Return of the snake oil salesmen

Discussion in 'Just Talk' started by quasar9, Sep 13, 2022.

  1. quasar9

    quasar9 Screwfix Select

    Recent price increase of energy prices seem to have drawn out the rouges promoting energy efficiency and promising big savings.

    A house nearby, recently had some badly installed solar panels which I estimate might just about generate a maximum of 1200 (roughly 6 sq meters) , but only on very sunny days and that too for only about 4 hours max, as it will be in shadow after the sun moves past true south. The cost of installation including full scaffolding, the reduced feed in tariffs mean ROI could be decades away.

    More of a laugh was todays Sun, showing a list of kettles that save money ! Electrical resistance heating is pretty much 100% efficient with practically no variation between manufactures. As element is in contact with water, there is practically no loss in transmission. The only difference I can think of is the heat loss from the body while the water is boiling. Leaving aside vacuum bodied ones for the moment, most are plastic bodied so should be similar in energy consumption (for a given volume of water and boiled till the kettle trips). Even the glass or the metal bodied ones can’t be very far behind.

    maybe time to bring back the fuel savers for cars that were all the rage in the 70’s and 80’s :D
  2. stevie22

    stevie22 Screwfix Select

    Always know in my house who has filled the kettle. SWMBO fills it, I put enough in for what I want. That is the best way to save power.
    CGN, Creek, gadget man and 3 others like this.
  3. FlyByNight

    FlyByNight Screwfix Select

    Much the same as turning the hot water temperature down ... you may not use as much energy to get to temperature, but you will need more hot water for the bath/shower.
    quasar9 likes this.
  4. Muzungu

    Muzungu Screwfix Select

    You get your coffee quicker as well (obviously). Is this a woman thing? I have noticed this as well, not only with my lady wife who is of course the light of my life in all other ways. I always tend to boil a kettle and then fill a pan when cooking. Not sure if that saves money but it appears to save time (induction hob).
  5. chesterw

    chesterw Well-Known Member

    Did someone mention Boris, our unloved ex PM, one of his last pronouncements to all those whinging about energy bills increasing by £3+k, buy a new kettle, you'll save yourself £10 a year, makes sense to me, buy 30 and save £300 a year.
    gadget man and quasar9 like this.
  6. teabreak

    teabreak Screwfix Select

    I save the kettle by drinking beer!;)
    malkie129, CGN and chesterw like this.
  7. rogerk101

    rogerk101 Screwfix Select

    Our friend Newton gave us his law of cooling ... Newton's law of cooling states that the rate of heat loss of a body is directly proportional to the difference in the temperatures between the body and its environment.

    Based on that alone, the hotter the water in the hot water tank, the greater the heat loss ... heat loss that goes on all day long for those who's thermostats are not governed by a timer function.

    I find that 40degrees is plenty hot enough for four people. All it means is that less cold water is added to the scalding temperature that most hot water tanks are set to.
  8. Ad_g

    Ad_g Active Member

    Just had a quote for our L shaped roof where the valley is south facing. Looks like that would produce 75%+ of our electricity requirements. The roof is clear and has no shading, the company has provided proper calculations based on panels, shading and where we are located. They’ve also said lead times on battery packs are long and the ones you can get are poor so recommended adding later.

    The daily fail amused me they ran an article on costs. They used the rating value for costs on an oven so 2hrs at 3kw for a roast dinner. Same for the iron and my favourite was it cost 88p to make two slices of toast in a toaster - anyone seen one with a 300A plug on the end? It was total tripe the whole article but I can see the readers believing it (I only saw as paper at in-laws).

    And yes I can confirm a new kettle won’t help.
    Abbadon2001 likes this.
  9. arrow

    arrow Screwfix Select

    That is a breeding ground for legionella, the reason the stat is set to 60 degrees is to stop this.
    There is a recent thread on the subject in plumbers talk.
    BiancoTheGiraffe likes this.
  10. rogerk101

    rogerk101 Screwfix Select

    If you feel strongly about legionnaire disease, then by all means set your thermostat to 65degrees once a month for a couple of hours. There is no sense in leaving it on permanently at a temperature that high.
    Rick1632 likes this.
  11. chesterw

    chesterw Well-Known Member

    Disgraceful, are you saying Boris, our unloved ex PM is a liar?
    gadget man likes this.
  12. Ad_g

    Ad_g Active Member

    as @quasar9 said there is little difference in the efficiencies of kettles, my wife used to work in that area and the only difference was generally how fast they heated up I.e. how big the element was.

    Not sure if a certain person skipped his Physics lessons at Eaton? Only way I can think you could save is if you need a small amount and a newer one has a lower min fill level?
  13. teabreak

    teabreak Screwfix Select

    Logic would say whatever the wattage, it still needs the same amount of heat to raise a given quantity of water to boiling. The only factor might be heat loss from the kettle, an insulated one would loose less heat and any residue would be transferred to the next water if you fill before it cools.
  14. FlyByNight

    FlyByNight Screwfix Select

    Dont forget the Specific Heat capacity of the kettle. Steel is around 500 J/kg°C with aluminium about 850-900 J/kg°C meaning it takes less energy for the steel to come up in temperature and plastics are around 1200-1600 J/kg°C which require even more, although allowances need to be made for density and thickness. Water is about 4200J/kg°C. So heating a full kettle of water would take less energy if made from thin steel than f it was made of thicker dense plastics.
  15. robertpstubbs

    robertpstubbs Screwfix Select

    Modern kettles tend to have the element in the base so the element isn’t completely in contact with the water. It should allow heating of smaller amounts of water though.
  16. AnotherTopJob

    AnotherTopJob Screwfix Select

    One good development is the reduction of standby current.
    I measured some old appliances quite a few years ago and was surprised to find an Aiwa stereo from the 90s was consuming around 10w, and an old microwave about 4w.
    Light bulbs are also worth the switch, it's surprising how many people are still running old halogen spots and security lights etc.
    Rick1632 likes this.
  17. Rick1632

    Rick1632 Active Member

    My microwave crazily consumes about 40W on standby. I now turn it off at the wall when not in use.
  18. chesterw

    chesterw Well-Known Member

  19. AnotherTopJob

    AnotherTopJob Screwfix Select

    That's pretty impressive. So if left plugged in, at current prices it would cost you around £100 a year!
  20. AnotherTopJob

    AnotherTopJob Screwfix Select

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