Ventilation a Pivotal Part of Home-performance Installations
Homeowners considering tactics such as air sealing to save energy and money
With heating and cooling accounting for more than half of the energy use in a typical U.S. home, per the U.S. Department of Energy (DOE), more and more homeowners are considering tactics such as air sealing to save energy and money. In fact, according to the American Institute of Architects (AIA) 2013 Home Design Trends Survey, 63 percent of responders desire greater energy efficiency in their homes. However, only 35 percent said they wanted improved indoor air.
Part of the disconnect between the two could be industry professionals are not doing an adequate job of explaining the importance of ventilation to homeowners. As home-performance contractors spend considerable time sealing air leakage in homes, much of this responsibility lands on them. Ensuring proper ventilation is one of the most important jobs for a contractor, according to David Richardson, curriculum developer and a trainer for the National Comfort Institute (NCI).
“Homes have been dependent on natural ventilation for so long, and you don’t get that with a house that’s sealed up, so it has to be taken care of mechanically,” said Richardson. “When it comes to ventilation, if it’s not done, there can be a lot of unintended consequences, especially when it comes to moisture control.”
Contractors should know the source of their ventilation air, said Richardson. “Contractors often install exhaust fans that pull air out of a house and then depend on entering natural air from wherever it enters to provide the necessary ventilation air. The problem with that is you don’t know where the air is coming from. It could be coming from the attic, a crawlspace, a fireplace, or the flue of a water heater. If you’re exhausting air from a fan to the outside, the laws of airflow don’t change. If 1 cfm is being exhausted out of the building, there’s 1 cfm coming back in someplace else to replace it. Knowing where that’s coming from and how it’s going to impact the customer is important. Putting in a fan like that could make a system worse, especially if the customer has asthma, allergies, or something like that.”
Testing and verification is also extremely important when it comes to ensuring a building has proper ventilation, Richardson noted.
“It’s common for guys to slap a fan, heat recovery ventilator [HRV], or energy recovery ventilator [ERV] in, hook it up, and say they’re done. They rarely verify it to make sure it’s truly performing as it’s supposed to. So, promises won’t be fulfilled and performance will suffer. You have to verify to ensure customers are getting what they pay for. You also don’t want to over-ventilate a house, because in a humid or mixed-humid climate, you can add moisture to the home faster than the HVAC system can remove it.”
Another aspect of testing and verification applies to home appliances. Richardson said contractors should be testing them for carbon monoxide before and after any work is completed. “You don’t want to go in and make an appliance more dangerous by changing the airflow patterns of the house.”
EMPLOYING POSITIVE PRESSURE
Without fresh-air ventilation, indoor pollutants, cleaning agents, and volatile organic compounds (VOCs) from paint and furnishings can build up and become dangerous to breathe, according to Eric Robnett, owner of Home Energy Experts in Reno, Nevada.
So, how do home-performance contractors solve this problem?
“They definitely should be introducing air into the home in a positive pressure,” Robnett said. “Negative pressure draws pollutants and contaminants into the home and can cause a reverse venting situation with any atmospheric appliances. Just like anything else that people buy from us, we must offer it [ventilation]. We use smoke to help people visualize air pressure in a home relative to the outside. We find most homeowners do not like to see what happens when outside air is pulled in, especially air from fuel-burning appliances, a flue pipe, or fireplace chimney.”
VENTILATION OVER ENERGY SAVINGS
Brett Nejmanowski, president of JT Dunn Heating and Cooling in St. Louis, has seen ventilation issues arise from energy-saving programs offered by utilities.
“A number of studies show energy savings as the No. 1 thing in consumers’ minds, yet indoor air quality and ventilation rank near the bottom as far as importance,” Nejmanowski said. “Those two should be flip-flopped, really. In order to obtain energy savings, they’re tightening up their homes to the point where they become too tight. And a lot of consumers aren’t aware of what they’re creating. These utility company programs are designed in such a way that their success is rated by how many watts they save. So, naturally, they want to tighten homes up as much as possible because that saves more watts.
“Utility companies tell consumers they only need to put bathroom fans in on an intermittent timer and that this bath fan will kick on and basically ventilate the whole house,” he continued. “That’s not totally correct because, let’s say the bathroom door is shut and this fan is kicking on, it’s not going to properly ventilate the house.”
Nejmanowski said whole-home ventilation systems should be installed instead so that every single room is receiving the proper amount of ventilation, not just the bathroom. “Unfortunately, in a quest for saving watts, power companies and a lot of heating and cooling companies are losing sight of what’s most important, and that is the health of the individual in the home. That means proper ventilation, not just a bath fan that kicks on intermittently as a ventilator.”
Customers are already calling heating and cooling contractors for comfort and energy savings, so contractors now need to make them aware of the health part of the IAQ and ventilation equation, Nejmanowski noted. “It’s critical that ventilation is implemented on a room-by-room basis, and a whole-home system does that. If we’re just focusing on certain rooms, the second little Bobby goes into his room and shuts his door, he could breathe in who knows what. There are so many products out there that people can buy that exhaust into the room and make them feel sick. There was that toxic drywall in China and children’s toys containing lead, so who knows what else is going into these building products. We can’t leave it to chance or luck that the home’s going to be full of fresh air.”
When it comes to selling ventilation to customers, it’s important not to make any assumptions, Richardson noted.
“Personally, everybody deserves
the best, but whether they can afford that or want to spend money on it is up to them. Make all the options available and let the customer choose. A lot of times, we may be guilty of providing a one-size-fits-all option when that may not be what the customer really wants.”
SIDEBAR: ASHRAE PUBLISHES 2016 RESIDENTIAL IAQ STANDARD
Multifamily units in all types of buildings are now covered in the scope of ASHRAE’s residential indoor air quality standard, marking one of the biggest changes to the recently published 2016 version.
ANSI/ASHRAE Standard 62.2-2016, “Ventilation and Acceptable Indoor Air Quality in Residential Buildings,” defines the roles of and minimum requirements for mechanical and natural ventilation systems and the building envelope intended to provide acceptable IAQ in residential buildings.
Prior to this edition, multifamily residential buildings four stories or taller fell under the scope of ANSI/ASHRAE Standard 62.1, “Ventilation for Acceptable Indoor Air Quality.” Now, the dwelling units themselves are covered by 62.2, regardless of building height, while common areas of those buildings remain in the scope of 62.1, according to Paul Francisco, chair of the Standard 62.2 committee.
Francisco said the change provides consistency of ventilation requirements for dwelling units regardless of building height. For new construction, this will result in a change of requirements for dwelling units in four-story-and-taller buildings. For the retrofit market, this change will result in coverage by ASHRAE ventilation standards for the first time in residential dwellings in four-story-and-taller buildings. The 2016 standard also includes a method to claim an infiltration credit for horizontally attached units.
Another major change in the standard provides a means of determining equivalency for a variety of ventilation scheduling strategies. This change also includes a maximum short-term exposure to make sure that meeting annual equivalence does not unduly compromise short-term IAQ.
For more information, visit www.ashrae.org/bookstore or contact ASHRAE’s customer contact center at 800-527-4723.
SIDEBAR: AMCA REVISES AIRFLOW APPLICATION MANUAL
The Air Movement and Control Association (AMCA) Intl. Inc. recently announced the revision of AMCA Publication 600, “Application Manual for Airflow Measurement Stations.” The new designation is AMCA Publication 600-16.
This application guide is intended to assist designers and users with the proper application, performance considerations, selection, and limitations of airflow measurement stations.
The March 2016 revision helps designers and users avoid problems associated with misapplied or incorrectly installed airflow measurement stations (AMSs). Problems may include incorrect location, inappropriate measurement range, mismatched accompanying instrumentation, and an AMS incompatible with intended application. AMCA 600-16 provides an overview of permanently installed AMSs and their application. It does not address portable devices used to measure airflow in test-and-balance applications. It is not the intent of AMCA 600-16 to be used for detailed specifications; rather, it serves as a guide for understanding the various types of AMSs available and items to be considered for their proper use.
AMCA 600 is the latest publication from AMCA covering air-monitoring stations. ANSI/AMCA Standard 610 (2012) is the rating test standard for air monitoring stations, and AMCA Publication 611 (2015) describes the AMCA Certified Ratings Program for air-monitoring stations rated in accordance with AMCA 610.
For more information on AMCA Publication 600-16, visit http://bit.ly/1qqgdAb.
Publication date: 4/18/2016