What election predictions can teach us about energy efficiency
Do the math. It's that simple. That's how you can build or renovate a home that can eliminate its energy bills forever.
Net zero energy means producing as much or more energy on your property as you consume inside your house. Many pundits in the building and renovation industry tell us that creating net zero homes is very difficult, if not impossible. But, net zero homes exist…in virtually every price category, including affordable housing. Rocky Mountain Institute's Amory Lovins says "if it exists, it must be possible."
So why are net zero buildings so rare? For an answer we can look to sports and political statistician (a.k.a. the Emperor of Math), Nate Silver.
In the 2012 elections Silver predicted the results of the Presidential and Senate races with 100% accuracy (assuming results in Florida hold) -- that's 50 out of 50 states in the electoral college and every single senate race. On November 6, the day of the election, pundits across the nation called the race "razor tight" (forgive them for the pathetic metaphor). In 2008, Silver missed only one electoral college state, Indiana, by a tiny margin and accurately predicted 100% of the Senate races. This is not luck. It's objective use of statistical probability.
Interpreting energy-efficiency data
What can Silver's election predictions teach us about making homes more energy-efficient and achieving the essential target of net zero energy? Like baseball and politics, there's a lot of energy efficiency data out there. The problem is that too many pundits rely on their guts and don't pay attention to the important and objective data. When predicting performance we must look at all the data and make common sense of it.
Read my OldHouseWeb.com article "How to Destroy the Planet from the Comfort of Home" for a discussion of how Oakland A's and Moneyball relate to energy efficiency.
Nate Silver says "there are many things that are much more complicated than looking at the polls and taking an average and counting to 270, right?" Similarly, energy efficiency and net zero energy are not that complicated. You simply tally up the energy consumption of every energy consuming item in the building and determine how that compares to the ability of the property to produce its own energy.
If you go down that list of every energy consuming product (yes - everything that consumes energy -- lights, furnace, stove, TV, clock radio, hair dryer, George Forman Grill, the TV Hat, anything from the SkyMall catalog, etc.) and adjust for maximum efficiency, you can get to the magic net zero number.
As in sports and politics, however, it's garbage in/garbage out. You need good data. Energy data exists for all appliances. Energy consumption data exists for all climate zones, family sizes and behavior. We need to put the numbers on paper and determine how they impact total consumption.
For example, for household lighting consumption we have reliable information on the watts per bulb and comparative efficiencies (LED is more efficient than CFLs which are more efficient than incandescent bulbs for the same amount of light) and that 60 percent of lighting costs go to light unoccupied rooms. When looking to improve our homes or to make a home net zero, we target the most efficient bulbs with the highest quality occupancy sensors to ensure that lights are off when rooms are empty. We can improve the probability of net zero energy performance by putting the most efficient combinations of technologies into our performance model. We can't just look at insulation, or windows, or Energy Star appliances. We must look at all of the consumption data.
The math is simple: determine how much a site is capable of producing (energy IN) and substract the total probable consumption of energy (energy OUT). If the energy OUT is greater than energy IN, go back and eliminate the useless use of energy. Lights in empty rooms provide zero value, but we pay 100 percent of the cost. Let's flip that model on its head.