Pea pods: They’re fresh. They’re green. They’re snappy.
Mark Rittle, one of the founders of PeaPod Homes, LLC, in Sturgeon Bay, Wis., calls the legume husk “nature’s perfect container.”
A PeaPod home is a house within a house — a little like a pea within a pod.
PeaPod designs use passive solar power and an envelope construction, plus several other patent-pending processes, to keep a home’s interior climate comfortable in any season in any part of the country, Rittle says.
PeaPod’s energy-efficient, prefabricated homes can be heated and cooled year-round for less than half the cost of an iPhone. Unlike iPhones, though, PeaPod homes are worry-free, he says.
“You don’t have to do anything to make all this happen; you just move in and it works all by itself,” according to Rittle. “It doesn’t require anything from its owners other than to live there.”
Even without turning on the furnace, on a frigid, sub-zero Midwest day, a PeaPod house won’t get any cooler than 55 degrees, Rittle says. That’s the set point temperature of the earth below the freeze line. So increasing the indoor temperature to a comfortable 70 degrees doesn’t take as much energy or effort because the starting temperature is higher than it would be for a typical house, even on the most frigid days.
They take less energy to cool than standard homes for the same reason.
Rittle and his two partners, Massachusetts architect Kathleen Lugosch and New York real estate investor Van Krzywicki, incorporated their company in 2008. Consultants include Charlie Curcija, a senior research fellow at the University of Massachusetts at the Center for Energy Efficiency and Renewable Energy, and Hernan Barufaldi, a University of Massachusetts expert in architecture and computer-aided design.
How the PeaPod design works
The house “works” by using heat from the sun and coolness of the earth to heat and cool air that circulates around the house, through a cushion of air between double walls.
An entire side of the house is made of custom-ordered glass that has greater insulating capabilities than typical window glass, according to Rittle.
The glass side (called the sun space) — which faces south and looks for all practical purposes like a sunroom — heats the air in the space before circulating it.
The heated air rises to the top of the sun space, goes through and across the attic, down the double north wall, through vents in the floor beneath the basement and then back into the sun space where the process begins all over again. It needs no fans to move the air, Rittle said.
Go with the flow
The circulated warm air from the sun space also heats an inner south-facing log wall. That wall, of Southern yellow pine, retains heat and radiates it to the inside of the house and its inhabitants like “a big radiator,” Rittle said. Wood is terrible as an insulator but good as a radiator of heat, Rittle says.
Different windows of the house use different kinds of glass – south-facing windows in designs for northern climes use glass that allows heat in but not out; east- and west-facing windows employ a hybrid low-e glass that allows light but not heat to enter.
“In the southern part of the country, you want less glass, and in the northern part, you want more windows on the south side,” Rittle said.
PeaPod homes take advantage of extra-large overhangs, whose dimensions vary according to the sun’s position, to shade in summer.
“While the sun pouring in during winter is great, it’s not so great in summer,” Rittle says.
PeaPod rooftops are super-insulated with structural insulated panels (SIPs) so heat can’t escape, Rittle explains.
Basements stay snug because polystyrene foam sheets serve as the concrete form for the poured foundation and basement, resulting in a heat retention level of R-40, Rittle says.
“When you have polystyrene, walls never weep, so you don’t get dampness,” he adds.
In winter, without any auxiliary heat at all, the temperature of a typical house will vary depending on the temperature outside. But a PeaPod house won’t get any colder inside than 55 degrees, Rittle says.
“If you have sunshine, you wouldn’t need any backup heat, but half the days here in Wisconsin are cloudy during the heating season,” Rittle says. “We draw on basement air that never gets below 55 degrees.”
In summer, the same process happens, only in reverse, using cooled air from the ground instead of air conditioning to cool the house.
But there are no worries about that dank basement smell: The air constantly circulating through the sun space prevents mold or mildew, says Rittle. Building codes mandate air exchangers, which regulate humidity, too.
“Moisture is something you need to be aware of in any house, but the air exchanger keeps it healthy and comfortable,” Rittle says.
Cool as a cucumber
Another difference between PeaPod designs and other energy-efficient envelope-style houses: Instead of the circulated air moving beneath the first floor as it does in some envelope homes, in PeaPod homes, the air travels under the basement floor. This maximizes the air’s contact with that coveted 55-degree setpoint temperature.
“We want the air to be in contact with the earth as much as possible (to cool it), so if we confine it down to where it is cooler, it acts as natural air conditioning in summer,” Rittle says.
In winter, that same 55-degree core temperature serves to ensure that the temperature circulating around the loop never drops below 55.
“As a result, the inner portion of the house (or inner envelope), thinks it’s only 55 degrees outside and … the heater only has to bring the temperature up from 55 degrees instead of whatever the outside temperature actually is” no matter if that’s 0 or 20 below zero, or whatever, he continues.
Rittle is a Chicago-area native with a 20-year career background in sales and marketing. He and his family relocated to Northeast Wisconsin a dozen years ago to own and operate a bed and breakfast inn in Algoma.
While running the inn, Rittle built an energy-efficient log home as an investment property. He and his family ended up selling the inn and moving into the log home when it lingered on the market longer than anticipated. He landed a job in sales with the builder of the log-house, and that’s when the platelets of the earth began to shift him toward a new opportunity in green housing.
Living in that house helped him see firsthand the product he was selling — its weaknesses as well as its strengths — and that led to the idea for PeaPod Homes. PeaPod’s concepts build on the strengths of the log home’s concepts but improve upon its flaws, Rittle explains.
“Every day I would wake up with something I thought could be done better,” he said. “It was a beautiful house, but it wasn’t as efficient as it could have been. When the climate was moderate I had low bills, but the house was made out of logs, and logs are not a good insulator.”
Rittle also didn’t like the fact that the log home he built used so much wood. “A log home like that can use 120,000 pounds of lumber,” he notes.
The packages PeaPod puts together call for locally grown or locally produced components, such as structural insulated panels (SIPs). A SIP is two sheets of plywood sandwiched around six inches of polystyrene for wall panels and 10 to 12 inches for roof panels.
Nurturing the idea
PeaPod recently embarked on a collaboration with Energy Panel Structures (EPS) of Iowa as its chief supplier of SIPs, as well as floor trusses, glulams, structural beams, insulated concrete forms for basements, internal framing material, support beams, pre-made staircases and other building components.
“If you have to ship (components) 2,500 miles on semis, that’s an enormous waste of energy,” Rittle said. “There are manufacturers of SIPs all over the country and usually within a few hundred miles of almost any building site in the country. We use materials from as close to the site as possible.”
“Basically the entire structural package is what we’re providing PeaPod, less the windows, shingles and that kind of stuff,” says EPS housing consultant Don Jahnke.
PeaPod will be able to pass along to customers the cost savings it receives from buying from one manufacturer, Rittle adds.
“Being able to put more materials in one package saves on trucking and helps with cost controlling,” Jahnke says.
All of the pieces for PeaPod homes arrive at the job site pre-cut to fit before they arrive, which “grossly reduces” waste, Krzywicki says.
And here’s another gold star on the green card: Whereas some prefabricated homes are built in a factory and moved sometimes hundreds of miles to a site, PeaPod homes are built on-site by local builders.
“We support the local economy, and that’s a part of the sustainability model, as well,” Krzywicki said. “In our model, we bring the efficiencies to the homeowner and keep the local economy intact.”
PeaPod’s basic home models are designed to be easily expanded upon as a client’s needs or family structure changes. PeaPod has six basic designs, including single-story, two-story and addition modules. Homes can be as small as 600 square feet to 2,800 square feet — “limited only by your budget,” Rittle says.
Price-wise, they cost about 5 percent more to build than a typical house with similar dimensions and amenities, Rittle says. The extra expense comes from the high-performance windows and additional wood in the thermal-mass inner south wall (inside the sunspace).
“In life-cycle costs, you can offset that much in the first few years you live there with the energy savings you should realize,” Rittle says.
PeaPod houses can be built in the middle of a city, or on a 100-acre lot – almost anywhere, except next to a 40-story building that would obstruct the sunlight, Rittle says.
“PeaPod stands out from other home designs because they’re performance engineered,” Krzywicki adds. “Our design and decisions are largely guided by how the house performs.”