Contractors Custom Build Their Most Efficient Ventilation Systems – ACHR NEWS

There is not one universal blueprint when it comes to high-efficiency air movement and ventilation equipment in residential spaces. Energy recovery ventilators (ERVs); heat recovery ventilators (HRVs); blowers, and high-volume, low-speed (HVLS) fans are all important HVAC components that can deliver the high-end, highly efficient performance consumers are looking for.

And these options are certainly in high demand.

According to a recent report from Navigant Research, worldwide revenue from ERVs will nearly double from $1.6 billion in 2014 to $2.8 billion in 2020.

Along with new standards and regulations, the heightened sensitivity to how the health and comfort of office workers affects productivity is driving increased acceptance of IAQ technologies in more buildings, said Benjamin Freas, research analyst with Navigant Research, per a release. ERVs are growing in popularity because they provide energy-saving benefits without sacrificing IAQ.

Manufacturers consistently deliver new products in high-efficiency categories (as detailed on Page 12), so where do contractors even begin when they are deciphering the options available to them in the high-efficiency arena? Are there certain types of products that are essential? Or, is each situation truly unique?

To try and tackle these questions head-on, members of The NEWS advisory board were presented with a simple prompt: If you were to design a high-efficiency movement/ventilation equipment system, what products would you choose for the job and why?

Those with experience in this highly specialized area of HVAC answered in a variety of interesting ways.

Rob Minnick, CEO and president of Minnicks Inc. in Laurel, Maryland, said he would choose a ductless system, an ERV with bath fans tied into it, and maybe a dehumidifier, if the job required it.

[These options are] more efficient, offer more control for comfort, and there is no duct-loss outside of any ductless system that may have some ducts usually in the bedroom area, he said. The efficiency benefits of both an ERV and HRV are substantial.

HRVs minimize energy loss by taking cooled or heated air and swapping it with exterior air. This process transfers some of the heat or coolness from the internal air to the air entering the space. The issues presented by ERVs and HRVs are often the fact that not all contractors have the knowledge to install them. They can require a great degree of maintenance but when installed and maintained properly, they provide honest value to homeowners.

I often receive similar questions from customers asking what I installed in my house and why, said Travis Smith, owner, Sky Heating and Cooling, Portland, Oregon. Well, when I custom built my house last year, my first priority was my HVAC system. My 3,500-square-foot home in Portland, Oregon, has a WaterFurnace Intl. Inc. 3-ton variable capacity geothermal system with variable-speed pumps and four zones. The system has an air scrubber, Trane CleanEffects whole-house air-filtration system, and a Lifebreath 155ECM HRV for ventilation since the home was very well sealed. The ductwork was sealed with Aeroseal LLC duct-sealing equipment that gave us less than a 10-cfm leakage on the ductwork. We have a WaterFurnace NSW025 geothermal water heating system to provide hot water and a Mitsubishi Electric FH15 ductless system to heat, cool, and dehumidify the garage since its a below-ground garage.

Smiths second home is smaller, at 2,100 square feet, so he didnt go with a geothermal system but still wanted a high-efficiency system in place.

This home has a 2-ton Trane XV18 variable capacity air conditioner with a S9V2 dual-stage gas furnace and a two-zone Trane system. Because this home is in the high desert, we have an Aprilaire steam humidifier and plan on adding a Navien Inc. tankless combi-boiler and a radiant floor for the lower floor of the home. We will also be aerosealing the ductwork soon, but we bought this house and did not custom build it.

When considering high-efficiency options, Russ Donnici, president of Mechanical Air Service Inc. in San Jose, California, believes that equipment selection, as long as it meets the projects requirements, is actually less important than duct sizing and installation quality.

A high-efficiency system has to produce measurable high-efficiency results and be quiet, he said. Branch duct sizing should be 0.07 inch to 0.09 inch of static. In addition, register selection is important since not all registers of the same size have the same net free open area. We select registers for NC [noise criteria] 20-25 rating.

The California Energy Commission requires testing of duct systems to be sure their leakage is 6 percent or less of the systems airflow capacity, so Donnici said his company seals and tests to 3 percent, so they know they are delivering the proper airflow.

We are a Bryant dealer and use the companys variable-speed condensing furnaces and fan coils, he said. In special cases, we may use some Trane commercial equipment or build up a system we design for high efficiency that may need to overcome the pressure drop of high-efficiency particulate air [HEPA] filters. Typically, we would use a Greenheck fan or a similar fan depending on the total external static pressure [TESP] of the system.

Rich Morgan, president, Magic Touch Mechanical Inc., Mesa, Arizona, said his company does quite a bit of work on the home-performance side of the business, and because of that experience, the companys efficiency improvements often include air sealing and other measures that tighten up a homes envelope.

This often means adding a means of mechanical ventilation, said Morgan. We typically opt for an HRV in these scenarios. Most often, we specify the Lennox Intl. Inc. Healthy Climate HRV as weve found them to be reliable, easy to install, and homeowners are both familiar and comfortable with the brand.

Publication date: 5/15/2017

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Contractors Custom Build Their Most Efficient Ventilation Systems - ACHR NEWS