"Green" housing has become something of a trend lately, especially as energy prices have been climbing and climate concerns have increased.  Later this month my wife and I will observe the 25th anniversary of moving into our new passive solar house.  That's right, we built the home in 1983, largely in response to the gas crises of the 1970's.

We wanted to combine our desire for a contemporary-styled dwelling with that of being energy-efficient.  There was a company back then, called American Barn and Habitat, up in Massachusetts, that designed and sold post-and-beam homes in pre-cut and panelized "kits."  They had a series of passive solar homes, and we decided we would build the Passive Solar V, a design of 2064 square feet.  What was especially nice about the design was that because it was post-and-beam construction, there were no load-bearing walls, and I could design the interior the way we wanted it to be - and I did.

ORIENTATION The essentials to a passive solar are its orientation to the sun, its ability to store heat during the day to release at night, the absolute lack of any pumps, etc., common to active solar, and substantial insulation. The orientation is crucial because you have to be able to obtain the most solar gain every day during the winter months.  In order to do that, the south-facing side of the structure must have a lot of glass to gather the gain.  The house is built on a north-south axis, somewhat turned from the street in front.

HEAT STORAGE  A passive solar home must also have some sort of storage medium (water is best, but masonry works well) that can be heated during the day.  In our case, we had a 14 x 24 sunroom with a six inch concrete (and ceramic tile) floor, insulated from the ground by heavy duty polyethelene and rigid foam.  That is the only living space that is not on a full basement.  Little heat is lost to the ground.  We also have twelve foot wide, sixteen foot high masonry fireplace in the middle of the house, at the back of the sun room.   Heat is stored in the masonry floor and the masonry fireplace during the day, and at night that heat is released to the air inside the house.

GLASS   Probably the most important physical characteristic of such a building is the roof overhang on the south side to prevent summer sun from penetrating the building through glass.  For about six months out of the year there is no sunlight shining in the sun room.  But in the winter, when the sun is low to the horizon, we get a lot of sun in the room.  On December 22, the shortest day of the year, the sun is shining five feet up the fireplace, which is twelve feet from the glass sliders.  Because of the solar penetration, we want the maximum transmissivity of its rays.  That flies in the face of the latest "low-e" glass that reflects heat, winter and summer.  When we replaced the two triple sliding doors two years ago, we sought out and got doors with the highest transmissivity - but it is not has high as I would have liked.  The original windows were triple-glazed, the sliders double.

INSULATION  Newer homes back in the 1980's boasted about the R-value of insulation - up to R-11 in the walls.  Wow!  We went a little bonkers by specifying six-inch exterior walls, instead of four-inch.  Fiberglass bats gave us an R-19, and an additional one inch of rigid foam gave us another couple of R numbers.  The basic design of the home, however, was what caught our eyes.  A contemporary design, the sun room and all second-floor bedrooms had cathedral ceilings.  The ceiling itself was 2 x 6 cedar tongue and groove, and on top of that was a rigid panel of about 3.5 inches of polyeurathane insulation, topped off with a half-inch nail base of pressed paper, essentially, then roof shingles.  The claimed R-value was 39.  Although there is no attic, there is ample storage, and the effect is dramatic, since the house is pretty much open, making it easy to circulate heat through the house from the sun room.

We resisted the siren song of hyper-insulation and sealing of the "envelope."  Later reports from northern climates described serious health problems for inhabitants of such homes.  Off-gassing of building materials was just one issue, and removal of moisture before it leads to mold, was another, as I recall.  We had outside air supply for our fireplace, and an outside vent for both the kitchen and one of the baths (the other baths had a window or operable skylight).  We did not, however, provide for fresh air to our gas furnace (our backup heating system used a lot).

What are my thoughts about passive solar twenty-five years later?  Stay tuned.

Montgomery Township is located on the northern border of Princeton, but at the southern end of Somerset County.  Although it has not suffered as much from the subprime crisis as Somerset County overall, it is not as strong a market as its neighbor on the northern border, Hillsborough, which though experiencing volume decline, has seen prices increase slightly.

For the year through September 30, Montgomery has experienced a drop in sales volume of more than 18%, compared to the same period last year, just as the subprime crisis hit.  Price changes have been minimal, but in the downward direction.  The average sale price through the third quarter this year is 2.7% less than last year for the same period, although the median sale price is virtually unchanged ($550,500 this year vs. $550,000 last - a miniscule increase this year).

There are significantly fewer listings available this year in Montgomery on October 1 - 117 vs. 142 last year, but a few more listings were taken in September 2008 than 2007.  With a lower number of sales reported in September, the supply/demand ratio is down compared to 2008.  The absorption rate climbed a full month since August - to 8.4 months, a market usually considered to favor buyers.

With the current financial troubles, buying or selling a home in Montgomery Township should not be done without a solid knowledge of the market.  Be sure to seek the advice and counsel of a Realtor® who is familiar with the market.