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.

Location Efficiency is More Important than Home Efficiency for Energy Savings


An EPA-supported study shows that if you’re concerned about energy use from urban development (in this case, residential buildings), you should look at location efficiency first, rather than building efficiency.  The study describes location efficiency this way:

Housing that is located in a walkable neighborhood near public transit, employment centers, schools, and other amenities allows residents to drive less and thereby reduces transportation costs.  Development in such locations is deemed to be “location efficient,” given a more compact design, higher-density construction, and/ or inclusion of a diverse mix of uses.

As the graph above shows, locating housing in location-efficient neighborhoods has a greater impact on the combined housing-transportation energy use than improving the performance of buildings and automobiles.  EPA says that locating homes in these areas, where some automobile trips can be replaced with transit or other transportation modes, lead to reductions in household energy use of 39 to 50 percent.  While I’m a little hesitant about the study’s assumptions of a 45 percent reduction in vehicle miles in TOD neighborhoods, the larger point is still valid: location has a large impact on energy use by urban development, larger than is often assumed, and deserving of more attention than it’s given.

The study uses energy consumption data for housing and transportation that was collected as national averages, not for any particular location.  The “energy-efficient” homes data was based on Energy Star homes.  So, of course, results from specific regions or cities may vary.  Also, Energy Star is not the most energy efficient way to build a home, but it’s relatively affordable and has large market share compared with other home rating systems.

While location efficiency may be more important than building efficiency in terms of energy savings, it’s obviously a more complicated and politically charged topic than building energy efficiency.  Improvements to buildings bring nearly immediate and focused benefits to owners, while decisions about density and location have benefits which are more widely distributed and whose paybacks accumulate over a longer period.  Matthew Lister, who works for the firm that prepared the study, told Environmental Building News we shouldn’t just focus on the energy savings, though:

“The underlying story is about quality of life.” The choice to live in a densely settled, mixed-use neighborhood, Lister argues, is not just about saving money or even the planet; it’s about “less time in the car and access to more choices,” as well as more work opportunities. The report also touches on social equity, he said. “People have to drive further and further out so they can afford a house,” but then end up “shackled to two car payments,” which raises the effective cost of their housing.

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

What locations in the Twin Cities are eligible for LEED ND: Part 1

In a previous post, I talked about the news that HUD will begin scoring grant applications based on location efficiency, and using the LEED ND rating system to do so.  While it is not yet clear what exactly HUD means by this, we can do our own exercise to look at the ND system, compare it to the existing built environment and see what locations in the Twin Cities might be eligible.

This isn’t just about HUD and their projects, it is a way of determining what the best locations are for new development that would ensure compact, contiguous development that makes the most efficient use of infrastructure and has multiple transportation options.  Or in other words, it’s a method to begin planning a more sustainable region.

Before the analysis, a little background on LEED ND is appropriate:

The rating system is divided into five topic areas:

  • Smart Location and Linkage
  • Neighborhood Pattern and Design
  • Green Infrastructure and Buildings
  • Innovation and Design Process
  • Regional Priority Credit

The first three topic areas have prerequisites, or requirements that a project must meet in order to be eligible.  All the topic areas have credits, from which a project proposer can choose to achieve to meet the various certification levels (Certified: 40, Silver: 50, Gold: 60, Platinum: 80).

While the LEED ND system is long and complex, there is really one topic area of the five in the rating system that deals with location and what land is off-limits versus eligible: Smart Location and Linkage (SLL).  In this topic, there are five prerequisites and nine credits.  For the purposes of this exercise, we’re going to be looking at just the prerequisites for LEED ND SLL, because once you get into credits, you have to start making lots of assumptions about how the project will be designed and what features it will contain.  In addition, the other four topic areas deal primarily with the design of the project, or what is inside the project boundary, something we can’t know until a project is proposed.  We want to know just what locations are at minimum eligible, and that means focusing on prerequisites in SLL.

Read on for the details of Smart Location and Linkage and the results.

Continue reading

HUD to start scoring grant applications using LEED ND. So what does that mean?

The Department of Housing and Urban Development (HUD recently announced that they would start scoring grant applications by their “location efficiency” and use LEED for Neighborhood Development as a tool to do so.  Location efficiency means new projects would have greater accessibility to surrounding jobs, commercial areas and transportation options.

HUD distributes over $3 billion in grants, so this policy change could potentially have a big impact on where and how new housing gets built.  HUD provides many affordable housing programs, builds public housing, oversees the FHA, and regulates Fannie Mae and Freddie Mac.

So what does it mean that they will begin scoring applications with LEED ND?  The details aren’t out yet, but the rating system certainly has a lot to say about location efficiency as well as what locations are appropriate for development based on environmental significance.  So, where might future HUD grantees be able to propose projects?  Well, location efficiency will likely make up only one of many scoring categories, and I would be surprised if projects could be rejected solely based on poor location.  However, we could start with the assumption that those locations that meet at least all the prerequisites for LEED ND would score highest.

In the next series of posts, I’ll look at what locations in the Twin Cities metro meet the prerequisites for LEED ND, as best as I can without having real project details.  This exercise isn’t just about HUD, the goals of LEED ND are to promote smarter growth, make more energy efficient communities, provide real transportation options and generally build stronger, more sustainable communities.  Thinking about the locations in the metro that are eligible for LEED ND is another way of thinking about where new growth should be planned that could provide the most sustainable outcome.  If anyone ever wanted to do true regional planning, perhaps this is a place to start.

New Year News – Trains, Plans, and Automobiles (miles traveled)

What with the holidays and all, Net Density has been on a bit of a hiatus.  Many pieces of news dropped while I was enjoying some relaxation, and in order to catch up I simply don’t have time to give them all the detail they deserve.  So, instead of skipping them altogether, I’ll try to cover them all, giving a few of my editorial comments for each.

A draft of the Minneapolis North Loop Small Area Plan was completed and put out for public comment, with a twist.  You can edit the document directly using a wiki, which the city and the neighborhood hope will encourage more participation.  Put me in the skeptical camp. Wikis work best when with a small audience who is very knowledgeable about the topic, or a really large audience (see Wikipedia) where the size of the audience enables content to be vetted and inaccurate information to be weeded out.  The North Loop plan wiki may see a small audience, which will mean little peer review, and they will also likely be unaware of the requirements for plan content.

TransForm, a transportation policy advocacy group from the Bay area, has released its GreenTRIP rating system to fill the gaps in LEED ND and rank developments based on their ability to reduce VMT.  I say hoorah for the premise, we need to tackle VMT to address climate change and other issues, but do we need another rating system?  How about some regulation?

Saint Paul adopted a requirement that all new buildings projects which receive $200,000 or more in city funding must meet the standards of one of seven ratings systems such as LEED. Projects must meet Minnesota Sustainble Buildings 2030 energy standards.  Saint Paul is a model.  Any development that receives public dollars should at least meet these basic energy requirements when the payoffs (and paybacks) are so obvious and available.

Last, but certainly not least, MNDOT released its statewide Passenger and Freight Rail Plan.  The plan lays out near and long-term corridor priorities and shockingly (or maybe not shockingly) does not clearly pick the river route as a winner for high-speed rail to Chicago.  The alignment saga will continue, but if MNDOT’s cost-effectiveness figures are correct, building a link to Chicago makes good sense (and not just because of the lack of full-body scanners).

Welcome to 2010!  I hope your best laid plans all reach the implementation stage this year!

Dakota County firsts

image source: Met Council

image source: Met Council

Ok, my-own-horn tooting time.  Or, my employers horn I guess.  Dakota County had some cool firsts recently that I thought I should briefly mention.

In April the Lebanon Hills Visitor Center became the state’s first LEED-certified County building.   Dakota County also completed a greenhouse gas inventory for their operations, a first for any Minnesota County (take that Hennepin County).  Click through for more details.

Continue reading