Generac has been making powerful claims about its 20-kilowatt stationary generator, perhaps too powerful. When the company said that its machine was more powerful, longer-lasting, quieter, safer to operate and the "most environmentally friendly generator on the market" competitor Kohler took notice. Its complaints to the National Advertising Council, a watchdog group, resulted in the recommendation that market-leader Generac discontinue some claims and modify others.
Kohler contended that Generac, in sales brochures, press releases, and other documents, made "unqualified superiority claims." The NAD's decision addressed these point by point.
Generac's claims about power included phrases such as "highest output" and "best in class" power quality. Kohler tested the power output and voltage regulation of both its own and Generac's 20-kilowatt stationary (also called "standby") generators and said its own offering, on average, ranged about 2 kW higher. Kohler also said that its product maintained voltage within plus or minus 1 percent of the rated 240 volts while Generac's models "deviated significantly" under a steady load. While Generac responded that its own tests back up the claims, it conceded to the NAD that its generators do not have the highest output or more power than its competitors.
The complaint that Generac's products have a longer life than its competitors is based on Generac's use of engines with full-pressure lubrication systems, claimed to deliver "better performance, less maintenance, and significantly longer engine life." Kohler argued that Generac's promotional materials aren't clear in that the comparison is against products whose engines don't have full-pressure lubrication. NAD agreed that, from the claim's wording, it seems Generac is saying its generators "have a longer engine life than all other generators on the market." Because Generac did not provide head-to-head testing to support its claim, NAD recommended it be discontinued.
Kohler's complaint about noise resulted from the company's own tests of Generac's products and charged Generac was basing claims only on measurements taken in front of the unit. Citing a standard from the Electrical Generating Systems Association, an international trade group for on-site electric power generation, Kohler said the back and sides of Generac's units were almost twice as loud as the front. Generac countered that many manufacturers do not follow the testing protocol but, again, the NAD recommended that Generac modify its claims to clearly state that reported decibel levels are from the front and that other points around the unit are louder.
The claim that Generac's Guardian Series line is "the most environmentally friendly generator on the market," centered around Generac's shorter "exercise cycle," the periodic startup and self-diagnosis routine that stationary generators run. Generac claimed that since its exercise cycle was shorter, it used less fuel and was more environmentally friendly. The NAD recommended that Generac tout the shorter exercise cycle if it wanted but drop claims about environmental superiority.
Concerning how close a stationary generator can be placed to the home, Generac claims these generators can be installed only 18 inches away; Kohler argued that National Fire Protection Association standards require installation at least five feet away, and that some local fire codes prohibit installation as close as Generac specifies. While Generac said its instruction manual warns that local codes might supersede the product's instructions, NAD recommended Generac put that warning in the promotional material and that it warn shoppers that the unit cannot be placed near doors, windows, or other fresh-air intakes because of the risk of carbon-monoxide poisoning.
Generac issued a rebuttal that it "respectfully disagrees" with some of these recommendations but said it would accept all of them "in the spirit of cooperation with the self-regulatory process."
Consumer Reports didn't test the large Generac 20-kilowatt stationary model in its latest tests of generators but the brand earned a CR Best Buy in both the portable (Generac GP5500 5939) and stationary (Generac CorePower 5837) categories. The Kohler 8.5 RES-QS7, $3,200, at 8.5 kW, was our top-rated stationary model.