Still smarting from your 2009 taxes? Start whittling the bill for next April.

A good place to begin: two federal tax credits for homeowners who want to save energy, one of which expires at the end of this year. The credits have appeal both for true green diehards and those who are staying put due to housing market doldrums.

The credits took effect in their current form in February 2009. Both offer dollar-for-dollar write-offs against taxes, not just a deduction from income. And unlike many tax benefits, there are no income limits on who can use them.

Yet experts say many people are still unaware they exist. Bill Shaw, a remodeler in Houston, says his best marketing has been done by — of all people — tax preparers. “Since January, my phone has been ringing off the hook with people whose accountants told them” about the credits, he says.