In regions where winter temperatures are fairly mild, heat pumps provide more efficient heating than gas heat. However, since they draw heat from the air or ground outside, their efficiency drops as temperatures fall.
Heat pumps use compression to increase the temperature of the air, and this heat is circulated through the home. While the potential savings promised by heat pump technology can be tempting, the cost of the electricity required to operate in cold areas can quickly eclipse the cost of using natural gas boilers or furnaces. To deal with unusually cold temperatures, heat pumps also contain an emergency setting, which uses electrical resistance to generate heat, although this setting leads to even worse efficiency.