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					                     ENERGY STAR GOES
                     MULTIFAMILY
Multifamily




                     Along with beautifully designed brickwork and a landscaped
                     backyard with a children’s play area, residents of 1212 MLK
                     Apartments can enjoy affordable apartments, low energy bills,
                     and healthy indoor environments.

                     by MARC ZULUAGA and
                     GAYATHRI VIJAYAKUMAR




               U         p until recently, high-rise mul-
                         tifamily buildings have not
                         been able to reap the perfor-
               mance and marketing benefits associated
               with the Energy Star label.That changed
               when, earlier this year, EPA launched its
               pilot program for Energy Star multifam-
               ily homes in New York,Wisconsin, and
               Oregon. As the New York Energy and
               Research Development Authority
               (NYSERDA) has taken a national lead-
               ership role in developing the pilot, it is
               perhaps not surprising that New York is
               the location of the first of the pilot pro-




                                                                                                                                                                   SWA
               gram buildings to be completed. Built
               by Dunn Development Corporation
               and Beulah HDFC, Incorporated, 1212          1212 MLK Apartments contains 54 units of affordable housing: 10 studios, 15 one-bedroom
               MLK Apartments is a six-story building       apartments, 28 two-bedroom apartments, and 1 three-bedroom apartment. A dozen energy efficiency
               on Dr. Martin Luther King, Jr., Boule-       measures have been implemented. The building is the first to earn Energy Star status through a pilot
                                                            program for multifamily buildings.
               vard in the Highbridge neighborhood of
               the Bronx. The first tenants moved in
               during the summer of 2006.
                   The company we work for, Steven
                                                            Affordable Housing                                    mon areas, and other first-floor spaces.
               Winter Associates, served as an energy       at Its Best                                           The brick and concrete masonry unit
               consultant for the project and assisted         1212 MLK Apartments contains 54                    (CMU) block walls rest on a crawlspace
               Dunn Development in meeting the              units of affordable housing: 10 studios, 15           foundation.The boiler room is located
               program requirements. NYSERDA is             one-bedroom apartments, 28 two-bed-                   on the roof.
               using data from the pilot to establish the   room apartments, and 1 three-bedroom                     In order to meet the NYSERDA
               up-front cost of efficiency and to set        apartment. In addition, the first floor has             program requirements, 1212 MLK
               cost-effective efficiency goals for future    a community room with a kitchen and                   Apartments includes a dozen energy
               construction projects. The experience        bathroom, a laundry room, utility rooms,              conservation measures (ECMs) that
               gained from the pilot project in New         and three offices. Residents and their                 were incorporated into the design in
               York will help EPA generate standards        guests can enjoy a beautifully landscaped             order to reduce the modeled whole-
               for Energy Star labeling of high-rise        backyard with a children’s play area and              building energy use by 20% compared
               multifamily buildings nationally.            plenty of benches. The building totals                to a baseline ASHRAE 90.1-2004-
                                                            51,000 ft2, including apartments, com-                compliant building (see Table 1).




              14                                            www.homeenergy.org                                   NOVEMBER/DECEMBER 2006 • HOME ENERGY
    The building walls are insulated with   resulting in an assembly U-value of       a significant improvement over
R-4.3 Roxul 1-inch rigid (mineral           0.44.These windows also feature a cus-    conventional 80% efficient
wool) insulation and R-13 fiberglass         tom-made removable panel below a          atmospheric equipment. These
batts within 3 1/2-inch interior steel      standard double-hung unit. During the     boilers have a fully modulating
framing. The rigid insulation, placed       summer, an insulated replacement panel    firing rate of 25%–100% and are
between the steel studs and the CMU         with a cutout for a window A/C unit       used in combination with two
block wall, minimizes thermal bridging      will be installed in the bottom section   119-gallon indirect storage tanks
through the steel. In New York City, for    of those windows where tenants desire     to meet domestic hot water




                                                                                                                             Multifamily
multifamily buildings with more than        window air conditioning.The panel for     (DHW) needs efficiently.While
four units, the Energy Conservation         the A/C is replaced with a window         combustion efficiencies of
Construction Code of New York State         panel during the winter to provide        90%–95% are possible with con-
requires a continuous layer of R-3 insu-    extra light. The developer decided to     densing boilers, actually achieving
lation with metal framing. However, this    try this new window design approach       this performance level requires a
requirement is usually ignored, resulting   in order to avoid air conditioner         boiler return water temperature
in a standard practice for new construc-    sleeves, which are prone to air leakage   that is low enough to allow for
tion that does not address thermal          and limit the potential efficiency of      condensation. The boiler return
bridging through steel studs.               A/C equipment.                            water       temperatures         of
    The windows are low-e, argon-filled         Two 87% efficient, direct-vent          140ºF–180ºF in a standard
aluminum frame with a thermal break,        Lochinvar boilers meet heating needs—     hydronic baseboard loop will not




HOME ENERGY • NOVEMBER/DECEMBER 2006                                  www.homeenergy.org                                    15
                  yield condensation in the                                                                               sure drop across the damper
                  combustion stack. In this                                                                               exceeds 50 Pa in order to regulate
                  type of conventional                                                                                    air flow. At 1212 MLK Apart-
                  application, a condensing                                                                               ments, the CAR dampers are inte-
                  boiler will result in com-                                                                              grated with an exhaust grille and
                  bustion efficiency com-                                                                                  fire damper assembly.
                  parable to that of                                                                                          High-efficiency fluorescent
                  direct-vent equipment.                                                                                  lighting is used throughout the
Multifamily




                     It is possible to lower                                                                              building.Apartments feature wall
                  return water tempera-                                                                                   sconces with four-pin CFL bulbs
                  ture enough to take                                                                                     (2 x 13W),T-8 lamps with elec-
                  advantage of condensing                                                                                 tronic ballasts for kitchens (2 x
                  equipment by increasing                                                                                 32W), and 55W fluorescents for
                  the radiation output of                                                                                 the bathrooms. Overhead fixtures
                  the hydronic loop with                                                                                  in public corridors are CFLs (2 x
                  larger baseboard units.                                                                                 26W), also with electronic bal-
                  The cost-effectiveness of                                                                               lasts.To further minimize electric-
                  this type of approach                                                                                   ity bills, occupancy sensors were
                  was not evaluated,                                                                                      installed throughout the offices,
         although it may represent the                                                                                    community room, and janitor
         next logical step in improving                                                                                   closets. In each public corridor,
         heating-plant performance.                                                                                       ceiling-mounted          long-range
             More than any other factor,                                                                                  occupancy sensors are wired to a
         mechanical ventilation drives the                                                                                power switch pack (PSP) that




                                                                                                                   SWA
         heating load in new multifamily                                                                                  turns off every other overhead
         buildings in New York City. The building walls are insulated with R-4.3 Roxul 1-inch rigid (mineral              light fixture when these spaces are
         Small apartments combined wool) insulation and R-13 fiberglass batts within 3 1/2-inch interior                   not being used. The overhead
         with strict exhaust CFM steel framing. The rigid insulation, placed between the steel studs                      light lamps that are not controlled
         requirements in the city’s               and the CMU block wall, minimizes thermal bridging through the steel.           by the PSP are designated
         building code result in                                                                                                     emergency fixtures with
         relatively high mechani-                                                                                                    battery pack backup for
         cal air change rates. At           Table 2. Simulation Summary—1212 MLK                                                     power failures.
         1212 MLK Apartments,                                                                            Final design
         the ventilation system                                               Baseline simulation simulation
                                            Annual energy cost, all fuels $65,000                        $52,000
                                                                                                                                     Competitive
         was designed to mini-                                                                                                       Costs
         mize overall apartment             Electricity consumption           262,000 kWh/year           210,000 kWh/year
                                            All other fuels consumption 1,700 MMBtu/year                 1,300 MMBtu/year
         air change rate while still                                                                                                     SWA compared the
                                            Total estimated energy            2,600 MMBtu/year           2,000 MMBtu/year
         meeting code. The                  consumption
                                                                                                                                     specifications and com-
         design exhaust ventila-                                                                                                     ponent costs for a base-
         tion rate for all bath-                                                                                                     line building to the
         rooms is 50 CFM. Most                                                                                                    ECMs implemented in the
         kitchens qualified as “super kitchens,”                 These ventilation requirements are                 building (see Table 1).The baseline build-
         which are greater than 59 ft2 floor area            met by a central exhaust system with                   ing specifications were determined using
         with a pass-through to an adjacent room            roof-mounted exhaust fans connected to                 Appendix G of ASHRAE Standard 90.1-
         with operable windows, and did not                 duct riser shafts with takeoffs at each floor           2004 along with a few minimum-perfor-
         require mechanical ventilation.The stu-            for bathroom and kitchen exhaust grilles.              mance standards required by NYSERDA.
         dio kitchens are smaller than 59 ft2 and           Bathroom doors are undercut to provide                 Since ASHRAE 90.1 is a relatively strin-
         can’t use the living area as a pass-through        for makeup air. As an improvement on                   gent standard, baseline requirements
         to get to an operable window. Indeed,              this standard-practice ventilation system,             exceed standard practice for New York
         the living area is also a sleeping area in a       1212 MLK Apartments also incorporates                  City. Pegging the program to a national
         studio apartment. The small kitchens               Aldes Constant Air Regulator (CAR)                     standard will eventually allow for the nor-
         therefore required a provision for 120             dampers at each bathroom exhaust point                 malized comparison of buildings in differ-
         CFM of mechanical ventilation (not                 in order to assist in balancing exhaust air            ent parts of the country, as is done with
         necessarily continuous). Ironically, the           flows from floor to floor and from season                 single-family homes. From a developer
         smallest apartment requires the most               to season. CAR dampers incorporate a                   standpoint, this baseline approach does
         ventilation by code.                               silicone bulb that expands when the pres-              not give credit for those specifications that




          16                                                 www.homeenergy.org                                 NOVEMBER/DECEMBER 2006 • HOME ENERGY
are found in ASHRAE 90.1 but                                                                                     Next Steps
have not been included in a                          Estimated Annual Energy Costs,
developer’s previous projects.                       MLK Apartments                                                   Now that the 1212
However, the goal of this pro-                                                                                    MLK Apartments are
gram is to raise the bar and                                         Appliances: $19,400                          occupied, SWA will col-
                                                                     (37%)
encourage the construction of                      Lighting:                                                      lect utility bills for a year
better buildings.                                  $14,800                                            Cooling:    in order to provide a real-
                                                   (29%)          Heating:        Hot water: $7,200   $3,400      ity check on simulation




                                                                                                                                                       Multifamily
                                                                  $8,000          (14%)               (5%)
Whole-Building                                                    (15%)                                           results and to provide
                                                                                                                  feedback to Dunn Devel-




                                                                                                           SWA
Energy Performance                                                                                                opment Corporation and
   Energy savings were evaluated                                                                                  Beulah HDFC, Incorpo-
by comparing simulations of the                                                                                    rated, on building perfor-
building to the baseline building.                 Estimated Annual Energy Costs,                                  mance. In addition, with
All simulations and projected                      Baseline Building                                               funding from HUD’s
energy savings have been devel-                                                                                    Partnership for Advancing
                                                                      Appliances:
oped using TREAT, Version                                             $24,900
                                                                                                                   Technologies in Housing
3.0.19 software.The final design                                       (39%)                                        (PATH) program, SWA
                                                Lighting:
resulted in a 20% reduction in                  $17,100
                                                                                                     Cooling:      also installed long-term
estimated energy consumption                                                         Hot water:      $2,300        monitoring equipment to assess
                                                (26%)              Heating:
                                                                                     $8,900          (3%)
compared to the baseline build-                                    $11,200                                         ventilation system performance
                                                                   (17%)             (14%)
ing. Put another way, the energy                                                                                   in one line of six apartments.




                                                                                                           SWA
performance of 1212 MLK                                                                                               Dunn Development Corpora-
Apartments is 20% better than                                                                                      tion has already incorporated
that of an already pretty good            Figures 1 and 2. Installing four high-efficiency front-loading
                                                                                                                   some details from 1212 MLK
(ASHRAE             90.1-compliant) clothes washers in the first-floor laundry room was the most cost-               Apartments, such as the 1-inch
building (see Table 2 and Figures effective ECM. Both electricity and hot water use of clothes washers             Roxul insulation, into its standard
1 and 2). Projected costs are is reflected in the “Appliances” wedge of the pie charts.                             specifications for future projects.
based on energy prices of                                                                                          SWA hopes that information from
$0.15/kWh and $1.49/therm.                                                                                         the field monitoring will prove
   Installing four high-efficiency front-                                                                    useful, both by giving the developer
loading clothes washers in the first-floor                                                                    confidence in the performance of new
laundry room was the most cost-effective                                                                    building systems and by helping to
ECM. Both electricity and hot water use                                                                     identify opportunities for further
of clothes washers is reflected in the                                                                       improvement.
“Appliances” wedge of the pie charts.
Based on an assumption of nine loads of                                                                     Marc Zuluaga and Gayathri Vijayakumar are
laundry per day per washer, upgrading the                                                                   engineers at Steven Winter Associates.
Modified Energy Factor (MEF) of equip-
ment from 1.04 (baseline) to 1.89 (as                                                                       Steven Winter Associates would like to thank
                                                                                                  SWA




built) will result in a savings of $5,127 per                                                               Mike Colgrove at NYSERDA for his work in
year.As is typical in New York City, wash-                                                                  developing the pilot program and Mark Zimet
ers and dryers are leased, which means                                                                      at Dunn Development for his open mind
                                                    1212 MLK Apartments also incorporates Aldes
that one of the most important ECM                  Constant Air Regulator (CAR) dampers at each            throughout the whole process.
decisions was not finalized until the very           bathroom exhaust point. In order to regulate air
end of the construction process.                    flow, CAR dampers incorporate a silicone bulb
   Installing top-of-the-line OTIS Gen2             that expands when the pressure drop across the
                                                    damper exceeds 50 Pa.
“machine room-less” elevators was the
least cost-effective ECM. Using an on-
line Otis Energy Expense calculator,               ing.These results indicate that in a six-
SWA estimated a savings of 800 kWh                 story multifamily building, state-of-the-                   FOR MORE INFORMATION:
per year.This savings estimate was based           art elevator technology is not justified
on an assumption of 360 rides per day              based on energy savings alone (there are,                   For more on 1212 MLK Apartments, go
for the building that was derived from             of course, maintenance and reliability                      to www.dunndev.com/L3/mlk.html.
research done by Henry Gifford in                  benefits associated with new elevator
another six-story New York City build-             technology).



HOME ENERGY • NOVEMBER/DECEMBER 2006                                                 www.homeenergy.org                                              17

				
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