Product review (4 stars): Cuts lingering odors & cooking heat with good task lighting. A few minor issues but cost effective.
Our Western NY location requires a tight house for winter so odors linger without an exhaust fan. We now use the fan often because of the low mechanical and airflow noise. The kitchen heat build-up which previously effected the entire house heating (and hopefully cooling) is now negligible.

The improved direct task lighting was an unanticipated benefit. We use 2 - 4.8 watt A15 LED bulbs providing 300 lumens each (80 watt total incandescent) which will probably operate for less than $2.00 a year. Their use may reduce the lens replacement issues often noted for the Broan hoods. We don't use the one-setting nightlight but it is nice with dimmable bulbs.

Broan rates the QT230SS as an intermediate value hood and I agree it is above all makers economy models quality after visiting the big box displays (all non-working) for a visual reference. It has a slight 60 cycle hum and fan balance vibration which seems to quit after several minutes, costing it the fifth star, that we don't find objectionable. The 3" x 10" damper provided is flimsy and I took precautions with it during installation. But overall we found the cost and benefits outweigh the minor issues.

The Broan replaced a seldom used 10" Nutone which sounded like a jet starting. Ours is horizontally vented thru the wall with the Broan #639 Exterior Wall Cap. It needed a piece of 3-1/4 x 10" x 3" long duct to extend through our thicker wall. All duct connections were sealed with silicone caulk and a good foil tape to prevent air leaks and whistling noises. I sealed around the duct running inside the wall with insulation and fireblock spray foam to rigidize it. Where the duct terminated on the interior wall I installed foam weatherseal (3/8" W. X 3/16" Thk.) on the wall around the duct opening perimeter so it would provide an air seal against the back of the installed hood. I rigidized the provided 3" x 10" damper by installing it on the hood in a bed of silicone caulk and let it set. When set, I pulled the electrical feed through the knockout, then positioned the hood by inserting the attached damper into the wall duct opening while lifting it in place against the weatherseal and shelf above and fastened it with the provided screws. (5/4 x 12-1/2 x 30-1/2 laminated Doug Fir shelf)

After connecting the power and running at full speed the attached damper opens 100% and the wall cap damper about 90%. The dampers occasionally flap on windy days but there is little backdraft compared to the old Nutone damper.

FOR THE PURIST/ENGINEER and PROBABLY NOT APPROVED BY BROAN, I also placed the same wall weatherseal on the inside of the provided damper for the movable blade to rest against in its closed position to minimize backdraft/airleakage prior to installing it on the hood. The damper is fragile unattached and it was a delicate and tedious procedure to get 100% contact of the blade against the weatherstrip so be duly warned and verify the blade moves freely as you do so. I didn't do this to the exterior wall cap damper because the moisture from cooking vapor will condense and may freeze the blade shut in frigid weather, however the interior damper should be immune to that.