Buying a unit that's too small leads to cold showers; buying one too large wastes money.

The first crossroad is deciding whether you want to store water or heat it on the fly.

: Large families, homes with high-end "spa" showers, and those looking for long-term energy savings. 2. Fuel Type: Efficiency vs. Infrastructure

Modern heaters aren't just tanks anymore. Look for features like (automatic shut-off if a leak is detected) and Wi-Fi connectivity , which allows you to adjust the temperature or set "vacation mode" from your phone via apps like Rheem's EcoNet .

: A leader in high-efficiency condensing tankless systems that capture heat that would otherwise be lost through the exhaust. The 2026 "Smart" Edge