Federal Rebates
http://www.energystar.gov/index.cfm?c=products.pr_tax_credits
State and Local Rebates
For the most up to date information on state and local incentives, please visit www.dsireusa.org. Click on Pennsylvania and you’ll see a list of local rebates, grant and loan programs for both commercial and residential properties.
PA Home Heating Equipment Rebate Program – Starting April 21, 2010, residents of Pennsylvania will be eligible to receive rebates for the purchase of qualifying high efficiency home heating equipment. Qualifying products will be non-electric ENERGY STAR-qualified water heaters, furnaces, and boilers.
UPDATE: As of August 2, the home heating program has INCREASED their rebate amounts!