Launch Slideshow

Recovery Time

10 heat-recovery ventilators and energy-recovery ventilators.

Recovery Time

10 heat-recovery ventilators and energy-recovery ventilators.

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    Dan Walbridge

    Trane. The FreshEffects ERV achieves up to an HVI-certified 78% heat recovery efficiency using a high-performance, permanently lubricated ball-bearing motor and a plate energy transfer core with humidity control. Filters slide out for easy cleaning and maintenance. The heavy-gauge, powder-painted steel cabinet features closed-cell gasketing for insulating value and placement in unconditioned spaces; the cabinet design allows various installation options. Adjustable controls enable automatic ventilation. 903.581.3660. www.trane.com.

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    Carrier. Performance Series ERVs (pictured) and HRVs achieve 84% recovery and exchange efficiencies. Cross-flow (or counterflow) heat exchange cores ensure no mixing of the incoming and exhaust air. The units also feature a pre-filter for incoming air, automatic defrost, and either end ports (shown) or top ports for installation flexibility. Various sizes and cfm ranges are available per square footage and required air exchange rates. A trio of control options includes automatic recirculation and dehumidistat modes and continuous or intermittent fan operation. 800.227.7437. www.commercial.carrier.com.

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    RenewAire. HVI-certified EV Series ERVs achieve up to 76% heat recovery efficiency and serve general and spot ventilation needs. The units offer up to 315-cfm airflow rates to accommodate various conditions and requirements, feature MERV-8 filters, and consume less than 1 watt in standby mode. Cabinets are fully insulated with large internal cores for high efficiency and installation in conditioned or unconditioned spaces. Optional automatic proportional runtime control and push-button control are available. 800.627.4499. www.renewaire.com.
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    Honeywell. HVI-certified HRVs and ERVs (pictured) recover up to 80% of heating/cooling energy from exhaust air using about the same amount of energy as a 100-watt light bulb, says the company. Five-speed control, including frost control, enables optimum occupant indoor comfort; ERVs also regulate humidity to reduce indoor moisture problems. An optional adjusting dehumidistat and fan timer controls are available. 800.328.5111. www.forwardthinking.honeywell.com.
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    Panasonic. The WhisperComfort spot ERV is the first ceiling-inserted energy-recovery ventilator in the U.S., says the maker. Designed to address moisture-generating areas, the affordable unit enables builders and homeowners to scale their ventilation options while still meeting ASHRAE 62.2 standards. A low-rate, continuous-balance air flow powered by an enclosed AC motor vents and replaces VOCs and other indoor air pollutants with fresh air; a capillary core transfers heat and moisture to the supply air. A frost-prevention mode automatically activates at 32 degrees F (outdoor temperature) to prevent core freezing. 800.405.0652. www2.panasonic.com.
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    UltimateAir. The HVI-certified RecoupAerator ERV offers up to 200 cfm and 95% heat-recovery efficiency. The unit features a proprietary control for optimum energy efficiency (as low as 40 watts at 70 cfm) and a dehumidistat to monitor and balance humidity levels automatically and without desiccants. It can be mounted vertically or horizontally and connects to 6-inch galvanized or flex ducts. The unit features a 20-gauge-steel insulated casing with powder-coated finish and optional CO2 monitoring, MERV-12 filtration, and high-efficiency defrost. 800.535.3448. www.ultimateair.com.

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    Rheem. The HEPA 3.0 HRV is HVI-certified up to 75% of heat recovery and offers airflow rates up to 270 cfm. It serves up to 3,000 square feet per unit and features removable and washable metal-framed air filters, a smart defrost system to prevent freeze-ups, and 6-inch round inlets and outlets for easy duct connections. The 20-gauge, pre-painted steel with corrosion-resistant finish and sturdy damper design address adverse weather conditions. A standard HEPA filter captures 99.97% of all particles as small as 0.3 micron to enhance indoor air quality benefits. 334.260.1500. www.rheem.com.

  • Goodman AC

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    Frank White

    Goodman. The HVI-certified HRV series offers up to 92% heat recovery, according to the manufacturer, with cfm rates from 123 to 247 to accommodate various residential conditions and requirements. The units feature a 22/24-gauge galvanized steel cabinet that is fully insulated with 1-inch high-density polystyrene foam to help prevent condensation; other features include washable, electrostatic panel-type air filters and factory-balanced EBM motors with permanently lubricated sealed motor bearings. The aluminum core is configured for efficient cross-flow ventilation and to withstand extreme temperatures. An optional dehumidistat and air-quality sensor are available. 877.254.4729. www.goodmanmfg.com.
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    Fantech. The HVI-certified VHR 1404 heat-recovery ventilator is rated to recover and exchange 62% of exhaust air heat. The unit is equipped with two factory-balanced EBM motors with permanently lubricated sealed bearings for durability and low maintenance. An aluminum heat-recovery core is configured for efficient cross-flow ventilation; washable electrostatic panel-type air filters enable easy care. A preset defrost sequence automatically activates to protect the unit in extreme cold temperatures while maintaining fresh air intake and heat exchange. 800.747.1762. www.fantech.net.

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    Venmar Ventilation. The HVI-certified EKO 1.5 heat-recovery ventilator recovers and exchanges up to 80% of heated or cooled air. Two high-performance ECM motors consume 13.5 watts each at low speed and operate at 2.53 cfm per watt, making the units among the most energy efficient available. Four speed settings adjust to changing needs, especially when automatically controlled by a programmable touchpad (included). A defrosting system mitigates ice buildup on the recovery module. The unit’s compact size enables more installation options. 800.567.3855. www.venmar.ca.

The regulator also can add humidity to the fresh air as needed to maintain an optimum level for comfort and health, using a rotary wheel core and desiccants such as silica gel. As a result, ERVs extend their value in terms of indoor air quality beyond simply refreshing the indoor air. The bit of moisture vapor captured by an ERV also helps keep the exchanger core warm, lessening the potential for freezing damage and related repair or replacement costs during the winter.

Cost vs. Value

At upwards of $1,500 or more plus some extra labor by a heating contractor in a new construction environment, ERVs and HRVs are a relatively expensive choice to provide controlled ventilation and some measure of energy efficiency, especially in affordable housing.

“If equipment prices and the cost of installation went down, we’d probably go back to using an HRV,” says Brianna Conrow, project manager at HOST Development in Portland, Ore., which used HRVs for the first phase of an affordable project before switching to a supply-air-only system of whole-house fans. “And in small homes, there’s not a reasonable payback in energy savings for HRVs.”

There’s also a remarkable shortage of hard evidence that mechanical ventilation, and specifically an ERV or HRV, is truly as effective as the presumed benefits of energy savings or improved indoor air quality that equipment manufacturers and building scientists purport. “It’s become a Holy Grail to ask for definitive research on the air quality impacts of [controlled] ventilation,” says Sam Rashkin, national director of the Energy Star for Homes program at the EPA, whose team has scoured for and requested reports from manufacturers and the building science community without success—despite pressure from those groups to add controlled ventilation into the Qualified Homes standard. “The evidence [that controlled, mechanical ventilation reduces indoor air quality hazards] is anecdotal, at best.”

In addition, Rashkin’s team found field reports and observations that HRV/ERV equipment showed a high propensity not to work properly once installed, from dampers being pinched shut to kinks in the ducting systems that restricted airflow and clogged or misplaced intakes.

It’s also a “big leap of faith,” he says, that homeowners will follow through with scheduled and necessary maintenance of the equipment. “We suspect that a high percentage of systems will be installed poorly or be set up to fail because the owners won’t do things necessary to keep them running properly,” he says. “Having a ventilation system is a feel-good thing, but there’s a tremendous behavioral component that’s hanging in the balance.”

That’s an assertion that Gentry, among others, disputes. In his experience, maintenance is an easy chore for a properly trained homeowner, consisting of cleaning the filters and blowing dust out of the system twice a year and out of the core (or heat exchanger) annually—which many owners simply add to an HVAC service contract. “Every once in a blue moon you may have to replace the heat exchanger,” he says, “but in four years of selling ERVs I’ve never had to.”

In addition, emerging technologies such as electronically commutated motors (ECMs), which use less energy and have been a standard in larger HVAC equipment for years, and controls that allow the installer and the homeowner to more easily and reliably program, monitor, and adjust the equipment, appear to address at least some of the current concerns.

Despite Rashkin’s reservations, he and his team resolved to mandate minimum ventilation thresholds into the upcoming Energy Star Qualified Homes standard, likely spurring HRV and ERV use, because the 2011 version significantly boosts building envelope performance. “The new [2011] standard raises the bar so much higher for a home’s tightness that we have to get fresh air into them,” he says.

Rashkin also admits that, if properly installed and maintained, HRVs and ERVs are an upgrade over exhaust-only or supply-only systems because the air in and out of the equipment is balanced and therefore better ensures the proper amount of fresh-air flow and maintains a pressure balance inside the home.

As for the energy efficiency of HRVs and ERVs, Energy Star is working to create standards to qualify the heat recovery performance and label the equipment within a new product category for the federal program; the 2011 Qualified Homes ventilation thresholds will require Energy Star–labeled HRVs or ERVs to comply (if that ventilation option is chosen by the builder), just as the current standard does for exhaust-only (spot) ventilation units.

Already, the Home Ventilating Institute (HVI) independently certifies the performance of HRVs and ERVs to provide builders with a gauge to compare products and assess their value in terms of heat recovery and airflow rates, if not their impact on air quality.

Even so, HVI considers (if not certifies) the health benefits of controlled ventilation, including ERVs and HRVs, to be a critical factor in their use. “Even with construction materials … with low-VOC off-gassing, normal activities such as cooking and bathing overwhelm the home,” with potential pollutants that ERVs and HRVs can and do address, says Peter Grinbergs, the trade association’s chairman and the director of product development/engineering for Airia Brands, a ventilation equipment manufacturer.

For Gentry, that’s a theory he’s seen in action. “Getting fresh air into the house helps more than anything, and especially achieving healthy indoor air,” he says. “This isn’t smoke and mirrors.”

Rich Binsacca is a freelance writer in Boise, Idaho.