The State of Maine offers tax credits for home improvement, including solar and heating.
Incentives:
http://www.maine.gov/doc/initiatives/wood_to_energy/funding.html
https://www.efficiencymaine.com/
Maine also offers low interest loans.
For more information visit:
http://www.dsireusa.org/
The Federal Government offers tax credits for Energy Star compliant heating systems, indirect water heaters and solar systems.
For more information on Energy Star visit:
http://www.energystar.gov/index.cfm?c=products.pr_tax_credits
For the Federal tax form visit:
IRS Form 5695
Rebates:
Efficiency Maine http://www.efficiencymaine.com/
George F. Doughty Plumbing & Heating 