High-performance home is model of efficiency

PITTSBURGH — Talk about a knowledgeable owner! Brad Oberg knows about innovative p-h-c products before most contractors.

Oberg is president of IBACOS, a research firm that works with the U.S. Department of Energy doing research on energy-efficient homes. IBACOS also works in the private sector with large home builders to build what Oberg calls high-performance homes.

"We deal primarily with production builders who are in the 200 houses and up range, typically 400 to 800 homes," Oberg told CONTRACTOR. "Anything smaller than that and they don't have either the time or the marketability to leverage what they learn out of the research process. We cover pretty much everything from building durability to comfort performance, so we work with the builder on framing efficiencies, exterior finishing, groundwater management, siting, mechanical system sizing and comfort delivery."

Consequently, when it came time to build his own home, Oberg knew exactly what he wanted.

The house includes a hydronic radiant floor in the basement slab, a residential fire sprinkler system and highefficiency HVAC in the upper levels.

The exterior starts with lots of insulation. The basement is surrounded by the Tuff n Dri waterproofing system from Tremco Barrier Solutions.

"We used a full foam underlayment on the slab to improve the thermal performance of the radiant floor using the Wirsbo underslab floor system," Oberg said. Pedicone Plumbing in Gibsonia, Pa., installed the Wirsbo tubing, including that used in the residential fire sprinkler system.

All the sidewalls are insulated with a foamed-in-place insulation called Isynene, made by a Canadian company of the same name. Inside the basement there's extruded polystyrene insulation inside the framing.

Oberg selected Anderson windows with a Low-E coating.

Todd Rhule, owner of AComfort Service in Pittsburgh, installed a Munchkin boiler from Heat Transfer Products and a 20-gal. Super Stor tempering tank, also made by HTP. An 80-gal Super Stor tank handles domestic hot water needs. Rhule used a Taco control system with outdoor reset control and Grundfos circulators.

The boiler feeds the tempering tank. Prior to that the domestic water pump goes off separately to the 80-gal. tank. The domestic hot water, which is a recirculating system, is set up as a priority zone. The primary loop comes from the tempering tank to the manifolds.

"A tempering tank helps, especially on smaller systems when one zone calls for heat and the circulator comes on and you get flow into other zones that are not necessarily the one calling for heat," Rhule said. "So the tempering tank allows the pumps to operate independently of each other without lifting up the check valves.

"If your system doesn't have enough water storage, you may drive the temperature up to the reset control point and then it shuts off, so the boiler cycles on and off. But if you put more water in the system, it stays running longer and you get better mixing in the return water."

Rhule said he wasn't aware of the technique until he did the Oberg house and he was going to install a tempering tank in his own house.

The tempering tank has four connections, boiler water in and out, and primary loop supply and return. Rhule piped the tank so the streams would have to meet in the middle and mix thoroughly. The reset control is plugged into a sensor well in the middle of the tank.

The primary loop feeds the manifold and circulators control most zones, except for one with both a pump and zone valves. He selected Honeywell spring-closed zone valves because he said they're reliable and inexpensive.

The entire cold water supply was fed through a residential sprinkler system from Wirsbo. The idea is that cold water flows through the system any time a fixture is used, so the water never stagnates in the sprinkler piping. Each of the sprinkler heads has four water connections.

"The quality of the tubing is superior," Oberg said. "The way they produce piping it's more highly cross linked and the fittings use a triple thickness of pipe and stretch the pipe over the fitting."

Oberg noted that there were 54 sprinkler heads and about 400 fittings in the system, and no leaks.

"It was really easy to work with," said Mike Morse, foreman for Pedicone Plumbing.

Oberg explained that Wirsbo performs the hydraulic design for the system based on the house plans. He noted that when the system was filled, water arrived at the test sprinkler head through all four pipes almost simultaneously.

The kitchen and baths contain all Kohler fixtures.

"I like the low-flush models they have," Oberg said. "Also, they came out with bronze finished faucetry for the kitchen, so that drove us that way. And we also did a handicapped accessible guest bath for the main floor."

The HVAC system, installed by White Heating in Pittsburgh, includes a Carrier Puron 14 SEER air conditioner and a 94% AFUE Carrier condensing furnace, controlled by a Thermidistat.

" We [ IBACOS] have a research relationship with Carrier and helped develop the Thermidistat for them," Oberg said.

The system, which also contains an air-to-air heat exchanger, uses fiberglass ductboard throughout with flex duct runouts for both thermal and acoustical performance.