Home Building Curiosities: Ecocor

July 1st, 2020

Dear Readers,

Welcome to our third Home Building Curiosity, Ecocor! As with the first two Home Building Curiosities, Ecocor is not only a curiosity, but an inspiration in the field of sustainable building. Ecocor is exceptional in how it actually meets all five of William and I’s foundational principles in our mission. Based in Searsmont, Maine, Ecocor designs and manufactures prefabricated, Passive House (PHI) certified, net zero ready, small footprint, healthy living building components and homes. 


Ecocor is very proud of their wall panels, and they rightly should be! Their walls are prefabricated at their Searsmont location, allowing for a climate-controlled build of each panel. Every wall panel meets Passive House standards, and has a specific assembly structure that is even being patented. 

The manufacturing of individual wall panels allows Ecocor, the architect, and the buyer to get creative, while still achieving a quickly and quality built home. They promote the motto of “If it can be drawn, we can build it.”1 Think of their walls as super insulated, airtight, lego blocks, that allow you to build your own unique passive home. 

While their wall panels are prefabricated and allow custom builds, Ecocor does have a sector devoted to prefabricated, Passive House certified, modular homes. This branch is called Solsken, which means “sunshine” in Swedish. All of the homes in their Solsken Ecocor collection are named after flowers, which William and I love (because we were actually thinking of naming our potential pipe-dream homes after trees)! 

Their Solsken homes are interesting in that Ecocor does not necessarily provide the ‘whole’ home. For example, their model ‘Clover’ is a 1,052 square foot home. The elements provided by Ecocor start at $206,000 and include…

  • The sub slab and perimeter insulation/form system
  • Exterior Wall Panels
  • Interior Walls
  • Ventilation System (but not installation)
  • Roof Structure
  • Air-Sealing and Insulation
  • Windows
  • Exterior Doors

The elements that are provided by others start at $130,000 and are…

  • Concrete and rebar
  • Standing seam metal roof
  • Interior and exterior fit and finishes
  • Mechanical
  • Electrical
  • Plumbing
  • Ventilation system installation

Site work and installation of well, septic, and utilities are also not included..and the cost of the land itself of course.2

Passive House

The homes and building components (walls and roofs) Ecocor builds are all Passive House certified by the Passive House Institute (PHI). PHI is the Passive House Institute based in Germany, and has slightly different criteria for meeting their Passive House standards than the Passive House Institute of the United States (PHIUS). While the criteria may be different, the foundational principles are the same for a passive home: highly insulated, airtight home that retains significantly more energy than it loses. 

As an individual building component to a home, the walls, themselves, are PHI certified. They have an R-value of 58.6 and are made airtight with the help of Huber’s ZIP system sheathing and Pro Clima’s Tescon Vana tape used on the seams (this tape is a zero-VOC adhesive and was “originally designed for the aerospace industry”).3 

For their windows, Ecocor partners with a PHI certified window manufacturer based in Poland, CDM Drewno. The windows are triple pane and have an installed R-value of 6.67. The windows are European tilt/turn windows which have a better air seal than double-hung units. You can either open the whole tilt/turn window like a door, or, with a flip of the handle you can secure the hinges at the bottom of the window, and then open only the top.4   

For their foundations, Ecocor has three options for consumers, one being their very own Ecocor Passivslab. Their Passiveslab is a primary assembly of plastic foam, lego-like, blocks which ensure that the 8-inch concrete slab poured on top retains heat and is protected from moisture and radon. Ecocor’s Passivslab is certified by PHI “to be free of thermal bridging” and has an R-value of 47.7.5 

Net Zero

All Solsken homes by Ecocor are net zero ready as far as energy usage. Being all built to Passive House standards, they are already highly energy efficient in themselves. Ecocor also makes sure to orient the home’s windows in a way that they take advantage of the free energy of the sun when the home is built on-site. Put some solar panels on top, and it’s like an energy bursting ice cream sundae. 

Small Footprint

One of the foundation options provided by Ecocor is…

…drum roll please….bum badadada bumbum…

a  helical pier foundation!!

William and I were considering using a pin foundation, which is very similar to a pier foundation in its ease of installation and environmentally friendliness. The main difference is what’s below ground~ a pin foundation uses multiple pins at different angles to root the foundation, where as a helical pier is like a big screw that goes into the earth. Both foundations are less disruptive to natural soils and groundwater flows, while also being just as structurally sound as a typical foundation- and, in Ecocor’s case, insulative. Their pier foundations support a framed floor system with R values ranging from R 58 to R 81.

Ecocor also aims to use only locally produced wood products in their homes. And, as we have expressed before, wood is not only beautiful and renewable when harvested sustainably, but it is also great at carbon sequestration! 

Their patented passive certified walls are also insulated with “100% mineral borate treated, fiberized cellulose insulation.” To break that one down to its small footprint form…borate is from boric acid, which naturally occurs in the environment. Boric acid can be found in soil, water, and plants (who need the borate from boric acid in order to grow).6 Borate has the magical ability to deter pests, as well as act as a fire retardant- hence, the advantage in treating your insulation with it! Cellulose insulation, in simple terms, is a conglomerate of recycled paper materials. 

Healthy Living

Within their Solsken homes, Ecocor promises to minimize the “use of paint, varnishes, and formaldehyde” in their building materials, thereby achieving a “near-zero VOC.”7 VOC, by the way, is an acronym for ‘volatile organic compound.’ Think of super stinky paints. Having as few of those in your home is probably for the best…

In conclusion!! 

Ecocor has been enlightening and inspiring to research, and William and I are so incredibly excited that they are putting sustainable homes on the market. We cheer them on as they grow and learn, and look forward to the day that we can help contribute to the ‘green building’ market! 

Stay tuned!


Shelby Aldrich

1. Ecocor. “Flexible, Efficient, Panelized Construction,” 2020. https://www.ecocor.us/rethink-building. Accessed on 21 April, 2020.

2. Solsken, Ecocor. “Clover,” 2020. https://www.solsken.us/plans/clover. Accessed on 21 April, 2020.

3. Ecocor. “Walls-Engineered Panels,” 2020. https://www.ecocor.us/walls. Accessed on 21 April, 2020.

4. Ecocor. “Windows & Doors,” 2020. https://www.ecocor.us/windows-doors. Accessed on 21 April, 2020.

5. Ecocor. “Foundations,” 2020. https://www.ecocor.us/foundations. Accessed on 21 April, 2020.

6. National Pesticide Information Center, “Boric Acid,” Dec. 2013. http://npic.orst.edu/factsheets/boricgen.html. Accessed on 21 April, 2020.

7.  Solsken, Ecocor. “A Healthy Home,” 2020. https://www.solsken.us/. Accessed on 21 April, 2020.


  1. I really like that type of insulation. Just think, it can keep bugs away!!!!!!!!!!!! But the best part is being fire retardent. The bug part might not bother many people, but, little ones are like puppies, they will find that one bug and play with it, or worse, try to eat it!!!!!!

    • Ha! That is so funny…I literally just watched my dog play with, and then proceed to consume, a small spider. Sad to watch happen…but a point has been made! Borate treated insulation can not only save the puppies and children, but also the bugs themselves.


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© 2020 Sustaining Tree