But they also employed a cheap substance, simple to use, that no greenie should be without: caulk.
It's a secret weapon in the home energy arsenal.
Hellman and his crew should know. Every day, the city's Energy Coordinating Agency, a nonprofit organization that administers Philadelphia's energy-assistance programs, sends Hellman's crew, and 35 others like it, out to weatherize homes.
In 2008, the agency weatherized 1,743 low-income homes alone.
Hellman is amazed. He keeps thinking they'll run out of places, but they never do.
Philadelphia's old homes - and surely the distinction doesn't stop at the city's borders - are notoriously leaky. So perhaps not surprisingly, heat is a huge portion of the overall energy cost, expected to run more than $2,000 per household this year, according to the agency.
The federal government's Energy Star program estimates that residents can save up to 20 percent on heating and cooling costs by sealing leaks.
Unfortunately, they muddy the statistic by including both caulking and insulating.
Nevertheless, on many homes, caulk can be "a great first step," said the ECA's executive director, Liz Robinson. A tube, depending on type, can cost as little as $5 or $10. And other than being slightly icky and messy for the inexperienced, the work goes fast.
In the case of the Port Richmond home, caulk was the finishing touch.
Hellman was using siliconized acrylic caulk, which cleans up with water. But at least one manufacturer of silicone caulk claims that kind is better, even if more expensive, because it's waterproof and flexible, won't shrink or crack, won't freeze . . . and so on.
