How We Test Heaters

At, we take heater testing seriously. We have dedicated professionals who thoroughly evaluate both space and water heaters in our specialized testing facilities.

I'm Ted Curley, a licensed electrician with decades of experience installing and repairing all kinds of heating systems. I head up our space heater testing program in my electronics workshop. There, my team and I assess portable space heaters across a range of criteria from heating capacity to safety.

For testing water heaters, we have Steve Donaldson take the lead. Steve is a Master HVAC technician with over 30 years of experience dealing with water heating issues. He oversees testing storage tank and tankless water heaters in our plumbing shop. Steve and his team have developed a rigorous testing system to measure water output, efficiency, durability, and ease of use.

With seasoned heating professionals conducting the testing, we're able to provide shoppers with in-depth, unbiased reviews on all major heater models. Our hands-on approach gives us the data and insights you need to choose the right heater.

In this article, I'll walk you through the step-by-step process I use to test space heaters in my workshop. And Steve will do the same for water heaters.

Testing Criteria

There are several key factors I evaluate when testing any type of heater:

  • Heating capacity – How much space can the heater adequately heat? For water heaters, how quickly can it heat water and in what volumes?
  • Efficiency – How efficiently does the heater convert energy to heat? This is important for operating costs.
  • Safety features – What safeguards does the unit have for overheating, tip-over, electrical faults, gas leaks, etc.?
  • Durability – How well is the heater constructed? Does it feel sturdy and well-made?
  • Ease of use – Is the heater straightforward to install, operate, and maintain?
  • Warranty – Does the manufacturer provide adequate warranty coverage?
  • Cost – How does the price compare to the value you get?

I grade heaters in all of these areas and synthesize the results into an overall rating and recommendation. The testing process helps me thoroughly evaluate the pros, cons, and real-world performance of each heater.

Space Heater Testing

Testing space heaters involves evaluating portable heaters designed to warm smaller areas of a home. Here is my full testing methodology:

Test Lab Setup

  • I test heaters in a closed workshop that allows me to control the ambient air temperature.
  • The test area is a simulated living room approximately 300 sq. ft. with furniture, carpet, and a test dummy on the couch to simulate a human body.
  • I use calibrated thermocouples to measure air temperature at various points around the room.
  • An anemometer measures airflow speed and direction at the heater outlet.
  • I test under controlled ambient temperatures of 50°F (10°C) and 70°F (21°C).

Heating Capacity Tests

  • With the ambient temperature set to 50°F, I operate the heater on maximum heat output and measure how long it takes to raise the room's temperature to 70°F.
  • I repeat this test in Eco/low mode to evaluate performance and energy efficiency.
  • I note if any areas of the room fail to heat up adequately due to uneven heat distribution.

Safety Tests

  • I check for tip-over safety shutoff by tilting the heater at various angles on a test platform.
  • I test overheat protection by obstructing inlets/outlets and operating until automatic shutoff.
  • I verify the machine cuts power if lifted off the ground as a child safety feature.
  • I evaluate the exterior temperature with an infrared thermometer to check for potential burns.

Durability Evaluation

  • I leave the heater running overnight to verify consistent operation.
  • I assess the quality of materials and construction.
  • I review the warranty coverage for defects and faults.

Ease of Use

  • I evaluate the setup process, control panel, remote operation, cord length, portability, and other ergonomic factors.
  • I verify the heater can maintain a stable room temperature without constant adjustment.

Water Heater Testing

Testing water heaters includes assessing storage tank and tankless/on-demand models for home use. My water heater testing procedure is:

Test Lab Setup

  • I plumbed a test apparatus that draws heated water from the heater into insulated storage tanks for measurement.
  • The apparatus includes a “return loop” that sends water back to the heater to simulate household usage patterns.
  • I attached precisely calibrated thermocouples and flow rate meters to the apparatus.
  • For tankless heaters, I use a variable water pump to simulate different household flow rates.

Heating Capacity Tests

  • I start with a completely cold tank of water and measure the time required to heat it to 120°F (49°C) on maximum setting.
  • For tankless systems, I quantify the temperature rise through the unit at various flow rates. The highest achievable flow rate that provides a 40°F rise is the optimal capacity.
  • I assess the temperature maintenance by drawing heated water in intervals over a simulated day of usage.

Safety Tests

  • I verify the pressure release valve activates at the correct threshold to prevent explosion.
  • I check that electrical components are properly grounded and sealed from water exposure.
  • I review safety certifications from testing agencies like UL, ETL, CSA.

Durability Evaluation

  • I review the warranty terms for coverage of leaks, rust, electrical failures, etc.
  • I examine the thickness of the steel tank and quality of insulation.
  • For tankless heaters, I verify the heat exchanger and components are adequately robust.

Ease of Use

  • I assess the installation requirements and procedure.
  • I review the maintenance procedures & difficulty of tasks like draining the tank.
  • I evaluate the temperature controls and diagnostics systems.

Putting It All Together

After completing the battery of tests for each heater, I compile the results into a review. I score the heater in each testing criteria category and synthesize it all into an overall rating from 1-5 stars.

My goal is to provide readers with detailed, empirical testing data alongside practical first-hand experience using the heaters. This gives consumers the information they need to select the right heater for their home and budget.

I also make sure to update reviews after using the heaters for an extended period. Any changes in performance get noted. This helps identify potential long-term durability or reliability issues.

Testing heaters thoroughly takes time, but it's worth it. I know from years of hands-on experience that not every heater performs the same, even if the specs look similar. There are always differences uncovered through rigorous head-to-head testing. I'm committed to putting heaters through the wringer to separate the best from the rest.

So next time you're reading one of my heater reviews, you'll know it comes backed by hundreds of hours of controlled testing and evaluation. My aim is to make your buying decision easier and get you the right heater for your home.