The almost $800 billion economic recovery bill includes a bigger tax break for residential solar hot water installations.

Homeowners already could take a tax credit on up to 30 percent of the cost of a solar hot water system installation, but the total amount was capped at $2,000. The economic stimulus bill, signed by President Barack Obama Feb. 17, removes the cap.

This puts residential solar thermal systems on par with residential solar photovoltaic systems. Last year, a massive financial industry bailout bill renewed the federal tax credits for both solar PV and thermal for eight more years. However, a separate provision lifted a $2,000 cap on the federal tax credit for solar electric systems for homes.