Green Homes: Solar Panels vs. Energy Efficiency

While it’s not as sexy as a rooftop rack of silicon, improving a home’s energy efficiency tends to be the more cost-effective way to trim carbon emissions. So why are politicians showering subsidies on residential solar instead?

That’s the question posed by Matt Golden, president of Sustainable Spaces, a company specializing in optimizing the energy performance of homes. He convinced the Olssons to think first about energy efficiency, but with every new solar subsidy, it gets harder for him to get homeowners’ attention and contracts.

While I like solar panels (and creative loans to make them easier to purchase), I like implementing the most cost-effective ways to save energy even more.

How can homeowners figure out which are the most cost effective ways to save energy? Energy audits:

Energy officials say they want homeowners to make such rational assessments, but audits cost several hundred dollars and fixes can be time-consuming. That makes it tricky to agree on when and how homeowners should be pushed into the process.

One obvious moment: when a house goes up for sale.

Getting real estate agents to add an energy-efficiency rating in the database of homes for sale would dramatically boost awareness of energy audits. The ratings would act like an auto fuel-efficiency sticker for homes, says Golden.

An energy audit when a home goes for sale is a great idea, as I have written about before.

And what are three examples of technologies that get a better bang for the buck than solar panels?

One, solar water heating:

According to their analysis, published in the International Journal of Global Energy, as the payback time for a solar water heating system is about two years (with a lifespan of 20), this is a far more cost-effective use of solar energy in the developing world than using it to generate electricity.

Two, passive houses:

The concept of the passive house, pioneered in this city of 140,000 outside Frankfurt, approaches the challenge from a different angle. Using ultrathick insulation and complex doors and windows, the architect engineers a home encased in an airtight shell, so that barely any heat escapes and barely any cold seeps in. That means a passive house can be warmed not only by the sun, but also by the heat from appliances and even from occupants’ bodies.

His new home uses about one-twentieth the heating energy of his parents’ home of roughly the same size, he said. And in Germany, passive houses cost only about 5 to 7 percent more to build than conventional houses.

Decades ago, attempts at creating sealed solar-heated homes failed, because of stagnant air and mold. But new passive houses use an ingenious central ventilation system. The warm air going out passes side by side with clean, cold air coming in, exchanging heat with 90 percent efficiency.

Check out this cool graphic on how passive houses work.

Third, improved weatherization:

Call it CSI: Thermal Police — energy experts armed with mostly low-tech tools but strong sleuthing skills, finding flaws that let the air inside a house go through a full exchange with the outdoors twice an hour, instead of once every two or three hours.

Correct those flaws, and heating and cooling costs are typically cut by 20 percent to 30 percent, a saving of more than $1,000 annually in some households. In addition, carbon dioxide emissions and the strain on the national electric and gas systems are reduced.

Typical repairs require expertise but generally cost $2,000 or less. The most significant improvement for the Ficks’ house was an inch-thick piece of foam board, which Mr. Kinzer shaped with a utility knife and applied to the exposed heating duct. The repair cost less than $100, including $10 for materials, but it will cut the Ficks’ heating bill by several hundred dollars per heating season, said Tim Kenny’s father, Tom, a veteran weatherizer.

Weatherization could also create a significant amount of jobs:

About 140,000 houses will be weatherized with public help this year, a total that President-elect Barack Obama has promised to raise to one million, to reduce energy consumption and cut energy costs for households and taxpayers, who often absorb those costs for the poor. This would represent a historic shift in emphasis for the federal and state governments, reducing poor people’s energy bills instead of helping to pay them.

Weatherizing a million homes annually would also create about 78,000 jobs for a year, according to the federal Energy Department’s weatherization project director, Gil Sperling.

The current 140,000 annual total creates about 8,000 jobs, Mr. Sperling said.

Congress added $250 million to the weatherization budget for the fiscal year that began Oct. 1. Energy experts say that money could be effectively spent in low-income households and in households that have no need of public assistance.