116 3rd St SE
Cedar Rapids, Iowa 52401
WILTON - By all appearances, Dan and Michelle Marine's four-story stone house in rural Wilton has little in common with the single-story ranch Michelle's parents, Lynn and Fran Shafer, had their son-in-law build in town earlier this year.
The Marine home sits on a rural acreage shared by the couple's business, Oak Tree Homes, while the Shafers' home is lodged on a town lot across from a retirement center. One house has five bedrooms and three bathrooms and is home to the Marines and their four children; the other is a modest three-bedroom, two-bath home just right for the retired Shafers.
Appearances aside, the two houses share a German-born building design called Passive House, adopted by and administered through the Passive House Institute US. The designed is based on fairly stringent criteria to make the homes - or apartments or commercial buildings - extremely energy efficient without sacrificing comfort and, in some cases, luxury. Buildings are designed with specific insulation, air sealing and energy consumption requirements - continuous insulation throughout the building, triple-pane windows and doors, and an extremely airtight construction along with a ventilation system that reuses heat and moisture from the atmosphere. Buildings rely on solar energy for heating in the cooler months and
to aid in the prevention of overheating in warmer months.
'The shape of the Passive House is very simple,” Dan Marine said. 'You limit the number of corners in these homes, and don't put in as many windows and doors - all of this helps keep the house efficient and minimize leaks. The goal of the Passive House is to reduce energy consumption, and solar energy really helps with that.”
In fact, Marine said, the solar panels generate enough heat that in the winter, his family often opens windows to 'dump” some of the excess heat out of the house.
Although residences are among the most efficient buildings - more than apartments or business buildings - there still is room for savings, said Michael Nolan, founder and architect at Horizon Architecture of Iowa City. Nolan worked with Marine in designing the Shafer home.
'We wanted to look at what more we could do,” Nolan said. 'These Passive Homes are very comfortable homes - the indoor environment is constant, with fresh air recirculating and being reused in other ways. We're just making an extremely comfortable, energy-efficient environment.”
Marine went through the building training program through Passive House Institute US to learn how to build the Passive House for clients, but also for his own home.
'I feel the only way this program is really going to take hold is to build it and let people see what it does,” Marine said. 'So we did.”
The Passive House design controls air intake and output, as well as filters out contaminants and pollutants through an intricate ventilation
In addition to saving energy, Marine said, the Passive House works with water conservation. The water heater has a five-second temperature increase allotment, so less water is going down the drain while you wait for a shower or faucet to get warm.
Overall, Nolan said, the Passive House uses about one-tenth of the energy used by a 'traditional” home, while still looking like any other home.
'Part of the goal is to make it blend so well you don't even notice that it's different,” Nolan said.