Performance
Hot water for four. The Rheem XG40T09HE40U0 is rated to provide up enough hot water to meet the needs of moderately sized families of up to four people. The controls are easy to use, and while this isn't the most technologically advanced hot water heater you can buy, it's economically priced and has proved to be reliable. The low nitrogen-oxide (LNOx) burner doesn't meet the strictest standards in place in some parts of California, but still reduces emissions. For those who live at higher elevations, the Rheem XG40T09HE40U0 gas water heater is certified for installation up to 10,100 feet. The electronic ignition does away with the need for a pilot light, improving safety and cutting gas use. User reviews are highly positive, and owners largely agree that the Rheem XG40T09HE40U0 delivers every bit of the hot water it promises. For larger households (of up to five people), the 50-gallon Rheem XG50T09HE40U0 Performance Plus 50 Gal. Tall Water Heater (Est. $590) is similar, and similarly well liked.
Efficiency
Sufficient efficiency. This 40-gallon gas hot water heater isn't the most energy efficient model available, but that doesn't mean that it's not very efficient compared to earlier models. It has a .62 Energy Factor, which means it meets the current NACEA regulations, which set a high bar for water heater efficiency overall.
Reliability and warranty
Excellent track record. This Rheem hot water heater is covered by an excellent warranty for a model in this price class -- nine years overall plus two years of in-home labor. While you'll find some lemons with any product, the XG40T09HE40U0 enjoys a very strong track record, and we didn't spot any pattern of complaints that might indicate a potential sore spot.
Also see: COLEMAN HEATER Review
Our Sources
1. Home Depot
Contributors to HomeDepot.com, As of September 2017
More than 1,760 owners have commented on the Rheem XG40T09HE40U0 at HomeDepot.com, though those reviews also include a number originally posted at the manufacturer's web site. Regardless, feedback is near stellar. It earns a score of 4.6 stars, with 96 percent of owners saying that they would recommend this gas water heater to a friend.
2. FurnaceCompare.com
Editors and contributors to FurnaceCompare.com, March 25, 2016
The Rheem Performance Plus series (in both gas and electric) is the third highest rated line of hot water heaters at FurnaceCompare.com. The editors note that the water heater "is self-cleaning and features a premium grade anode rod for longer tank life." User reviewers that post here give the water heater a rating of 4.1 stars.
