When we first moved into our house, there was already a forced air gas furnace installed.
The furnace was relatively new and in good condition.
It easily managed the coldest winter temperatures and maintained a consistent comfort in every room. Our only complaint was the lack of air conditioning. I scheduled an appointment with a local HVAC company with the plan of getting a free estimate on the installation of central air conditioning. The technician looked over the ductwork and heating equipment, measured our square footage and calculated the exact demands of the home. He then recommended that we purchase an electric heat pump rather than an air conditioner. A heat pump costs quite a bit more to buy and implement than a conventional air conditioner. I was suspicious that he was simply after a bigger commission. He then explained that partnering a gas furnace with an electric heat pump is called a dual fuel system. This style of system maximizes cost savings by making use of the most efficient fuel source for every type of weather. During the warmer months, the heat pump acts very much like a traditional air conditioner. It pulls heat out of the home and transfers it outside by way of refrigerant. When the outside temperature cools off, the heat pump is capable of reversing operation and taking advantage of ambient heat. In heating mode, an electric heat pump is far more energy efficient than a gas furnace. However, it loses efficiency as the temperature drops. It automatically switches over to the furnace at the most beneficial time.