By Steve Spaulding
Of Contractor's staff
Many people when they set out to build their dream home begin with a list of things they want — the enclosed porch or the whirlpool bath, the stairwell skylight or the basement bar. The owner/builder of the 20,000-sq.-ft., luxury home under construction in Anchorage, Alaska, found part of his inspiration in the things he didn’t want. For example, carpets.
The owner of the $2 million-plus house is also the father of a 5-year-old boy who suffers from asthma. In educating himself about his child’s illness, the owner became keenly aware of such indoor air quality hazards as carpets that can collect dust, mold and pet dander.
Researching ways to remove airborne particles in the home led him to a seminar on building ventilation where, quite by chance, he discovered a program run by the American Lung Association that combines the highest standards for residential indoor air quality with building efficiency. After doing his homework, the owner decided that his dream house would be a Health House.
The American Lung Association’s Health House project began in 1993 with a team of architects, builders, manufacturers and health professionals working together to design and build a house that would set the gold standard for residential indoor air quality and energy efficiency. In the course of construction, the project observed how the various disciplines worked together to greater advantage. Once built, the house became a showcase for the technology and techniques used to build it.
In 1997, after the completion of the first Health House in Eagan, Minn., the project was expanded with the launch of Health House Advantage, an educational program for builders and homeowners, as well as a certification program for houses meeting the stringent Health House standards. To date, more than 120 houses in 30 states are certified Health Houses.
To meet both his own high expectations and the Health House standards, the owner/builder of the Anchorage house found several of the top contractors working in the country and hired them as employees. One of those employees is construction manager Mike Stewart.
“Dirt work and the actual construction phase began last June,” Stewart says. “We hope to have the exteriors completed by June of this year and have everyone moved in by August.”
The rapid progress on the large home is due to all the employees — the carpenter, the electrician, the roofer, etc. — being hired full-time for an entire year. “That way work keeps moving,” Stewart explains. “These guys aren’t going from job to job and trying to fit different things in on different days.”
Airtight, insulated construction is the hallmark of a Health House. It is the first step to controlling moisture, air quality and energy costs. In a decision that suggests industrial more than residential work, the entire house uses monolithic construction; the walls and floors are made of poured concrete.
“A lot of the air issues people have,” Stewart says, “involve leakage — even if they have a high level of insulation. With these monolithic pours there are very few holes in this structure.”
The basement walls are 10 in. of concrete, the first floor has walls that are 8 in. thick and the second floor walls are 6-in. thick. All walls were poured into forms lined with 5 in. of foam insulation. Moreover, the massive walls support concrete floors on the first and second stories that are a full 3-in. thick. The concrete floors are needed for the nearly 31/2 miles of radiant tubing that heats the home.
“One of the advantages of the insulated concrete is that you can cure at low temperatures,” Stewart says. “All you have to do is leave a little insulation on top, and the chemical reaction of the curing concrete keeps it warm enough. So we were able to pour when it was down really cold,” a real benefit when building in Alaska.
High-end windows with low-e argon glass and heavy-duty weather gasketing complete the protective “skin” of the house. Very little air enters the home that isn’t deliberately vented in; very little leaves that is not deliberately vented out. The overall result is an exceptionally tight home with excellent temperature stability and moisture control.
The house is heated top-to-bottom with an in-slab radiant system. While radiant systems have become popular in high-end homes over the past decade for the comfortable, even heat they provide at low noise levels, they are well-suited to Health House construction standards.
Radiant systems work best in heavily insulated homes. They require no ductwork that can harbor dust or microbes. They will not scorch the air like many forced-air systems, making humidity easier to manage. And radiant turned out to be the perfect solution to the owner’s original carpet problem: even bare floors with radiant heating are warm and comfortable.
All the radiant work in the home is done with a newly developed composite plastic and aluminum pipe.
“Most [radiant] tubing tends to pop-up on you when you’re trying to loop it,” Stewart says. “This stuff will lay flat as you’re working. It really cut down on construction time for the floors.”
All the inside radiant lines are filled with water. The outside radiant lines (for the driveway snow-melt system) are filled with a water/glycol mixture to prevent freezing. As an added bonus, the domestic hot and cold water distribution system was plumbed using the vary same piping.
“This is the first time flexible plastic piping has been used for domestic water in the state of Alaska,” Stewart says. Using the same piping for both the radiant system and the domestic water helped reduce material and tool costs.
A single contractor, Fred Kenly and his team from Kenly Construction Services, Anchorage, installed both the radiant heating system and the domestic water supply.
Power for the system comes from two boilers. Like all heating appliances in a Health House they work using sealed combustion: All combustion air is drawn from the outside, and all combustion products are vented back to the outside. The heat is all that’s let into the house. The smaller, backup boiler is able to provide 165,000 Buth. Standards for the larger main boiler were set considerably higher.
“The potential design load contemplates circumstances that would never happen,” Stewart says. “Like 50° below weather and snowing like crazy with lots of call for heat from all systems — all the showers going at once, that sort of thing.”
The final load calculation for the house was a little more than 1.5 million Btu. The main boiler is a model used primarily for schools and office buildings that is able to modulate from 150,000 Btu in 15 steps up to 2 million Btu. Both boilers run on natural gas.
The system features 13 manifolds, 11 for the house, one for a snow-melt system in the driveway and a final one to heat an 82-ft. long heated indoor pool. Right now, the home is divided into broad zones based on each manifold.
“We’ve determined initially to go with controlling just the manifolds themselves. We’ll have the capability eventually of going with telestats to control each loop,” Stewart says. First the family members — who have never lived with radiant heat — are going to see what their comfort level is like during the first few weeks of occupancy. The controls for the system will be integrated into a larger home automation system. “We haven’t made the final decision yet on digital vs. analog,” Stewart says. “What we see happening is that the controls will be addressed by a Windows 2000 professional operating system computer, and it will coordinate all the various building systems.”
Those systems include not only the radiant heating and the ventilators, but also the closed-circuit TV security cameras, telephones, alarms and the fiber-optic lines for the computers.
One of the final recommendations for a Health House is the use of energy recovery ventilators, or ERVs, to provide a continuous supply of fresh air while exhausting stale, contaminated air. In cold weather, ERVs can capture as much as 80% of the heat energy from outgoing air and transfer it to the incoming fresh air before circulating it through the home. Depending on performance standards, a typical erv can provide a complete change of air in the home once every four hours on low speed, or once every two hours on high speed.
The two ERVs in the Anchorage Health House are being used as a complete air management system. “We’re using a HEPA filter inboard of the ERVs,” Stewart says. “Even though what’s coming in should be absolutely pristine Alaska air, we’re also going to pop it through that filter just to be sure.” ERVs will also function as humidity controls — an important consideration in Alaska, where long periods of below-freezing weather can draw almost all the moisture out of the air.
“We’re told,” Stewart says, “the ERVs we’ve chosen put the moisture in the house back in on the incoming side, so we’ll see how well that works. If it’s not able to keep up we’ll stack something downstream of the air filter to put more humidity back in.”
The ducting on the ERVs has been sized to accommodate air conditioning, should family members decide they want it after living through an Alaskan summer. For right now the thinking is that with precise humidity controls and plenty of circulating fresh air, A/C might not be needed to keep them comfortable. Despite all the bells and whistles on display at the Anchorage Health House, the owner/builder is still trying not to do any more than necessary for the level of comfort he wants.
Money on the back end
The family that will soon be living in the 20,000-sq.-ft. luxury Health House is right now living in a home only 3,200 sq. ft. The best calculations the owner has been able to do at this stage in construction show that the monthly energy bill for the larger home will still be significantly lower than that of the smaller one.
Granted, it may take decades for the energy savings to pay for some of the systems involved, but the house itself was made to last for generations. In the meantime, the owner will have to settle for all the money the family is saving in cough and cold medicine and trips to the doctor, thanks to the healthy environment he has worked to create.
Which is probably where the real success of the completed home will be. Because while there’s a price that can be paid for luxury, and even for comfort, there’s no way to put a price tag on not having to watch a loved one endure an asthma attack.