Deep energy retrofit of two hundred year old house

Originally published on Treehugger.

explanation© Jeff Geisinger

A Deep Energy Retrofit is defined as " a whole-building analysis and construction process that achieves much larger energy cost savings—sometimes more than 50% reduction—than those of simpler energy retrofits and fundamentally enhances the building value." They can be hard to do, working with an existing building with so many special conditions and limitations. There is also still a lot of science that has to be resolved, and no single pat solutions.

That's why this renovation of an 18th-century house is so interesting. Architect Jeff Geisinger has not only done a really interesting renovation, but he has shown the how and why in such wonderful graphic form so that the client (and the rest of us) can understand the how and the why.

The architect describes the project:

A new double-height space gives a sense of connection to the living areas and brings natural light into the heart of the house. The design preserves and expresses the 18th-century heavy timber building frame, juxtaposing new and old. A new stair provides a clear circulation pattern while incorporating additional storage and informal seating areas.

At 475 High Performance Building Supply, they go into more detail about the problems of working with such an old house.

With a recently re-clad exterior and no way to expand outward, this project had to make the most out of limited interior space. The clients were understandably unwilling to give up much at the walls. Jeff compromised by furring the wall inward by about an inch with a new staggered line of studs that provided a thermal break (see drawing at right). This also had the nice added benefit of squaring the wall.

They also make an important point that is often missed and misunderstood:

Airtightness Before Insulation

We like to say “airtightness trumps insulation”. This project perfectly illustrates that truism. Even without the thermal break, the airtight INTELLO [a so-called "smart vapor retarder] potentially added about R-4 to the wall assembly by optimizing the insulation performance. Airtightness provides greater comfort, resilience and cost savings – essentially for free.

energy savings© Jeff Geisinger

In many renovations, people just pile on the insulation. But in fact, you can have too much of a good thing; it can take up a lot of space, and in old brick or stone buildings can actually cause deterioration of the wall. You can actually save a lot of energy just by properly tightening up the envelope. As this graph demonstrates, air sealing reduced the heating load almost as much as the insulation (roof + wall) did- a full 16 kWh/m2. It is just a tiny bit less than changing the windows. Yet it is so often overlooked or underestimated. A writer I admire once wrote: "Most old buildings merely slow the wind-down. They are abysmally hard to heat, as any reading of period novels will tell you. I cannot support using energy to heat sentiment." However, this house shows that to be patently untrue.

There's so much going on here; technical sophistication, retaining the old while adding new bracing and support in such an upfront way, serious energy efficiency, historic preservation and wow, what wonderful and thorough presentation and documentation. Lots more to see at Jeff Geisinger Architect's website and blog

Views: 355


You need to be a member of Home Energy Pros Forum to add comments!

Join Home Energy Pros Forum

Comment by Diane Chojnowski on July 26, 2018 at 3:28pm

@Lucy The architect & blogger is Jeff Geisinger at

Comment by Lucyna de Barbaro on July 26, 2018 at 12:46pm

Would anyone know what was involved in the window retrofit? Was it starting from single pane or double pane windows? I ask because I'm curious about the statement that air sealing improved efficiency almost the same as the new windows. And then, any detail on what was the original leakage vs achieved/target air leakage?


Lucy de Barbaro

Latest Activity

Franco Oyuela commented on Chris Laumer-Giddens's blog post A Green Home - It's Just Good Design
"HVAC Zoning. Multizone systems constitute innovative technology that’s already changing the…"
4 hours ago
Brett Little posted an event

Building Green & Beer Series: Benefits of going all electric in buildings at Founders Brewing Co

November 28, 2018 from 5pm to 7:30pm
Going all electric in buildings and homes during new construction and renovation offers major…See More
5 hours ago
Jim Gunshinan's blog post was featured
11 hours ago
John White replied to Gordon Smith's discussion Duct Cleaning? Good value or a waste of money?
"Ductless air conditioning systems allow you to break away from larger units that weave ductwork…"
18 hours ago
John White posted a blog post
20 hours ago
Paul Raymer posted a discussion

Green Home Solutions Franchise

Seems like a good concept to franchise cleaning up mold in people's houses.  People are afraid of…See More
Franco Oyuela commented on Tom White's blog post Why We Save: When the Cost of Energy Hits Home
"How to Save Money With a Mini-Split System. The Energy Star program provides detailed information…"
Jim Gunshinan posted a blog post

© 2018   Created by Home Performance Coalition (HPC)   Powered by

Badges  |  Report an Issue  |  Terms of Service