Heat and Hot Water
When it comes to heat, this Flagstaff home has all its bases covered
After months of excavation, concrete, framing, sheathing, and drying in, it’s time for the fun stuff: the mechanical systems.
First up is Navien's tankless water heating system. Owens Construction's Bill Owens says he and his team were interested in finding one of the top performers when it came to tankless water heaters, and when they went to the EnergyStart website, Navien's NPE was a top pick. "We can cascade up to 16 units; we can take a half-inch gas line up to 24 feet; and we can run 2-inch PVC venting up to 60 feet," Owens says. "The internal recirculating pump and buffer system that you can find on this unit is another one of our favorites. The internal heat exchanger has one of the longest warranties in the business, at 15 years."
The Navien NPE is a universal unit—it can be used indoors or out—which was really attractive to the Flagstaff team, and is useful for any home on the market. "We'll be looking to do more of these as time goes on, and use Navien as a partner," says Owens. "I think this is really worth looking into for anyone who's building a high-performance, energy efficient home." TJ Karlson, owner of T3 Plumbing, has a long history with Navien systems and came in for the install.
Then it was time to turn attention to heat, to be handled by a mini split heat pump system from Goodman Manufacturing with three linesets to heat pumps on the south side of the home, feeding nine combination heating and cooling systems. The inside units have automatic adjustment to maintain indoor temperature no matter what is happening outside. They are effective down to 5°F for heating, but Flagstaff is no stranger to single-digit and below-zero temps. So what then?
Owens Construction's Bill Owens and the Goodman Daikin people have that figured out, with not one but two small furnaces: one to keep the chill off the crawlspace, the other as a heat back-up during sub-zero nights or power outages. Both units run off propane. The units inside that deliver heat (or A/C if needed) are mostly Daikin’s Emura wall-mount devices with a curved contemporary look, accompanied by a couple concealed units, where only the intake and discharge show.
Although the system is electric, Flagstaff’s average electric rate is 11.96 cents/kWh, a rate that is in the lower quarter of electric rates in the U.S. Each heating/cooling device has a motion sensor switch, so that when there is no activity sensed in the space, the device switches to energy savings mode, kicking back up to full output only when someone enters the room.