Eemax EEM24027
Amazon customer rating as of
Tankless Geek editorial score: 4.2/5
The Eemax EEM24027 is a 27 kW, 240-volt residential electric tankless — Eemax's whole-home unit in a compact, digitally-controlled cabinet with 1/2-inch flex connections that skip soldering. It's among the most efficient electric heaters on paper at about 99.8%, self-activates at a low 0.25 GPM, and delivers up to 5.3 GPM at a warm rise. Eemax positions it for up to a shower and two sinks at once in cold climates, or as many as four fixtures in warm regions.
At 27 kW the electrical demand is heavy: three dedicated 40-amp double-pole breakers and substantial wiring, so panel capacity is the gating factor. Real-world flow follows inlet temperature — the 5.3 GPM peak falls to roughly 2.6 GPM at a hard winter rise. Owners praise the all-digital setup and quiet, space-saving operation once installed, with the usual reminder that a 27 kW unit needs serious electrical service. For a warm-to-moderate-climate home with the panel for it, it's a high-output, efficient electric choice.
Key Features
Best Use Cases
Our Verdict
A high-output 27 kW residential electric tankless with top-tier efficiency and an easy digital interface — well suited to warm and moderate climates. The gate is electrical: three 40-amp circuits and a capable panel. Get those right and it delivers strong whole-home flow for the price.
Technical Specifications
| Power | 27 kW @ 240 V |
|---|---|
| Electrical | Three 40 A double-pole breakers |
| Max flow | Up to 5.3 GPM (warm climate) |
| Efficiency | ≈99.8%; activates at 0.25 GPM |
| Connections | 1/2" flex (no soldering) |
| Dimensions | 14 × 10 × 4 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) — capped at max | 5.3 GPM |
| 45 °F | Mild climate (65 °F in → 110 °F) | 4.1 GPM |
| 60 °F | Cool climate (50 °F in → 110 °F) | 3.1 GPM |
| 70 °F | Cold climate (40 °F in → 110 °F) | 2.6 GPM |
Usable flow at a 110 °F target from 27 kW: kW × 3412 ÷ (ΔF × 500), capped at 5.3 GPM. The 4-fixture claim assumes a warm inlet.
Pros
Cons
Buy it if…
- Warm-to-moderate-climate homes wanting high electric output
- Buyers who value efficiency (≈99.8%) and digital control
- Panels that can supply three 40 A double-pole circuits
- Solder-free installs (1/2" flex connections)
Skip it if…
- Cold-climate whole-home use (flow falls to ~2.6 GPM in winter)
- Panels that can't handle the heavy 27 kW load
- Buyers wanting a gas unit's cold-climate capacity
Installation Requirements
Professional vs DIY
The solder-free water side is easy, but the three-circuit/~113 A electrical work calls for an electrician and a permit.
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 (4.1/5 Amazon customer rating, 89 ratings, as of 2026-09-06). These are owner opinions, not our own bench testing.
Owners repeatedly praise the all-digital control for making temperature setup and daily use simple.
The high efficiency and small footprint earn praise as a space-saving upgrade from a traditional tank.
The 27 kW load and three 40-amp breakers are the main planning challenge; confirm your service before buying.
The 1/2-inch flex connections are noted as a time-saver that simplifies installation.
Eemax EEM24027 FAQ
What electrical does the EEM24027 need?+
Three dedicated 40-amp double-pole breakers and heavy-gauge wiring. At 27 kW it's a large load — verify your panel with an electrician first.
How many fixtures can it run?+
Up to about a shower and two sinks at once in cold climates, or as many as four fixtures in warm regions, following inlet temperature.
Is it really a whole-home unit?+
In warm and moderate climates, yes. In cold climates its winter flow drops to roughly 2.6 GPM, which is closer to one to two fixtures.
How efficient is it?+
About 99.8% — electric resistance heating converts nearly all input to hot water, with no standby loss like a tank.
Can a typical 200 A home panel handle the EEM24027?+
Only with room to spare. The EEM24027 is a 27 kW unit that draws about 112 A across three 40 A double-pole breakers — well over half of a 200 A service on its own. On a 200 A panel that's usually workable after a load calculation, but on a 100 A or 150 A service it almost always forces a panel or service upgrade. Always have a licensed electrician confirm capacity and wire sizing before ordering; the whole-home flow this unit advertises depends on that full 112 A actually being available.
Product sources
Specifications verified 2026-09-06. Manufacturer documents are treated as the primary source for model specifications. Retailer pages are used only for customer ratings and owner-feedback themes.
- Eemax EEM24027 — Lowe's (27 kW, 5.3 GPM) (accessed 2026-09-06)
- Eemax EEM24027 — official product page (accessed 2026-09-06)
- Eemax EEM24027 — Home Depot listing (accessed 2026-09-06)
Price range from leading retailers
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