Progression in the Building Process

The ABC Green Home building planning continues to come together by creating more collaborations and finding its first location.

By John Morton

I am happy to report the ABC Green Home is making great progress — the most important of which being that we have found its first location. The great staff at the Orange County Great Park in Irvine, Calif. has agreed to house the ABC Green Home there for the first year of its life. This is a great advantage to the project because it will get extensive exposure. With the amount of people that visit the park rising each year, we should be able to educate hundreds of thousands of potential homebuyers along with the home building industry. The project team is looking forward to our partnership with the Great Park.

The design of the home is making great progress as well. We are quickly getting the specifications locked in. I have focused in on the building envelope in order to reduce the temperature swings within the house. The more constant the inside can stay the less the heater or air conditioner will have to come on. We started from the outside and worked our way in.

LP TechShield is an innovative product used on the home that helps block radiant heat in the roof from entering the attic, keeping the attic cooler, lowering energy costs and making the home more comfortable. The exterior will include LP siding and by using this product we are able to keep our craftsman look to the home. Underneath the siding there will be the Henry air barrier product. Furthermore, underneath the air barrier will be two inches of rigid foam, a drainage wrap and then the Oriented Strand Board (OSB). Once inside the wall you will find 2X6 studs 24 inches on center and two stud corners. These features were selected to enable us to fill the wall cavity with as much insulation as possible.

Finally, there will be a half-inch drywall and all of these layers will be sealed to make for an airtight assembly. We feel this envelope design will provide a near constant indoor air temperature and allow the home to be comfortable without the need for the HVAC system.

In terms of the HVAC system, the project will include Daikin Altherma system. This is heat pump technology combining both the HVAC system with the domestic hot water system. We have designed the home to ensure all ductwork remains in conditioned space. That being said, we will still ensure we have extremely tight ducts.

For the water distribution system we will use a manifold system with pex tubing. This should make the hot water distribution as efficient as possible.

The attic design is still up for debate at the time of publishing this article. One option being considered is including raised heel trusses and applying R-50 to the ceiling level of the attic. This would be a more traditional approach. The raised heel trusses will allow us to ensure that plenty of insulation gets to the exterior edges of the house. This area is more often neglected which provides an easy path for air transfer from the outside, to the attic and to the conditioned space below. Since there is no equipment in the attic this may be an effective solution.

The other option is putting the insulation at the roof level. This will be accomplished by either adding rigid foam or spraying insulation onto the underside of the roof sheathing. This option will allow us keep the temperature change in the attic space to a minimum. By doing this, it gives us space to work with in the attic and gives the future homeowner more flexibility in using the attic space. Stay tuned for more details.

Since the last article, we have been meeting with several agencies and organizations to inform them about the many benefits of this house. There are several exciting ideas that are being discussed in regards to this project. While I cannot get into details on some of them quite yet, let me just say some of them can pioneer a positive change in the industry. This project has the ability to not only educate the building industry professionals and potential homebuyers; it can also help introduce a new and flexible working relationship with city officials and policy makers. We are leaving no stone unturned as we look for ways for this project to benefit everyone involved with the homebuilding process.

The final step in the planning process will be to find the homes' permanent location, as these discussions are underway. We are excited by the possibilities being discussed and with each new conversation I am more confident that this project will be successful. Until my next article, please check in on the project website (www. abcgreenhome.com) to stay up to date on the project. We will be posting updates on all the items in this article, along with some I have not mentioned. I want to thank all of our partners and contributors for all of their hard work and dedication. Without all of you this project would not be what it is.

John Morton is program manager, California Advanced Homes, for Southern California Edison. He may be contacted at john.morton@sce.com.