Even though this winter has been Chicago’s coldest in more than a decade, Bill and Andryea Natkin are only about half as unhappy as their neighbors.
Unhappy about the cold, sure. But when it comes to heating bills, they just sit back and smile.
That’s because they haven’t had to crank up the furnace once so far this long, cold winter to heat their house in West Rogers Park. The house doesn’t even have a furnace.
“It’s a passive solar house,” says Bill’s father, Bob Natkin, who helped build it.
Interested in conservation for years, Bob Natkin had done intensive research on energy-saving techniques by the time his son and daughter-in-law bought their Jarvis Avenue lot in 1985. That year, the couple, with help from Bob, decided to build a house so energy-efficient that it wouldn’t require a furnace.
Working on standard a 30-foot city lot, and maximizing available sunlight during Chicago’s cold, dark winters, the project sounded impossible. Yet using widely available building materials and no solar panels, the Natkins’ experiment has worked.
What little electrical heat and air conditioning the house (completed in late 1985) needs adds only about $150 a year to standard electrical bills, the Natkins say.
Though the 1,580-square-foot Natkin home is unusual in many ways, what’s key is a fortified shell of insulation combined with a wall of windows that takes advantage of a large southern exposure, Bob Natkin says.
Although Bob is a professional builder and Bill an electrician, both say the building materials they used were readily available from area supply houses and cost virtually the same as standard materials.
With their combined construction experience, more care than usual went into the building of the home, the Natkins concede, but that’s because Bill, 39, and Andryea, 41, did much of the work themselves.
“This technology is available to all architects, but you never meet one who knows about it,” Bob says. “The Canadian government is involved with all kinds of builders and gives out huge grants to experiment with. They came up with things that are represented in this house.”
Most of the conservation features of the Natkin house were the ideas of Rodney Wright, the Osseo, Wis., architect who designed it and wrote “The Hawkweed Passive Solar House Book” in the 1970s. Super-insulation and southern exposure were the key ideas behind the book, Wright says.
Energy savings already have paid for the extra building expenses after eight years, according to the Natkins.
Key features of the project include:
– Insulation. A foot of Fiberglass insulation surrounds all outside walls, bringing them to an R-rating of 40. A standard house generally is insulated to R-11 or R-19 by carpenters who slap Fiberglass between joists without the care Bill and Andryea used, Bob says.
Two 12-inch layers of insulation blanket the roof, bringing it to an R-rating of 80, compared with the more usual R-19. Two inches of foam insulation also line the foundation. A Dow product called Sill Seal separates the frame of the house from the foundation, keeping out more drafts and bugs.
“The insulation cost, at the most, $500,” Bill says, “but our labor might have cost $2,000, because the walls had to be double-studded to accommodate the extra insulation.”
Since so much work was do-it-yourself, pricing the house is difficult, but Bill and Andryea estimate the project, including the lot-but not counting their labor-cost $100,000.
– Solar power. The Natkins’ house isn’t exactly a “solar greenhouse,” but it has a space that functions pretty much as one. The south end of the living room and two upstairs rooms are adjoined by a greenhouse-like space about five feet deep created by a wall of windows 16 feet high and 22 feet wide.
This “greenhouse,” separated from the rest of the house by sliding glass doors, collects sun-heated air during the winter. In summer, blinds shut out unwanted heat and glare.
In winter, two large air ducts with electrical ventilation fans pull the sun-heated air from the top of the greenhouse into a chamber underneath the living room and kitchen.
This chamber, which Bob calls a “mass,” is the single most unusual feature of the home. Built beneath the main slab, the mass was constructed of a layer of thick plastic sheeting, two inches of Dow Styrofoam insulation, a layer of cinder blocks (through which the warm now air circulates), a layer of corrugated sheet metal and, finally, the five-inch concrete slab itself.
Working as a giant air-filled heating pad, the mass required a few hundred dollars’ extra in materials and took Bill and Andryea one day to build.
On sunny winter days, the greenhouse reaches 80 degrees, and with the warm air flowing through the mass, the flooring above it can be warm to the touch, they said.
An attached garage, highly insulated with standard materials, shields the house from cold winds and never freezes inside. The roof of the garage, slanted at about 60 degrees, works as an air-foil to further deflect north winds over the whole building.
Although there are few windows facing the cold, dark north, a skylight showers light into the north section of the house, while the bright southern wall illuminates the rest of the interior rooms.
Small, electric baseboard heating units augment natural heating during the really cold and dark days. Each room has its own thermostat-controlled unit. While most Chicagoans were turning on the heat by the end of October, the Natkins didn’t need to use any of these units until December, Andryea said. And, she adds, they came in handy during the recent cold weather.
Next to the garage, a 12-foot entryway that Bill calls an “air lock” warms outside air between the exterior R-15 storm door and a heavy front door and then another insulated weather-stripped door leading to the house.
Pella windows with R-3 ratings and heavy doors on the home are all energy-efficient. Holes in walls for electrical conduit and plumbing also were insulated with great care.
Since the house is almost airtight, the Natkins also installed an air exchanger, which blows air from the kitchen and two bathrooms outside. At the same time, the exchanger pulls in fresh outside air, warming it as it travels through slatted ducts in the walls.
Bill says this system cost no more than typical kitchen and bath exhaust fans.
A water preheating system was icing on the cake. City water flows into a warm attic above the greenhouse, runs through a series of four 30-gallon uninsulated steel tanks and is warmed to as high as 90 degrees before it enters the typical electric hot-water heater downstairs. This system cost about $1,500 extra, and Bill calls it a “nice passive way to heat the water.”
The Natkins say life in the home with their two daughters, Mara, 6, and Clara, 3, has brought them no unpleasant surprises.
The wall of windows along the open living area lend plenty of light. Track lighting and a collection of artwork, painted by Andryea, add to a relaxed elegant atmosphere.
And with that thick blanket of insulation, the place is dead quiet. The Natkins hear none of the usual street noises, and of course, no furnace sounds.
About the only time the Natkins’ peace was disturbed, the family says, was during construction when a stream of curious executives from Dow, engineering professors and students and city inspectors stopped by for a look. Word of their experiment had spread quickly.
