Energy audit

The big kahuna.

Yesterday (Friday, July 1, 2011) was our NYSERDA energy-audit, done by Lang Heating & Cooling, our HVAC contractor.
NYSERDA is New York State Energy Research and Development Authority.
The idea of an energy-audit was to see how energy-efficient our house was.
“Why did you even want an energy-audit?” the guy kept asking after he finished. “I’ve never seen numbers so good.”
“We wanted to see if we had gas-leaks, and if our efforts designing this house made any difference.”
“This house is designed to the hilt,” I said before the guy started.
“Foot-thick insulated shell walls, all eight-foot ceilings, 22 inches of blown fiberglass insulation atop the ceiling, all the entrances from the outdoors are air-locked, few windows, and they’re all casement.
Our old house in Rochester was about 900 square feet, yet this one is about 1,900. And both use the same size furnace, 60,000 BTU. In our old house we were heating the outdoors.
And it’s passive. No solar, no underground plumbing. All it does is sit.”
The guy checked all our gas appliances; stove, dryer, high-efficiency furnace, tankless water-heater. No leaks.
A tankless water-heater is just that. It heats the water on demand — as it passes through. There’s no holding-tank, like most water-heaters.
We got it when our old tank-type puked out.
There was a rebate, but it cost a fortune.
I don’t know as it saves natural-gas. You tend to blast away with it, because it doesn’t run out.
“Okay, we need to turn on the dryer and the kitchen rangehood,” he said. “Both exhaust internal air to the outside.
WOW! This house is tight. I’ve never seen such a pressure-drop.”
He had a gauge that measured inside air-pressure versus outside air-pressure.
Finally, the big kahuna (see illustration); the fan in the front-door opening to pull inside air out of the house.
He went around with a smoker to find air leaks.
There were a few tiny leaks, but hardly any.
Biggest was around our fire-door to the garage. It was never installed that well originally.
There was a gap between the wallboard and the steel door-frame; about 1/32nd of an inch, and it leaked garage air into the house.
Our house was designed by us (with an architect), trying to make it as efficient as possible.
There were alternative schemes (this was 20 years ago), but I wasn’t burying it, nor using technology I’d have to maintain.
So super-insulation, which itself has challenges.
One was it would be so tight it would need ventilation. —For that we’d have an air-to-air heat-exchanger.
Another was water-vapor, and a possibly disintegrating vapor-barrier.
We specified 10-mil vapor-barrier; it’s very thick and heavy, so won’t split.
The best our builder could do locally was three-mil.
I stuck to my guns, and my wife found a supplier in Minnesota that could ship 10-mil.
So 10-mil is what it is.
We also insulated the sill-gap ourselves with one-inch styrofoam board, custom-cut, with bat insulation behind, styrofoam calked in place.
“This house is incredibly tight,” the guy said.
“This gauge says only an 88 square-inch opening to the outside. My own house is over 300. 88 square inches ain’t much; about the size of one of your single windows.
We can’t do anything. No improvement needed,” he declared.
“Except I wouldn’t mind calking that garage-door,” I said.
“But you could do that yourself. Ya won’t need a contractor.”
“We had a lot of fun designing this house,” I said. “I remember making a cardboard model of it in Grand Jury, because the architect’s plans made the roof look too high.”
“Your efforts were worth it,” he said. “These are the best numbers I’ve ever seen!”

• “HVAC” is heating-ventilation-air conditioning.
• The “sill-gap” is where the floor-joists sit atop the foundation. Between floor-joists has to insulated individually.
• “Grand Jury” duty was years ago (1989), and I had a lot of spare time.