Oregon Passive House Aims To Slash Energy Bills

On a blustery, wet hillside in North Plains, Ore., construction workers and designers are making progress on the construction of one of the most efficient home designs in the country. Called the Pumpkin Ridge Passive House, the structure is designed with tough standards for insulation and thermal efficiency, and is expected to significantly reduce energy bills by as much as 50 percent, compared to a conventional home.

The Pumpkin Ridge house—being built by Hammer & Hand, based in nearby Portland, Ore., and designed by Scott Edwards Architecture—is one of six homes across the Pacific Northwest to be featured by the  Northwest Energy Star program as demonstrations of how well a “super-efficient home” can perform.

Image via Hammer & Hands

Image via Hammer & Hands

To achieve these results, Pumpkin Ridge is built around several core passive house principles, the chief being the use of “super-insulation” to eliminate thermal bridges, or places where poor insulators can carry heat through the home’s thermal envelope. Pumpkin Ridge includes a layer of foam insulation as thick as six inches that wraps entirely around the home, from the bottom of the foundation to the peak of the roof.

This schematic shows the seven layers that make up the super-insulated walls of the Passive House. Image via Hammer & Hands.

This schematic shows the multiple layers that make up the super-insulated walls of the Passive House. Image via Hammer & Hands.

Other key principles in the passive design is to make the house as airtight as possible by sealing all gaps in windows and doors, ventilating the house with energy recovery and optimizing passive solar heating gains. The windows in the house are designed to maximize the amount of sun it receives in the winter and includes enough shading to keep it cool in the summer.

Image via Hammer & Hands

Image via Hammer & Hands

Speaking on a segment for KGW-TV’s “Greater Portland Today” program, Sam Hagerman, president of Hammer & Hand, described how the cost of building the 3,500-square-foot single-family residence will have roughly the same monthly cost of a conventional home, once mortgage, taxes and insurance are included. Once completed, however, the indoor air quality will be improved in a passive house and annual heating and cooling bills will plummet to less than $50. Again, that’s $50 per year, not per month.

Currently, the foundation and structural framing on the house is just about complete. On the Hammer & Hands blog, three new videos were uploaded on Dec. 20, showing the recent progress. In the videos, the project’s lead carpenter, Val Darrah, describes the details of the wall assembly and the importance of getting a good seal on all joints to maintain the integrity of the insulating air barrier within the walls. All joints are covered, he says, with a liquid sealant applied with a caulking gun, which provides a more airtight bond than standard tape and produces much less waste

Completion of the Pumpkin Ridge house is expected in 2013. To keep tabs on the progress of this and other passive house projects, stayed tuned to the Field Notes section of the Hammer & Hands blog for future videos and updates.

Randy Woods is a Seattle-based writer and editor with 20+ years of experience in the business publishing world. A former managing editor of Seattle Business, iSixSigma, Claims and Waste Age magazines, he has covered topics that include newspaper publishing, entrepreneurism, green businesses, insurance, environmental protection and garbage hauling (yes, really). He also contributes to the Career Center Blog for The Seattle Times and edits a photography magazine called PhotoMedia. When not working, he likes to hide out in Seattle movie theaters and attend film festivals—even on sunny days.

    • http://twitter.com/MartinHolladay Martin Holladay

      Randy,

      I’m afraid that you are mistaken with your headline. It simply isn’t true that this “Oregon Passive House Aims For 90 Percent Energy Reduction.” A more accurate statement would be, “Oregon Passive House Aims to Reduce Its Space Heating Energy Use by 90 Percent Compared to an Older Home That Doesn’t Meet Minimum Code Requirements.”

      Or, in headline speak: “Oregon Passive House Aims For About 50 Percent Energy Reduction” — compared to a code-compliant new home.

      • Randy Woods

        Thanks for point that out, Martin. I thought that the comparison to an older home would be implied, but I can see how my original headline was misleading.

        • http://twitter.com/MartinHolladay Martin Holladay

          There were two problems: (1) the headline didn’t clarify whether the reduction was in comparison to an old home or a new one, and (2) the headline referred to “energy” reduction instead of “energy used for space heating” reduction. There is a big difference.

    • ergodesk

      Wow, all those layers, I’m impressed on the numbers.

    • billb

      One wonders where all those toxic chemicals will go from the out-gassing of the various non-natural high-tech materials used herein will go? To me ‘Liquid Sealant’ says unstable toxic air-emissions. They will be sealed inside with you, and the superior systems will keep them there. Look forward to headaches, sick-stomachs and general nausea.

      • http://www.facebook.com/stephen.beili Stephen Beili

        i’m not involved with this project, so i can’t speak to how toxic their products are, but certainly that can be a concern in such an air-tight house. the article does mention that they are providing mechanical ventilation probably through an ERV (energy recovery ventilator), and this will actually increase the amount of fresh air they’re getting over the old-school leaky house while decreasing the amount of energy lost in a leaky house by transferring this energy to the fresh air as it comes in. quite a cool dealio. i also really like more natural building whenever possible (wall materials, finishes, everything).

      • Skylar Swinford

        Bill,

        I am part of the team at H+H building this project. Stephen is correct that this house will have a continuous and reliable source of fresh air 24/7. The house will be equipped with a high efficiency Zehnder Comfoair 350 HRV. Unlike an older home that relays on flaws and accidental air-leaks for ventilation, this house will have fresh filtered air supplied throughout the home at all times. Having an HRV or ERV is like having your windows open all year round, without the drafts or wasted energy.

      • Skylar Swinford

        Bill,

        I haven’t heard from you so I just wanted to clarify a few things. Other than the below grade insulation that is in contact with the ground, this house is insulated with natural wood fiber insulation. It doesn’t get any more natural than that. The so called toxic ‘liquid sealant’ that you mentioned was developed here in Portland by a local chemist and is phthalate, solvent and isocyanate free. This ultra low VOC product even meets the stringent red list criteria set by the Living Building Challenge. Furthermore the product is applied on the exterior of the air-barrier so it will have little or no communication with the interior of the home.

        I encourage you to get your facts straight before making uninformed and alarmist claims.

    • billb

      Skylar, thanks for the info. I am familiar with the ERV idea, I am personally not moved by the promise of it. In my twenty years designing homes, I have heard a lot of feedback from customers about uneven performance of air handling systems. I have heard of dead spots in rooms, and even whole rooms that seem to not get air changes. I can say I would not do a tightly sealed scheme on my projects, I don’t want customers telling me their kids are getting sick from the house. But I wish you well with the project.

      • Skylar Swinford

        Bill,

        It sounds like you have suffered from poorly designed, installed, and maintained ventilation systems. Unfortunately, even a “leaky” house built to today’s minimum code will still have IAQ issues without a ventilation system.

        If you are not designing a ventilation system into your homes, where are the occupants of your home getting fresh air? Crawlspace, attic, air-leaks from behind the sink and bathtub caused by poor workmanship? None of these places sound like a good source of fresh air to me. I’m guessing your clients wouldn’t be too pleased with this approach if they understood they were breathing through the armpits of their home.

        If you don’t air-seal, do you also omit insulation? Anyone that has ever worn a sweater on a cold windy day knows that without a wind breaker their sweater is useless. Insulation does not work when air is flowing through it. This is a simple fact.

        How do you prevent wind driven rain from driving into your wall systems without an air-barrier system?

        I’m interested to hear your approach.

        The second you walk into an air-tight high performance building with a well designed and installed ventilation system, the first thing you will notice is the freshness and quality of the air. We independently duct all of our ventilation systems to supply fresh air to the bedrooms while exhausting the kitchen, bathrooms, and laundry 24/7.

        I’m happy to take you to a project to experience this for yourself.