Marey ECO180
Amazon customer rating as of
Tankless Geek editorial score: 4.1/5
The Marey ECO180 is an 18 kW, 240-volt self-modulating electric tankless positioned as a budget whole-home unit for warm climates. It uses a stainless water channel and heating chamber, a corrosion-resistant heating element, and is ETL certified, with a 5-year warranty. Marey advertises 4.0 GPM at a 36 °F rise (up to 4.4 GPM at 31 °F), enough for up to three points of use in hot climates — but only about 1.5 GPM at an 80 °F rise, which is the honest cold-climate reality of any 18 kW unit.
Two things deserve emphasis. First, the electrical demand is real: Marey calls for two 50-amp double-pole breakers on 6-gauge wire and recommends at least 150-amp service — heavier than some competing 18 kW units. Second, and more important for buyers, the ECO180 carries a notably mixed support and reliability record. Owner reports include unresponsive customer service, difficulty getting parts and warranty help, heating-element and thermostat failures, and newer units drawing enough current to dim house lights. When it's installed correctly and works, owners are happy; the risk is what happens if it doesn't.
Key Features
Best Use Cases
Our Verdict
A cheap way into an 18 kW whole-home electric heater for a warm climate — with a real asterisk. The performance is standard for 18 kW, but Marey's documented support and reliability problems make it a gamble compared with pricier brands. Consider it only if the low price outweighs the risk, your panel can supply the heavy load, and you have a qualified installer.
Technical Specifications
| Power | 18 kW @ 240 V, self-modulating |
|---|---|
| Electrical | Two 50 A double-pole breakers · 6-gauge · ~150 A service |
| Advertised flow | 4.0 GPM @ 36 °F rise (4.4 @ 31 °F) |
| Cold-climate flow | ≈1.5 GPM at an 80 °F rise |
| Build | Stainless channel & chamber; ETL certified |
| Dimensions | 13.8 × 10.3 × 3.5 in |
Specifications verified against the linked source documents. See Sources below.
How much hot water you'll actually get
Usable flow drops as incoming water gets colder. Figures are calculated from rated output (kW) and labeled as such — not bench-tested by us.
| Temperature rise | Typical scenario | Usable flow |
|---|---|---|
| 35 °F | Warm climate (75 °F in → 110 °F) | 3.5 GPM |
| 45 °F | Mild climate (65 °F in → 110 °F) | 2.7 GPM |
| 60 °F | Cool climate (50 °F in → 110 °F) | 2 GPM |
| 70 °F | Cold climate (40 °F in → 110 °F) | 1.8 GPM |
Usable flow at a 110 °F target from 18 kW: kW × 3412 ÷ (ΔF × 500). Marey's 4.0–4.4 GPM claims assume a warm 31–36 °F rise; plan around these figures.
Pros
Cons
Buy it if…
- Warm-climate homes wanting 18 kW capacity at the lowest price
- Budget buyers who accept a mixed reliability/support record
- Panels that can supply two 50 A breakers and ~150 A service
- DIY-capable owners who can troubleshoot without much vendor help
Skip it if…
- Cold-climate whole-home use (output falls to ~1.5 GPM at 80 °F rise)
- Buyers who need responsive manufacturer support and parts
- Panels that can't handle the heavy electrical demand
Installation Requirements
Professional vs DIY
The ~150 A service recommendation makes an electrician and permit the right call; check your panel first.
Cold-climate output drops to ≈1.5 GPM at an 80 °F rise — size for your winter inlet.
Gas and electrical work should be done by a licensed professional, and most installs require a permit and must meet local building codes — DIY work can void the manufacturer warranty. Always confirm the unit's own manual for exact clearances, venting, and sizing.
What owners report
Themes summarized from retailer customer feedback (3.9/5 Amazon customer rating, 127 ratings, as of 2026-09-13). These are owner opinions, not our own bench testing.
Many owners report it installs easily and delivers reliable endless hot water in warm climates for the price.
A recurring, well-documented theme: owners struggle to reach Marey for parts or warranty help, citing unanswered calls and emails.
Some owners report heating-element and thermostat failures, and note installation instructions that didn't match the unit.
Reports include newer units pulling enough current to dim house lights on activation — confirm your service can handle it.
Marey ECO180 FAQ
What electrical service does the ECO180 need?+
Marey specifies two 50-amp double-pole breakers on 6-gauge wire and recommends at least 150-amp service — a heavy load, so confirm your panel before buying.
Will it run a whole house?+
In a warm climate, roughly three points of use at ~4 GPM. In cold climates it drops to about 1.5 GPM at an 80 °F rise — effectively a single fixture.
What's the catch with this unit?+
Price is its strength; support is its weakness. Owners frequently report trouble reaching Marey for parts or warranty service, so factor that risk into the decision.
Is it self-modulating?+
Yes — it adjusts power to demand for efficient operation, which is standard for quality electric tankless units in this class.
Product sources
Specifications verified 2026-09-13. Manufacturer documents are treated as the primary source for model specifications. Retailer pages are used only for customer ratings and owner-feedback themes.
- Marey ECO180 18 kW — Amazon listing & reviews (accessed 2026-09-13)
- Marey ECO180 — Lowe's listing (accessed 2026-09-13)
- Marey ECO180 — Home Depot owner reviews (accessed 2026-09-13)
Price range from leading retailers
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