The statewide Recharge Colorado program offers to cover 40 percent of the total job cost for high efficiency furnaces up to $500. This program will end when funds run out.

Colorado Natural Gas and Source Gas both offer rebates of up to $300 for efficient furnaces as well as $25 rebates for programmable thermostats.

Xcel Energy offers the Home Performance with ENERGY STAR rebate program, which includes up to $120 in rebates for efficient furnaces and an additional $10 for thermostats. To get started with the Home Performance program, you'll need to start with an energy audit for your home.

If you choose a 95 percent efficient furnace, you may also qualify for the federal income tax credit, which is designed to cover 30 percent of the equipment and installation costs for up to $1,500.