| Vol. 9 | No. 4 | Fall 2007 |
 |
Close to Home
Saving Energy by the Numbers |
In 1970 UCS member Wes Foell was a young assistant professor at the University of Wisconsin at Madison, looking for an affordable home near campus. He and his wife Ankie chose a modest Prairie-style home with lots of large windows to take advantage of natural light. That winter, the Foells discovered they had a problem when the floor-to-ceiling single-pane windows were repeatedly covered with a quarter-inch-thick sheet of ice—on the inside—that would melt into puddles in the living room.
Wes, an energy systems and policy analyst, put his academic knowledge to use in solving that problem, and unwittingly embarked on a 35-year quest to track and optimize energy use throughout the house (see below for a chart showing his annual energy consumption). With each of many home improvement projects, Wes has considered the initial financial investment and its payback time to determine which upgrades will give him the "biggest bang for his bucks."
Windows of Opportunity
Wes began by calculating the heat loss from all exterior house surfaces in order to prioritize potential improvement projects; the large ice-laden windows were clearly the highest priority. At the time, double-pane insulated thermal windows were not available in large sizes, so he had to order custom storm windows. They were expensive (one cost $270), but provided an immediate payoff: no frost on the inside. And they are still in use today, more than 35 years later. Gradually, Wes continued to replace or retrofit the house's 40 windows—the last three were done just this year.
In 1978 Wes began to address the home's hot water usage. Taking advantage of President Carter's tax credits, he was able to install a solar hot water heater at a reasonable cost. Almost 30 years later it is still going strong, helping to reduce the Foells' water heating bills from spring to autumn. During these warmer months, Ankie and Wes wait until the solar tank gets above 120 degrees Fahrenheit before running the dishwasher or clothes washer, or taking a shower, which helps minimize their use of a backup gas-fired water heater (which has a pilot-less ignition and is highly insulated for maximum efficiency).
Keeping Warm, Consuming Less
When the home’s original furnace (estimated to be 65 percent efficient) gave out in 1984, Wes seized the opportunity to reduce his home heating costs by replacing it with a condensing furnace, which draws additional heat from the water vapor formed during the combustion process. This 90 percent efficient furnace paid for itself in just eight years. Twenty years later, the Foells upgraded again, to a 94 percent efficient furnace with a variable-speed fan that saves energy by slowing down when the target temperature is reached.
There are some projects that Wes has not yet pursued. For example, some walls are not well insulated, but Wes determined that, for the time being, the potential energy savings were not sufficient to justify the complicated renovation work required to accommodate the additional insulation. Still, Wes says, "for an old house with unusual architecture, it’s doing very well."
Also in this issue of Earthwise:
Dialogue
How serious is the problem of invasive species in firewood?
