Party Walls

Last week, I had the opportunity to visit the DURAhome, New York City College of Technology’s entry for the 2015 Solar Decathlon. This project is currently nearing completion at the Brooklyn Navy Yard. Over the past 3 months, more than sixty students have toiled around the clock to finish construction in time for the contest, which will take place October 8-18 in Irvine, California. The Solar Decathlon is the U.S. Department of Energy’s biennial competition that challenges college and university student-led teams to design and build solar-powered net-zero homes that are affordable, energy-efficient, and aesthetically appealing.

TeamDURA’s focus was to create a prototype of post-disaster housing that is suited for New York City’s high-density urban environment, and could serve as a shelter in the aftermath of a catastrophic storm. As such, multifamily, multistory solutions were preferable to traditional single-family trailers, which have larger footprints. DURAhome consists of several prefabricated modules that can be packaged and shipped on standard-sized tractor trailers for quick response at low cost. These flexible modules can then be joined in standalone configurations or stacked for multifamily uses. Like the city, the DURAhome is diverse, urban, resilient, and adaptable.

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I love to cook. And like most cooks, I love to cook on my gas range. But I am also a building science researcher, and the researcher in me doesn’t understand how we allow gas ranges in homes. Building codes and energy efficiency programs have pushed the housing market towards all combustion appliances being sealed combustion and direct vent. Our furnaces, boilers, water heaters, and fireplaces are all going towards sealed combustion. Soon it is likely that building codes won’t even give you the option of using open combustion devices. This push for sealed combustion is an effort to drastically reduce the health hazards of carbon monoxide poisoning and other contaminants in our homes. As a researcher, this makes complete sense to me…but I, like many others, say “Don’t touch my gas range.”

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According to the Institute for Market Transformation, fourteen cities, two states, and one county in the U.S. now have energy benchmarking and transparency policies in place for large buildings. This means that continually more cities and jurisdictions will have an understanding of how their buildings perform. It also means that these policies and their outcomes can be compared against each other and ultimately improved.

 

With these improvements in the policy landscape impacting the built environment, the question was asked: How can the data be analyzed, and what impacts do the policies themselves have on building energy usage, greenhouse gas emissions, and the local economies?

At the end of May the Department of Energy (DOE) published the DOE Benchmarking & Transparency Policy and Program Impact Evaluation Handbook, which provides “cost-effective, standardized analytic methods for determining gross and net energy reduction, greenhouse gas (GHG) emissions mitigation, job creation and economic growth impacts” for jurisdictions that operate benchmarking policies.

Also released in May was the New York City Benchmarking and Transparency Policy Impact Evaluation Report which utilized real NYC data using the same methodologies.

SWA worked with the Navigant Consulting and DOE teams to review data from two jurisdictions and develop methodologies for analysis.

The general findings of the research team were: (more…)

Ten years ago, seeing a solar electric system on a building was noteworthy. Now they’re popping up everywhere. Lower cost is obviously a big driver of this solar surge; photovoltaic (or PV) system costs have dropped 50-70% in the past 10-15 years. Over the past decade, SWA has helped developers and owners install PV systems on hundreds of buildings. The systems are reliable, they have no moving parts, and they will convert sunlight to electricity for decades.

The cost effectiveness of PV, however, is not always clear. In fact, SWA has seen a concerning trend where the cost benefits of PV are exaggerated. Although costs vary with region and application, installed costs of PV are usually $3,000 – $6,000 per kWSTC.

Then there are incentives, including two key federal programs:

• 30% Federal tax credit
• Accelerated depreciation (for businesses)

Other incentives vary greatly from region to region:

• State, local, and utility rebates or credits
• Sale of Renewable Energy Credits (RECs)

The Database for State Incentives for Renewable Energy (dsireusa.org) has a good summary of these regional incentives. Federal and regional incentives can easily lower PV system costs by 50% — often more.

The final piece in assessing cost effectiveness of PV is the electricity savings. With PV generating electricity for your building, you’ll obviously be paying less to the utility. But how much less? (more…)

 

Calendar year 2015 marks the start of the third year of mandatory Local Law 87 compliance in NYC. The Law—which requires buildings over 50,000 sq ft to conduct an energy audit and retro-commissioning study once a decade—has, to date, been characterized by market uncertainty and a somewhat hesitant response from the real estate community. These conditions stem largely from an unclear expectation as to what the future will hold, and what, if any, blow back there might be for being the owner of a poor-performing building.

This lack of clarity has created a wide diversity in the approach that owners opt to take in complying with Local Law 87. A notable pool of building owners, for example, have viewed the law as a burden enacted by NYC, and have opted to take the cheapest available, low-bidder approach to compliance. A large number of newly formed energy consulting firms have popped up to provide “cheapest-in-class” services, this despite the fact that many of these startup firms lack the qualifications and experience necessary to actually perform a compliant Local Law 87 project. As is almost always the case, you get what you pay for. On the other hand, a different set of building owners have viewed the law as an opportunity to improve the performance of their buildings by engaging the service of discerning engineering service providers. These owners see the value in having a 3rd party vet the operation of their buildings, as they realize that operational cost savings drop straight to the bottom line, driving improved NOI, increased asset value, while guarding against the risk of future volatility in the commodity markets.

The real estate community has, by and large, accepted Local Law 87 as a fact of life, but the lack of a clearly demonstrated vision of future goals has created a deeply fragmented understanding of how the Local Law 87 process can and will impact a building’s operation. Signs, though, are pointing toward a clarification of what this process will require into the future, and there is reason to believe that the lay of the land will be quite different in years to come. For starters, the DeBlasio administration, in the fall of 2014, issued their One City Built to Last plan. This ambitious plan provides a policy framework for achieving 80% emissions reductions in NYC by 2050—no small task, to be sure. The aggressive nature of the plan requires that the city dig deep into the performance of the built environment in order to achieve these reduction targets, as buildings account for about 70% of NYC emissions. The DeBlasio administration has taken a “carrots and sticks” approach toward compelling change and ensuring adherence to their agenda: state and local incentives have been dangled in front of the real estate community to encourage proactive adoption of energy conservation practices by building owners, while the not-so-thinly-veiled threat of future mandates loom on the horizon for those actors that fail to take appropriate action. As DeBlasio was quoted in a September Real Estate Weekly article, “For private buildings, we’ll set ambitious targets for voluntary reductions, but if steady progress is not made, we will issue clear mandates,ˮ said deBlasio, adding, “Our long-term goal is bolder still — charting a path to a full transition from fossil fuels.” Again…not so thinly veiled.

Notable carrots include limited time incentive programs, such as the Demand Management Program offered jointly by NYSERDA and ConEd, and the forthcoming establishment of a retrofit accelerator program, which will scrub Local Law 84 (benchmarking) and 87 data to facilitate engagement between key stakeholders as the City attempts to play matchmaker in a Love Connection style game of emission reduction through market transformation. Many in the real estate and sustainability arenas see great promise and opportunity in these models.

Love it or hate it, the real estate community and others need to acknowledge that the landscape is changing, and the vision of the future—at least as how Mayor DeBlasio sees it—is taking shape.
Early adopters of emissions reduction practices—e.g., buildings that participate in voluntary programs such as the Mayor’s Carbon Challenge and those that take a more rigorous approach to the Local Law 87 process—stand a better chance of avoiding the “heavy hand of government” that DeBlasio so publicly campaigned on. And they might even get to munch on a few carrots along the way.

Measurement enables Management; Transparency enables Accountability… The quintessential concepts driving adaptation of mandatory energy benchmarking legislation.

Mandatory energy benchmarking represents a pivotal step towards reforming energy usage in American cities, as it galvanizes populations through collective reduction. Like any immature “innovation”, the practice faces barriers and static hindering widespread adaptation and dissemination into the mainstream.

What factors influence proliferation?

Unique building stock and varied regulatory needs necessitate city-specific reporting plans. Until there is a scaleable model of best-practices, development will continue to be resource and time intensive for administration.

Complexity in execution threatens data integrity and program usefulness. Unintentional errors, difficulty in obtaining information, and unfamiliarity with ENERGY STAR’s Portfolio Manager all weaken database strength. The remedy lies in educating elected reporters. Program handlers must be well versed with the operations and techniques necessary to perform their role effectively.

Stakeholder push-back during implementation deters participation and damages program reputation. Greater visibility of post-retrofit results will dispel doubts of program usefulness, while increased availability of financial incentives will quiet claims of marginalization [under-performers stigmatized as poor living options] and unfair penalization [fining of historic buildings or financially underserved properties].

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Energy Code. We could use that term for many things: how you feel after a cup of coffee, before a dreaded workout, or even at 2am when you’re staring at your bedroom ceiling knowing you have to be up in 4 hours. But here we’re talking about buildings, specifically in NYC.

Apparently, nine out of every 10 buildings have failed to meet the energy code, a set of standards that have been in place for a whopping 30 years. Crain’s New York published an article about it, featuring the NYC DOB’s audit results of thousands of architectural plans for new and renovated office and residential buildings.

Worried that your building might fail? Don’t fret, SWA’s in-house energy code expert, Michael O’Donnell, answered a few questions for us. Get the low down on what the energy code is all about and what these results mean.

Party Walls: So tell us, what is the energy code? And what (or who) brought about the need to enforce an energy code?
Michael O’Donnell: The energy code contains the minimum requirements that buildings must meet with regards to energy efficiency measures. According to the Department of Buildings, to meet the City’s goal of reducing greenhouse emissions by 30% by 2030, the New York City Energy Conservation Code (NYCECC) sets energy-efficiency standards for new construction, alterations, and changes to existing buildings. All new building and alteration applications filed on or after December 28, 2010 must comply with the 2011 edition of the NYCECC. The need to for an energy code has been around for many years but it is only really being enforced relatively recently.

PW: What are the benefits of a building meeting the energy code?
MO: Buildings that effectively meet the energy code will be better insulated, have better HVAC systems, and better lighting systems. As these systems are designed, implemented, and optimized, reduced operating costs for both owners and tenants will result. There are also environmental benefits of reducing greenhouse gas emissions achieved by utilizing less electricity and/or heating fuel.

PW: What are the potential risks of not meeting the energy code standards?
MO: Potential risks of not meeting the energy code include tenant comfort complaints, higher operating costs for electricity and/or heating fuel, and, more recently, action by the Department of Buildings. Energy code audits of building plans have the potential to stop a project in its tracks as well as impose fines for constructed buildings that are not meeting the code.

PW: What are the biggest reasons buildings fail to meet the energy code?
MO: There are a few reasons buildings fail to meet the energy code. Specific details are often missed or not included in the construction drawings and specifications. If details are not included, the contractor will not incorporate these items into what actually gets built. Even if specific energy related items are incorporated, the contractor may not have the knowledge to properly install or execute what is shown. Finally, it takes a trained inspector to know what to look for to ensure buildings are compliant with energy code. NYC requires the large majority of projects to file a “TR8: Technical Report Statement of Responsibility for Energy Code Progress Inspections” form through which a licensed architect or engineer takes the responsibility of inspecting for energy code compliance. This form is required in NYC, but other jurisdictions, which do not require the progress inspection run the risk of having items overlooked or missed since there is not a third party inspecting specifically for energy code items.

Read the Crain’s New York article here:
http://www.crainsnewyork.com/article/20140818/REAL_ESTATE/308179994/9-of-10-building-plans-fail-basic-test

In multifamily buildings, particularly in the Northeast, exhaust ventilation strategies are the norm as a method for meeting both local exhaust and whole-unit mechanical ventilation. We can easily measure that air is exhausted. What we don’t know is where the make-up air is coming from…

Is it “fresh” from outside, from the neighboring apartment, from a pressurized corridor, or the parking garage via the elevator shaft?
Well-intentioned design teams are providing fresh air in many forms, ranging from fully-ducted systems that deliver air directly to apartments, to more passive systems utilizing designed penetrations in the envelope such as trickle vents or fresh air dampers. With funding from DOE’s Building America program, SWA is conducting field research in several multifamily buildings with different types of mechanical ventilation systems to assess how make-up air is provided under the variable pressure conditions that can occur throughout the year.

The Approach
Even though it does not comply with fire codes in at least some jurisdictions, SWA‘s approach is to leave a gap under the apartment door to allow make-up air to enter from the corridor. The general strategy is to pressurize the corridor using outside air and depressurize the apartments through local exhaust. This strategy is being assessed in a 3-story, 78 unit building, where the design called for 5,250 CFM of supply air to the corridors and common areas and a total of 4,980 CFM of exhaust from janitor’s closets, and trash rooms, and continuous exhaust (30-50 CFM) from each apartment.

Measuring the Airflows
In order to extrapolate airflow measurements based on the varying conditions in the building, SWA measured airflows across the apartment door under normal operating conditions for eight apartments. Our team also monitored the pressure differential between the corridor and apartment over a two-week period for five apartments in the building.

Here’s a “Snapshot”
The measurements in the eight apartments showed that while exhaust fans were measured to continuously exhaust 30-40 CFM, the flow into the apartments through the doors ranged from 0 CFM to only 28 CFM. When bathroom exhaust fans in the apartments were activated to their “high” setting ( ~90 CFM each), the flow through the doors increased to an average of 37 CFM, still indicating that a majority of the make-up air is not from the corridor.

The long-term measurements in the five apartments showed airflow across the door into one apartment to max out at 24 CFM. The other four exhibited net airflow from the apartment into the “pressurized” corridor, as much as 40 CFM! Why?! One potential reason: measured supply and exhaust flows in the corridors showed that the supply systems were 25% lower than design and exhaust from the trash rooms was 25% more than design.

Stay tuned for a future post on our findings and recommendations.

Properly Sizing Mechanical Systems in Multifamily Buildings

Multifamily buildings can be a unique challenge when it comes to selecting effective heating and cooling systems. In the Washington, DC region’s mixed-humid climate, humidity control becomes a central challenge because of a couple inescapable realities.

1. There is a lot of moisture added per square foot from cooking, bathing and even just breathing due to the dense occupancy.
2. The small exterior envelope areas mean the air conditioner won’t kick on very often, and thus won’t have a chance to remove moisture.

High humidity can lead to complaints over comfort, condensation on registers and exposed duct work, and even mold. To effectively remove moisture, the air conditioner should run for long stretches. This means properly sizing mechanical system. Unfortunately many project teams exacerbate the problem by selecting grossly oversized cooling equipment that runs even less frequently.

Steps to Right-Sizing Mechanical Equipment

1. Perform accurate calculations using the Manual J process to estimate peak heating and cooling loads
2. Consult the manufacturer’s performance data at design conditions, and
3. Select the smallest piece of equipment that will meet the load.

Common Problems When Sizing Mechanical Systems

 “Can’t I just use the worst-case orientation?”

No. In most cases the largest envelope load in apartment units is the windows. A unit with floor-to-ceiling windows facing west will have very different loads than the same unit facing north, so be sure that the load calculation reflects the actual orientation. If the same unit type occurs in more than one orientation calculate the loads for each orientation and make selections accordingly. This may require different selections and duct layouts for different orientations.

“Can I use commercial software?”

Yes, but you have to be careful. Commercial load software like Train TRACE and Carrier’s HAP are primarily geared towards non-residential space types that have very different use profiles. For instance, in an office setting you would expect lighting and equipment to be 100% on during the peak afternoon cooling hours. However, in a residential setting few if any lights are on during the day.

The commercial programs also like to include more outdoor air than you actually see in apartments. A reasonably well-sealed apartment will have very little natural outdoor air infiltration (remember only 1 or 2 sides of the apartment “box” are actually exposed to outside) and mechanical ventilation should only be about 20-35 CFM depending on the size of the unit. It is not uncommon for loads to drop by half once those inputs are corrected.

 “Will small systems have enough power to get the air to all the rooms?”

Absolutely. First of all, the smallest split systems available are 1.5 tons, which is really not that small. Second of all, 1.5 tons air handlers are rated to 0.5 IWC external static pressure just like 2 and 2.5-ton systems. If that sounds like gibberish it means 1.5 ton systems have the exact same “power” to push air through long runs as larger systems.

The blower motor is smaller only because it’s pushing less air, just like a motorcycle has a smaller engine than a car but can still accelerate as quickly. We have seen 1.5 ton systems used in 1500+square feet  2-story homes. If you can’t get air to a 900 square foot apartment you have a duct sizing issue, which would be a problem no matter what size the air handler.

 “Doesn’t each room need 100 CFM of airflow for comfort?”

Well, maybe. Is 100 CFM what the load calculations show is needed? There is no such thing as a minimum airflow threshold for each room. The amount of air required is in direct proportion to that room’s heating and cooling load. If the calculations show a small load and only 40 CFM required you should supply 40 CFM. In fact, oversupplying 100 CFM will actually cause discomfort since that room will always be a few degrees off from the rest of the apartment. Sitting under an oversupplied register could be loud and drafty as well.

“But can’t I just size by bedroom count?”

No, rules of thumb don’t cut it anymore. For buildings built to 2009 or 2012 code in our climate zone (CZ4), most apartment units will have loads less than 1.5 tons, no matter how many bedrooms. There may be a few 2-ton or (rarely) 2.5-ton systems for larger apartments on the corner or top floor, but those are the exception.

If your mechanical plans show 1.5 tons for all 1 bedrooms and 2 tons for all 2 bedrooms it probably means

1. Accurate sizing procedures were not followed, and
2. A lot of those 2 bedrooms actually only need 1.5 ton systems

The only way to know for sure is to perform the calculations.

Conclusion

Most of these issues are the result of a very natural instinct to be conservative in the face of uncertainty. The truth is there are a lot of variables that will change the real-world heating and cooling load in a unit: how many people are in the apartment, when they are cooking, are they using blinds. The problem is in this case “conservative” means designing for temperature control at the expense of humidity control. Every extra ½ ton capacity means less dehumidification – that’s a fact. The only way to control both temperature and humidity is to perform accurate calculations, resist the urge to add extra safety factors, and size the equipment strictly according to the calculated loads.

As an added benefit, smaller equipment requires smaller electric service capacities. Especially in a rehab situation with existing service, choosing right-sized equipment is more likely to allow the use of existing service instead of requiring expensive service upgrades.