Cost of running dishwasher

[Munroast]

Because we have PV our dish washer only runs during the day

It was sunny today so it was free.

do you not export ? if so it costs you 15p per unit

 

[Harry Bloomfield]

... I'm not personally aware of any hot-fill or gas-powered dishwashers (if they exist, they must be extremely rare!), so I'm not sure that I understand what point you're trying to make?

I read it as meaning - compared to using hot water from a combi, of gas heated stored cylinder, and doing the washing up in a bowl.

 

[Murdochcat]

do you not export ? if so it costs you 15p per unit

DIY install by myself so any spare energy first heats the hot water, then any excess goes to the grid and we get nothing

Octopus claim to accept non MCS installs but ask for £250 just to access your application

I’m happy with the situation

 

[JohnW2]

You don't understand because you are stupid, every one else realised I was comparing with a washing up bowl and hot water

Well, whether because I am stupid or whatever, I didn't understand that - which is why I asked what point you were trying to make.

 

[JohnW2]

I read it as meaning - compared to using hot water from a combi, of gas heated stored cylinder, and doing the washing up in a bowl.

... which is what I have now been told was the intended meaning. However, that was not immediately apparent to me, apparently because I am stupid.

 

[JohnW2]

DIY install by myself so any spare energy first heats the hot water, then any excess goes to the grid and we get nothing

Why do you bother to ever export any, then - just to help save the planet, perhaps?

 

[Harry Bloomfield]

you have a spare tv set ?

We have two decent sized ones, in two bedrooms, a smaller one in the kitchen, and an even smaller one in the caravan, plus the main one in the living room.

and if it takes a "minimum amount of effort, to wash up in a bowl" why have a dish washer, I will tell you why; washing dishes is a nightmare of a job, does my back in for starters - dishwashers are 7x more important than a TV set (I really should have a spare one just in case)

My back too! I bought it 15 years ago, for my then partner, without discussing it with her. She preferred to hand wash, rarely made use of it. Avril is similar, she's used it rarely.

The use to call radios, wireless sets, it maybe stuck.

 

[Harry Bloomfield]

Because we have PV our dish washer only runs during the day

It was sunny today so it was free.

No PV, no wind generator, but mine, from the grid was also free for 2 hours today, and an hour yesterday.

 

[Murdochcat]

Why do you bother to ever export any, then - just to help save the planet, perhaps?

Odd comment to say the very least

How would you suggest I prevent it

And FWIW what’s wrong with a little going to the grid

 

[Munroast]

I wonder what it costs to run a bowl of hot water to wash up with? If I run a bowl full, that is really two bowls full, as need to run nearly a bowl of cold water before the hot water gets through. So would guess 0.4–0.5 kWh to fill the first bowl with water, the second bowl more like 0.2–0.3 kWh as the pipes now warm, so two bowls required as need to rinse the plates, and in my sink can wash around half the dishes which would fit in the dishwasher, so looking at 1.2–1.6 kWh to handwash the dishes.

how far is your tank away, ?
just checked ours and hot after 1.5 litres
But i would run it all into the bowl, if I didn't start to fill the bowl until running hot, I would have to add cold at the end

our bowl is 8 litres, and we keep our hot water at 50º, lets assume mains water is 10°. so we are heating 8 litres through 40°
energy required (lets assume 10 lires if your tank is a long way away)
10 litres x 4.18 specific heat x 40 degees = 1672 joules / 3.6 = 464 watts

boiler 85% efficient so we will need 546 watts of energy

11 kwh of energy in a unit of gas so we will need 0.05 units of gas
lets assume 7p per unit - therefore cost to heat water for one bowl would be a whopping 0.35p

or 3 bowls per penny

That was a good excuse to get the fag packets out (1 cig = 75p or 2.25 tonne of hot water)can't afford to heat my house on benefits, but i smoke like a chimney bolluxs)

 

[Munroast]

DIY install by myself so any spare energy first heats the hot water, then any excess goes to the grid and we get nothing

Octopus claim to accept non MCS installs but ask for £250 just to access your application

I’m happy with the situation

its just a rip off - we had to pay SP Networks to rubber stamp our application a whopping £550, it literally is day light robbery

we had to wait weeks for them them to do next to nothing, I was able to configure our inverter not to export, did not want my inverter cooking away, wearing itself out lining their greedy bastard pockets

 

[ericmark]

any spare energy first heats the hot water, then any excess goes to the grid and we get nothing

I had the same for 18 months, 6 kW of panels, 5 kW inverter and to start with 3.2 kWh battery. The fitting of a smart meter resulted in being able to have an EV tariff from British Gas, so could charge batteries overnight.

However, we realised we were exporting even when batteries not charged, as maximum charge rate was 2 kW, so doubled up on the battery, to 6.4 kWh, this allowed us to use 4 kW to charge batteries, it also increased discharge from 3 kW to 5 kW, so no export unless batteries fully charged.

Sunset to off-peak was also improved, we were running out of battery between 9 and 10 pm, extra battery resulted in not running out before off-peak started.

However, off-peak end to sun rise very different, we would still have a 50% charged battery, so we were exporting power we had earlier paid for, so really wanted to limit how much the battery was charged. But looking at yesterday and today, yesterday at this time 62% left in battery today 25% left, been a bad day for solar in mid-wales, so it was a guessing game, how much to charge battery overnight.

In fact, for the week we had with no off-peak in April, we were better off without it. However, once we were being paid for export, it did not matter if we bought it at 8.5p as we were then getting 15p for the export, so no need to guess what tomorrow's weather would be like.

We could have not bothered with off-peak and got a third battery, but come December solar is very poor, around 3 kWh average, Today only 5.1 kWh yesterday was 19.6 kWh in December 0.1 to 10.3 kWh per day, so the off-peak saved more money to the solar.

We should use the big three, that's the dishwasher, washing machine and tumble drier at night, using off-peak, but until December it does not matter that much.

But I think around 10 programs with our dishwasher, and I am sure there must be a variation in how much each uses, but if items need re-washing then it needs more detergent so want to avoid that.

 

[JohnW2]

Odd comment to say the very least ... How would you suggest I prevent it

Since your PV was a "DIY install by yourself", I feel sure that you would have had the expertise to design and construct it such that it never did (and never could) export to the grid.

And FWIW what’s wrong with a little going to the grid

Absolutely nothing, and I didn't suggest that there was. I even mentioned one reason why you might want to do it.

 

[JohnW2]

We should use the big three, that's the dishwasher, washing machine and tumble drier at night, using off-peak, but until December it does not matter that much.

If one doesn't count any DHW heating that may be in the equation (and obviously assuming that there is no electric space heating), those are indeed, probably 'the big three' for most people, but the third one very much trumps the other two.

 

[morqthana]

it seems in the USA they fill the dishwasher with hot water.

Surely dishwashers are even less suited to that than washing machines? We have cold-fill appliances because they fill up before a hot-fill one starts to get hot water, particularly if you use a combi, and all you've done is fire up the boiler and not use any of the hot water its made. (Yeah - I know combi boilers are quite rare in the USA, or at least a lot less common than here).

Same as if you just want to quickly wash your hands anywhere more than a couple of m from the boiler. Just use cold.