Understanding where in the US the house is being built gives a better defioitinn of what is Affordable . In DC, The Empowerhouse is considered affordable. There are several criteria that weigh to Affordability in the District. $229K would not be affordable in Manhattan, Kansas lets say for example. But in DC, it is. It's not the cost of materials, but also the value of the home in the market of which it is being built in. If you want affordable to actually reflect the accurate AMI (Area Medium Income), then take action in Policy not just architects/designers. True, there are materials that are costly, but this house uses materials that any contractor/developer uses. The energy savings and affordability comes with HOW to use the standard material, like wood and cellulose insulation. By using those inexpensive building materials properly, you minimize the amount of additional materials, like Photovoltaic Cells (Solar Panels), which ARE costly. Also understand, that with a Cost Benefit Analysis, the homeowner of this supper efficient home will be making a return on her investment in 8 years; don't you think the fact that she will be saving over $30K in energy bills account to affordable? Well it does in DC.