The Iowa Nest Residence is featured on the SketchUp Blog as a case study in Net Zero Energy design. The article includes key lessons that were learned during design, including the importance of the overall shape of the home on performance and cost, and the importance of looking at passive measures and HVAC system holistically.
What does it mean to be “comfortable?” This presentation at the DAAPx Symposium on Experiential Design in September 2020 uses the Iowa Nest Residence to explore the idea of designing for “thermal delight” (a term coined by Lisa Heschong in her book of the same name). It discusses how comfort is far more than just air temperature, and how these additional physical sensations were used in the Nest Residence to maintain comfort largely through passive measures.
The Nest Residence won the 2020 ICF Builder Award in the category of Small Residential. The annual project-of-the-year competition is widely regarded as the biggest event in the Insulated Concrete Forms (ICF) industry.
The design of this home was, in part, a test of a design process—of a philosophy of design—known as performance-based design. The central idea is that performance analysis (energy, daylight, and thermal comfort analysis, among others) has a central role to play in informing design decisions at every step of the process.
The 13th edition of Mechanical and Electrical Equipment for Buildings (AKA “MEEB”) has just been published by Wiley. Chapter 1 on Design Process prominently features the Iowa Nest Residence as an exemplar of high-performance design — incorporating much of the material that has been discussed in detail on this blog.
We set out to design a Net Zero Energy house at conventional per-square-foot costs. We got pretty darn close. Sans solar panels (which will be installed after two years of operation), the house came in at 8% less than a conventional new home. With solar panels, the house is still 2% less than conventional.
Here’s a full cost breakdown, and the seven strategies we used to get there.
Things have to come through the walls, roof, and floors — even in an airtight house. How do we detail these elements in a way that (1) keep bulk water out, (2) meets our ambitious (Passive House level) air-tightness goals, and (3) avoids risk of condensation? Here are my details.
How should you design and detail a wood stove in an airtight Passive House? Here are some of the considerations, and the approach we used on this project.
First off: should you even have a wood stove in a Passive House? This is rightly a matter of some debate. It’s certainly not necessary, as our temperature data have shown: this particular house has proven it can stay habitable even through the coldest of cold snaps—maintaining ~55 degF even in -20 degF outdoor temperatures without mechanical heating.
And, a wood stove in a Passive House comes with downsides and risks: