Thanks to a recent remodelling, patrons seated indoors experience the ambience of dining outdoors at O’Toole’s Irish American Grill & Bar, except there are no mosquitoes, flies, vehicle emission odours; and the temperature is always a comfortable 74°F.

The remodel included improvements to the outdoor patio and the HVAC systems. However, the most critical factor in creating the outdoor experience is seven air curtains over the 46 feet of retractable glass walls and overhead doors. The air curtains separate the indoor environment from the outdoor elements of flying insects, heat, cold and nearby street vehicle emissions when the glass walls and doors are opened.

The fact that the Royal Oak, Michigan-based restaurant’s sales jumped 25-30% after the remodelling is no coincidence. It proves the open frontage is inviting to passersby and that suburban Detroit patrons prefer an outdoor dining experience, but also want air comfort and indoor air quality (IAQ), according to Keith Wadle, owner, a 25-year veteran of the foodservice industry, who opened O’Toole’s 14 years ago.

O’Toole’s Irish American Grill & Bar’s air curtains over closed windows

Wadle expects the increase in sales to deliver a short payback on the renovation investment. Wadle knew opening up the sidewalk frontage would increase business but wasn’t sure how to keep outdoor elements out until he visited a Florida restaurant that protected multiple open doorways with air curtains. Wadle called the air curtain manufacturer, Berner International, in New Castle, Pennsylvania. Berner’s Detroit area representative, Buyline Building Products, in Rochester, Michigan, engineered the project for the best sized models and installed them during the remodel.

During moderate weather in spring and autumn, and nearly every day from May through September, Wadle opens up the 30 feet of retractable glass doors manufactured by Nana Wall Systems, in Corte Madera, California, plus two eight-foot-wide glass overhead doors. The air curtains, which are mounted to the interior top of the frontage wall, discharge a “curtain” of air that meets just inside the threefoot- high exterior sill. Insects, car emissions, rain, and outdoor air can’t penetrate the curtain of air. While energy savings wasn’t the primary goal, the air curtains prevent more than 75% of the air conditioning or heating from escaping outdoors.

Air curtain selection and sizing was challenging for Buyline Products President, Rudy Aho. Air curtains are designed for doorways and openings, but typically occupants don’t sit in or near the opening. O’Toole’s most popular seating is at the frontage and under the air curtains. Therefore, Berner’s engineering department customised the blower assemblies for a lower velocity, but they still provide the necessary 1,407-feet/minute at three feet above the floor (window sill level) for performance. The customisation was a factory-tested balance of protecting the opening, but also preventing napkins or paper money tips from blowing off tables. The air curtains also include adjustable three-speed fans for precise onsite environmental separation.

Too La Roo’s open windows + air curtains

O’Toole’s air curtain performance was so successful, Wadle ordered six more air curtains for the newly opened second location, Too Ra Loo, a family restaurant in neighboring Rochester, Michigan, named after the Irish lullaby. Too Ra Loo’s conversion from a former Middle Eastern cuisine to a family-style restaurant also included retractable windows and the air curtains, which are even more critical for preventing emissions, since vehicles idle at a stoplight 10 yards away.

The air curtains are critical for indoor air comfort, but equally important for indoor air comfort is O’Toole’s HVAC system renovation, a design/build project by Pro Mechanical Services Inc., in Trenton, Michigan. Pro Mechanical Services replaced ageing 5 TR and 7.5 TR rooftop HVAC units with two high efficiency 5 TR units and one 7.5 TR unit, all manufactured by Carrier, a division of United Technologies Corp., in Farmington, Connecticut. Pro Mechanical Services’ design divides the restaurant into three zones of the kitchen, billiards/large screen TV and dining zones with their respective rooftop units, monitored and controlled by digital 24/7 programmable thermostats by White-Rodgers, a division of Emerson Climate Technologies, in St. Louis, Missouri. Steve’s Sheet Metal Shop, in Hazel Park, Michigan, fabricated rectangular ductwork for down flow and kitchen ductwork; however, the restaurants’ more aesthetic spiral round duct in the bar and dining areas were manufactured by SEMCO LLC, in Columbia, Missouri, and installed by Pro Mechanical Services.

Too La Roo’s remodel included replacing two 10 TR rooftop systems with three 10 TR high-efficiency Carrier rooftop units installed by Pro Mechanical Services.

The fact Wadle never hesitated to include air curtains when planning his new Too Ra Loo location’s remodel is perhaps a testament that the technology works and can improve any restaurant’s indoor environment, save energy and increase sales.

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