Featured Article

Walls and Roof/ASHRAE Solar ZEB Article 3

ASHRAE Solar ZEB Article 3

Our third ASHRAE Journal article, “Walls and Roof”, discusses economic optimization of wall and roof insulation thicknesses for Equinox House. A house is a system of components that need simultaneous consideration in order to economically optimize its elements. For example, the thickness of wall insulation is dependent on climate, cost of electricity, efficiency of heating and cooling systems, occupancy, occupant activities, window area, window orientation, and more in a complex and seemingly impossible array of decisions to make. Fortunately, several decades of making mistakes and improving our understanding has clarified how to attack these design challenges in a logical manner.

Wall and roof insulation account for roughly 1/6 of a home’s energy usage in today’s high performance homes. Windows and infiltration/ventilation each account for another 1/6. The remaining half of energy usage are from human activities! As discussed in our article last month, humans and weather can be averaged, but there is no such thing as an average human and average weather. Our research indicates that high performance homes with 2.5 or more occupants in challenging climates, such as Vermod homes in Vermont, are dominated by occupant energy needs rather than climatic conditioning energy usage.

We can determine optimal insulation thicknesses for the walls and roof independent from many other aspects of a home’s design, but need to recognize the interdependence of wall/roof insulation on seemingly unrelated factors. For example, a home with high internal energy loads, perhaps someone who bakes a lot or has some other energy intensive hobby or need, may significantly shift the results of our wall/roof insulation analysis. Simultaneous modeling of factors using ZEROs or other comprehensive design model is recommended in order to check our results. In general, the economic insulation optimization design procedure described in our ASHRAE Journal article is simple to use and will be very accurate for the majority of homes.

Insulation thickness is most strongly impacted by the climate, efficiency of heating and cooling systems, and cost of energy. For example, electric resistance heating in a northern climate with significant heating loads requires thicker insulation that a home using today’s high performance heat pumps that are 3 times more efficient than electric heating. The cost difference is important because selection of an inefficient heating system with excessive insulation cost uses valuable capital that could have been spent on a solar PV array or a vacation (see the example in our Minisplit Mania report appendix).

In our third ASHRAE Journal article, Ben and I discuss the economic optimization process used for selecting wall and roof insulation levels for Equinox House. We used SIPs (Structural Insulation Panels) for Equinox House, and because wall and roof panels cost the same per square foot and per thickness, the optimal wall and roof insulation thicknesses are the same. In other construction methods, such as blown ceiling insulation, insulation cost per area and thickness may be different than that of a wall, resulting in different optimal ceiling insulation thickness. For example, cellulose insulation added to the ceiling of our net zero Build Equinox facility cost about 25% of SIPs insulation.

House design requires simultaneous solution of many variables, but like Rubik’s cube with 43 trillion possible combinations, strategic solution paths eliminate many non-optimal solution choices. Use Build Equinox ZEROs, and follow our 7 Steps for Designing an Economical Net Zero Home process (or watch YouTube 7 Steps from the Green Home Institute). And yes, I can solve the cube….once you get the “daisy” on the left, it’s as easy as designing a house.

We hope you enjoy our 3rd article. Next month, windows! The most complex home envelope component.

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March 13, 2020 Featured Article – Light and Delight/ASHRAE Solar ZEB Article 4 20200313
March 10, 2020 News – CERV Voted One of the Top 16 Coolest Things Made in Illinois! 20200310
March 5, 2020 Special Edition – Fighting COVID-19 with Fresh Air 20200305
February 24, 2020 Featured Article – Walls and Roof/ASHRAE Solar ZEB Article 3 20200224
February 24, 2020 Tech – Magic-Box Mechanicals 20200224
February 24, 2020 Events – Designing Exceptional Homes for Exceptional People Webinar (Video + PDF) 20200224
January 30, 2020 Events – Visit us (Booth 17) at Energy Design Expo in Duluth (2/25-26) 20200130
January 14, 2020 Tech – Designing Exceptional Homes for Exceptional People 20200114
January 14, 2020 Featured Article – Designing for Zero/ASHRAE Solar ZEB Article 2 20200114
December 19, 2019 Events – Free Webinar: Smart Ventilation & Air Distribution (Video+PDF) 20191219
December 19, 2019 Events – CERV2 Smart-er Ventilation Product Demo (Video + PDF) 20191219
December 19, 2019 Spotlight – Acorn Glade: 2019 NAPHC Awardee! 20191219
December 16, 2019 Featured Article – Equinox Origins/ASHRAE Solar ZEB Article 1 20191216
November 19, 2019 Events – Visit our booth at 2019 NAPHC in Washington DC! 20191119
November 19, 2019 Spotlight – Equinox House Turning 10! 20191119
November 19, 2019 Featured Article – Handling Humidity Pt.4 Putting it All Together 20191119
October 16, 2019 Events – Mechanical Systems for Passive Buildings (Chicago, Oct 16) 20191016
October 16, 2019 Featured Article – Handling Humidity Pt.3 Methods for Managing Moisture 20191016
October 16, 2019 Events – Free Webinar: Handling Humidity (Video + PDF) 20191016
October 16, 2019 Events – Free CEUs: Building Green & Beer at Founders Brewing (Oct 28) 20191016
October 16, 2019 Spotlight – Inter House Wins Solar Decathlon Africa!!! 20191016
September 20, 2019 Featured Article – Handling Humidity Pt.2 Climate Moisture Variations 20190920
September 20, 2019 News – Brand New Release: Colorfil VOC Absorbing Filters! 20190920
September 20, 2019 Tech – From CERV to CERVEZA: a Quest for Smart Beer 20190920
August 27, 2019 Events – Earn Free CEUs with the Handling Humidity Webinar (Aug 29) 20190827
August 27, 2019 Featured Article – Handling Humidity Report Series 20190827
August 12, 2019 News – Listen to the Building HVAC Science Podcast, ft. Ty Newell! 20190812
July 29, 2019 Events – CERV2 Smart-er Ventilation Product Demo (Aug 27, 2019) 20190729
July 29, 2019 Featured Article – Poor Home Maintenance = Increased Health Risks 20190729
July 29, 2019 Tech – Say Hello to Our New Server! 20190729
June 19, 2019 Featured Article – Watch out for Cranky Heaters! 20190619
June 19, 2019 Events – Free CEU Webinar: Smart Ventilation & Air Distribution (July 10) 20190619
June 19, 2019 Spotlight – Marrakech Express! CERV2 Heading to Africa! 20190619
May 13, 2019 Featured Article – Taylor Home CERV Testimonial 20190513
May 13, 2019 Events – 7 Steps for Designing an Economical Net Zero Home (Video + PDF) 20190513
May 13, 2019 Tech – AeroBarrier Demonstration 20190513
April 15, 2019 Events – Indoor Air Quality Metrics Free Webinar (Apr 24, 2019) 20190415
April 15, 2019 Featured Article – CERV2 Geo–Boost Release 20190415
April 15, 2019 Review – 2019 National Home Performance Conference 20190415
April 15, 2019 Tech – CERV2 Sketchup Model Now Available 20190415
March 28, 2019 News – Visit us at the Chicago 2019 National Home Performance Conference 20190328
March 28, 2019 Featured Article – Happy Equinox, St. Patrick’s Day, and Super Moon! 20190328
February 27, 2019 Events – Free CEU Webinar: Smart Ventilation & Air Distribution (Mar 12) 20190227
February 27, 2019 Featured Article – Smart Ventilation and Smart Air Distribution Reports 20190227
February 27, 2019 Spotlight – El Salvador NZEB Update 20190227
February 25, 2019 Events – CERV2 Smart-er Ventilation Product Demo (Video + PDF) 20190225
January 22, 2019 Events – Smart Ventilation & Smart Air Distribution Webinar (Video & PDF) 20190122
December 26, 2018 Spotlight – Progressive Canada 20181226
December 26, 2018 News – Happy Holidays from Build Equinox! 20181226
December 26, 2018 Review – CERV2 at Greenbuild 2018 20181226
November 26, 2018 News – CERV OEM Filter Store is OPEN!!! 20181126
November 19, 2018 News – Check Out Our Social Media! 20181119
October 24, 2018 Events – Free CEU Webinar: Duct Design & Performance (PDF Download) 20181024
October 24, 2018 Featured Article – CERV2 is UL Approved! 20181024
October 24, 2018 News – Stop by Our Booth at Greenbuild Chicago (Free Tickets!) 20181024
October 24, 2018 Spotlight – University of Illinois Students Visit Build Equinox 20181024
July 23, 2018 Featured Article – Happy 10th Birthday, CERV and Sunflower! 20180723
July 23, 2018 Spotlight – Good News from El Salvador! 20180723
June 22, 2018 Tech – Installing a Ductless Mini-split 20180622
June 22, 2018 Featured Article – Mini-split Mania! 20180622
April 30, 2018 News – Now offering on-demand webinars for CEUs! 20180430
April 30, 2018 Events – Free CEU Webinar! (May 2, 2018) 20180430
April 30, 2018 Featured Article – Ductology Part 2 20180430
February 19, 2018 Review – 2018 Better Buildings by Design Conference, Flu and Colds 20180219
February 19, 2018 Featured Article – Hot Water! 20180219
January 22, 2018 Events – Visit us at BuildingEnergy Boston! (March 7-9, Boston, MA) 20180122
January 22, 2018 Events – Efficiency Vermont Better Buildings by Design Conference (Feb 7-8) 20180122
January 22, 2018 Featured Article – Ductology (Part 1) 20180122
November 20, 2017 Featured Article – Heat Pump (Hybrid) Clothes Dryers are Coming! 20171120
October 31, 2017 Featured Article – CERV2 Measures IAQ at NAPHC & NAPHN 20171031
September 25, 2017 Featured Article – Introducing CERV2 20170925
August 21, 2017 Events – Free CEU Webinar! (Sep 27, 2017) 20170821
August 21, 2017 Featured Article – Quiz 20170821
July 27, 2017 Events – New IAQ Metrics Webinar (Video + PDF) 20170727
July 25, 2017 Featured Article – Endotoxins: Small But Very Significant 20170725
May 22, 2017 Events – Economical Net Zero Design Webinar (Video+PDF) 20170522
May 22, 2017 Featured Article – Styrax Japonicus 20170522
April 28, 2017 Events – 7 Steps for Designing an Economical Net Zero Home (May 25) 20170428
April 28, 2017 Featured Article – Engineering Net Zero Homes 20170428
March 20, 2017 Featured Article – Build Equinox Zero Plus Facility 20170320
February 14, 2017 Featured Article – February Flu 20170214
January 20, 2017 Events – HRV, ERV and Smart Vent Systems, Free CEU Webinar (Feb 15) 20170120
January 20, 2017 Events – NESEA IAQ Metrics Presentation (Mar 9, Boston, MA) 20170120
January 19, 2017 Featured Article – The Perfect Dust Storm 20170119
January 12, 2017 Events – Efficiency Vermont Better Buildings by Design Conference (Feb 1-2) 20170112
December 26, 2016 Featured Article – Happy Holidays from Build Equinox! 20161226
November 29, 2016 Featured Article – Geo-Boost 20161129
November 29, 2016 Spotlight – This Old Passive House 20161129
November 29, 2016 Review – House Music 20161129
October 28, 2016 Featured Article – Comparing ERV, HRV, and CERV 20161028
October 28, 2016 Spotlight – Net Zero Eco-House (Monticello, IL) 20161028
October 28, 2016 Spotlight – Forty Under 40 20161028
September 28, 2016 Events – Free CEU Webinar (Oct 5th): Why are new Indoor Air Quality metrics needed? 20160928
September 28, 2016 Review – 2016 North American Passive House Conference 20160928
September 28, 2016 Featured Article – New CERV-ICE IAQ Analytics Released! 20160928
September 28, 2016 Spotlight – CERVs in Passive Homes, pt. 2 20160928
August 18, 2016 Featured Article – Understanding the House as a System 20160818
August 18, 2016 Spotlight – CERVs in Passive Homes 20160818
August 18, 2016 Review – “What is IAQ?”, P. Ole Fanger 20160818
August 18, 2016 Tech – CERV CO2/VOC Library 20160818
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