Point-of-use (PoU) water heaters are small electric units installed near a single fixture — under a sink, in a remote bathroom, in an ADU, in an RV, or at a specialty application like a wet bar or workshop sink. They eliminate the long hot-water pipe run from the main heater and the chronic wait-time problem at distant fixtures. Two product types: mini-tank storage (4–20 gallons) and electric tankless (3–11 kW).

Mini-tank point-of-use (storage)

Small electric storage tanks (typically 4–20 gallons) that plug into a standard 120V outlet (smaller sizes) or 240V circuit (larger sizes). The 120V plug-in option is the big advantage — no electrical work required for under-sink installs.

Rheem Performance 6G (XE06P06PU20U0) — 120V plug-in, 14" cube fits under most sinks. Single-fixture only.
Rheem Performance 10G (XE10P06PU20U0) — 120V or 240V configurations. Small remote bathroom (low-flow shower) or pool house.
Rheem Performance 20G (XE20P06PU20U0) — 240V, supports a full normal shower. ADU or small cabin.
Bosch Tronic 3000 T 4G — Euro-engineered compact mini-tank.
Bosch Tronic 3000 T 7G — mid-tier Bosch mini-tank.
AO Smith Conservationist 30G — point-of-use sized for whole-house single-occupant ADU.

Electric tankless point-of-use

Small electric tankless heats water on-demand, eliminating standby losses. Caps lower than whole-house electric tankless.

Rheem RTEX-04T — 4kW, single-faucet only. Smallest in the Rheem ladder.
Rheem RTEX-06T — 6kW, single low-flow shower at warm inlet.
Rheem RTEX-08 — 8kW, single-bathroom warm-climate whole-house.
Rheem RTEX-11 — 11kW, 2-person warm-climate whole-house.

Specialty: the Rheem RTEX-AB7 booster is point-of-use-class hardware but designed to BOOST already-warm water (dishwasher input, distant-shower boost). See our Rheem booster page.

Common point-of-use applications

Under-sink remote bathroom or kitchen — 6G mini-tank (120V plug-in) is the standard pick
RV / fifth-wheel / boat — 4–6G mini-tank for occasional use
Garage utility sink — 6–10G mini-tank for hand-wash
Pool house or guest cottage bathroom — 10–20G mini-tank supports a low-flow shower
ADU / mother-in-law suite / garage apartment — 20–30G whole-fixture (mini-tank or small standard tank)
Wet bar with hot-water faucet — 4–6G under-counter mini-tank
Workshop hand-wash with degreaser — 6kW tankless (RTEX-06T) for higher temperature on-demand

Mini-tank vs point-of-use tankless

The trade-off is operating cost vs capacity:

Mini-tank: standby losses (keeps water warm continuously) but no flow-rate cap. Best for occasional use where you'll want hot water available immediately.
Tankless PoU: no standby losses (heats on-demand) but capped at the unit's GPM. Best for high-frequency low-demand use where standby losses add up.

For typical residential PoU installs (a single under-sink fixture in occasional use), the 120V plug-in mini-tank wins on install simplicity. For commercial-light applications with continuous use, electric tankless wins on operating cost.

Install considerations

Under-sink mini-tank install: $150–$350 for plumber to plumb inlet/outlet on existing 120V circuit. ADU or pool-house 20G mini-tank: $400–$800 including 240V circuit run if needed. Electric tankless PoU (RTEX): $300–$700 depending on whether the 240V dedicated circuit needs to be added.

Drain pan recommended for all under-sink installs to protect cabinet floor against the eventual T&P discharge or connection leak.

Bottom line on point-of-use water heaters

Point-of-use water heaters solve the remote-fixture problem cheaply and reliably. The volume pick across the category is the Rheem 6G under-sink mini-tank — 120V plug-in, 6-year warranty, fits standard vanity cabinet. For shower-supporting remote bathrooms, step up to the 10G or 20G mini-tank. For high-frequency continuous use, electric tankless point-of-use (RTEX-04T through RTEX-11) wins on operating cost. For whole-house ADU service, see the 30-gallon electric category instead.