[Greenbuilding] tax credits/grant opportunties?

[Stephen Young]

Does anyone know of a source for information on potential tax credits and grant opportunities for building energy efficient housing?

My parents are pushing the developer of their retirement community to make the homes as efficient as possible, and one of the push backs is the above question. They plan to build single-unit houses (and let's not get into why that's a bad idea here!)

Thanks for whatever help/resources anyone can provide.

Stephen