Indoor home IAQ is known to be pretty bad - generally worse than outdoor air, depending on the region. With homeowners becoming more interested in tightening their homes, and awareness and opportunities increasing due to federal and local incentives, IAQ problems could be addressed from the start by introducing more fresh air, according to Nelson Warner, vice president of R&D for Tamarack Technologies Inc.

That’s why his company has introduced the Multi-Aire IIP and IIN balanced ventilation system. The system introduces fresh, filtered air into the home, balances air pressure, and pulls stale air out of the house.

“The product is based on a couple of known issues,” said Warner. “First off, IAQ in most homes is relatively poor, worse than outdoor air.” With this system, “if you have a relatively tight house and are concerned with IAQ, you can run this system from a max of 400 cfm to about 100 cfm total, to get whatever your ventilation requirement is.”

The Multi-Aire II system relies on two mechanical devices, one of which pulls in outdoor air while the other exhausts polluted indoor air. It offers both negative and positive air exchange, thus creating balanced airflow even in very tight homes.

“As an industry we have done an exceptional job building more energy-efficient homes,” said Tamarack CEO Tom Colasanto. “However, we’ve overlooked the negative health effects created by trapped air in a tight home.”


The Multi-Aire IIP and IIN units can be used together or independent of each other. The Multi-Aire IIP (positive) draws filtered outside air into that home at a rate of 400 cfm through four 4-inch ductable ports. Its MERV 13 filter cleans the air before it enters the living space.

The Multi-Aire IIN (negative) unit exhausts indoor air at a rate of 500 cfm through its four 4-inch ductable ports. Used alone, it can function as a whole-house fan, multiple bath fan exhaust, garage exhaust, or combination of all.

“We created these two systems to be used either in conjunction with each other or separately,” said Warner. “They address different climate zones. Here in the Northeast, for example, we have forced-air systems and, if you wanted a slight but continuous outdoor air rate, you could do it without affecting the efficiency of the heating system.”

The four-part system (four 4-inch ports) can be ducted up to 25 feet, he said. There is one 8-inch inlet and MERV 13 filtration system. “If you have access to an attic or crawl space, it’s a relatively simple installation,” Warner said, requiring standard line voltage supply. “You could use a fan speed control.”

The effect on efficiency is minimal, he added. “You have to either reheat or cool the air. If it’s adjusted right when it’s installed, the impact is minimal.”

The system was designed to give builders and contractors maximum flexibility, Warner said. “From a makeup air standpoint, if the house is very tight, you might not have enough supply air for all of its gas devices to work properly.” With the Multi-Aire system it can be controlled by virtue of an interlock. “When one appliance engages,” said Warner, “it gives you a supply source to make up the air that the range hood is exhausting.”

There is potential for backdrafting from any number of appliances. “If you don’t balance it, either they’re not working to their maximum capability, or they’re pulling from areas where you prefer they don’t.” According to Warner, “It can be wired in such a way so that when the appliance engages, it comes on or engages at a low speed.” It can function on continuous duty cycle with boost capability as needed. It could also be used on low volume, for smaller houses, for continuous cooling with a couple of air changes/hour. “People have used them for ductable whole-house fans.”

A voltage-varying device controls on a demand basis; the positive and negative can be wired together. Air Track Advantage, a clock-based product, can operate the system fan or a bathroom fan in conjunction,” Warner said.

The AireTrak 62-2 can be used in existing homes or new construction, “provided your bathroom fan has a constant duty-cycle rating. If you know your type of fan, and you wanted to set that for a 25-cfm standard, you would take that fan and turn it into a two-speed fan.” It could also be run 24 hours a day with the ability to boost it. The product was designed specifically for today’s weatherization market.

Approximately 55,000 to 60,000 AireTraks have already been installed, he said. “We’ve worked with a number of ESCOs, they recommend them to builders,” Warner said. These companies perform energy audits for a number of different types of housing. “It gets specced into a whole project, at least 100 units at a time.”

The Multi-Aire II units can be fitted in a closet, attic, garage, storage area, etc., and ducted throughout the home’s ductwork.

The Multi-Aire II system exceeds the requirements of California’s ASHRAE 62.2 Title 24 building code for exhausting stale air through mechanical ventilation. “If they’re looking for a simple way to introduce filtered supply-side system, or they have concerns about negative pressure, it’s certainly the way to go,” Warner said.

For more information, contact Tamarack Technologies at 800-222-5932;

Publication date:09/28/2009