Most Brazilian homes have no water heater at all. They still shower hot every morning. The heat happens in the showerhead itself, where a bare nichrome coil sits directly in the water path and dumps 4,500 to 7,700 watts into whatever flows past it, on a 220-volt supply, with a summer and winter switch on the side. Nothing is stored, nothing is pre-heated, and no insulated pipe run loses anything on the way, because the water is cold until the instant before it hits your shoulders. The unit costs around $20 and screws onto a standard shower arm, against $1,200 to $2,000 for an American tank heater installed. The catch is that the live element and the water share one chamber, and grounding in older homes is often improvised, which is how the thing earned its traveler's nickname: the suicide shower. The wiring is usually 10-gauge and it runs straight back to the panel. Shocks are common enough that Brazilian electricians treat the shower as its own dedicated circuit with its own breaker, and newer units use a plastic isolation chamber to keep the element out of direct contact. Nobody in Brazil finds any of this strange. The scale of it shows up on the national grid. Electric showers are the single largest electricity end use in the average Brazilian household, running about a quarter of residential consumption in national end-use surveys, and they all fire inside the same two windows, morning and evening. Utilities plan generating capacity around bath time the way British grid operators once planned around tea kettles at the end of a television broadcast. It is genuinely cheaper per shower, and it will never work here. Running 5,500 watts for 8 minutes is 0.73 kilowatt-hours, roughly 12 cents at 17 cents per kilowatt-hour, and there is no tank losing heat the other 23 hours and 52 minutes of the day. A whole-house electric tankless unit sized for American incoming water temperatures and American flow rates needs 18,000 to 36,000 watts, which is 120 to 150 amps of dedicated service. Most US homes have a 100 or 200 amp panel for the entire house, so the upgrade costs more than the water heater and that is the end of the conversation