Avitsa offers $400 rebates on high efficiency natural gas furnaces. Also, if you're converting from an electric to a natural gas furnace, you may qualify for a $750 rebate. Avista also offers $250 rebates from converting from an electric water heater to a natural gas water heater.

Inland Power and Light Company doesn't appear to offer rebates on 95 percent efficient furnaces, but they do offer a $400-$500 rebate for PTCS certified duct sealing on homes that have electricity as their primary heating source.

If you purchase and install a 95 percent efficient furnace before the end of 2010, you may be eligible for the federal energy efficiency income tax credit. The credit will cover 30 percent up to $1,500 of cost of both the equipment and labor costs for your furnace installation.