Nadair SD-659-32SF Central Vacuum Power Unit, 659 AW, 8,000 Sq Ft

The Nadair SD-659-32SF is a central vacuum power unit built for larger homes, rated at 659 air watts and sized for coverage up to 8,000 square feet. As with any built-in system, the power unit stays mounted in a fixed location and pulls debris through piping to inlet valves placed throughout the house.

An 8,000 square foot coverage figure signals this unit is meant for a home with a longer total pipe run than a typical single-family layout, whether that comes from a larger footprint, multiple floors, or both. Air watts, the combined measure of suction and airflow, is what determines whether that longer run still delivers strong performance at the inlets farthest from the unit, and 659 AW gives the SD-659-32SF meaningful reserve for that job.

Larger coverage ratings generally call for closer attention to pipe layout during planning. Extra elbows, long vertical runs between floors, and inlets placed at the far end of the house all add resistance that a power unit has to overcome, so a home at the upper end of a unit's rated coverage benefits from a pipe layout that keeps runs as direct as the framing allows.

• Model: Nadair SD-659-32SF
• Rated output: 659 air watts
• Coverage: homes up to 8,000 square feet
• Motor: 6.6-inch Ametek Lamb by-pass, semi-commercial grade
• Performance: 135.8 CFM airflow, 144.9-inch water lift
• Canister: 8.45-gallon spun aluminum bin
• Filtration: self-cleaning hybrid

Confirm your home's finished square footage sits comfortably within the SD-659-32SF's rated coverage, and discuss pipe layout with your installer if the run will include multiple floors or an unusually long trunk line. A power unit rated near the top of its coverage range for a given home has less margin to spare if a future addition or finished basement adds square footage later, so it is worth sizing up rather than down if your plans are not yet final.