Why high electricty usage

QrizB

StarTrekkie007 said:

Do you have any figures on this ?

Dishwashers (both manual and automatic!) vary, but there are various sources that seem to agree the machine is cheaper than the hand.

See for example:
https://www.thisismoney.co.uk/money/experts/article-12114807/Is-cheaper-use-dishwasher-wash-hand-sink.html

Alnat1

Many who handwash the dishes do it more often than you would run a dishwasher, sometimes several times a day.

A dishwasher can keep the kitchen looking tidy until it's full and ready to run.

TheElectricCow

StarTrekkie007 said:

TheElectricCow said:

Krakkkers said:

Wash dishes before putting them in the dishwasher? isn't technology great.
I wash them by hand.

Really depends on the model of the dishwasher I imagine. I’ve always found a simple plate scraping to be quite adequate for my dishes before letting the machine handle the rest.

Even after accounting for electric, water use, dishwasher tablets, and a small allowance for salt & rinse aid, my dishwasher on off-peak energy still comes out cheaper than washing up by hand with hot water, and it will get everything far cleaner than if I’d done it manually. And that’s before considering the time/convenience factor of not actually having to do the washing up.

I'd always thought a dishwasher was a more expensive convenience over handwashing since handwashing you just fill a tub with hot water and wash all your dishes in it

Do you have any figures on this ?

I do, although it goes without saying that these figures would only apply to my own specific model and circumstances and exact consumption figures are naturally approximations.

I run mine on a 50c “Eco” cycle every time as standard and as per the manufacture specs this consumes 1.02kWh in electric and 11.7l of water. I’ll use the Octopus E7 Eastern off peak rate here as I have that to hand (16.31/kWh) putting the energy cost at 16.64p for one load. 

The cost for the 11.7l water in my area would be 2.24p and I use Wilko lemon dishwasher tablets at a cost of 8p each.

So far that’s 26.88p per load, so I’d round that up to 30p to account for a small amount of salt/rinse aid per wash (a negligible cost really, comparable to a fresh pack of sponges for hand washing). After 1.5 years of use I’m only on my second bag of salt and have yet to open my third rinse aid, albeit I am a low user.

If I were to heat my immersion tank to do the washing up at a similar temp it’d need at least 2kWh, costing 32.62p plus an allowance for water and soap. I’d probably put 4-5l of water in the bowl, a d to do the same amount of washing as I can fit in one dishwasher load would need to change that water once maybe twice (plus additional for rinsing). Total cost would be at least 35p all in. Granted, I’m not particularly good at washing up by hand so perhaps others would be more efficient.

Boiling a kettle would of course use less energy for the heating without a big tank to heat, but that would also be done on day-rate electric so some quick calculations based on standard SVT rates puts that still at around 30p just for the water.

A direct hot water gas boiler would of course be a different story which I don’t have the figures to hand for unfortunately. I imagine that may come out a little cheaper but still wouldn’t outweigh the time/convenience benefits in my mind.

Krakkkers

I use 7 liters of water (2p) 
and water heated from solar panels via diverter so 0p
and 10ml of LIDL W5 washing liquid 0.8p
1kw is more than half my daily consumption of electricity from the grid and an extravagance.

Spoonie_Turtle

Krakkkers said:

I use 7 liters of water (2p) 
and water heated from solar panels via diverter so 0p
and 10ml of LIDL W5 washing liquid 0.8p
1kw is more than half my daily consumption of electricity from the grid and an extravagance.

Could you not equally run the dishwasher using solar power?

I have read that the tipping point for dishwasher using less water than daily handwashing is two occupants, but I haven't checked to cite any sources.  And I doubt that many of us here use it daily.

JGB1955

Spoonie_Turtle said:

I have read that the tipping point for dishwasher using less water than daily handwashing is two occupants, but I haven't checked to cite any sources.  And I doubt that many of us here use it daily.

There are only the two of us, and we definitely use it daily.

Petriix

Krakkkers said:

I use 7 liters of water (2p) 
and water heated from solar panels via diverter so 0p
and 10ml of LIDL W5 washing liquid 0.8p
1kw is more than half my daily consumption of electricity from the grid and an extravagance.

Your solar panels and hot water diverted weren't free so it's not quite as simple as that but, as you've invested already, you may as well use it.

On the other hand, my dishwasher runs during the day when it's sunny enough so the electricity is also 'free' for me (without the hot water diverter) otherwise overnight at 9.5p per kWh. The 'eco' mode uses about 0.75kWh and I estimate it holds around 3 days' worth of washing up.

I'd always considered it cost-neutral with manually washing up, but with significantly less labour and far better aesthetics. Primarily it's a cupboard you put the dirty things away in so they're off the surfaces. 

mmmmikey

...I found that even when I had a dishwasher I'd still use a small bowl of hot water for wiping down the surfaces, rinsing the dishcloth and washing the odd thing that isn't dishwasher safe. I'd do that at least 2 or 3 times a day even if I only ran the dishwasher every other day. Assuming you do the same you need to take that into account when doing the sums. If you wash up by hand there's no extra cost because the water's there anyway, but if you use a dishwasher it's going to eat into or possibly wipe out any savings.

In the end, I can't imagine there's a big difference either way and I guess it just comes down to personal preference.

Alnat1

Wiping down surfaces with a dish cloth, rinsing it and using it again several times during the day is really unhygienic. A damp cloth left at room temperature is the perfect place for bacteria to multiply.

Much better to use once then chuck it in the washer

markin

Krakkkers said:

I use 7 liters of water (2p) 
and water heated from solar panels via diverter so 0p
and 10ml of LIDL W5 washing liquid 0.8p
1kw is more than half my daily consumption of electricity from the grid and an extravagance.

15p if you had exported it, so at least 18p.


If you give plates a quick rinse so that food won't harden on, 2 people should be able to get away with only using the washer every other day.