Sunday, March 14, 2010

Massachusetts Zero Energy Challenge Winning Home

This is a very impressive less than zero energy home.  It uses a
combination of reasonable size, excellent thermal envelope, very
efficient appliances, some passive and some active solar heating, and a
PV driven mini-split heat pump for additional heat and cooling.

The end result is a true zero energy house that can be built within a reasonable budget.

I cover a few of the highlights below, but all the details on the house are in the article here...

The monthly performance chart below speaks for itself.  For the year 2009, the house produced significantly more energy than it used.

Double stud, R42 walls insulated with cellulose insulation.
R100 cellulose attic insulation.
Triple glazed R5 windows with R7 interior thermal shutters.
Very good infiltration sealing.
Emphasis on south windows for solar passive gain.
Concrete slab floors for heat storage thermal mass.
Solar water heating
Solar air heating collector to for additional space heating.
Exceptionally efficient appliances and lighting.
Heat recovery ventilation system.
Efficient mini-split heat pump for heating and AC.
4.9 KW grid-tied PV array supplies all electrical power and then some.

Double stud R42 cellulose insulated walls
Total cost of the house without land is $180,000.

Altogether, and exceptional house.

Thanks very much to Doug and Tina for providing this material.



  1. Nothing like a house that beats passive house standards by a country mile. In the "construction and energy use is provided here" link it says the proposed house would use 4.33e6 btus/year for heating,but actually was hers verified at 2.7e6 btus/year. Either way, the claims beat passive house by a lot. Either way, I don't believe either figure for a second. Passive house "requires" 4.75kBtu/sf/yr.

  2. Hi Rick,
    Can you expand a bit on what your last sentence means? Is this a comment heat loss calculations in general? or?

  3. Never mind my comment. On second look, from the information given, I can't tell what total amount of heating is needed for a season for that house--so therefore I can't tell how it does relative to PH. It seems they only gave the amount of mechanical heating that would have to be added for a season. The net amount of passive solar heat from windows is not given, for one thing (at least I didnt see it given). Their only statement is that it's close to acheiving PH standard. It looks like they would need more than 50% passive solar and/or other internal heat sources to reach PH standard, and they probably don't get that.


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