The 5 KW PV system you see on the roof generates all the power for both space heating (via a mini-split heat pump) and for all the homes electrical loads -- it actually generates substantially more power than the home uses on a yearly basis.
The house design is very effective but also simple and the home is affordable at $180K.
Doug has now made the "as built" plans for the home available as a free download -- thanks very much to Doug for doing this!
Information on the Montague Zero Energy Home ...
Plans for Montague Zero Energy Home ...
Some pictures of the home below.
The double stud, cellulose insulated wall provide cost effective super insulation with no thermal bridging.
Section showing raised heel roof trusses which allow for deep attic insulation.
Double stud walls are also visible.
This small mini-split heat pump provides all the heating for the super-insulated and well sealed home.
The house also includes very efficient windows, solar water heating, south facing glazing for passive solar heating, very efficient appliances and lighting, a Heat Recovery Ventilation system, and many other energy efficiency measures...
Gary