AeroBarrier is touted as the best route to never fail another blower door test. The technology, which involves pressurizing a space with a blower door fan while misting a water-based glue into the air from multiple points throughout the space, is most often being used on new multifamily buildings after drywall is installed. SWA first experimented with the technique on the Cornell Tech high-rise building. Back in March, I reached out to Yudah Schwartz at SuperSeal Insulation, Inc. about a personal project, the gut rehab of a 2,500 SF detached single family home. While renovations aren’t something they normally do, Yudah and his team agreed to try a demo. Here’s what happened.
Tag: Product Reviews
Does Your Exhaust Fan Suck? Part 2
If you recall from Part 1 of this article written back in September, we discussed why exhaust fans often don’t operate as they are intended. Now, let’s discuss how to rectify these issues. First, we need to understand that all fans are not created equal. To do this, SWA participated in a “blind” study that analyzed a number of today’s common exhaust fans. The study emphasizes the importance of fan selection. With this understanding, we will then discuss solutions and best practices for installing bathroom exhaust ventilation.
The “Blind” Study
To get a comprehensive performance dataset for a number of exhaust fans, the Riverside Energy Efficiency Laboratory (REEL) was engaged for a “blind” study. REEL is the HVI/ESTAR neutral, third-party testing facility. In total, 7 multi-speed fans, 7 single speed fans, and 6 low-profile fans from six manufacturers were sent to REEL without manufacturer markings. In general, ten-point airflow tests were conducted on each fan. Testing adhered to standards used in the industry, namely, ANSI/AMCA Standard 210 and HVI Publications 916 and 920, where applicable. While the dataset is extensive, this paper focuses on the 50, 80, and 110 cfm ventilation rates, as these are the most common specified fan speeds for bathrooms. These fan curves show the relationship of airflow that will be delivered at various static pressures of the duct system.
Figure 1 shows fan curves for single speed fans that were tested. The units are rated for 80 cfm unless noted otherwise in the legend (two are rated for 70 cfm and one for 90 cfm). While all of these fans performed in a similar manner, would it surprise you that two of the fan curves in Figure 1 are for exhaust fans that use DC motors? People often assume that all fans using DC motors are the same and result in constant airflow for a range of static pressures (let’s say up to 0.4” w.g.).
It is clear in this data (Figure 1) that flow rates decrease rapidly when static pressure rises over 0.3” w.g., as it often does in real world installations. Oh, are you still wondering which two fans have DC motors? It is actually SS-05 and SS-06. A bit surprising, isn’t it?
What is the Carbon Footprint of Your Holiday Shopping?
Have you ever wondered about the carbon footprint of your shopping habits? Is online shopping better for the environment than brick and mortar shopping? There are many studies on the subject and there are myriad factors to consider when answering these questions. To try and make this process a little easier, we have pulled together existing research and have developed a guide to reducing your carbon footprint this holiday season.
One 2013 study by MIT looked at the impact of online vs. in-store shopping for a few items (a t-shirt, a Barbie Doll, and a computer) and concluded that a few key factors can tip the scales in either direction. While this study ignored the impact of the embodied carbon of these items (more on this later), let’s look at the biggest factors that could contribute to your holiday shopping carbon footprint and factor into the store vs. online debate.
Low-Carbon Concrete: Reducing the Embodied Energy of a Notorious Emitter
It is safe to say we are in a climate crisis. Of the last 17 years, 16 have been the hottest on record. Sea level is expected to rise by as much as eight feet by the end of the century. And by 2050, as many as 140 million people will have been displaced by climate change. The time to act is now, and a major area of impact is buildings, which account for 40% of carbon emissions in the United States. Better envelopes, lighting, and mechanical systems are helping buildings become more efficient, which means an increasing proportion of carbon—up to 68% of a building’s lifetime emissions—is locked up in materials. This “embodied” carbon gets released during a material’s extraction, manufacture, transport, maintenance, and, eventually, disposal.
If our industry is to meet the 2030 Challenge of carbon neutrality by the close of the decade, we will need to reevaluate building materials and select low-carbon alternatives.
Figure 1: Courtesy of Faithful+Gould
Innovations in Accessible Products
Our accessibility consultants are constantly on the lookout for improvements in product design that will make it easier for our clients to comply with accessibility criteria. As manufacturers become more familiar with accessibility requirements under applicable federal, state, and local regulations and building codes, a number of innovative, accessible products have emerged to make compliance simpler and more stylish.
Here are just a few examples of accessible products that we have been recommending recently…
Arc – A Performance Approach
“What gets measured, gets managed” – Peter Drucker. This old management adage couldn’t ring more true in the world of sustainability.
The green building industry increasingly relies on the collection and analysis of data to inform a spectrum of building improvements, including monitoring and mitigating the impact of operations and management. The GBCI has embraced this new direction by developing and releasing a new online platform, called Arc, which collects, manages, and benchmarks building performance data as projects move toward LEED certification.
The Adventures of Mo and Her No Mow Lawn
I always thought the phrase ‘about as interesting as watching grass grow’ conjured a vision of ultimate boredom. That was before I attempted to grow my own no mow lawn. It turns out that watching grass grow can be a roller-coaster of emotions: the angst of wondering whether my inability to precisely follow directions would matter… the excitement of seeing the first blades of green poking up… the anguish over bare spots… and the pride over healthy, lush sections.
For years I advised clients to consider no mow lawns in their green homes, but I had never seen the end product through a full cycle of seasons. Friends of friends who own a turf farm expressed their interest-slash-skepticism at my undertaking, which more or less echoed the sentiments of a whole stream of landscape architects before. “Sure, you could try no mow if you really WANTED to… ” A search of local nurseries turned up nothing available. I couldn’t figure out why something that sounded so ingenious wasn’t more popular! An internet search for “no mow grass” turns up Prairie Nursery in Westfield, WI as a major supplier. A colleague used their product, and they were extremely helpful on the phone, so I ordered the No Mow Lawn Seed Mix online.
It Can Take Years – A Market Adoption Story
Earlier this year, at the AHR Expo in Orlando, the biggest trade show for HVAC professionals, Aeroseal’s duct sealing technology was declared the Product of the Year, the top honor of the Innovation Awards. Aeroseal was recognized as “a groundbreaking solution to an industry-wide problem.”
The unique appeal of the Aeroseal technology is that it seals ducts from the inside. Walls and ceilings do not need to be removed or damaged to gain access for traditional mastic sealing. Aerosolized vinyl polymer particles from 2 to 20 micrometers are injected into a pressurized duct system. The particles stay suspended in the air stream until they reach the leaks, where they are deposited and built up at the leak edges until the leaks are sealed.
The Aeroseal technology has been around for more than two decades. It was developed at Lawrence Berkeley National Laboratory in the early nineties and patented in 1997. It has received many awards over the years including the Best of What’s New award from Popular Science magazine in 1996 and the Energy 100 award from the U.S. Department of Energy.
So what’s the big deal?
Recalculating Solar Savings
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…)
The $300 Investment Every New Construction Home Should Make
Whether code built or energy efficient, if your new home has a poured concrete foundation and floor slab, please pay particular attention to the following. While older, leaky homes result in low interior moisture levels (thus the desire for humidifiers on central furnaces); newer, tighter homes will typically have relative humidity levels in the 25-50% range naturally.
In some cases, there is a need to actually dehumidify to maintain relative humidity below 50% during the winter. In the first 1-2 years after the home is built, concrete foundations expel massive amounts of moisture as part of the concrete curing process called “hydration”. As the concrete cures, some of the water in the concrete mix reacts chemically with the portland cement and forms the hardened concrete, and some of the water evaporates to the surrounding air. The exterior water resistant/proof coating on the below grade portion of the foundation prevents moisture from escaping that way. Typically only a 1-2 foot tall area along the perimeter of the above-grade portion of the foundation is available for drying to the exterior. It is more likely that the moisture will be expelled to the interior of the home and therefore, must be managed to prevent deleterious moisture-related problems such as condensation, mold, wood rot, etc. Framing lumber also contributes: lumber that starts out kiln-dried at 18% moisture levels, will eventually end up at 6%.
How to deal with that moisture? Here is that cheap investment alluded to: an ENERGY STAR dehumidifier with a built-in humidistat. This unit should be plumbed to a drain to allow continual operation (without having the occupants empty a bucket). In addition, the dehumidifier should be installed in the basement or crawlspace as soon as the structure has been enclosed and power is available. In terms of the construction process, it is recommended that the foundation be the last item to be insulated to allow for the internal construction moisture to be removed prior to enclosing. After a year or two of occupancy, construction material moisture levels will become stabilized at “normal” levels. In the interim, remember to “build-tight and ventilate right”, but also manage that construction moisture.