Debra Rucker Coleman, Architect
Custom Energy Specs
The preparation of Custom Energy Specs is a custom service provided along with the purchase of Construction Prints or CAD Files.
House Plan Order Custom Energy Specs
For pre-designed house plans orders from the Sun Plans' list, the architect makes recommendations in the Custom Energy Specs for possible changes to be made during construction based on the climate in which the home will be constructed. This is a rare service offered in the house plan industry.  The recommendations provided can be based on the homeowners' energy priorities such as a HERS score goal, Energy Star, Zero Energy Ready, Passive House, PHIUS, etc. Homeowners would then work with a local design professional experienced in one of those programs as a third-party professional to work along side the builder and guide them based on the builder's experience with one or more of the various high-performance programs espeicially if the homeowners desire certification. 
Adapt-A-SunPlan Custom Energy Specs
For Adapt-A-SunPlan projects, the design is adapted for the particular climate and the homeowner's energy priorities as mentioned above. The Custom Energy Specs then elaborate on those details.  
Create-A-SunPlan Custom Energy Specs
For Create-A-SunPlan projects, the house is designed from the start for the particular climate and the homeowner's energy priorities including the level of energy savings desired per above. The Custom Energy Specs then elaborate on those details.
Customer Energy Priorities
In each case, the homeowners can state their energy priorities or rely on Sun Plans to recommend from code minimum (not recommended/seldom chosen), Energy Star (30-50% savings), Zero Energy Ready (50-80% savings) or net zero energy with 100% savings when PV solar panels are added. Sometimes clients intend to have extremely high levels of insulation and air tightness of Passive House or PHIUS standards in addition to being net zero energy.  (Sun Plans can help choose a local building science professional to provide certification for those programs if necessary.)
As a minimum, Sun Plans recommends building to Energy Star standards (at least 30% better than code).  The Custom Energy Specs typically recommend higher insulation values that result in about a 60% savings. The plans are designed to earn the Zero Energy Ready label if those guidelines are followed by the builder and a third-party independent Home Energy Rater that can test and verify such things as the insulation installation and tightness of the home.
Sun Plans homes routinely perform at least 50% below new homes standards, but actual performance is often better (all the way to Zero Net Energy or Passiv Haus / Passive House / PHIUS) especially when the owner chooses a high level of efficiency.
For pre-designed plans, after the order is placed, please advise Sun Plans of the desired energy savings and or program intended to follow. With CAD Files, a local design professional certified in one of those programs can make the adaptations for you.
Climate and Location Analysis
Also, after the order is placed, please advise Sun Plans of the location (city, county, state, or province) where the home will be constructed.  (Custom Specs are only prepared for locations in the U.S. at this time.)  If the proposed orientation of the south wall has to face other than true (not magnetic) south, tell us that too since sometimes that causes the overhang length to change. Small lots can be limiting in orientation. If the exact orientation is not known, and if the land allows for some flexibility, let Sun Plans recommend an orientation as the Custom Energy Specs are prepared. Often a slight easterly orientation may be recommended for improved summer shading.
After a climate analysis, the orientation, magnetic north, insulation values, south glass, thermal mass, and overhang lengths are reviewed along with the construction details for the particular house design. Both the passive solar heating and cooling elements will be considered prior to preparing the Custom Energy Specs. If there are concerns as to whether or not the plan can be "field modified" for the climate, the architect will advise; however, this has never happened.
Typically, several options are typically written in the Custom Energy Specs for roofs, walls, floors, windows, etc. to allow for flexibility and choice based on local availability of types of insulation, materials, and builder preferences based.
With Adapt-A-SunPlan, any recommended modifications are made in the house plans prior to finalizing the design and making the Construction Prints.
With Create-A-SunPlan, the Sun Plans architect designs the house from the start based on the particulars of the climate and location.
Prior to ordering a pre-designed plan, if a homeowner has concerns about the house fit on land, best wall, roof, or foundation insulation, or other energy-related concerns, consider engaging Sun Plans in Adapt-A-SunPlan or Select-A-SunPlan Consulting Services prior to placing the order.
"I am contacting you to compliment you on the Specifications you have provided for the Nature's Corner Project currently underway here in Asheville. I review a lot of plans and specs, and I appreciate your thoroughness, which is at a level I don't see often. We are the area's local experts in Building Performance and have provided Building Envelope services for hundreds of satisfied clients throughout the Western North Carolina region...I've been very impressed with your carefully detailed specs. I thought you might like to hear this from another professional in the industry."
Ryan Gore, Building Performance Specialist, Home Energy Partners