Fridge/freezer on Economy 7 possible energy-cost-saving trick?

devondiver

victor2 said:

Does ALL the energy consumed by the fridge/freezer ultimately get released back into the room as heat? So, a fridge using say 1kWh per day gives out 1kWh of heat into the room? Presumably some of the energy consumed is effectively stored in the cold/frozen items?

Interesting argument @[Deleted User]. So the saving in electricity consumed at the cheaper off-peak rate compared to the peak rate has to more than offset the extra energy used to heat the room the fridge/freezer is in during the day? Assuming it is in a room you heat.

I think the answer to your first question has to be almost 99% 'yes' - especially if anything you use from the freezer is defrosted in your fridge (as recommended). This ties in to my original energy-saving concept of using 'stuff' (phase-change-materials - remember?) which was frozen on 'cheap' rate then transferred to the fridge to help keep it cool during 'expensive' rate.

And I suspect that this principle will override in significance the other considerations explored above. But the question remains - whether or not the savings possible warrant the effort. Perhaps someone will do the controlled experiment necessary to answer this?

devondiver

dunstonh said:

When electricity is cheap, you don't think about being a money saver.   Now, the mindset of many people is changing and it isn't that difficult to change some habits to reduce your electricity use. 

Very true. I wonder if we'll see a lot more dishwashers and tumble driers going to landfill now.

dunstonh said:

Whether I will feel the same way next year after our PV array is running, I don't know.   I probably will as I quite enjoy resource management, logging and trends etc.

I certainly hope so. We still have a planet to rescue. 

victor2

devondiver said:

dunstonh said:

When electricity is cheap, you don't think about being a money saver.   Now, the mindset of many people is changing and it isn't that difficult to change some habits to reduce your electricity use. 

Very true. I wonder if we'll see a lot more dishwashers and tumble driers going to landfill now.

dunstonh said:

Whether I will feel the same way next year after our PV array is running, I don't know.   I probably will as I quite enjoy resource management, logging and trends etc.

I certainly hope so. We still have a planet to rescue. 

We gave away our tumble drier quite a few years ago, but we're lucky enough to have a utility room where we do the laundry and hang it to dry in the winter.

As for dishwashers, I'm not convinced they cost more to use than washing by hand. Modern ones have "eco" programmes and use a very small amount of water - and only that amount is heated by the machine itself. Washing by hand, to the same level of cleanliness, would probably require more hot water and energy to provide that. Of course you'd save on the drying cost, but it would be interesting to see if anyone has actually done a "scientific" study into how much energy each process requires.

Alnat1

You tend to wash up more often if you don't have a dishwasher, to make the kitchen tidier. Or is that just me that can't stand dirty dishes hanging around?

victor2

Alnat1 said:

You tend to wash up more often if you don't have a dishwasher, to make the kitchen tidier. Or is that just me that can't stand dirty dishes hanging around?

First thing we had to buy when we got a dishwasher was more dishes and cutlery because we didn't have enough for a full wash!

RelievedSheff

Alnat1 said:

You tend to wash up more often if you don't have a dishwasher, to make the kitchen tidier. Or is that just me that can't stand dirty dishes hanging around?

Not just you. Can't stand having dirty dishes around.

We have a dishwasher but very rarely use it 🤔 

Never seems worth it with just two of us in the house.

devondiver

victor2 said:

As for dishwashers, I'm not convinced they cost more to use than washing by hand. Modern ones have "eco" programmes and use a very small amount of water - and only that amount is heated by the machine itself. Washing by hand, to the same level of cleanliness, would probably require more hot water and energy to provide that. Of course you'd save on the drying cost, but it would be interesting to see if anyone has actually done a "scientific" study into how much energy each process requires.

I'm afraid I am not at all convinced by "eco" dishwasher settings - unless of course it has a cold water option (unlikely).

I/we have for some time now, for the most part, been using only cold water to wash up - and to a perfectly clean standard of cleanliness. "Impossible!" - some might say. Well, we are quite health conscious and rarely eat meat or other fatty/fried food - and when we do it is a simple matter to largely degrease plates etc. with kitchen roll or similar before soaking and washing in cold soapy water.

(BTW - we all know what happens to grease washed down the drain, liquidised initially by hot water but adding to "fatbergs" once it cools and re-solidifies, or at the least adding significantly to our water treatment costs.)

Thick grease aside, the reason that hot/warm water cleans faster than cold is fundamentally that all the molecules are moving faster so all the detergent reactions are speeded up. The same reactions occur at low temperature but it just needs a bit more time and agitation - or elbow grease.

But, to be honest and under spousal pressure, I do have a dishwasher - sitting in my garage waiting for me to re-do our kitchen. I have yet to look into it but I'm hoping I can plumb it to use cheap/free hot water supplied via our back-boiler wood stove. I just need to get a round tuit. Might need to change the dishwasher model as well. 

victor2

Here you go @devondiver

Can't help with the dishwasher though!