efficient refrigerator. 

  • Installed a super-efficient combination washer/dryer. 

  • Enclosed the shower to retain heat and steam, thereby reducing hot water demands. 

  • Installed a small PV panel specifically to charge battery-powered gadgets. 

  • Installed CFLs. 

  • Added a storm door. 

  • Replaced a desktop computer with a more efficient laptop.

Like Rypka, some of the steps were truly about modifying resident behavior, with simple changes that add up to savings. For example, he:

  • Added a clothesline. 

  • Opened the windows during the summer. 

  • Installed an energy monitor that helped the family reduce plug loads by 30%. 

  • Installed a power strip to shut off power to the microwave. 

  • Began using a thermos to keep coffee warm instead of keeping the machine on all morning.

Such changes seem small, but, as the three consultants found through the power of experimentation, each element combines with larger steps that together can add up to significant savings.
“We’re not going to build our way out of this climate problem,” said Dalrymple. “We’re going to remodel our way out of it.”

Katy Tomasulo is Deputy Editor for EcoHome.