Geothermal heating systems are also one of the most eco-friendly ways to heat a home. These systems use the earth's constant temperature as a source of heat in the winter and a sink for warmth in the summer. They're highly efficient, with a coefficient of performance (COP) rating as high as 5.

Electric furnaces heat air to a lower temperature, so they typically operate more frequently than gas furnaces. Electric furnaces are more thermally efficient, but in most climates, gas furnaces are more efficient overall.

Hydronic heating doesn't blow allergens and contaminants around your house or give them a place to hide in the ductwork. There is no trade-off between healthier air and a more comfortable living space.