A homeowner considering a 26-kilowatt standby generator raised a crucial question: Could it handle a large heat pump's startup demand, even if it could provide enough power to keep the equipment running?
Here's what to know
In a post on Reddit's r/Generator community, the homeowner described plans for a Kohler generator installation that would power three single-speed heat pumps rated at 2.5, 3, and 5 tons.
The largest heat pump would remain outside the planned load-shedding controls. Only the two smaller units would be subject to that system, which temporarily prevents selected equipment from drawing power.
The possibility of overwhelming and tripping the generator at startup left the homeowner unconvinced by assurances that the configuration would work. The 5-ton heat pump has a locked-rotor amperage, or LRA, rating of 142 amps.
More background
A generator's ability to power equipment once it is running does not necessarily mean it can handle the surge needed to start a motor.
The response offered an explanation, not a documented test of the homeowner's equipment. One commenter pointed to the Kohler unit's motor-starting capability and explained that residential breakers do not necessarily trip as soon as current reaches their rated amperage.
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The discussion did not establish whether the proposed combination would start successfully. It also provided no installation price, soft-start cost, or verified savings estimate, leaving no basis for calculating a financial benefit.
What can be done?
The homeowner suggested adding a soft-start kit to manage the 5-ton heat pump's startup demand.
The kit would address the largest unit's startup behavior, while the planned load shedding would control power demand from the two smaller units. These measures serve different purposes within the backup-power setup and are not interchangeable fixes.
The thread did not document a soft-start installation. The unresolved question is whether the kit would be necessary and sufficient for the 26-kilowatt Kohler setup — something the generator's advertised output alone cannot settle.
Where can I learn more?
Other homeowners sizing generators for heat pumps have run into similar startup questions. These stories cover backup heating choices, soft starts, and whole-home generator sizing.
• An Idaho homeowner asking about generator-powered heat learned to use the gas furnace during outages.
• A North Carolina homeowner considering generator-powered air conditioning heard that a soft start was essential.
• For central air, reducing startup demand with a soft start can halve portable generator sizing needs.
• An all-electric homeowner considering a bigger generator heard why a smaller one may last longer.
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