9 Meadow Drive, Albertson

An existing two-storey, wood-frame single-family home on Long Island, where the owner is finishing the cellar — about 780 ft² of new living and storage space with a new egress window and window well. A finished cellar has almost no windows, so it cannot rely on the outdoors next door: fresh air has to be brought in by duct, filtered, and warmed in winter, and the opening has to close tightly when the fan is off. The house already has electric heating and cooling, with an indoor air handler and two outdoor units (one for each floor), and a direct-vent natural-gas water heater; those stay as they are. The work is filed with the local building department under the New York State codes.

Mechanical: we ran the code ventilation calculation for the cellar — 780 ft² with no regular occupants needs 46.8 cfm of outdoor air — and provided 100 cfm, more than twice the minimum. Outdoor air enters through a 10 × 10 in. louvre with a fire and smoke damper and a Class I motorized damper (air leakage not more than 4 cfm per ft² at 1.0 in. w.g., tested to AMCA 500D), is filtered at MERV 11 by a 100 cfm inline fan (115 V, 4.8 A), warmed by a 3 kW electric duct heater with an SCR controller, thermostat, disconnect and air-flow switch interlocked with the fan, and is supplied through an 8 × 8 in. ceiling diffuser. The damper is interlocked with the fan and the fan runs on a time clock; the intake duct is insulated, the fan has rubber-in-shear isolation and flexible connections, and fire and smoke detectors are required on ducts that pass through rated walls. We scheduled the fan, the duct heater and the diffuser, and issued two sheets in April 2024: the cellar mechanical plan with the ventilation calculation and schedules, and a details sheet for hanging ductwork, flexible connections, the motorized louvre damper, louvres and low-velocity elbows. Coordination: the new equipment was laid out with the home's existing electric air handler, its two outdoor units, the 140,000 Btu/h direct-vent water heater and the hard-wired, interconnected smoke and carbon monoxide detectors, and checked against the home's approved energy analysis (2018 IECC, climate zone 4), which passes 5.3% better than code.