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Musings of an Energy Nerd

Visiting Energy-Smart Designers and Builders in Maine

The Energy Nerd heads east — Down East — to learn about deep-energy retrofits and new construction along the Atlantic coast

Architect Chris Briley considers the merits of a vinyl-framed triple-glazed window made by Intus, a Lithuanian manufacturer, at the June 7 meeting of the Building Science Discussion Group in Portland, Maine.
Image Credit: Martin Holladay
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Architect Chris Briley considers the merits of a vinyl-framed triple-glazed window made by Intus, a Lithuanian manufacturer, at the June 7 meeting of the Building Science Discussion Group in Portland, Maine.
Image Credit: Martin Holladay
Richard Renner faced his rooftop photovoltaic array to the southeast rather than due south because he preferred the array to be parallel to the street.
Image Credit: Martin Holladay
Richard Renner climbs the steel staircase leading to his low-slope EPDM roof.
Image Credit: Martin Holladay
The low-slope roof of Richard Renner's Portland apartment includes two tubular skylights installed on high curbs. To the right of the light tubes are planting trays containing low-maintenance perennials.
Image Credit: Martin Holladay
On sunny days, the light-tube skylight provides plenty of illumination for Renner's windowless bathroom.
Image Credit: Martin Holladay
Accurate Dorwin is one of the few manufacturers that sells triple-glazed double-hung windows. According to Richard Renner, this window leaks more air than he considers acceptable.
Image Credit: Martin Holladay
Architect Jesse Thompson is working to complete a deep-energy retrofit of his Portland ranch home.
Image Credit: Martin Holladay
Jesse Thompson added a second story over one section of his remodeled ranch.
Image Credit: Martin Holladay
After installing 6 inches of recycled polyisocyanurate insulaton on the exterior walls, Jesse Thompson screwed vertical rainscreen strapping over the foam. The flared strapping at the base of his walls will eventually be sided with roofing slates. All of the existing windows were replaced with new triple-glazed windows from Inline Fiberglass.
Image Credit: Martin Holladay
A few days after my visit, Jesse Thompson began installing recycled slates as siding on the flared lower portion of his walls.
Image Credit: Jesse Thompson
To ventilate his very tight house, Jesse Thompson installed a Zehnder HRV in his basement. The main reason he chose the Zehnder is because it is so quiet.
Image Credit: Martin Holladay
Phil Kaplan checks his e-mail as Jesse explained that the cooktop, dishwasher, and undermount stainless-steel sink are recycled items that were purchased at the local Habitat for Humanity ReStore.
Image Credit: Martin Holladay
Jesse Thompson sent GBA this "before" photo of the undistinguished ranch house he purchased in Portland.
Image Credit: Jesse Thompson

I recently spent a couple of days in Maine, where I visited with an active group of energy-conscious architects and builders. My tour of seven job sites facing Casco Bay in the Atlantic Northeast nicely balanced my tour of several job sites facing the Puget Sound in the Pacific Northwest in March.

At the second-floor office of Kaplan Thompson Architects in downtown Portland, I was greeted by Phil Kaplan and Jesse Thompson. Phil and I sat down for some brainstorming for a deep-energy retrofit course we will be teaching at Yestermorrow school in August. Later that afternoon, architect Chris Briley arrived, and I joined Phil and Chris for a recording session of their popular podcast, Green Architects’ Lounge. (Unfortunately, because the hour was early, the featured beverage was coffee rather than stronger spirits.)

Building science talk and beer

At 5:00 p.m. we drove a few blocks to Maine Green Building Supply, a materials showroom and warehouse operated by retailer Steve Konstantino. Steve is the gracious host of a monthly get-together known as the Building Science Discussion Group, a hot-dogs-and-beer party that meets in the loading bay in back of the store. The discussion group is an opportunity for designers, builders, energy raters, and manufacturers’ representatives to talk about energy-efficient construction methods.

Everyone benefits by participating in the information-sharing and learning that happens at such a collaborative gathering. I figured that these meetings were important enough to merit an article on the topic, until I remembered that Michael Maines beat me to it. His January 2010 blog about the Building Science Discussion Group was titled Steve’s Garage.

At the June 7 meeting, about 40 attendees participated in a charette to review plans for a deep-energy retrofit of a 3,000-square-foot building on Victory Avenue in Biddeford. The building is owned by Community Partners Incorporated (CPI), a nonprofit agency that provides support services to individuals with developmental disabilities. (CPI was the winner of last year’s BrightBuilt Retrofit contest.)

The discussion was very productive, with participants expressing diverse opinions on ventilation options, masonry chimneys, and the tricky problem of how to superinsulate an existing exterior wall with an attached multi-story porch. By the end of the evening, consensus had been reached on several points.

A noisy HRV and a leaky window

The next morning, I visited the Portland office of architect Rick Renner. Although it was my first visit, I recognized the building from photos published in the GBA case study and the Fine Homebuilding article on the building.

Renner’s retrofit of an old brick commercial building transformed the lower floor into an architectural office and the second floor to an elegant, light-filled apartment. He specified top-notch materials, including triple-glazed windows, and builder Dan Kolbert paid meticulous attention to air sealing and insulation details, so the building uses very little energy; its HERS Index is 43. (For more details on Renner’s retrofit and other projects I visited, be sure to check out the photos and captions on this page.)

When I asked Renner whether any of the materials he used were disappointing, he noted that his heat-recovery ventilator (a RenewAire Breeze, model BR70) is noisier than expected, and that his triple-glazed Accurate Dorwin double-hung window (chosen because it complies with egress requirements) leaks more air than he considers acceptable.

Rick also shared a nagging worry: he knows that his decision to install closed-cell spray polyurethane foam on the interior side of the existing brick walls has changed the average moisture content of the bricks and mortar, and he wonders whether this will lead to future deterioration. So far, so good, he said; he’ll continue to keep his eyes peeled for any evidence of problems.

An architect works on his own house

My next stop was the Portland home of Jesse Thompson, an architect who grew up a few miles from my home in the Northeast Kingdom of Vermont. (When I moved to Vermont in 1975, Jesse’s father, Dr. Lloyd Thompson, ran a family medical practice with his partner, the late Dr. John Elliott, out of a white clapboard house next to the White Market in Lyndonville.)

Jesse is nearing the end of an ambitious deep-energy retrofit of a 1960s ranch house that he purchased a few years ago. He’s managed to survive a stressful process — working on his own house (mostly on weekends and evenings) while still fulfilling full-time responsibilities at his architectural office. Oh, and did I mention that he and his family are living in the house while it’s being worked on?

Jesse stripped the old siding off the house and covered the wall sheathing with 6 inches of recycled polyisocyanurate purchased from Insulation Depot, followed by vertical rainscreen strapping and new siding. He also raised the roof and installed new scissors trusses. The truss bays are filled with dense-packed cellulose, creating a sloped insulated ceiling without any ventilation channel between the insulation and the roof sheathing.

In a comment posted on a Q&A page on the GBA site, Jesse shared some lessons learned from his project. He provided the following advice to anyone thinking of installing recycled polyiso on their walls: “Try very hard to have all penetrations (dryer vents, boiler venting, ventilation, etc.) planned for, installed, taped and sealed before adding foam. Let’s just say I know from personal experience how much harder it is to do the in the opposite order.”

He also lamented the difficulties of installing polyiso of inconsistent thickness. “We had sheets of salvaged polyiso vary by up to 1/4 in. over a 48 in. sheet, which meant the strapping need to be shimmed before siding, which was slow and tedious. In fact, if I was doing it over, I would probably specify salvaged EPS foam instead and use thicker layers to make up for the lost R-value. Salvaged foam can be very affordable; we’ve skinned a house 4 in. to 6 in. thick for only $2,500 in foam.”

A few fun features of Jesse’s retrofit:

  • The new triple-glazed entry doors include German hardware and meet German air-sealing standards, but cost significantly less than German doors. Manufactured in Poland by Drewexim, the doors cost about $1,750 to $2,000 each; they are distributed in Maine by Fenestration Plus of Bangor.
  • The new windows are triple-glazed units from Inline Fiberglass.
  • Many materials — including the cooktop, dishwasher, undermount stainless-steel sink, wall tile, bathtub, lavatory, and lighting fixtures — used in the retrofit project are recycled materials purchased from the local Habitat for Humanity ReStore.
  • During their first winter in the newly remodeled house, fuel burned for space heat and hot water amounted to only 200 gallons of propane and 1 1/2 cord of firewood.

Photos showing Jesse Thompson’s house after all the retrofit work was completed were published in the June / July 2013 issue of Fine Homebuilding magazine and in the November / December 2013 issue of Sierra magazine.

In next week’s blog, I’ll resume my account of my visit to Maine. Stay tuned for reports on two projects by master builder Dan Kolbert: a deep-energy retrofit of a post-and-beam house and a compact new-construction project with stellar energy performance.

Last week’s blog: “Helping People With Multiple Chemical Sensitivity.”


  1. User avater
    Jesse Thompson | | #1

    Existing Conditions
    Martin, Thanks for the posting, it was great to have you in our area. Where's the next stop on your tour?

    For anyone interested, here's a picture of the house we bought to start the project: a very distressed 1962 single story ranch house a few blocks from our kid's school, 15 minutes from downtown by bike, a very typical style of house in our area (and all across the country...).

  2. User avater GBA Editor
    Martin Holladay | | #2

    Next stop on my tour?
    I've been trying to convince my bosses at Taunton that there are all kinds of interesting green projects in the south of France, but for some reason no one has offered me a plane ticket yet.

  3. Doug McEvers | | #3

    Energy rehab
    Nice article, Martin

    There are many opportunities to buy existing homes in good neighborhoods for a reasonable price today. Most homes are structurally sound but need energy upgrades and some TLC. Twenty years ago I moved from building new homes to the refurbishment of existing homes. I have found upgrading existing homes to be more enjoyable than starting from scratch. Homeowners I have worked with have a strong connection to the neighborhood and have a good idea of the improvements they would like to make. Highly skilled remodelers are in demand, builders should take advantage of this.

  4. Brennan Less | | #4

    Noisy HRV
    Martin, I have to say that I've heard a LOT of complaints about noisy HRV/ERV units. Most complaints tend to be when the units are set to medium or high fan speed, at which point you have two blowers going, often pulling between 250-350 watts. Anyone have any positive experience with units they would characterize as legitimately quiet HRV/ERV? I guess the other issue is, why are we ever ventilating at the rates these units provide on high/medium (right around 200 cfm), particularly given the large amounts of fan energy required?

  5. User avater GBA Editor
    Martin Holladay | | #5

    Response to Brennan
    As I noted in the caption to one of the photos of the Thompson job, the Zehnder HRV has a reputation for being very quiet. Of course, it costs an arm and a leg. You get what you pay for.

  6. User avater GBA Editor
    Martin Holladay | | #6

    Low-wattage ventilation
    If you have a small house, and you want low-wattage ventilation, you can't beat an exhaust-only system using a Panasonic FV-05VK3 exhaust fan, which moves 50 cfm using only 4.3 watts. Talk about electrical efficiency! And it's super quiet.

    Of course, you don't have the heat recovery than an HRV provides, so (compared to an HRV) you pay a thermal penalty.

  7. User avater
    Jesse Thompson | | #7

    Brennan, the Zehnder is the quietest unit I've been around, on high you can hear the air moving fast through the registers, but you don't hear much of any loud fan noise from the machine itself unlike most units we've worked with in the past.

    It is well worth checking the wattage of the HRV / ERV unit on the HVI website: Units like the Venmar EKO and Zehnder now only draw 65 watts or so on high, very different from less expensive units or in the past.

    Good quality bath fans do always win on first cost, quiet and electricity draw however, but by our numbers it usually takes heat recovery to get down to truly low-energy house levels that meet our climate change goals.

  8. J Chesnut | | #8

    nice projects
    I like your treatment of the lap siding and the integration of more modern detailing with the windows and exterior insulation.
    You make me look bad. I'm working on my own place in the evenings and the weekends. I backed off of adding the exterior insulation because it created more work and figuring through transition details (I'm fighting a deadline with the city because of a flaking paint violations notice so I have to work quicker than I would have hoped). Nice work. Trust me I know how much effort is involved.

  9. User avater
    Jesse Thompson | | #9

    Thanks! But, I'm not going


    Thanks! But, I'm not going to claim we did all that work ourselves, there were a lot of different people who helped build this project. We hired out just about everything that takes more than one person to do. That leaves plenty, however...

  10. Dan Kolbert | | #10

    Discussion Group
    As I posted way back when Michael wrote his blog, I think the discussion group has been a great improvement to the local building scene. We've learned a lot, met each other, helped talk each other through some interesting and tricky situations, and met like-minded designers, distributors, trades people, consultants, etc. A mutual support group if nothing else.

    I would encourage anyone with any kind of population density to try putting together a similar effort in your own community. Greater Portland isn't very big - about 60-70,000 people - and we regularly attract anywhere from 20-40 or more people to our meetings. The on-line world is great, but there's nothing like being together in a room with a chalkboard (and beer). Plus many of these conditions are local - the housing stock, the suppliers, the economy, the weather, etc.

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