Bradford White RG250L6N (lowboy) vs RG250T6N (tall 50 gal)

The two tanks share their burner, venting and efficiency, so the differences are volume and shape. Both run a 40,000 BTU/h natural gas burner at UEF 0.63 under the medium-draw test, both recover 43 US gal/h (163 L/h) at a 90 °F (50 °C) rise, both vent through a 3 in or 4 in draft hood into a chimney or B-vent, and both draw combustion air from the room and need no electricity, so hot water continues during a power outage.

The tall RG250T6N is the stronger performer on paper: 50 US gallons (189 L) nominal and 48 US gallons (182 L) rated storage, an 81 US gallon (307 L) first-hour rating, a 22 in (559 mm) jacket and a 154 lb (70 kg) shipping weight. The lowboy RG250L6N trades volume for height: 48 US gallons (182 L) nominal and 47 US gallons (178 L) rated, a 77 US gallon (291 L) first-hour rating, a 24 in (610 mm) jacket and 170 lb (77 kg).

The shape trade is the point. The lowboy is about 8 1/2 in shorter (48 1/16 in against 56 5/8 in to the top of the heater) but 2 in wider and 16 lb heavier, and it is the widest jacket in the Defender atmospheric line. It is the form for under-stair closets, attics with low joists and basements with limited ceiling height where the tall tank simply will not stand. One further difference: the tall model offers an optional top temperature-and-pressure valve location, which must be specified when ordering, while the lowboy does not.

Neither reaches ENERGY STAR's 0.81 UEF threshold for the size, and both require a working chimney or B-vent and room combustion air; neither can be side-wall vented. Anode inspection every two years applies to both, and the warranty excludes labour and anode consumption. If the space allows, the tall tank's extra four US gallons of first-hour delivery comes at no cost in efficiency or input; the lowboy is a space solution, not a capacity upgrade. Whether CANRO supplies a given form for a job is confirmed at consultation.