In Troy McMullen’s House of the Week column [Geothermal New York [WSJ]](http://online.wsj.com/article/SB113893560436064114-search.html?KEYWORDS=housing+prices&COLLECTION=wsjie/6month), he presents a $7.8M Manhattan townhouse listing with an unusual heating system, especially on an island made largely of rock.

WSJ

_An unusual geothermal energy system provides heating, cooling and hot water. Pipes extend about 1,400 feet into the earth, where the temperature is always about 52 degrees, according to architect Alexander Gorlin, who writes about the home in his book “Creating the New American Townhouse.” The pipes transfer energy to the house, where two-layer-thick concrete exterior walls, filled with thermal materials, trap the energy and distribute it, Mr. Gorlin says. (All floors also have radiant heating systems.)_

I suspose installation of this sort of system would be especially difficult in Manhattan with its labrynth of underground subways, water pipes, wiring, sewers and of course…rock.