LEED BD+C: Homes v3 - LEED 2008
Villa Alegre Phase 1 & 2
LEED Platinum 2011
* This profile has been peer-reviewed by a USGBC-selected team of technical experts.
The below stakeholder perspectives address the following LEED credits:
WEc2, WEc3, SSc2, EAc1, EQc5.2, IDc1, IDc2, MRc1.5, MRc2.2
Goals and motivations
What were the top overarching goals and objectives?
The overarching goal was to create a sustainable project that had the smallest environmental footprint possible. This was more difficult than one might think because community members often had different ideas on what was sustainable. One also has to keep in mind that Santa Fe is a fragile high desert environment with less than 12 inches of rain a year. By the end of our design charrettes, we determined that focusing on energy and water efficiency would achieve our goals on multiple levels and make the most appropriate use of the grant money obtained.
What were the motivations to pursue LEED certification and how did they influence the project?
- Cost/Utility Savings
- Integrated Design Process
- Funding Stipulation
This project did not start as a LEED project. But the project competed for Low Income Housing Tax Credits in the yearly Mortgage Finance Authority (MFA) process, and when it received this award, pursuing LEED for Homes was a requirement. LEED became the road to quality through additional construction observation, third party testing, and visual inspections. It was also a goal to reduce residents' utility bills to the greatest extent possible.
What were the most notable strategies used to earn LEED credits?
The major focus defined in the design charrettes was energy and water efficiency: Water because we have so little water and energy because we have so many opportunities. We knew these strategies would also reduce the bills of the affordable housing occupants (leaving them more money for other critical life needs) and reduce the project's environmental footprint.
The Santa Fe area receives less than 12 inches of water per year, so our strategy was to reduce the overall demand for water, focusing on WE Credits 2 (Irrigation System) and 3 (Indoor Water Use). We installed the most efficient fixtures possible to reduce indoor water use. Outdoors, we chose plant materials closely and created swales to keep all of the water in and on the site, using as much possible for the landscape itself. We received exemplary performance for our irrigation system, which features 99% drip irrigation throughout the entire project and controllers that turn it off when there is rain or snow. Along with the systems design, we also earned SS Credits 2.2, 2.3, and 2.4 (Landscaping). Although we did not install cisterns, all systems were designed to be plugged into future ones, with the idea that because operating costs for the management company are so low, it can invest in cisterns later.
We assessed all-electric versus a combination gas/electric system, swamp coolers (which use water to cool) versus package units, envelope systems, biomass, and all alternative energy systems. In the end, we decided on an all-electric system that reduced the average tenant utility bills by well over 60%, reduced the amount of sulfur dioxide (SO2) and nitrogen oxide (NOx) emissions by 2,500 pounds per year, and reduced carbon dioxide (CO2) emissions by over 350 tons per year. The major strategies that made this achievable were a high-efficient envelope, a geothermal exchange system with ground-source heat pumps, and a 240-kilowatt photovoltaic system. The project achieved between 25 and 28 EA Credit 1 (Optimize Energy Performance) points, depending on the unit configuration. We chose the Performance Path in the EA credit category because we wanted to be able to do energy modeling and really look at all of the alternatives. We selected a huge photovoltaic system - one of the biggest not owned by a utility company in the state of New Mexico which, coupled with the ground-source heat pump system, provides almost all of the homes' heating and cooling needs. After this focus on energy efficiency, building envelope performance testing showed a very low five air changes per hour (ACH) at a pressure difference of 50 pascal. To ensure good indoor air quality, the team decided to go for EQ Credit 5.2 (Enhanced Local Exhaust) by using MERV 10 filters.
What cutting-edge strategies or processes were implemented?
The most cutting-edge strategy on this project was the energy-efficient combination of ground-source heat pumps (GSHP) and a photovoltaic (PV) solar system. There is a big upfront cost on these systems, so they weren't part of the initial schematic design, but once we received stimulus monies from the U.S. Department of Housing and Urban Development (HUD), we decided this was the best use of that money.
The GSHP system is essentially an eight-inch diameter well drilled 200 feet into the earth for each unit, where a closed-loop pipe system circulates a fluid and acts as a heat exchanger back to the heat pump in the unit. The GHSP serves as the HVAC system, with the pipe taking coolness from the 55-degree earth in the summer and using the heat in the winter months. There's a well for each unit, so we had roughly 115 on the project. We have an all-electric system for water heating and HVAC, so there is no gas used by the project. The PV systems are solar panels on the roof tied back into the grid, where we are getting a credit from the local utility company. Because the project has no gas and the heat pumps are electric, utility bills for the residents are only $20 per month.
In early design meetings, we looked at different options, including radiant floor heat with a hydronic system. The HERS rater did energy models, and we determined the GSHP and PV combo would offer the biggest bang for the buck. Upfront cost and research was required first; we had to do a GSHP well test boring to determine how deep it needed to be, with our mechanical engineer analyzing all of the data for feasibility.
How was the integrative process applied and what was the greatest benefit gained?
This project was my first LEED project, so my learning curve was huge. But the integrative process from early design all the way through to construction was wonderful because it facilitated my learning curve and was also beneficial to the project outcome. The Homes LEED AP and the Green and HERS Raters were especially helpful in discussing the construction system in the design phase, offering ideas for the best ways to create an energy-efficient building. For example, the HERS Rater determined that adding an inch of rigid insulation to the exterior, using a building wrap with an R value of 5, would create a really efficient envelope.
Also, I enjoyed watching what the Green and HERS Raters looked for during site inspections. Their extra efforts in the field, beyond a typical non-LEED project where only the architect may observe during construction, were instrumental in making this a tighter, better, greener project. For example, we did a blown-in fiberglass insulation and the HERS Rater ensured on-site that the insulation met the specified R factor by actually measuring attic insulation, which was way beyond anything I've experienced on a typical construction process.
As a team, we educated the subcontractors, many of whom were brand-new to LEED. It was huge having the Green and HERS Raters in the field talking directly to the subs. We educated the subs on the first units and then we were able to step back. Without a doubt, this level of LEED team interaction with not only the contractor, but the subcontractors, contributed to the project's overall return on investment.
Aside from LEED certification, what do you consider key project successes?
Garnering public support for this project was an essential success. We wanted to develop quality-constructed units (especially within the Low Income Housing standard) and maximize housing opportunities in the Santa Fe historical downtown area. The City of Santa Fe requires a neighborhood meeting (referred to as "Early Neighborhood Notification") when a development is a certain magnitude, such as Villa Alegre. We ended up having not just one required meeting, but several, to really listen to neighbors and respond to their input. We had not committed to LEED at this point, so the neighbor's comments were more aesthetic and traffic-related with basic green building input.
Achieving neighborhood acceptance and then enfranchising them in the process was important, as we then had support instead of opposition at the rigorous Santa Fe City approval meetings. By having more than the "required" neighborhood meeting and listening, neighbors became a proponent of the project and actually helped facilitate the approval process. Acceptance from the neighborhood was huge and the fact that the project was instantaneously leased speaks for itself. There was a waiting list to live in the Villa Alegre community.
What were the most important long- and short-term value-add strategies and what returns on investment (ROI) have been experienced or anticipated?
As to ROI, the best example in this project is the extensive use of photovoltaic panels and the geothermal system. The CFRC ARRA grant paid for a majority of the alternative energy sources, so they are of immediate benefit to the project. The short-term value-add goes directly to the tenants in the form of substantially-reduced monthly utility bills from a non-polluting energy source, in contrast to the prevalent coal plant-sourced electricity available here in New Mexico; 40 percent of the energy consumed is produced on-site. Panelized construction also contributed to ROI by reducing overall costs through reducing on-site waste, speeding construction, and enhancing accuracy.
Additionally, our initial investment in quality materials is expected to pay off because not only will the construction remain viable and strong as a housing project and as a community for some time, but the long-term operations and maintenance will be much lower. For this project, we selected high-quality materials that were durable. There is no carpeting in the units, but tile flooring throughout with wood flooring on the stairs. The exterior finish is high-quality stucco that is well-insulated with a durable brick edge on the top of the parapet, which in addition to being long-wearing, is a traditional material for this area. And, the appliance packages are high-quality with state-of-the-art washers and dryers.
What project challenges became important lessons learned?
One of the biggest challenges was that the duct system was designed so that it was partially in conditioned space and partially in the attic. This caused problems with duct sealing and maintaining the air barrier between the conditioned space and attic. The first ten to 12 units were a comedy of errors of sealing and re-sealing; testing and re-testing. The ducts were, in some places, in a position where it was extremely difficult to seal them. We realized that it would have been better to seal that section of duct before putting it in place. We learned two main lessons from this. The first was to, if at all possible, keep ducts in conditioned space and not penetrate the air barrier. The second was a sequencing lesson: Sometimes it's better to leave off some of the framing, get the ducts sealed, then get them in place and test them when they're still accessible, before building the framing around them. Phase 3 of this project, now under construction, has very similar units and these lessons learned have already been applied; we've put all of the ducts in conditioned space and the subcontractor is sequencing things differently on this project, as well as on other projects on which I am working with him currently.
A second challenge happened toward the end of construction when we were putting in the landscape. SS Credit 2.2 (Landscaping: Basic Landscape Design) requires that turf not be placed on a slope greater than 25%. For one of two small turf areas on this project, you couldn't tell from the plans what the slope was. While I was on site inspecting, I decided we needed to measure it, and it turned out to be closer to 40%. We didn't want to lose the two points associated with this credit, but this realization was at noon on the day prior to sod delivery. So, we trucked in nine tons of dirt that day and leveled it out, getting the slope down to between 15 and 20%. The irrigation was already in place, so the irrigation subcontractor had to come out and lengthen the spray head connections to be above the new dirt. It was a real team effort to get this all done in less than 18 hours.
Since this, our first LEED project, we've made our preliminary rating meetings much more rigorous and we emphasize past issues like this. We go through credit-by-credit what the requirements will be and make sure we review the plans in depth prior to the preliminary rating meeting.
What was a pivotal moment that impacted the project's direction?
The project started as a demolition/disposition of 104 public housing units and its redevelopment was a combination of two Low Income Housing Tax Credit allocations (family 9% and senior 4%) that received 2009 tax allocations. The economic conditions at that time could not have been worse for developing an affordable project and equity investors were hard to find. We were prepared to cancel the 4% senior deal because the funding didn't make economic sense, but when we received both TCAP and CFRC ARRA grants, the numbers worked. These grants allowed us to enhance insulation, windows, and low-VOC paints, and to use ground-source heat pumps and install a 240-kilowatt photovoltaic system, as well as numerous other construction upgrades - making LEED Platinum viable.
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