Honing In on Hybrid Systems
June 21, 2010
Roger Findley, president, Just Right Heating and Cooling, White Lake, Mich., has offered hybrid heating and cooling systems - a fossil fuel furnace combined with an electric heat pump - for years, even though natural gas prices in his area have remained relatively inexpensive. As oil and propane prices have crept up over time, though, he’s found that more customers are becoming interested in hybrid systems.
And his customers are not just interested in basic, minimum efficiency hybrid systems; Findley has found that homeowners are developing an appetite for 98 percent AFUE modulating furnaces paired with 18 SEER heat pumps. While the installation of high-end modulating furnaces is nothing new for Findley, he has been surprised that customers are also interested in super high efficiency heat pumps.
“For Michigan, heat pumps are somewhat unusual to begin with, and 18 SEER is a really high rating for around here,” he noted.
Federal tax credits and generous manufacturer rebates may be fueling some of the interest in high-end hybrid systems, but for some customers, the lure of better comfort and lower energy bills are the main reasons behind their decision to invest in high efficiency, dual fuel, heating and cooling equipment.
HEAT PUMP WANTEDSuch was the case with one of Findley’s customers - Craig Petku - who knew he wanted a heat pump for his 2,500-square-foot, 20-year-old home in Clarkston, Mich. While Petku’s extremely noisy heating and cooling system was still operational, it was original to the house, and he worried about its reliability, as well as rising operating costs and future service calls.
Influenced by a friend who had recently installed a heat pump, Petku, a trained engineer, researched the technology, did some calculations, and decided to replace his old air conditioner and furnace with a new heat pump. A recommendation from another friend led Petku to Findley, who proceeded to open Petku’s eyes about the beauty of modulating furnaces.
“When I arrived to give an estimate, Mr. Petku was thinking about installing a heat pump with a single-stage furnace - he knew nothing about modulating furnaces,” said Findley. “I explained that a single-stage furnace heats the thermostat a couple degrees past the setting and then shuts off, dropping another four or six degrees before the furnace comes back on, creating a temperature swing in the house. On the other hand, a modulating gas furnace runs continuously, trying to keep the house at an even temperature - within one-half degree in most cases - and eliminating hot and cold swings in the process.”
Petku was intrigued by this technology, which resulted in Findley designing a $9,000 system that included a 98 percent efficient, 100,000 Btu, Luxaire Acclimate modulating gas furnace, along with a 4-ton 18 SEER Luxaire Acclimate heat pump. A humidifier and air cleaner were also installed to address IAQ concerns.
Petku was particularly pleased to hear that the operation of his new energy-efficient system would be quiet - as low as 47 dB for his 98 percent AFUE furnace. In addition, gaskets installed around the doors ensure an air leakage rate of less than 1 percent.
VENTING ISSUEThe one-day installation was fairly routine, noted Findley, with only a small problem arising due to the fact that there were no clear routes for the intake and exhaust of the high-efficiency furnace. “We ended up taking the PVC through a closet and a bathroom, all the way down to the other end of the house. We had to do the same for the new lineset as well. Venting can often be an issue with high-efficiency furnaces, but 99.9 percent of the time, we can find a way.”
Fortunately, Petku’s ductwork was located in a well conditioned space and was in very good shape, so Findley only had to install the normal transitioning from the supply returns back to the new system. A wireless remote thermostat was installed upstairs, as it was not possible to pull wires from the upstairs thermostat to the furnace in the basement. Petku considered zoning but decided to live with the system awhile before deciding whether to add that feature to his system.
A year later, Petku is still pleased with the job Findley did and the energy savings he is experiencing with his new system. “When I first looked into air-source heat pumps, I found it difficult to believe that they could heat a 2,500-square-foot house more efficiently than a gas furnace at temperatures all the way down to freezing, however, the system installed does just that.”
He continued, “I firmly believe the quality of the custom installation was just as important as the equipment in satisfying my needs. I trusted [Roger] to work with me and do the job right, and that’s exactly what he did!”
Publication date: 06/21/2010