You can claim a credit of up to 30% of the cost of these appliances. You can include the cost of installation. (I don't know what an "electric furnace" is.)
(i) An electric or natural gas heat pump water heater.
(ii) An electric or natural gas heat pump.
(iii) A central air conditioner.
(iv) A natural gas, propane, or oil water heater.
(v) A natural gas, propane, or oil furnace or hot water boiler.
The maximum credit you can claim per year for this type of property is $600.
For the credit, the appliance must be installed on a dwelling that you use as your main home (where you live most of the time). You don't have to own the home, but it must be your main home.
"Efficient" for this credit means that it meets or exceeds the "highest efficiency tier (not including any advanced tier) established by the Consortium for Energy Efficiency which is in effect as of the beginning of the calendar year in which the property is placed in service.)". This is not necessarily the same as Energy Star certification. Check with the CEE (they have a web site) or the appliance manufacturer to confirm eligibility.
