The impe­tus for build­ings to decar­bonize and move towards rad­i­cal energy and water

effi­ciency is increas­ingly strong and iden­ti­fied as a pri­or­ity within the green building

sec­tor. The tiny house move­ment offers an oppor­tu­nity to both address the challenges

of afford­able hous­ing and con­tribute to res­i­den­tial build­ing decar­boniza­tion. Tiny

houses de-​​emphasize mass con­sump­tion and exces­sive belong­ings and have potential

to address equity issues such as gen­tri­fi­ca­tion by pro­vid­ing liv­ing spaces to lowincome

res­i­dents in desir­able hous­ing loca­tions. This paper ana­lyzes the Tiny House

in My Back­yard (THIMBY) project, inves­ti­gat­ing build­ing sus­tain­abil­ity concepts

through the design-​​build-​​occupy process in a three-​​year-​​old struc­ture. THIMBY

demon­strates energy and water effi­ciency tech­nolo­gies inside an award-​​winning small

liv­ing space (18.5 m2). THIMBY was designed to reduce energy and water use by 87

and 82% com­pared to Cal­i­for­nia res­i­den­tial aver­ages. In prac­tice, it has reduced site

energy by 88% and has emit­ted 96% fewer car­bon emis­sions than a 2100 square foot

Cal­i­for­nia Energy Com­mis­sion 2016 Title 24 min­i­mally com­pli­ant home. We discuss

the dif­fer­ences between design and per­for­mance of energy and water sys­tems, which

we find offer impor­tant lessons for the fur­ther expan­sion of the tiny house movement

and other alter­na­tive and micro green hous­ing types. We find that opti­miz­ing such

houses through inte­gra­tion of energy and water sav­ing tech­nolo­gies, home energy

man­age­ment sys­tems, and strong com­mu­ni­ca­tion between mod­el­ers, builders and

occu­pants will be essen­tial to achiev­ing dra­matic energy (87%), water (82%), and

car­bon (96%) savings.