Switching to geothermal heating and cooling in Derwood, Md.

Last week the Washington Post featured a great article by Christopher Gearon, a Derwood, Md., homeowner who told the story of how he had a geothermal heating and cooling system installed for his house.

The surprise for me was how cost-effective it turned out to be, thanks to federal and county tax credits and a state grant. The geothermal heat-pump system (to heat/cool his 4,400-square-foot home) totaled $23,950, but with a 30 percent federal tax credit ($7,185), $2,000 from the Maryland grant program, and $5,000 Montgomery County property tax credit, his net cost was $9,765 -- about the same as if he had installed a new oil-burning HVAC system.

Gearson said he'd make back the cost of the system, through savings on his energy bills, in about three years. Wow!

Note: The costs don't include what it'll take to re-landscape his front yard, which had to be dug up in order to drill two 375-foot holes for underground pipes. (Check out this WaPost graphic for how geothermal works.)

If you can cover the up-front cost, this seems like a great deal. (As for the tax credits, Bethesda Green has a good summary of energy-related tax credits for Montgomery County. You can find Maryland state info here and here. )