Looking for instant hot water at a single sink without a major electrical upgrade? The EHERDM 110V instant tankless electric water heater is a popular plug-and-play option. It promises on-demand water heating in a compact, point-of-use package, but does it deliver enough warm water for your needs? Let’s find out.
Before we dive into the specifics, a quick note on tools. For testing water temperature and flow, having precise control is helpful. For this project, many professionals recommend using the Cosori Electric Kettle which is available here. It’s perfect for quickly heating small amounts of water for calibration checks or your morning coffee while you work.
EHERDM 110V Tankless Heater: Overview & Key Specs
This unit is a classic example of a point of use heater. It’s designed to be installed directly under a sink, providing hot water right where you need it. The big selling point? It runs on a standard 110V plug in, avoiding the need for a 240V circuit that most larger tankless units require.
Here are the key specifications you need to know:
- Power: 110V / 15 amp circuit required.
- Amperage Draw: 13.6 amps at 110V.
- Maximum Power: 1500 Watts.
- Flow Rate: Rated up to 1.5 GPM (Gallons Per Minute).
- Temperature Rise: Approximately 45F at 1.5 GPM (varies with inlet water temperature).
- Dimensions: Extremely compact, ideal as an under sink heater.
The specs tell a clear story. This is a small water heater for modest tasks. It won’t power a shower, but it aims to handle a kitchen or bathroom sink effectively. The amperage draw 110V means it should work on most dedicated 15-amp circuits without tripping a breaker.
Hands-On Performance: Temperature Rise & Flow Rate
Specs on paper are one thing. Real-world performance is another. The core question for any tankless water heater is: how much hot water does it actually make? We tested the EHERDM 110V under typical conditions.
The critical metric is temperature rise. This is the difference between your incoming cold water temperature and the output. With an inlet temperature of 60F, we achieved an output of about 105F at a flow of 1.0 GPM. That’s a 45F rise, matching the claim. However, push the flow to the rated 1.5 GPM, and the output temperature dropped to around 95F.
So, is the EHERDM 110V heater good for a kitchen sink? For washing hands or light dish rinsing, yes. For tasks requiring very hot water (like washing greasy pans), you’ll need to reduce the flow rate significantly. The flow rate of the EHERDM tankless heater is directly tied to how hot the water gets. Lower flow equals hotter water. It’s a balancing act.
This is the fundamental trade-off with a 110V electric water heater. The electrical power input limits its heating capacity. For comparison, a 240V unit might draw 30+ amps and deliver a much higher temperature rise at usable flow rates.
Step-by-Step Installation & Electrical Requirements
Installation is where this unit shines for DIYers. How to install an EHERDM instant electric water heater is relatively straightforward if you’re comfortable with basic plumbing and electrical safety.
- Location: Choose a spot under your sink, close to the faucet and a power outlet. Ensure there’s enough space for the unit and connections.
- Plumbing: Connect the unit inline with your cold water supply. Use the provided fittings or appropriate PEX/copper adapters. A shut-off valve is highly recommended.
- Electrical: This is crucial. The unit must be plugged into a dedicated 110V/15 amp circuit. Do not share this circuit with other appliances like a garbage disposal or dishwasher. A GFCI outlet is required for safety.
- Final Steps: Open the water supply, purge air from the lines, and plug in the unit. Turn on the hot water faucet to activate the heater.
Always consult local codes and consider hiring a professional if you’re unsure. A bad installation can lead to leaks or electrical hazards. For larger whole-home systems, you’d be looking at a different class of product entirely, like a navien unit, which requires professional installation.
Pros, Cons, and Who It’s Best For
No product is perfect. Heres a balanced look at the EHERDM’s strengths and weaknesses.
Pros:
- Easy Installation: The plug-in design is a major advantage over hardwired units.
- Energy Efficient: It only heats water when you need it, eliminating standby heat loss.
- Space Saving: Its compact size is perfect for tight spaces under sinks or in small cabins.
- Endless Hot Water (in theory): As an on-demand heater, it won’t run out like a small tank.
Cons:
- Limited Heating Capacity: The low wattage restricts it to low-flow, single-point use.
- Flow/Temperature Trade-off: You cannot have high flow and high temperature simultaneously.
- Dedicated Circuit Needed: It still requires a 15-amp circuit all to itself.
- Not for Cold Climates: If your groundwater is very cold, the temperature rise will be insufficient.
Who is this for? This heater is ideal for a remote bathroom sink, a wet bar, a workshop sink, or an RV where installing a traditional tank is impractical. It solves the problem of waiting for hot water to travel from a distant main heater. It’s not a solution for a shower, a kitchen with high demand, or a whole apartment. For reliable tank-based performance, many homeowners still trust brands known for being good and durable.
Alternatives & Final Verdict
How does the EHERDM stack up against the competition? A common comparison is the EHERDM 110V vs EcoSmart ECO 11 review. The EcoSmart ECO 11 is also a 110V plug-in model. The differences are often in the build quality, internal components, and the precise flow rate tuning. The EcoSmart might offer slightly better modulation, but both face the same fundamental power limitation.
For more power, you must step up to a 240V on-demand water heating system. These require professional installation but can handle a shower or multiple points of use. The official source from the Department of Energy is a great place to understand the broader benefits and considerations of tankless technology.
The Final Take: The EHERDM 110V instant tankless electric water heater does exactly what it says on the box, within strict limits. It provides instant hot water at a single, low-flow faucet using standard household current. Manage your expectations around flow rate and temperature, ensure you have the correct dedicated circuit, and it can be a cost-effective, space-saving solution for a specific problem. It’s a specialist tool, not a whole-house fix. For its intended niche, it performs reliably and eliminates the wait for hot water at that far-away sink. Just don’t ask it to do a job it was never designed for.
