Massachusetts Ranch House Gets Solar Thermal Heat

marrapese solar thermal home

Three thermal collectors were mounted vertically on the south wall of the original ranch house.


Jennifer and Bill Marrapese bought an inefficient 1977 ranch house out of foreclosure, in chilly Massachusetts.

They planned a deep energy retrofit.

Jennifer, as executive director of the Northeast Sustainable Energy Association (an ASES chapter), had access to a panoply of resources and experts.


insulated slab

To pour the new slab, Jeffords had to jack up the entire house.

Beginning in the spring of 2012, general contractor Sean Jeffords of Beyond Green Construction jacked up the house in order to replace the soggy concrete slab.

A new slab, covering 1,350 square feet, was poured over four inches of blue-board rigid foam.

The slab was also designed to accommodate four loops of 5/8-inch PEX hydronic tubing, about 900 linear feet in all, installed by Beyond Green Construction.

Donavin Gratz of DA Gratz Solar installed the solar thermal system, the heart of the home’s cold-weather performance.


Stiebel Eltron thermal

The clerestory addition house not windows but Stiebel Eltron flat-plate thermal collectors.

Six Stiebel-Eltron collectors, 168 square feet in all, feed a 50-50 glycol mixture to a 160-gallon SBB 600 storage tank, with a two-stage heat-exchange system.

The heated water goes to the domestic water system and, at 105°F, through the radiant coils in the floor. Two loops are laid in a tight pattern close to the perimeter of the house, and two in a loose pattern across the interior.

Back-up heat comes through a 20-kilowatt Hydro-Shark electric boiler.

The whole system is controlled by a Steibel Eltron SOM controller/SolarWave DL-2 remote monitoring circuit, and a Nest Labs thermostat system, which senses motion in the rooms and directs heat where it’s needed.

When outside air temperature dips below 15°F, the heating system kicks into high gear.


control system

A thermal control system sends heat to occupied rooms, with an electric boiler as back-up when the weather goes below 15 degrees Fahrenheit.

Construction was completed in December; the house stayed warm through January’s bitter cold snap. Cost of the electric back-up heat totaled about $100 a month over the heating season.

Gratz estimates his crew put about 85 head-hours into the heating system, in two stages: rough-in on the new clerestory to take building-integrated collectors, and plumbing the tanks and controls before the walls were closed.



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One Response to Massachusetts Ranch House Gets Solar Thermal Heat

  1. Leonard Lindenmeyer Reply

    July 27, 2016 at 3:53 pm

    Hydronic radiant floors are great. I only wish more people knew about them. I built a 24×14 Sunroom addition on my house in Maryland with a radiant floor running off a 20 gallon hot water heater. The addition was Post and Beam and was very well insulated. I added 6% to my net square footage and reduced my utility bills by 8%. The key was a very well insulated enclosure along with the radiant floor heating so I did not have to upgrade my existing heating system.

    That experience led me to build a retirement home, two story plus a basement. I put a radiant floor system on all 3 floors. Walking on warm floors at night and having the heat where you live cannot be beat. I recommend it to anyone living in a winter zone state. I wrapped the house in Structural Insulated Panels using urethane foam and added solar on the roof tilted at latitude. The net result is that my SREC income exceeds my electric bill for the year and I am charging a Plugin Prius once a day at a cost of about $100 per year to boot. It is amazing what today’s technology can achieve if we just deploy it intelligently.

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