What percentage of a washing machine's energy is used purely to heat hot water?

bob2302

All modern washing machine have an EU standardized cycle called Eco 40-60; on my Bosch series 4 this is almost always a cold wash. Most of the washes I do use around 0.18 kWh, but if I overload it, or add a lot of towels, that rises to about 0.7 kWh due to heating.  When I say cold I mean there's no heating at all - I've checked that with a tapo p110's graphs.

Note that there is typically a specific cycle for killing spores, bacteria, etc as most modern machines take the temperature setting as little more than a hint.

poppellerant

Sterlingtimes said:

It is the Ebac machine, as advertised on GB News,  that I ordered.

The headline claims by Ebac are:
save up to 27% a year in running costs; 
up to 64% less energy used a wash;
up to 21minutes quicker wash;
element lasts 43% longer

What is Hot Fill? - Ebac

The figures may be over-egged, but I think that for £30 extra for the hot fill, it is worth a try as a 531 kWh/year user. I will have my power meter at the ready.

Did you check any reviews of the Ebac machine? From what I've read, they are poorly programmed, overly sensitive to load balancing to the point that they don't always achieve the final spin speed selected for the cycle - particularly high speed cotton spins, with full loads.

Sterlingtimes said:

Chrysalis said:

With something like the octopus mini you might be able to do the maths, watch the live read out as it spins, as it pumps, and so on.  To get an idea.

That is a very good idea. Thank you. I will get some screenshots from our current cold-fill Beko and will repeat when the mixed-fill Ebac machine arrives next week.

My first screenshot shows that most of the activity above baseline occurs in the first 20 minutes.

What did you use to generate that graph? I assume that's a plug in power monitor which can talk to your phone. but which monitor?

TheElectricCow

bob2302 said:

All modern washing machine have an EU standardized cycle called Eco 40-60; on my Bosch series 4 this is almost always a cold wash. Most of the washes I do use around 0.18 kWh, but if I overload it, or add a lot of towels, that rises to about 0.7 kWh due to heating.  When I say cold I mean there's no heating at all - I've checked that with a tapo p110's graphs.

Note that there is typically a specific cycle for killing spores, bacteria, etc as most modern machines take the temperature setting as little more than a hint.

This program is one I’ve read a bit about before but have never been able to figure out, would love to know if anybody has any other information on it! 

My Bosch does have this program, but according to the manufacturer specifications it actually uses more energy than any of the other cycles below 60c, takes an hour longer, and leaves the clothes wetter once finished (impacting drying times). The only thing it seems to have going for it is water consumption, which compared with the program I normally wash on, uses just 1 litre less at the expense of around twice the energy (~0.5kWh vs 1.02kWh).

Perhaps I’ll look for the regulations the program is based on to try and make some sense of it all, as I’m sure there’ll be an explanation in how all the figures are tested/worked out. So far I’ve never understood the point in the EU mandated Eco program apparently being one of the least economical.

Granted I haven’t actually measured each program as the plug socket for my machine isn’t accessible, so this is just based on the documentation supplied with the machine which could possibly not be completely accurate in a real world scenario.

bob2302

TheElectricCow said:

My Bosch does have this program, but according to the manufacturer specifications it actually uses more energy than any of the other cycles below 60c, takes an hour longer, and leaves the clothes wetter once finished (impacting drying times). The only thing it seems to have going for it is water consumption,

In my experience this is all wrong - the specs are probably for the avoidable worst case scenario where it's been stuffed with towels or heavy jeans.

Eco 40-60 is intended to provide the same cleaning as a 40C or 60C wash at lower temperature, and to achieve that it's allowed to vary the parameters to match the load. When I switch to this mode the display shows 3:35, but within the first 30 minutes it's lost that extra hour in every wash I've monitored. I loosely fill my machine up to 80% of the way up and I find this typically stays in the range 0.17 - 0.22 kWh. 

The spin cycle defaults to the maximum speed of 1400 and I've not noticed it be any worse than a cotton cycle. I air dry in a spare room, and do less than 2 loads a week, so I don't really care. If you are short of time there's nothing to stop you doing an extra spin cycle - it wont cost much.

Spin drying can be a bit erratic because of the vibration detection. When excessive vibration is detected it slows down and tumbles the clothes to get a better distribution of weight. I've seen a nominal 10 minute spin stretch to an hour, and I suspect it just gave up in the end. 

Sterlingtimes

Test with new Ebac 15/01/2024 (revised)

I have my new Ebac Hot washing machine installed using HOT FILL.

Maximum load 10kg

Heavy load filling drum
Cotton saver
1600 RPM
40 degrees

Using Antela smart plug, Smart Life app, Home Assistant

Shown below are times and cumulative watt hours

Energy used for a cycle 1000 Wh

Energy used for a cycle by electricity, excluding water heating less than 200 Wh

Calculated use of gas for water heating, allowing for inefficiencies 800 Wh

Use of gas 80%

Use of electricity 20%

Note: The heating element spike lasts only seconds because all hot water is provided from the hot water cylinder. Approximately 3 litres of water is run off from the adjacent hot tap. 

pole_man

@Sterlingtimes Very interesting investigations. You say you run off 3 litres of water from the hot tap (and you've earlier shown the temperature rising as your run off several litres). Is this because you have a combi boiler? It can't be cold water sitting in the pipe, my own calc says an 8 metre run of 15mm pipe only has about 0.25 litres in it.

bob2302

Sterlingtimes said:

Test with new Ebac 15/01/2024 (revised)

I have my new Ebac Hot washing machine installed using HOT FILL.

...

Energy used for a cycle 1000 Wh

Energy used for a cycle by electricity, excluding water heating less than 200 Wh

Calculated use of gas for water heating, allowing for inefficiencies 800 Wh

Use of gas 80%

Use of electricity 20%

Still twice the price of  Eco 40-60, and less environmentally friendly.

Sterlingtimes

pole_man said:

@Sterlingtimes Very interesting investigations. You say you run off 3 litres of water from the hot tap (and you've earlier shown the temperature rising as your run off several litres). Is this because you have a combi boiler? It can't be cold water sitting in the pipe, my own calc says an 8 metre run of 15mm pipe only has about 0.25 litres in it.

No, I have a heat-only boiler with water stored at 50 degrees in the cylinder. I repeated the run-off experiment today, and the results are the same. After several months, I have seen a decrease in electricity consumption and a corresponding increase in gas consumption. The electricity saving for the hot fill is between 70 and 80%. 

The Ebac works well but throws up some error messages concerning load balancing. Also, the hot fill is only available on one of the many cycles. We have to restrict ourselves to a single cycle.

pole_man

pole_man said:

@Sterlingtimes Very interesting investigations. You say you run off 3 litres of water from the hot tap (and you've earlier shown the temperature rising as your run off several litres). Is this because you have a combi boiler? It can't be cold water sitting in the pipe, my own calc says an 8 metre run of 15mm pipe only has about 0.25 litres in it.

@Sterlingman I've discovered from site admin that as a newbie I can't edit my comments, so I have to re-comment to say that my calc was wrong. An 8 metre run of 15mm pipe only has about 1.06 litres in it.

Sterlingtimes

pole_man said:

@Sterlingman I've discovered from site admin that as a newbie I can't edit my comments, so I have to re-comment to say that my calc was wrong. An 8 metre run of 15mm pipe only has about 1.06 litres in it.

My measurements are consistent. I cannot see all of my pipe runs, but some of it is 22mm, especially where the first two or three meters exit the cylinder. Does that alter the calculation?