Archive for May 2015

Read Part 1, Sustainable Homebuilding: A Preview of What’s To Come


Supply and demand.  It’s an economic term I learned in college 35 years ago.  Since then I’ve learned it explains the economic and non-economic behavior for everything. Certainly a bold statement, but in reality I have yet to try and understand human behavior as it relates to anything that isn’t explained by supply & demand theory.

Green building and sustainability are no different.  In this case we’re talking about the supply of power to, and the demand for energy of, a typical household.  The definition of pure sustainability is when the supply of energy comes from the same source that is demanding the energy.  If the supply equals the demand then we have true sustainability.  The household “sustains” itself without the need for energy supplied by any source outside of the household.  Mother Nature for that household is in equilibrium.

There is no question in my mind that all of homebuilding is headed in this direction and it’s simply a matter of time until it is reality.

Last time I talked about me having to change what I thought was the next breakthrough on that path to true “net zero energy” “sustainable” homes.  City Ventures as a homebuilder put a renewable energy source, namely solar power, on our homes as a standard part of the home.  That supply of energy offset the demand of energy the homes took from the “grid”.  The grid was still necessary because the demand was still exceeding the supply.  We are limited on how much energy we can supply by the size of the roof.  Once we thought we reached full supply capability, I made the proclamation a few years back that the next step would have to come from the demand side.

If we were maxed in terms of the supply we can produce than the only way to get to “net zero energy” is to reduce demand to the same level as the supply.  How that was going to happen was a mystery.  But I assumed technology, as it does in many other industries, would step up and make it happen.

It is.

But I was wrong in which side technology is affecting first.  As it turns out, it looks like the technology will affect the supply side of energy in a bigger and faster way then the demand side.  I now believe that the near term outlook for demand will remain fairly static.  In other words the typical home will continue to demand the same amount of energy it does today for a while.  But what will change is the amount of supply we can provide as a homebuilder for two reasons.

First technology is increasing the capability of solar panels to produce more power per square inch so that what now takes a typical townhome roof to supply 2KW will soon be able to provide more KW given the same sized roof.  Like the computer chip in the 1980’s and 1990’s, technology will allow MORE power out of LESS space.  Instead of lessening the demand, we’ll increase the supply, and over the near term the two will converge towards net zero energy.

Second ,as with the computer chip, technology will enable the price of that supply of energy to fall even as the power per square inch goes up .  Soon it will cost less for a 3KW system than it does today for a 2KW system.  When that will be is anyone’s guess but the fact that it WILL be reality, is not a guess.

This may sound weird but if the supply of energy comes from a truly renewable source, the sun, and is associated only with one home, than why worry about the demand side of energy that home requires?  Who cares how much energy a home uses if its use doesn’t contribute to climate change and is powered by a free, permanent, supply of renewable energy.  The answer is no one should care.

My new proclamation is this is where homebuilding is headed.  But there’s one more supply side surprise on its way to reality.  Home energy storage systems.

Let’s talk about that next time.

Until then,



The Green Builder’s Journal is written by Herb Gardner, President of City Ventures Home Building Group. Herb has 30 years experience managing the building of residential and apartment communities in over 60 municipalities in 3 different states.

A big proponent of in-fill communities and the urban lifestyle Mr. Gardner has extensive experience in all aspects of residential home building, ranging from land acquisition to warranty management, he specializes in managing teams of people in delivering communities on time, on budget and to the quality standards the marketplace demands.

For Questions, Feedback or observations you can Click here to Email Herb