Support

Contact

Questions, feedback or a problem with a calculation? Email gpmediacontact@gmail.com. Include your iPhone model, iOS version and the app version shown in Settings.

Restoring Lifetime Pro

Lifetime Pro is a one-time purchase tied to your Apple Account. On a new or reset iPhone, open Settings → Restore Purchases in the app while signed in with the same Apple Account.

How the calculations work

Tank: the app converts each use during your busiest hour into hot water drawn from the heater, then reports the minimum First Hour Rating (FHR) to look for on the EnergyGuide label or spec sheet.

Tankless: the app adds the hot-water flow of fixtures that may run at the same time and reports the flow required at your temperature rise. Check that flow on the manufacturer's performance curve at your rise. Advertised maximum flow is measured at a 67°F rise.

Settings → How Calculations Work in the app lists every formula, default and source.

Important

Water Heater Sizing Calculator is an estimating and planning tool. Always verify final equipment selection against manufacturer specifications, installation instructions, applicable codes and local requirements.