Here’s some info on the tax credits available for alternative energy equipment installs..  Note: “placed in service” means:

The IRS defines "placed in service" as when the products or materials are ready and available for use – this would generally refer to the installation, not the purchase.

The client will need to file IRS Form 5695 with their taxes. In addition, they will need to keep at least receipts proving that they purchased the improvements and a copy of the manufacturer’s certification. Accountants and tax advisors should also be able to provide more guidance.

For Solar Domestic Hot Water or Photovoltaic Electric and other stuff, it is 30% on the total cost of the install

“placed in service” until 2016.  For installs of lesser-cost non-solar water heaters, or windows and doors,

roofs, new heating systems, and pellet stoves, done during 2009-2010, up to $1500 can be credited, in NH.

This will probably be extended, depending on the political mix in Congress.

For domestic fuel cells, 30%, up to $500 / half kilowatt capacity, will be credited.  We’re a long way off on this tech.

What’s important is that a tax credit comes right off the tax due on the adjusted gross income.

In general, a tax credit is more valuable than a similar tax deduction. A tax credit reduces the tax you pay, dollar-for-dollar. Tax deductions – such as those for home mortgages and charitable giving – lower your taxable income. If you are in the highest 35-percent tax bracket, the income tax you pay is reduced by 35 percent of the value of a tax deduction. But a tax credit reduces your federal income tax by 100 percent of the amount of the credit.

From the NHOEP website:

http://www.energy.gov/recovery/taxbreaks.htm

Residential Renewable Energy Tax Credits
Consumers who install solar energy systems (including solar water heating and solar electric systems), small wind systems, geothermal heat pumps, and residential fuel cell and micro turbine systems can receive a 30% tax credit for systems “placed in service” before December 31, 2016; the previous tax credit cap no longer applies.

Home Energy Efficiency Improvement Tax Credits
Consumers who purchase and install specific products, such as energy-efficient windows, insulation, doors, roofs, and heating and cooling equipment in existing homes can receive a tax credit for 30% of the cost, up to $1,500, for improvements "placed in service" starting January 1, 2009, through December 31, 2010. See EnergyStar.gov for a complete summary of energy efficiency tax credits available to consumers.

From the Energy Star website:

http://www.energystar.gov/index.cfm?c=tax_credits.tx_index

There is a full description on what is covered and what is not (and more importantly, for how long)…