
Tankless Water Heater Sizing: A Practical Homeowner Guide
You're probably looking at a tankless water heater quote that recommends a large GPM number and wondering whether bigger automatically means better. It doesn't. A unit can have enough heating capacity on paper and still deliver lukewarm water, overload the gas service, require an unexpected venting change, or fail inspection. Tankless water heater sizing is a layered decision. Start with the hot-water fixtures you expect to use together, calculate the required flow, test that flow against the coldest incoming-water condition,








