To echo Dan on efficiency of on vs. off: It's categorically more electrically efficient to turn your machine off when you're not using it. That's just the nature of the beast. However, I really don't think you save much, especially if you properly insulate your steam boiler (never insulate a PIDed brew boiler unless you seriously know what you're doing).

Having seen some heat exchanger machines that had very modest scaling in the HX portion that's in the boiler and heavy scaling in the grouphead itself, where the flushing and idle cycle means the temperature undulates dramatically more than anywhere else on such machines, I am a firm believer (without any scientific evidence) that scale forms the worst at the junction of hot and cold. I'd love to read more about this (or see it debunked) if anybody finds some good data.

Anyway, I've also left my machine on 24/7 ever since I came home to realize that the scale that accumulates on the vacuum breaker when it sputters when the machine cold-starts causes the steam boiler to start constantly leaking just a bit after a month or two, and progressively getting worse till you pull the thing apart and scrape the scale off the o-ring and conical teflon valve seat. I found this irritating and a cause for concern.

My GS3 appears to consume 160W of power at "steady state," according to my Kill-A-Watt. That measure has been consistent with readings averaged over a day and readings averaged over leaving it on for nearly a month. That said, I have read comments to the effect that these Kill-A-Watts don't work well for measuring PID'ed appliances because their metering frequency doesn't accurately read the spotty, split-second pulsing of the heaters operating with a PID control loop. I have no idea if that's true, but it's certainly salt to feed one's skepticism about the issue of power consumption, whichever side you fall on.

Dick, FYI my Kill-A-Watt also beeps when the machine is on FULL mode and doing a cold start. It also beeps occasionally after heating fully, when both boilers happen to tick on at the same time, which is actually extremely rare in my experience. I do have my machine on a 20A circuit, but I don't know that they make a 20A rated Kill-A-Watt.

My guess is that in flowing water, scale deposits at the constrictions, no matter where in the system it first forms as a compound in suspension. This explains the scale deposit we see in the brewing circuits of espresso machines, and also makes physical sense, i.e. junk floating in a river deposits at bends and narrows

. . . I'd love to read more about this . . .

I hope this link works (in more ways than one) - http://books.google.com/books?id=lazmQb ... &q&f=false
I have used products from this company to treat & clean engine cooling systems.

OK. Here are results of my first set of tests:

Both tests were run for 24 hours. For each test, I made three double shots, each of which involved filling a cup with hot water, briefly purging the group, running the shot, using hot water to rinse the cup and pf, running the group to brush it clean and doing a pf wiggle. One of the three shots involved steaming 6 oz of milk. Once per day I removed the screen, ran the group to wet a brush to clean the dispersion block, gasket and group perimeter, and did three plain water backflushes.

Test #1: On for 12 hours, off for 8 hours. Consumption = 3.53 KWH

Test #2: On continuously for 24 hours. Consumption = 4.48 KWH.

So, assuming the Kill-O-Watt is accurate, at least relatively if not abosolutely, the difference in consumption isn't linear. It takes only 27% more power to run 50% longer. I'm sure this is because making shots and cleaning the machine uses a higher percentage of the total consumtion than just keeping the boilers at temperature when idle. I should have recorded the usage before and after sessions, but didn't. I'll have to do that next time. I plan to repeat the tests with the machine set to HALF to get a sense of the savings that provides, if any.

We pay about 11.5 cents per KWH, so the difference is only about $40 per year (assuming two weeks of downtime per year.) I'm sure if I re-insulated my steam boiler, as Nicholas has done, the cost of leaving the machine on 24/7 would be even lower. Nicholas -- did that job require removing the steam boiler?

Your number for always on lines up with my number for augmented steam boiler insulation really well: 4.48 KW-Hr/day is about the equivalent of 187W of power consumption, meaning my insulation job (@160W) saves a net of around 27W or ~15%, which is low for an insulation job but makes sense given that you can't insulate the brew boiler.

Peppersass wrote:Nicholas -- did that job require removing the steam boiler?

Yes and No: You don't have to take the steam boiler off to augment the insulation, but there's not really enough room to do it if you don't take the pump motor out, which you do need to remove the steam boiler for. You could work around the pump motor leaving it in to some degree, but I'd be concerned that you'd be cutting off the airflow that lets the pump motor stay cool enough. I have no real idea if that's a legit concern, but it's something I would look into before doing additional insulation without pump-outboarding.

As we write, the BP Gulf oil spill continues to grow. I think we need to remember that saving money is not the only reason to reduce energy consumption.

A point well-taken, but let's see if you remain so conscientious when the vacuum breaker on your paddle GS/3 scales up in a few months and you have to fix it.

In case you don't know, it involves the following: Let machine cool completely, remove right side panel, remove rear panel, remove vacuum breaker valve, disassemble vacuum breaker valve, soak parts in vinegar or other acidic solvent for at least one hour, scrub any deposits off the parts, reassemble vacuum breaker valve, reinstall vacuum breaker valve, reinstall rear panel, reinstall right side panel.

It's definitely a pain when you haven't had your morning coffee yet. No big deal to let the valve sputter for a few hours, days or weeks? Well, water and steam sputtering out of the valve condenses inside the machine and can drip into the electronics box. Then you're asking for trouble. Best to address a sputtering vacuum breaker immediately. After you've done it once, and contemplate having to do it every 2-4 months, the idea of leaving the machine on and using 11 cents more electricity per day starts to look appealing.

This is a strange crowd to lecture about saving electricity. I don't see how anyone could possibly justify the amount of electricity we use just to make a few ounces of espresso and steamed milk per day. If we were truly serious about doing our part to save the environment (and the economy) we would sacrifice taste and switch to making big thermal carafes of drip or get our coffee from a shop where the energy efficiency per drink is much higher. I don't see very many people on this board who are willing to sacrifice taste for anything. I believe both you and I fall into the category of people willing to spend outrageous sums for it.

FWIW, I'm an early investor and Director of a company that makes unique electronic components for alternative energy applications, including hybrid and electric cars. At least I'm doing my part on the solutions side of the equation, if not fully on the conservation side. Now, if I can get the wife and kids to religiously turn off the lights when they leave a room, as my parents taught me to do, we'd save a lot more than $40 worth of electricity a year.

Hmmmm. I wonder how much electricity we would save if we turned off our computers instead of posting these messages?

Not meaning to get too far into this very august discussion, I might add that electrical utilities in many locales are moving towards pricing electricity at different rates during the day, depending on demand. I can't claim to know the ins and outs of systems like that, but I believe that in general the electricity is billed at a higher rate during the daytime, and at a much lower rate from late evening until morning. This is because electricity is not easily "stored," so there is a relative shortage of electricity during peak periods, and a surplus during slack periods. Since electrical utilities "waste" a lot of the energy they produce during non-peak periods (e.g. it is produced but not consumed, and cannot be easily stored), the argument for saving the planet by turning off your GS/3 when you go to sleep is a bit less compelling

This would suggest, at least to me, that the time period during which many home users would choose to turn off their machines, is exactly the same time period when electrical demand is at its lowest, and the pricing per KWH is apt to be the least. It is also the time period when air conditioner demand is at its lowest (during the summer) so the potential for taxing the home A/C system is much reduced.

With variable rate pricing throughout the day, the economic savings from turning the machine off in the evening only to turn it back on in early morning, is apt to be even less than the minimal savings that have been suggested on other posts in this and in other related threads.

ken

Unfortunately, smart grids like Ken describes are not yet pervasive enough for most HBers to worry. Another 10 years and hopefully our prosumer machines will be integrated with the grid so they know when to shut off automatically.

http://en.wikipedia.org/wiki/Smart_grid

I don't think you need anything nearly this complex in order to meter the electricity used at different rates throughout the day. I read an article in the WSJ about this within the last year, and differential metering is currently in use in a number of larger localities, and is on the way in many others. The article included interviews with consumers detailing how they were adapting their electricity usage to minimize their costs with this new system. As an example, they were doing things like the laundry during non-peak periods, and reducing the use of summer air conditioning during the day.

To my knowledge, all you need to do is to change the electrical meter at the location of use (e.g. a house in this case); you don't need to upgrade the entire grid.

I am not advocating the usage of this sort of electrical metering (in fact, I would find it to be a PITA personally); I am merely reporting that it exists, that it appears to be becoming more common, and that if you live in a place where this is in force (or will be in force) that turning off your espresso machine late at night might not save very much money.

ken