Is it More Environmentally Friendly to Switch my Espresso Machine off Overnight?
We’ve all been told, at some point in our careers, that modern espresso machines are so efficient that heating them up from cold actually uses more energy than leaving them running overnight. However, this myth is easily dispelled: whether you’re leaving the machine on or heating it up from cold, it only needs enough power to replace the heat lost to the atmosphere during the night. Heat loss is proportional to the square of the temperature difference, so a machine kept hot overnight will lose much more heat energy over the course of the night than one left to cool.
So does that mean we should switch the machines off to save the environment?
Unfortunately, it’s not that simple.
Firstly, how much electricity are we talking about? Over the past decade, espresso machines have made huge leaps in energy efficiency. For most of the history of espresso, nearly all machines followed the same basic design, with one or two large, uninsulated boilers. In the last ten years however several innovations have reduced energy consumption dramatically: especially the use of insulation on boilers, pipework, and even steam wands; and PID-controlled thermostats, which reduce ‘overshoot’ when heating a boiler.
“We estimate that it is possible to save around 30% of the energy [compared to a traditional machine] using a Black Eagle,” explains Nuova Simonelli’s Maurizio Giuli. “In some conditions, the energy saving can exceed 40%.”
Thanks to these technologies, a typical modern multi-boiler espresso machine might draw around 200W when idle – about the same as a couple of light bulbs. So while switching off will save some power, it’s likely a fairly small saving.
With this small energy saving in mind, let’s examine the downsides to switching off. Perhaps the most important is thermal stress – caused by metal parts expanding and contracting as the machine heats and cools. This stress can eventually cause leaks and other issues, resulting in the need for expensive engineer callouts and replacement parts, which also have an environmental cost themselves.
“Another important aspect to reducing energy consumption is to keep the machine clean with no scale inside,” says Giuli. Heating and cooling increase the formation of limescale, and over time, scale will reduce the efficiency of the elements, increasing electricity consumption. Sanremo’s Cafe Racer User Manual makes this explicit: “We recommend turning the machine off only if it will not be used for more than 8 hours. This limits the build-up of scale and saves electricity.”
Finally, the electronic components of the machine are most likely to fail during powering on. This is part of the reason that televisions still have standby modes despite concerns about the energy this wastes. Replacing electronic parts in a machine can be costly, and waste electronic equipment has a significant environmental impact.
Fortunately, some machines address these issues by having a ‘standby’ or ‘low consumption’ mode. Rather than turning the machine off, the boilers are held at a lower temperature, to save energy. The smaller temperature change compared to powering off completely reduces thermal stress and scale build-up — and it also prevents any electronic issues arising during powering on.
Our recommendation, therefore, is to use standby mode where possible to reduce consumption, rather than turning machines off completely, unless your insurance stipulates otherwise. For machines without a standby mode, turning them off will indeed save energy — but be prepared for some other unexpected costs in the long run.