RV Winterization Calculator

This calculator adds up the antifreeze needed to protect an RV's plumbing from freezing, then estimates the time and cost to do the job yourself or hire it out. Antifreeze Needed starts from RV Length (plumbing line volume), Number of Faucets / Fixtures (each trap needs its own dose), a fixed water heater bypass allowance, and flat add-ons for a Washer/Dryer or Ice Maker if installed, then applies a 20% safety margin and rounds up to the next whole gallon -- antifreeze is sold and poured by the gallon, so a fractional result isn't purchasable. That rounding means a small change to RV Length or Number of Faucets can leave Antifreeze Needed unchanged if it doesn't push the pre-rounding total across the next whole-gallon line; both still add real gallons to the underlying total, the rounding just doesn't always show it at any single input tweak. Water Heater Size is informational only -- during winterization the heater is bypassed rather than filled with antifreeze, so its value passes straight through to a reference output and never changes any cost or antifreeze figure.

DIY Time responds most to whether a Washer/Dryer is installed (a flat 15-minute addition) rather than to Number of Faucets, whose per-fixture time is smaller at the default fixture count. Professional Service Cost only rises once Number of Faucets exceeds four, adding $10 per fixture beyond that baseline. This is a planning estimate -- actual antifreeze needs vary with plumbing layout, fixture type, and how thoroughly lines are blown out with compressed air first.