- Which is better for a whole-home install?
- Both are 27 kW units meant for whole-home use, and both need three 40 A double-pole breakers. The Opti 27 states a 4.5 GPM flow rate; the EcoSmart does not publish one. In cold climates, check the sizing map for your incoming water temperature before buying either.
- Is the Opti 27 worth the extra $180?
- If you stay in the home, yes. The 25-year residential warranty is five times the EcoSmart's 5-year coverage, and you get Wi-Fi control and ultrasonic flow sensing. If warranty length and app control do not matter, the EcoSmart saves you $180.
- Which lasts longer?
- On paper the Opti 27, because its 25-year residential warranty is far longer than the EcoSmart's 5-year limited warranty. Both use copper and stainless steel components and have no tank to rust out. Actual life depends on water quality and scaling, so install a filter or softener if your water is hard.
- Do both need the same electrical setup?
- Yes, essentially. Both need 240 V service, three 40 A double-pole breakers and about 112 A at full draw, which usually means a 200 A panel. The Opti 27 also accepts 208 and 220 V. Confirm your panel capacity with an electrician before ordering either.
- Can either go in an RV or mobile home?
- The EcoSmart ECO 27 is listed for RVs and mobile homes. The Opti 27 is listed for residential and commercial indoor wall mounting, with no RV rating stated. For an RV, the EcoSmart is the safer pick.
- Which has better temperature control?
- Both hold temperature within about 1 degree F of your setpoint. The EcoSmart adjusts in 1-degree steps on a digital display. The Opti 27 adds ultrasonic flow sensing and app control, which helps when flow changes suddenly, such as when a second shower starts.
