When it comes to selecting the proper HVAC equipment, homeowners have no shortage of options to choose from. While gas furnaces have historically been the preferred choice for homeowners — especially those with ample access to natural gas — many are opting for the heating and cooling convenience of a heat pump.
While there are many factors to examine when considering a heat pump over a gas furnace, it may come as a surprise to some just how beneficial a heat pump may be — even in the northern most climates.
When deciding whether to select a heat pump or a gas furnace, it’s important to consider the geographical area, cost of energy, energy source, state of the home’s envelope, and more.
In temperate or near-temperate climates, gas furnaces tend to be the first choice economically and, in regions where cooling loads dominate, heat pumps tend to be much more logical choices.
The same cannot be said for gas furnaces in northern climates. Advances in heat pump technology, specifically the advent of inverter-driven compressors, allow heat pumps to serve as the primary heat sources in climates where temperatures dip as low as minus 22°F.
Aside from temperature, the cost and source of energy are primary concerns.
Electricity rates vary immensely state by state. Per Choose Energy, electricity rates in February in Louisiana, North Dakota, and Washington were 8.94, 9.15, and 9.54 cents per kWh, respectively, while Rhode Island, Massachusetts, and Hawaii registered rates of 21.66, 22.23, and 31.52 cents.
Likewise, the price of natural gas also fluctuates drastically. In the contiguous 48 states, Florida and Maine held the highest rates at $17.98 and $14.54 per thousand cubic feet in January, while the rates in North Dakota and Colorado registered only $5.85 and $6.60, per the U.S. Energy Information Administration (EIA),
Because natural gas and electricity are calculated using different units of measurement, and the efficiency levels of each piece of equipment are also a contributing factor, one must essentially formulate the energy cost in cents per Btu.
While the formulas can be complicated to decipher, numerous websites, including www.amsenergy.com, offer fuel cost calculators to simplify the calculations.
Every home and heat pump will have a unique balance point. Air-source heat pumps utilize the outside air as its heat source. As the outdoor temperature falls, the heating load increases, and the system’s capacity decreases. At a certain temperature, the capacity is equal to the load, which is recognized as the balance point.
When temperatures drop below the balance point, the home will require supplemental heat. While most balance points hover around the mid-30° range, each home is different based upon how well insulated it is, how tight the envelope is, etc. This is yet another factor to be considered when opting for a heat pump.
“When considering a heat pump, the first step is to seal the building and add ‘R,’” said Eric Kjelshus, owner of Eric Kjelshus Energy Heating and Cooling in Kansas City, Missouri. “Then, we can talk about cost saving of new ductwork and a heat pump and filtering the air. I have cut heat loss down 80 percent by sealing and filling stud walls, the attic, bringing duct into the building, etc. So a heat pump has a chance to work with a 23° temperature rise. That old 60 percent LP gas furnace with a flue temp of 800° had a 200° supply temperature.”
Adam Brill, service technician, Bertie Heating & Air Conditioning, Gainesville, Florida, said he never offers a heat pump unless clients insist.
“I find that if they’ve had gas heat, they’ll never be happy with a heat pump,” he said.
Joe Egenberger, owner/operator, JBS Mechanical, Rocky Point, New York, said heat pumps are rare in New York, though he just quoted one on a job this month.
“Where I’m at, electric is expensive, but this job has solar panels,” he said. “I am going to set up the heat pump to work primarily above 30° and the oil-fired boiler as backup for under 30°.”
When it comes to choosing the appropriate comfort system, Chuck O’ Guinn, sales manager, Pacific Air Systems, Tacoma, Washington, said it depends on the client and balance point.
“I wouldn’t recommend a heat pump to certain clients, such as the elderly, if they weren’t used to the lower temperature rises of a heat pump unless they were willing to invest in inverter technology,” he said. “The balance point also needs to be computed to determine if it makes economic sense for the client and the home.”
Robin Boyd, an HVAC consultant, agrees with those who prefer using a heat pump as a primary source of heat.
“In most cases, it will cost less in electricity for a heat pump system to heat the home during the milder part of the heating season, even if there is a high-efficiency gas furnace in the system,” he said. “If the cost of running the heat pump turns out to be more at any given time, it is easy enough to switch to the gas furnace only by setting the thermostat to emergency heat. Should anything happen to the functioning of the gas furnace, you still have a source of heat. For all electric homes and homes with oil and LP furnaces, the savings are even greater.”
Jim Crist, a commercial project manager/journeyman in Salisbury, Maryland, said he often recommends hybrid systems.
“We tend to use heat pumps with gas backups instead of the typical electric heat strips unless we venture to far northern territory,” he said. “I would also recommend a heat pump over traditional splits to landlords for easier maintenance and operation.
Jacob Woods, regional business manager, International Comfort Products, said contractors should always be offering heat pumps.
“Many of the new inverter heat pump systems, paired with variable-speed air handlers, gas or electric, can deliver comfort and cost savings even down into the low 30°s,” he said. “Inverter heat pumps, with the proper communicating thermostats, offer fantastic humidification control in the summer months and heat into the colder months, even in the Northeast. It’s all about proper pairing and control. Heat pumps help to take the strain off of gas furnaces.”
Regardless the climate zone, how expensive the fuel source is, how insulated a home is, or how resistant a contractor is to the idea, it’s almost always worthwhile to at least consider the benefits a heat pump could add to consumers’ residences. Contractors will never truly know how beneficial these systems may be until they take a deep dive into the numbers.
Publication date: 5/28/2018