HB wrote:The steam boiler may pressurize in 10 minutes, but the thermosyphon takes at least another 15 minutes to heat the grouphead. The whole group (boiler, thermosyphon, grouphead, portafilter, and misc. bits of metal) isn't truly temperature stable for 40-60 minutes, depending on how aggressively the thermosyphon circuit cycles water between the steam boiler and grouphead..

kamali wrote:Lets say you turned off the machine at 9 am (timer) and you turn it back on 30 minutes later would this minimize the time for heat up?

kamali wrote:Is there anyway to know when grouphead is heated (without buying an expensive adapter)? Possibly checking temperature of the shot?

HB wrote:This question comes up regularly and the FAQ points to several past discussions: Running an espresso machine 24/7, Electricity Usage Monitor, actual consumption (CoffeeGeek), and a poll.

My take on it from last time:

I can appreciate the convenience of always-on espresso machines, especially for commercial units that demand hours to stabilize. But I've still not heard any compelling evidence tying premature component failures to on/off cycling. Simply put: What components are more likely to fail if a machine is run four hours a day versus 24/7?

In past discussions, I've read the following disadvantages of on/off cycling:

• Inconvenient if one must wait, or added expense if one buys a timer; risk that machines without auto-refill with be turned on without water and burn out the heating element; risk that brew switch will be inadvertently be left in on position and burn out pump when timer starts it
• Increases scale build-up at the boiler's waterline
• "Stresses" connections of dissimilar metals (How does this manifest itself as a failure - boiler leaks? If so, from where?)
• Electronic components are subjected to changing temperatures, which increases the likelihood of them failing. The argument that failures are more common with frequently cycled computers is often cited in the same context
• Sensitive electronic components are subjected to electrical spikes when machine is turned on/off

I've read the following advantages of on/off cycling:

• Saves energy
• Increases the lifespan of gaskets
• Reduced usage decreases pressurestat's carbon buildup, which is the leading cause of failure
• Some "weaker" connections are made of nylon or plastic (tees, insulators). Exposure to less heat reduces their failure rates
• Reduced exposure to high temperatures increases the lifespan of sensitive electronic components like controllers (note: applies mostly to prosumer / semi-commercial machines; they are located outside of the case of most commercial units)

Looking at the list above, the one that sticks out for me is the pressurestat. They cost around $40-$60. If I remember correctly, that roughly equates to the added energy cost of approximately two years' 24/7 operation. It wouldn't surprise me if 24/7 operation would decrease some pressurestat's lifespan by that much (e.g., CEME, MATER).

The calculations for a cafe are a lot easier. If the cafe closes at 10pm and reopens around 6am, realistically they have little choice but to run 24/7. For those with machines that warm up in 30-60 minutes, it's an option. Is on/off cycling a more economical option? I don't know for certain, but my guess is yes, it is for most prosumer / semi-commercial units.

AndyS wrote:Turning the machine off overnight will always save electricity, no matter what size it is. People who say "it takes more electricity to warm it back up than you save by turning it off" are incorrect.

There are two caveats:
1. The amount of electricity saved may be quite low, as Mike says.
2. Some people claim that certain machine components (eg, gaskets) last longer when the machine is on 24/7. (Unfortunately, many of these people are probably just repeating anecdotal evidence that does not constitute real proof. One would think that the major machine manufacturers have a lot of good data on this, though.)

• Leave it on, or turn it off?
• Should an HX espresso machine be turned on/off
• Leave your La Marzocco GS/3 on
• Do you leave your espresso machine on all the time?
• Leaving a Prosumer HX Espresso Machine On DOES NOT SAVE ENERGY