“I cooled my house this summer for the price of a Big Mac,” Karen Dageforde said.
That gets your attention right?
It should. And considering the house Karen Dageforde cooled was a 2,869-square foot ranch-style house on an acreage northwest of Omaha, it should really get your attention.
Oh, and actually it cost a less than a Big Mac to cool the house.
Darren and Karen Dageforde outside their “extreme green” home, northwest of Omaha.
Presently Big Mac’s go for a little more than $4 in the U.S. It cost Karen Dageforde and her husband, Darren Dageforde, director of utilities in UNMC Facilities, Management and Planning, $2.68 to cool their home. So really it was more like the cost of a small shake.
An efficient amalgamation
As the Dagefordes built their home a few years back, they aimed to consolidate as many home energy efficiency measures as they could under one roof just to see how low they could take their energy consumption levels.
“We really don’t think it’s fair that our generation uses all of the earth’s natural resources and energy and leaves nothing for those who come after us,” said Darren Dageforde, who is a member of the UNMC LiveGreen team.
So how do they do it?
On the south side of their roof, the Dagefordes installed large solar panels, which generate gobs of electricity. How much electricity? Enough that many months, they actually produce more than they use, and that which they don’t use is put into the Omaha Public Power District system. So get this, rather than electric bills, the Dagefordes get credits from the power company.
“In that regard, OPPD views us exactly the way they do a coal plant or any other facility that generates energy,” Darren Dageforde said.
Power workers need to be sure to pull these switches on the side of the Dagefordes’ house lest they be shocked by the energy coming from the house. The combined result of the various energy efficiency measures in the Dageforde house is that many months, they generate more energy than they use.
The Dagefordes have switches on the side of their house that power workers must turn off before they do work on a nearby lines so that they can cut off the energy being put back in the system from the Dageforde house.
“If they forgot to do that, they could get shocked,” Darren Dageforde said.
About 60 feet to the north of the Dageforde house is a large tube that sticks four feet out of the ground. That is the “fresh air intake” on the Dageforde heating and air-conditioning system.
A small bathroom fan in their basement sucks air into the tube, which runs 13 feet below ground for a distance of 160 feet before it enters the home. When the air finally comes into the house, it has been thermally conditioned to about 60 degrees.
This pipe is the fresh air intake of the Dagefordes’ heating and air conditioning system. It runs 13 feet below the ground and then into the house. The ground temperature 13-feet down remains the same year round. So regardless of the weather outside, the air comes into the Dageforde house at the same temperature.
“It doesn’t matter if it’s 100 degrees out or negative 15, it stays the same temp at that level, so the air that comes into our house is always 60 degrees,” Darren Dageforde said.
The same principle is used in the radiant heating and cooling system that runs in the concrete floors of the Dageforde house. Radiant fluid is cycled through the floor and then out to geothermal wells that run 200-feet below the ground and back again to bring the 55-degree liquid into the floor. This helps keep house temperature cool throughout the summer. All it takes is a small circulating pump to run the system, which takes a negligible amount of energy.
The fluid for the radiant system is heated through the use of an energy efficient heat pump to raise the temperature to 75 degrees for warming floors in the winter. The amount of energy it takes to raise geothermal well water from 55 to 75 degrees also is small.
About those concrete floors
All floors and walls in the Dageforde home are made of concrete, which prevents air infiltration – a major cause of energy costs in typical homes.
“The concrete creates a solid seal,” Darren Dageforde said.
The concrete also is a huge thermal mass storage tank. The house can withstand extreme outside temperatures for several days without changing the temperature inside the home.
Karen Dageforde ties down radiant heating/cooling tube to the floor before concrete was poured during construction of the house.
The window overhangs in the Dageforde house were designed such that in the summer, when the sun sits high and produces the most heat, its rays are blocked and don’t penetrate into the house. Conversely, in the winter and fall, when the sun sits a little lower in the sky, more of its rays are let into the house, which means more natural warm air is created in the house.
This design as is known as “passive solar.”
Dageforde tells how his “passive solar” windows work. In essence, they are built to reduce amount of sun that gets into the house in the summer and increase the sun exposure in the house in colder months.
It must cost a fortune right? Right?
Aside from maximum efficiency, the Dagefordes also aimed to build their home in an affordable way. It’s no use in doing this, they said, if no one else could afford to replicate it.
The cost of building their “extreme green” home was very comparable to the cost of conventional build.
“We did this right at market value [builders’ standard cost per square foot for a conventional home], so cost isn’t really a deterrent,” Darren Dageforde said.
“The only thing that prevents more people from doing this is knowledge. And now our job is to get that out there.”
See a fact sheet for the Dageforde home.
Darren Dageforde calls the design a “game changer.”
“If this type of construction was adopted on a larger scale, it could flip the energy situation in this country on its head,” he said.
The Dagefordes have given tours of the home to students and others.
Contact Darren Dageforde at 402-559-5278 to inquire about a tour or to learn more about the house.