Everything you need to launch your trade business.
Everything you need to launch your trade business.
Two quick tools in one. Get the right water heater size for your home, then size the supply pipe in copper or PEX. Real plumbing numbers, no guessing.
Most homes get this wrong in one of two directions: a tank too small that runs cold mid-shower, or one so big you pay to keep water hot you never use. The water heater size calculator above skips the guesswork. Tell it how many people live in the home and how many bathrooms you have, and it gives you the tank size and first-hour rating that actually fits.
The rule of thumb plumbers lean on: plan for about 12 to 15 gallons of hot water per person, then size the tank so its first-hour rating (FHR) covers your busiest hour. A family of four usually needs an FHR of 60 to 80 gallons, which lands on a 50-gallon gas tank or a 65 to 80-gallon electric one. Gas recovers faster (40 to 50 gallons an hour) than electric (20 to 25), so a smaller gas tank can keep up with the same house.
Tankless units are sized by flow, not gallons. Add up the gallons per minute of every hot fixture that might run at once (a shower is about 2 to 2.5 GPM, a sink about 1.5), and that is your target GPM. The catch is climate: the colder your incoming water, the harder the unit works, and the less flow it can deliver. In the warm South a single unit can push 7 to 8 GPM. Up North with 40-degree ground water, that same unit might only hold temperature at 3.5 GPM, so bigger homes often need a high-BTU unit or two in series. Switch the calculator to Tankless a