How We Test Electric Kettles v1.0

According to the Environmental Protection Agency (EPA), boiling water requires a full rolling boil (212°F/100°C) for one minute and cooling before use. And, a good electric kettle should be able to boil water in a reasonably short period of time without any hassle, which is the premise of our evaluation.

All scores (segmental and total) are shown on an easy-to-understand scale of 0 to 10. To give you a rough idea, a good kettle with an overall rating of 8/10 should:

• Boil reasonably fast
• Be energy efficient
• Not be too noisy
• Have good heat retention
• Be easy to lift, carry, and pour
• Be user-friendly and easy-to-clean

Performance (40%)

Our tests are practical, simple, and focus on what matters to the user. Therefore, we test for boiling speed, energy consumption, noise level, and (not to be overlooked) heat retention.

Theoretically, water boils at 212°F/100°C. However, this boiling point changes according to altitude or the amount of impurities in the water.

Kettle designers combat this by incorporating two ingenious features:

• A two-layer bimetallic disk (a metal with two different thermal expansions) that ‘flips’ at a specific temperature and turns off the kettle.
• A thermostat that is separated from the water. Instead,  steam is directed to the thermostat via a channel, usually in the handle, to increase the ambient temperature to 212°F/100°C.

Evidently, in actual testing, we found all kettles to boil between over 99°C to 100°C without fail. Thus, we don’t use temperature accuracy as a scoring criterion.

We video the entire testing process for quality control and also comment on any mishaps along the way. All kettles are cleaned before testing to make sure no impurities affect the results. Since it’s impossible to impartially judge water quality without a lab test, we simply point out bad tastes or odors in the ease of use section below.

Boiling Time (45%)

Rapid boiling is often the most appreciated factor to a good electric kettle.

Our preparation includes 1.5 liters of room-temperature (80°F/26.7°C) tap water, a customized power outlet, and a digital timer. Read our Boiling Time test article to find out the details!

Based on water heat capacity and kettles’ power output, we have 5 min as our benchmark for a score of 10/10. In addition to our collected data, any time more than 11 min scores a zero.

Energy Consumption(30%)

Energy consumption is, in our opinion, the second most important aspect of a kettle’s performance because people may boil water multiple times a day.

This test is performed simultaneously with the Boiling Time test with a power meter connected to our customized power outlet . You can see our circuit analysis in the Energy Consumption test.

Using basic formulas, we set 140 Wh as our benchmark for a 10/10 score. Looking at our results, it seemed reasonable to deduct 1 point for each 5 Wh increase in energy consumption.

Noise Level (15%)

Nobody really likes a noisy kettle! Although there are ways to minimize the noise, it is nonetheless a key point.

Performing a Noise Level test is easy enough. All it requires is a noise meter to capture the peak sound pressure level as we perform our Boiling Time test.

From the CDC’s recommendation and our collated results, 80 dB was a suitable benchmark for an 8/10. We then devised the rest of our tabulation from there.

Keep Warm (10%)

Our Keep Warm test is to see how well the kettle maintains the hot water temperature 5 minutes after boiling. One reason is energy efficiency, but the other is that most people won’t get to the water as soon as the kettle switches off.

For this test, we simply need to count down and then use a two-probe digital thermometer to check the water temperature.

The kettle only needs to retain the water temperature at 208°F / 98°C to get a 10/10 and each 2°F / 1°C drop will result in a one-point drop.

Design (25%)

We evaluate the design of electric kettles based on their structural features—what they have and what they don’t have. For this purpose, we break down the kettle into four main parts: Carafe (50%), Handle (10%), Lid (20%), and Base (20%).

Carafe (50%)

For the kettle’s carafe, we care about the material and the diameter of its opening.Other noteworthy features are an LED ring, water-level markings, limescale filter, and a tea infuser.

Handle (10%)

For the handle, we mostly examine if it has a anti-slip feature or if it feels sturdy and comfortable to carry.

Lid (20%)

For the lid, we pay attention to the material, opening mechanism, how tightly it closes, and if it’s easy to pour in water.

Base (20%)

For the kettle’s base, we check the material, rotation, sturdiness, cord storage, anti-slip pads, and how well it fits the carafe.

Usability (35%)

Usability means how we assess the kettle’s User Control (30%), how well its design features work or Ease of Use (50%), and how easy the Cleaning (20%) is.

User Control (30%)

For User Control, we primarily pay attention to the design of the controls including the indicator light visibility. Other key features are automatic shut-off and boil-dry protection.

Ease of Use (50%)

Ease of use is all about hands-on experience. We spend time with our electric kettles to see if they’re easy to control, lift, open, fill, pour, fit the base, and wrap the cord.

Cleaning (20%)

The shape and design of the kettle will determine how easy it is to clean. We check if the kettle has any difficult-to-clean nooks and crannies and whether the opening is unobstructed and the filter removable.