Fresh Air, Energy Savings, and Comfort: The Case for Air Handler Accessories

The ACHR NEWS asked several manufacturers about some of these products and how contractors might want to start conversations with their residential customers about adding them. Here’s what they had to say. 

 

Add Fresh Air, Save Energy 

When a customer complains about stale indoor air, mentions allergies, or has a newer, tightly sealed home built to modern energy codes, it might be time to suggest an energy recovery ventilator (ERV). 

ERVs introduce fresh air into ducted systems and save energy by preconditioning that air with the help of exhaust air, which has already been cooled or heated, and a heat exchanger. ERVs can also wick moisture from incoming air when the weather is humid, and harness moisture from outgoing air when it’s dry or cold outside, to help maintain comfortable indoor humidity levels. 

“This translates into lower HVAC loads, especially in extreme climates, and can contribute to noticeable reductions in heating and cooling costs over time,” said Chrystal Jolliffe, an IAQ product manager at Carrier. 

Carrier’s Performance ERV line has models with airflow capacities of up to 210 cfm; the airflow can be adjusted by the users. 

“These units typically integrate with smart thermostats or analog controls that allow homeowners to modulate airflow based on comfort preferences or seasonal needs,” Jolliffe said. “Some models also feature auto-balancing for simplified setup and operation.” 

While residential ERVs are “a good option in any climate where humidity control is a concern,” Jolliffe said, they’re most popular in humid regions, like the Southeastern U.S., and tightly sealed homes, in more northerly regions, that need fresh air without sacrificing heating. 

“Airtight homes have high potential to build up and hold contaminants inside of the house much faster than ‘loose’ homes, impacting the IAQ,” said Szabi Fekete, sales and quoting engineer at Zehnder America Inc. “The majority of the U.S. has humidity issues during the year, so having a unit that handles sensible and latent transfer will benefit those homes. ERVs introduce less humidity to the home during the humid season and lose less to outside during the dry season.” 

Zehnder offers three models of its ComfoAir Q ERVs, named for their airflow capacity: 350, 450, and 600 cubic meters per hour. ComfoAir Q units can recover up to 94% of outgoing sensible heat, Fekete said, and up to 72% of outgoing latent heat. 

An important consideration when gauging the net energy savings of an ERV, he added, is how much power (Watts per cfm) is needed to move fresh air into the system.  

“Zehnder is using one of the most efficient ECM (electronically commutated motor) fans available,” he said. 

 

Clearing The Air 

Homeowners who have particular concerns about IAQ and airborne contaminants might want to hear about air-purification products, such as the kind made by AprilAire. 

AprilAire’s Model AUV24V UV-C system uses short-wavelength ultraviolet light (UV-C) to kill up to 99.9% of coil mold, plus kill or render inactive other contaminants, according to Brooke Nontelle, an AprilAire product manager. 

“Odors caused by mold or bacterial buildup on the coils can smell musty like ‘dirty socks.’ Homeowners noticing these odors should consider installing a UV-C sanitation system,” said Chris Howells, a senior training and development manager at AprilAire. “Contractors noticing visual buildup of mold or bacteria on the coils during maintenance, or smelling these odors upon entering the house or mechanicals room, can present the AprilAire UV-C Sanitation System as a solution.” 

The Model AUV24V UVC is attached to an air handler, near the coil, and should cover as much of the coil surface area as possible with UV-C light. The lamp should be a minimum of 8 inches from the top of the coil for a front-mount installation, and a minimum of 3 inches from the top of the coil for a side-mount installation, Howells said. 

The AUV24V UVC has the added benefit of helping maintain an HVAC system’s energy efficiency by guarding against the buildup of biofilm on the coil. Biofilm buildup can reduce the coil’s heat-transfer efficiency, Nontelle said, in addition to containing contaminants that can be sent into the air. 

AprilAire also makes the 1000 Series media air cleaners, which offer MERV 11 filtration that can be upgraded to MERV 13.  

“We have found successful HVAC contractors take a consultative approach around indoor air quality by first listening to homeowner needs and concerns with a focus on health and comfort,” said Howells. “HVAC professionals are key in educating homeowners on the benefits of whole-home air purification.” 

The 1000 Series air cleaners trap particles before they accumulate on the coil, which helps improve IAQ and keeps the coil clean and running efficiently, Howells added. 

A 1000 Series air cleaner features a 4-inch pleated filter, designed to last up to a year, that has up to nine times the surface area of a 1-inch filter and thus has more particle-trapping ability. The 1000 Series models also present low static air pressure, Nontelle said. 

An AprilAire 1000 Series should not be placed downstream of a UV-C light, as the light can degrade the filter media, the company said. 

 

Getting Humidity Right 

In dry climates, or in wintertime in much of the country, homeowners might be interested in humidification products. Carrier’s Performance large, fan-powered model can put up to 18 gallons of water into the air daily and is designed to humidify homes of up to 4,200 square feet. 

“The system integrates with the home’s HVAC controls to regulate moisture levels, and when paired with a compatible thermostat or humidistat, users can fine-tune humidity settings for optimal performance,” said Carrier’s Jolliffe. 

Humidifiers are most commonly found in colder areas of the U.S., Jolliffe said, where winter air is dry. They maintain proper indoor humidity levels, which helps protect occupants from dry skin, dried-out nasal passages, and static shocks. They also protect wood flooring and furniture from cracking due to dry air. 

Humidifiers also help save energy. 

“By making the air feel warmer, homeowners can lower their thermostat settings and reduce heating costs,” Jolliffe said. 

In homes where too much moisture is a problem, a whole-home dehumidifier, such as the Santa Fe Ultra V155, might be the answer. 

The Ultra V155, just introduced in June, features an 8-inch ventilation duct (up from 6 inches on previous humidifier models), MERV 13 filtration, dual-coated coils for moisture removal, and a secondary drain port, and is Energy Star-rated, said Nikki Krueger, director of marketing and business development at Santa Fe Dehumidifiers. The model can remove up to 155 pints (nearly 26 gallons) of water from the air daily and is designed for homes of up to 3,500 square feet. 

The larger ducts, Krueger said, help meet ASHRAE Standard 62.2 (ASHRAE’s recommendation for ventilation and IAQ in low-rise residential buildings), and also provide more outdoor air to align with the Ultra V155’s dehumidification capacity. 

The Ultra V155 ventilation feature is optional, and the fan can be controlled by a thermostat, Santa Fe’s DEH3000 controller, or its SmartAire power damper, which includes a fan timer. 

“We are supplying air to try to help put a slight positive pressure on the home to minimize infiltration of hot, humid air from the outside,” Krueger said of the ventilation feature. “This is recommended in the building science community and can help prevent condensation in walls when achieved.” 

Santa Fe typically recommends whole-house dehumidifiers in “green grass climates,” Krueger said. 

“These are areas where there is an inch of rain or more a week during the humid seasons, spring, summer, and fall,” she said. “As homes are being constructed tighter and tighter, the more need there is for whole-house dedicated dehumidification. Tighter houses mean less a/c runtime — which is ultimately the goal of a tight home.” 

In addition, Krueger added, modern a/c systems prioritize temperature reduction over moisture removal in order to meet energy-efficiency goals. “This shift often leaves latent loads unaddressed, resulting in humid indoor conditions,” she said.