Super energy efficiency for existing homes

 The Star Tribune has a story about the MinnePHit House in South Minneapolis.

Sometime in the next few weeks, Paul Brazelton will move his family into a 1935 Tudor in south Minneapolis that has no furnace. He’s just finished a massive renovation of the family home and even though winter’s bearing down, he removed the boiler and plans to use that basement space for his daughters’ home-school classroom.

He also took out the fireplace.

If this sounds like the most uninviting house (and classroom) in Minneapolis, there’s something else to know: Brazelton, a software engineer and passionate environmentalist, has nearly finished a retrofit of his house to the stringent engineering standards of the Passivhaus model, a German system of homebuilding that uses insulation and highly efficient doors and windows to save energy.

The finished 2,000-square-foot home could be warmed even in the dead of winter with a pair of small space heaters, Brazelton said, though the family plans to piggyback on their hot water heater and use an in-floor heating system in the basement.

The project is the renovation of an existing home to meet EnerPHit standard for energy performance. EnerPHit is a subset of the Passive House standard (hence the PH), which is an energy performance standard that requires very high levels of energy efficiency.  The Passive House Institute has a summary:

A Passive House is a very well-insulated, virtually air-tight building that is primarily heated by passive solar gain and by internal gains from people, electrical equipment, etc. Energy losses are minimized. Any remaining heat demand is provided by an extremely small source. Avoidance of heat gain through shading and window orientation also helps to limit any cooling load, which is similarly minimized. An energy recovery ventilator provides a constant, balanced fresh air supply. The result is an impressive system that not only saves up to 90% of space heating costs, but also provides a uniquely terrific indoor air quality.

Passive House is a performance standard, meaning it doesn’t specify design features like LEED, but has performance characteristics that the building must meet after construction is complete.  Namely an airtight building shell at  ≤ 0.6 ACH @ 50 pascal pressure measured by a blower door test and a total heating & cooling demand of <4.7 kBtu/sq ft/yr.  Total energy use needs to be ≤ 38.1 kBtu/ft2/yr.

In layman’s terms, this means Passive House designs are 11 times more airtight than a conventionally designed and built modern home.  As for energy use, a typical single family detached home uses 76 kBtu/sq ft/yr.  My own house was built in the 1920’s and currently has no wall insulation.  In 2010, we used 89 kBtu/sq ft/yr in total, and I think we’re fairly frugal with our electricity.  That means when the Brazelton family finishes their home, it will use less than half the total energy of my house and be 15% larger.

The Passive House standard doesn’t require or depend on renewable energy to achieve this high energy performance.  It’s focused on minimizing, to the greatest extent possible, the loss of heat and capitalizing on natural heat sources like sunlight and even body heat.  The MinnePHit house will be renewable-ready, but it won’t have renewables to start with.  Paul, the owner, puts it eloquently:

 …we decided to use our limited resources in building a house with the highest level of efficiency and durability.  If maintained correctly, solar panels can last decades.  On the other hand, insulation can last centuries.  Looking again at the long term, the best investment is using less energy, not alternate energy.

Last but not least, this home is energy efficient because it is location efficient, located in South Minneapolis with nearby access to jobs, recreation and services.  The Brazelton’s definitely don’t have to use an automobile for every trip, and they likely won’t be traveling far to their destination.  The other local example of Passive House design can’t make that claim.

LEED ND regional suitability analysis going national

Regular readers know I’m interested in how to use LEED ND as a tool for assessing regional development suitability.  I’ve been tardy in relaying news about good work being done in other regions.  Back in January, Jason Woycke contacted me about replicating the analysis for King County, in the Seattle region.  Jason is the President of Cascadia Planning and at the time was a Masters student in the planning program at the University of Washington.

The Cascade Land Conservancy was Jason’s client for the project, and according to Jason’s website, the maps will “help the Cascade Land Conservancy visually communicate the need for careful planning of where growth should be accommodated in the region and where growth should be avoided”.

Jason finished the analysis (I think near the end of spring semester 2011), and it looks great.  He generously agreed to provide me with a copy of the full report, which you can see here (large pdf).  Jason was awarded the UW Department of Urban Design and Planning 2011 Professionals Council Outstanding Professional Project Award for his work.

The analysis Jason used for King County appears to be very similar to my approach for the Twin Cities – focusing on the Smart Location and Linkage prerequisites.  I don’t believe any of the Neighborhood Pattern and Design prerequisites were included, which is a minor difference between the two approaches.

Is Chicagoland next?

More recently, I’ve heard from another aspiring urban planning masters student who is exploring the possibility of replicating this analysis for the Chicago region.  If this analysis happens, it will be complete in spring of 2012.

LEED ND resources for local governments

A friend tipped me off to this opportunity for local communities to get design assistance based on LEED ND.  EPA is funding this work as part of it’s Building Blocks for Sustainable Communities program.

Through a 3-day intensive visit and consultation, the Global Green team will evaluate a specific neighborhood. Prior to the visit the team will conduct an extensive review of existing plans, the neighborhood form, and the existing pattern of development. During the site assessment the team will identify the existing positive qualities of the neighborhood, consult with community stakeholders in meetings and a public workshop, and identify major opportunities to improve neighborhood sustainability.

At the conclusion of the visit the team will present recommendations for both physical and policy changes that may include street width reductions, ecological restoration, integrated energy and water infrastructure, creating standards for in-fill and transit-oriented development, or zoning code revisions to allow for urban agriculture or mixed-use development.

This is another significant output of the HUD-DOT-EPA partnership, one of the others being the metrics for sustainable transportation.

Another tool that I found from the Global Green website is A Local Government Guide to LEED for Neighborhood Development from USGBC, which includes multiple approaches local governments can take with the rating system, including reviewing plans for consistency with the rating system and determining what areas of the community might be eligible, which is a concept frequent readers of this blog might be familiar with.

Using LEED ND to strengthen existing neighborhoods

pride at loring park

I’ve written a lot about LEED ND, the rating system built to define sustainable neighborhoods, including how to use it as a framework for sustainable regional planning.  Typically, the rating system is applied to new development or redevelopment: when new streets, buildings and infrastructure systems are being built.  Rarely has it been applied to an existing neighborhood, where development or redevelopment is occurring at a slow pace and changes to major infrastructure systems are unlikely or occurring incrementally.  That application was simply not the original purpose of LEED ND.  I’ve always viewed LEED ND as providing an alternative to a model of traditional suburban development that has low connectivity, low density and poor location efficiency.  In its current form, it is best suited as a guide to help us plan and build new development more sustainably.

That doesn’t mean that there aren’t many valuable lessons for existing neighborhoods within the LEED ND system.  While we know that the greenest development is almost always the one that is already built, existing neighborhoods can often lack connectivity, walkability, density or other design features, which if retrofitted over time, could make them more livable and sustainable.

Neighborhoods and cities concerned about maintaining and improving livability, sustainability and financial viability are using LEED ND in just this way.  The Loring Park neighborhood in Minneapolis is in the process of creating a neighborhood master plan to shape their community for the next twenty years.  The neighborhood partnered with the University of Minnesota’s Center for Urban and Regional Affairs to assess the neighborhood’s sustainability using the LEED ND system.  Loring Park would also like to become officially certified as a LEED ND “project”, either under the current system or under a pilot existing neighborhoods program an alternative path for neighborhood and small areas plans that USGBC is developing.  A volunteer group, including yours truly, is working to help the neighborhood meet this goal.

The purpose of pursuing certification is to make this already green neighborhood even greener.  If Loring Park falls short in certain parts of the rating system, these shortcomings can be turned directly into goals for the master plan.  The Loring Park Draft Concept Plan includes a goal related to sustainable buildings and infrastructure and includes these goals for the use of LEED ND:

Further utilize the LEED-ND rating framework to:

  • periodically gauge neighborhood wide performance and progress toward sustainability goals
  • set in place (or augment) design guidelines or to set parameters for private project review and approval, or to gauge the merits of specific capital improvement projects
  • structure performance criteria for various incentives
  • preparation for government grants or other support from agencies that are familiar with LEED-ND rating system or that directly utilize LEED- ND standards as performance criteria

Our volunteer group, organized by the USGBC Minnesota Chapter and Loring Park residents, has just begun the certification process for the neighborhood.  This process will be a great opportunity to document the challenges of applying LEED ND to an existing neighborhood and review the rating system’s usefulness for a community planning process.  Stay tuned.


Explore The Twin Cities LEED ND Maps

View Full Screen

For a while I’ve been looking for a better way to display the maps I made for the LEED ND and Regional Planning series.  After some experimentation with the Google Maps API, I’ve got something functional.  There have been a few times when I’ve been presenting this topic and wished I had a way to pan around the metro and zoom in on specific areas.  This works well.

I haven’t quite figured out how to do a legend yet, so here’s the key: red areas are those place that are likely eligible for LEED ND based on the Smart Location and Linkage prerequisites. Areas in yellow may be eligible if the local comprehensive plan guiding (and accompanying zoning) were changed to allow density consistent with LEED ND requirements. View the map full screen.

For the full run-down on how I developed these maps, check out the whole LEED ND and Regional Planning series.

What locations in the Twin Cities are eligible for LEED ND: Part 4

Areas in the Metro Eligible for LEED ND

As part of a series, I’ve been exploring what locations in the Twin Cities metro are eligible for LEED ND based on the land use characteristics.  These locations could be considered “location efficient”, a concept which has gained importance recently due to changes in federal policy that direct the expenditure of federal money.  The benefits of location efficiency include “connecting conveniently and affordably to jobs, schools, shops and other amenities through a range of transportation options”, according to HUD Secretary Donovan.

I would argue that we can also use LEED ND as a guide for growing our region more sustainably.  The requirements of the rating system can show us where it would be appropriate to target future growth, what areas should be preserved until sufficient infrastructure is available, and what areas are totally off-limits.  HUD, DOT and EPA are promoting a similar line of thinking with their recent partnership on Sustainable Communities and corresponding grant opportunity. Continue reading

What locations in the Twin Cities are eligible for LEED ND: Part 3

Traditional Neighborhood Design - Minneapolis 1892

In an ongoing series, I’ve been trying to define areas of the Twin Cities metro that are “location efficient” using the USGBC’s LEED ND rating system.  The previous posts focused on those requirements of LEED ND that cannot be met through the design of the project itself: features of the built and natural environment that determine a minimum eligibility for LEED ND based on location.  This resulted in a map of areas in the region that met this basic level of “location efficiency”.

However, there are a few other requirements of LEED ND that can technically be met through the project design, but may not be able to be met in reality based on the existing built environment, or the current planning or zoning rules in a particular location.  For example, LEED ND requires a minimum density for both residential and non-residential uses.  Technically the density of the project is controllable by the project designer, however, if a city has land use regulations in place that only permit densities lower than what is required by LEED ND, plan and zoning amendments or variances would need to be granted before the project could go forward, all of which are not certain.  Many communities are averse to the levels of density required by LEED ND, and therefore elected officials would be unlikely to grant such changes to land use regulations. Continue reading

What locations in the Twin Cities are eligible for LEED ND: Part 2

After HUD announced that they would begin scoring grant projects on “location efficiency” using LEED ND as a guide, I got curious as to what that might mean for the Twin Cities region. In Part 1 of the series, I began looking at what requirements LEED ND has for “location efficiency” and came up with a map that identifies areas of the region that are basically off-limits due to special environmental or land use characteristics. This was based on prerequisites 2 – 5 in the Smart Location and Linkage topic area of LEED ND. This post will focus on the last prerequisite in Smart Location and Linkage: Smart Location.

This exercise isn’t supposed to be just about HUD, but about what planning in our region might look like if location efficiency, smart growth and infill development were prioritized over greenfield development.

Continue reading