In this composite split image, Placetailor carpenter Diego Gutierrez (left) guides air lines through the ceiling framing while project manager Travis Anderson (right) pulls the lines into place at the Air Pohoda heat exchanger and air handler.
Placetailor project manager Travis Anderson uses Siga tape to se…
Placetailor project manager Travis Anderson uses Siga tape to sel an outdoor air intake line for the Air Pohoda energy recovery ventilator at the Roxbury, Mass., “Supply House” job. Placetailor crafted a mix-and-match hybrid system for this project: The ERV unit shown is supplied by Air Pohoda, but the air intake and exhaust lines are an insulated expanded polystyrene (EPS) product supplied by Zehnder. Placetailor preferred the Zehnder ducting in this application because of its insulation qualities and its resistance to crushing in the dense-blown cellulose-insulated wall cavity.
Travis Anderson places a distribution manifold manufactured by Z…
Travis Anderson places a distribution manifold manufactured by Zehnder on top of the Air Pohoda ERV unit. The designers combined components from Zehnder and Air Pohoda for this installation.
Another look at the Zehnder air manifold that Placetailor couple…
Another look at the Zehnder air manifold that Placetailor coupled with an Air Pohoda ERV for the Roxbury project. The advantage designers saw with this distribution manifold was its sound control qualities. Looking inside the box, you can see the dark-colored mass-loaded vinyl core components, which tend to muffle and baffle mechanical sounds and the whistling or roaring of air movement. This is the supply manifold for the system.
This metal manifold, supplied by Air Pohoda, will serve as the r…
This metal manifold, supplied by Air Pohoda, will serve as the return manifold for the Placetailor-design ERV system at the Roxbury “Supply House” project. The manifold lacks any sound attenuation characteristics, but the designers considered it adequate for the return lines of the system. However, the designers chose a Zehnder manifold with sound-attenuating mass-loaded vinyl core elements for the supply side of the air distribution system.
Carpenter Diego Gutierrez runs air supply hoses from Air Pohoda …
Carpenter Diego Gutierrez runs air supply hoses from Air Pohoda in the ceiling system of the Supply House two-family building. Note the metal suspended-ceiling grid, which is designed for sound-proofing. The metal framework, suspended from the main floor system with wires and used to support the drywall ceiling, will help decouple the downstairs living space from the space upstairs, which is part of the building’s other unit. (The second story of the building is split between two apartments, one of which occupies the entire first floor while the other occupies the entire third floor.)
Carpenter Diego Gutierrez and project manager Travis Anderson in…
Carpenter Diego Gutierrez and project manager Travis Anderson install air supply tubing in the ceiling of a room. This photograph shows two supply registers with tubing already attached.
In this split image, Diego Gutierrez and Travis Anderson work to…
In this split image, Diego Gutierrez and Travis Anderson work together to run tubing from supply registers back to the Air Pohoda ERV core and air handler. At the air handler, Anderson labels each line to identify the location it serves at the other end. This aids in balancing the system when the house is commissioned.
An air supply register in the ceiling. Each register can be serv…
An air supply register in the ceiling. Each register can be served by either one or two three-inch lines, depending on the quantity of air needed. The system is fine-tuned by adjusting manifolds and fan speeds, and can be modulated as needed in service to respond to changes in the required exhaust and supply rates. The Air Pohoda system also offers active humidity control for the building.
Air-tight houses need mechanical ventilation for fresh air. In homes built to pass the tough Passive House standard, this requirement is even more absolute — the standard requires mechanical ventilation for many reasons, but one good reason is the envelope air-tightness. The basic Passive House standard calls for a blower door test of 0.6 ACH50, far tighter than even the most stringent building code. In a building that tight, natural air flows won’t supply adequate fresh air.
In practice, ventilation in a Passive House has to come from a heat recovery ventilator (HRV) or energy recovery ventilator (ERV). That’s because the Passive House standard also includes very low allowable energy use limits. To meet the spec, designers must avoid the heating or cooling load that would accompany fresh air ventilation without heat recovery.
This month, JLC visited Placetailor‘s “Supply House” spec project in the Boston, Mass., neighborhood of Roxbury to see an advanced ERV being installed (see slideshow). The project is a two-family building with one upper and one lower apartment on a sloped, wooded infill site on Roxbury’s Beech Glen Road, in an area that is seeing a building and remodeling boom as homebuyers and renters flock to the area in search of affordable housing.
Placetailor opted to install ERVs made by Air Pohoda, a newcomer to the U.S. market. The Air Pohoda units have an innovative feature: They come with an active pre-chiller for incoming air that serves to remove humidity from the incoming airstream in summer, when the humidity is concentrated. In theory, this offers the advantage of energy-efficient humidity control for the building along with energy recovery. Placetailor is one of the first U.S. builders to put Air Pohoda to the real-world test. (Watch this YouTube video of Air Pohoda technician Roman Salomoun introducing and explaining the Air Pohoda i ERV technology.)
The design for the three-story, two-family house has a downstairs unit occupying the entire first floor and half of the second floor, while the upstairs unit occupies half the second floor and all of the third floor. Heavy engineered beams in the floor structure supporting the second floor, which are necessary to achieve the open floor plan in the first story and to support the party wall dividing the two second-floor occupancies, would tend to obstruct the air supply and return lines for the ERV air distribution system. But the building’s double-stud exterior walls, designed to provide a fat insulated wall free of thermal bridging, also create a wide-open void for the three-inch corrugated plastic air hoses. Staying one step ahead of the insulators, Placetailor project manager Travis Anderson and carpenter Diego Gutierrez ran the lines from the ceiling registers through the ceiling and wall to the Air Pohoda air handler.
