Check off everything you want running during an outage. We add up the typical running watts, add 25% headroom, and round up to a standard standby size — a planning estimate you can take into a quote conversation.
Curious what that size costs installed? See the Hays County cost guide, then request a written quote below.
How This Estimate Works — and Its Limits
Method: Add the running watts of everything you checked, add 25% headroom so the generator isn't running flat-out, then round up to the next common residential standby size (10, 14, 18, 22, or 26 kW).
Running watts aren't the whole story. Motors and compressors — AC units, well and sump pumps, refrigerators — draw a brief starting (surge) load that can be two to three times their running watts. A generator that covers your running total on paper can still struggle when a big motor starts. Installers account for this; this calculator flags it rather than hiding it.
Load management changes the math. Smart load-shedding modules pause non-essential loads (a dryer, an oven, a second AC) for a few seconds while a motor starts, which often lets a smaller, cheaper generator cover a bigger home.
Fuel matters. Ratings differ by fuel — for example, Generac's 22 kW model is rated 22 kW on propane and 19.5 kW on natural gas. If you'll run on natural gas, treat the recommendation as the propane rating and confirm the natural-gas rating of any model you consider.
The final number isn't ours or yours. A licensed installer's or electrician's load calculation — from your panel, nameplates, and local code — governs the size you buy. Treat this page as a planning estimate for comparing quotes, not a specification.