Eccotemp i12 Indoor 4.0 GPM Natural Gas Tankless Water Heater

The Eccotemp i12 is an indoor-rated 4.0 GPM natural gas tankless water heater. The "i" designation distinguishes it from Eccotemp's outdoor portable units — this one is for permanent indoor installation. 80,000 BTU input, UEF 0.81 (non-condensing), Category III stainless steel B-vent. 4.0 GPM peak at moderate temperature rise — sized for 1-bathroom homes or sequential 2-bathroom use.

Eccotemp's positioning is value — the i12 sits well below Rinnai and Navien on price (about $700 unit versus $1,400 for the comparable Rinnai RL75iN) with corresponding trade-offs. The warranty is shorter (10 years on heat exchanger vs Rinnai's 12), the service network is thinner, and the build quality on the gas valve and modulation electronics is one tier below the premium brands.

Right buyer: a budget-constrained installer of indoor gas tankless in a 1–2 bathroom warm-climate home. The unit performs adequately for its rated capacity; the limitations are around long-term service support, not day-to-day function. Wrong buyer: cold-climate primary residences (winter GPM at 70°F rise drops below 2.0 GPM), households needing 199K BTU-class capacity, or installations where service network density matters more than upfront cost savings.