Answers to your questions about gardening, energy, homesteading and other sustainable living topics.
How can I determine if a new heat pump is a good option to reduce heating and cooling costs for my home (versus other heating and cooling options, replacing a gas or oil furnace, etc.)?”
It’s important to understand that there is no simple response to this question. That’s because there are so many potential variables with every home and its structural and heating, ventilation and air conditioning (HVAC) details. There are two main types of heat pumps: air-source and ground-source. People often get them confused. To complicate things even more, there are many variations on these two main categories. In any case, air-source heat pumps use latent heat in the air to heat or cool your home. However, air-source heat pumps are generally not good choices in cold northern climates where the winter temperature regularly falls below 32 degrees Fahrenheit. In cold winter conditions, ground-source heat pumps really shine.
Ground-source heat pumps, often referred to as geothermal heat pumps, rely on latent heat in the ground (or ground water) to heat or cool your home. It’s important to understand that some homes, due to structural or other site constraints, may not be appropriate locations for a geothermal system at all. In other cases, it might be a hard call: theoretically possible, but extremely difficult or costly from an installation standpoint. But in many instances, particularly with new construction, it’s a straightforward cost comparison issue.
Over the life of your heating appliance, the most important cost is for the fuel to operate it. And in general, it is reasonable to expect that the cost of gas and oil will continue to climb irregularly in the years ahead, making any heating appliance that depends on them a risky long-term choice. A heat pump, on the other hand, relies mainly on electricity, and while we can expect the cost of electricity to rise too, there is potential for more and more electricity to be generated from renewable sources in the future. What’s more, the cost of electricity will not be rising as quickly as the price for fossil fuels, offering an additional advantage for heat pumps.
The operating cost of a typical fossil fuel-based system is 95 percent the cost of the fuel and about 5 percent the electricity to run the system, according to Harold Rist, a respected and experienced ground-source heat pump installer in Queensbury, N.Y. The operating cost of a geothermal system, on the other hand, is about 70 percent to 75 percent nonpolluting “free earth energy” and about 25 percent to 30 percent electrical energy. Better still, an Energy Star-rated heat pump uses about 30 percent less electricity than a standard heat pump. It should be clear even from these rough estimates that over the long haul, a geothermal heat pump can offer the best heating and cooling option for many homeowners. In fact, the Environmental Protection Agency says that geothermal systems are the most energy efficient, environmentally clean option to heat and cool a home.
The main hurdle for most homeowners is the high initial investment in a typical geothermal system. This can run from about $8,000 to $20,000, depending on a wide range of variables. Air-source systems are generally less expensive, and generally run between $2,000 and $5,000. And if you live in an older home with a small (under 200-amp) electrical service entrance, you will need to upgrade to a 200-amp (or larger) service entrance. In any case, crunch the numbers, and see if a heat pump makes sense for you and your particular house. If you decide to install a heat pump in your home, you can relax in the knowledge that while fossil fuel prices will fluctuate wildly in the future, your primary fuel source will always be available — and free.
Check out Magic Heat Pumps, too.
— Greg Pahl, author of Natural Home Heating: The Complete Guide to Renewable Energy Options (Chelsea Green, 2003)
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