What’s the Difference? Heat Pump vs. Furnace

Keep your home’s interior at the ideal temperature with the right type of heating device for your climate and budget.
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Heat Pump vs. Furnace: Which Is Right for Your Home?
Photo: istockphoto.com

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Maintaining a comfortable indoor temperature is a priority for homeowners all year round, but in winter you’re bound to be even more aware of how well your heating system is working—and what to replace it with should it give out. A traditional gas or electric furnace lasts about 15 years, but before you purchase a new one, consider if a heat pump would be a better choice. Heat pumps, which also have an average 15-year lifespan, have been around for more a century but didn’t become popular furnace alternatives until the 1970s. Run through these eight comparisons—furnaces vs. heat pumps—to find out which one is best suited to your heating needs.

Heat pumps don’t generate heat—they transfer it.

A gas furnace generates heat by burning combustible fuel, such as gas or propane, while an electric furnace generates heat in much the same manner that a hairdryer would, by blowing air over a hot element.

A heat pump works on a different thermodynamic principle: It draws heat from the outdoors (even if it’s cold outside) and transfers that heat to your home’s interior. So while a heat pump will not generate heat, it is able to absorb heat via pressurized refrigerant lines and then release that heat into your home.

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Furnaces are better in cold climates.

Since heat pumps draw warmth from the outdoors, the warmer the outside air, the more heat they’ll provide. That doesn’t mean the outdoor temp needs to be balmy—a heat pump can draw warmth from air that’s below freezing—but as the temperature drops, heat pumps become increasingly less efficient. If you live in Climate Zones 1 through 3 (check out the U.S. Department of Energy’s Climate Zone Map), a heat pump might be a good choice, but if you’re in zones 4 through 7, a furnace will probably be your best bet. An exception to this rule is the geothermal heat pump, which buries refrigerant lines below the frost level, where the ground temperature remains a stable 40 to 50 degrees all winter, even though above-ground temperatures may be much colder. If you live in zones 4 through 7 and you want to install a heat pump, you’ll need a geothermal model.

Heat pumps are noisier.

While both furnaces and heat pumps can grind, clank, and screech when having mechanical problems, a heat pump is typically the noisier of the two when both are operating as they should. Heat pumps are notorious for clicking and knocking as the compressor that circulates the refrigerant through the lines powers up or shuts down, producing sounds from the air handler (the part of the heat pump that installs inside the home and emits warm air). This often worries owners of a new heat pump until they realize the noise isn’t a symptom that something is amiss. Furnaces, however, are often located away from the living area—in a basement or utility room—and a soft whoosh of air is often the only sound they make.

Heat pumps require less space.

Furnaces, which are typically installed indoors, can take up a lot of square footage because manufacturers and local building codes often require a 30-inch clearance on all sides for fire safety purposes. The compressor part of a heat pump, which is located outdoors but close to the house—in a similar manner to an air conditioner—requires a minimum 24-inch clearance around its outdoor unit. Since a heat pump’s indoor air handler does not use combustible fuel or generate its own heat, it doesn’t need additional safety clearance. Depending on the type of air handler that comes with your heat pump, you might be able to mount it high on the wall so the unit doesn’t encroach on any floor space.

Heat pumps can heat and cool your home.

While a furnace is designed to generate only heat, a heat pump warms your home in winter and cools it during the summer months. During hot weather, a heat pump operates in an identical manner to an air conditioner, by reversing the pressure and the flow of refrigerant through its coils. This can be a big benefit for homeowners who would otherwise need to purchase a separate air conditioner.

Heat Pump vs. Furnace: Which Is Right for Your Home?
Photo: istockphoto.com

Furnaces cost more to operate than heat pumps.

Generating heat requires a lot of fuel, but because a heat pump doesn’t generate heat, it only needs enough electricity to circulate the refrigerant through its pressurized lines. A heat pump uses much less energy than an electric or gas furnace. While exact operating costs depend on the climate where you live, the unit’s efficiency, and local utility costs, for a single winter season, heating costs run an average of $1,550 for a propane furnace, $850 for a natural gas furnace, $900 for an electric furnace, and just $500 for a heat pump. Since heat pumps work on the same principle as air conditioners during the summer months, the costs to cool your home with either will run about the same—$300 or more, depending on your climate.

RELATED: 10 Home Heating Mistakes That Spike Your Bills

Installing a heat pump is often cheaper.

The cost to have a gas furnace installed averages $4,500, and the cost to install an electric furnace runs about $4,000, but you could pay up to 10,000 or more for a high-efficiency model of either type of furnace. To install the most common type of heat pump—an air-to-air model—you’ll pay an average of $3,500 to $4,500, depending on size and efficiency. Installing a geothermal heat pump, however, can run as high as $25,000, due to the added cost of excavating to bury its refrigerant lines. When you consider that a heat pump is also used to cool a home, you may save even more money by not having to purchase an air conditioner.

Both should be professionally sized and installed.

When it comes to selecting either a furnace or a heat pump, make sure to have a professional heating-and-air technician measure the volume of air in your living space, factor in your climate zone, and consider your budget to help you choose the right size furnace or heat pump for your home. A unit that’s too small won’t keep you warm on the coldest days and will force the unit to work overtime, which can reduce its lifespan and increase the need for repairs. A unit that’s too large will cycle on and off frequently, which can result in indoor temperature variations. Likewise, installation isn’t a DIY project. Both heat pumps and furnaces require direct wiring into a home’s main electrical panel, and most local building codes require a professional HVAC technician to connect a gas line to a furnace.