Some folk have asked what kind of equipment we use when we try things out so here’s a list of the most frequently-used items:

• Infra red spot thermometer
  • Non-contact temperature measurements; oven or wood-burning stove surfaces and the like
• Contact/probe thermometer
  • Checking the internal temperature of food or measuring the temperature of water, etc.
• Clamp ammeter
  • Measures higher currents (via a breakout for corded devices like fridges)
• Power meter
  • RMS values of voltages, checking mains frequency and (fairly low) current

We are mostly making comparisons rather than looking to discover absolute values so having laboratory calibrated instruments isn’t overly critical.

For some things, the rating plate on the device – a kettle, for example – will be accurate enough for comparison purposes, plus they’re either off or on: there’s no ‘using a bit of power but not as much as we could’ mode on a kettle. Compare that to, say, a conventional fridge which will draw 0W when the door is closed and the compressor is off, 5W if the door is opened (turning the light on) or 160W or so when the compressor starts running: harder to figure out the actual consumption over time when the value jumps up and down so we turn to the meters for the data.

For measuring time, we generally use nothing more sophisticated than the stopwatch function on a phone or handy computer.

The other tool we try to use in all our tests and data is a large dose of common sense: we’re not about to splice into a gas supply line to measure the absolute volume of gas a boiler uses to reheat a full tank of hot water!