Cold Fill Washing Machines

Hot or cold fill washing machine?

Should I buy a cold fill washing machine or hot and cold fill?

The short answer is, you don’t have much choice these days although if determined it’s possible to find one with a hot water valve. However, the majority of people are probably fine with a cold fill washing machine, especially in the UK where many houses have gravity fed hot water cylinders, and if you read this article you will see that you may find little or no benefit from having a hot valve anyway.

Why have they removed the hot water valve?

They say they did it for us – but I’ve always suspected that the main reason hot water valves in washing machines disappeared was because it suits the manufacturers. It clearly saves a reasonable amount on production costs which have been under constant pressure for many years. Removing the hot valve reduces manufacturing costs by saving money on the following –

  • Hot fill hose
  • Hot valve
  • Wiring to the hot valve
  • Hose from hot valve to dispenser

Here’s the long answer, and an analysis of the reasons why the manufacturers say the valve has been removed (and the implications)

Washing machine manufacturers say that a cold fill washing machine increases washing efficiency when using biological detergents and washing at 40 degrees. This is because the enzymes in the detergent work best at low temperatures and die off at high temperatures. They also say it is more economical to heat the small amount of water up inside the washing machine than to use the inefficient hot water systems in many UK homes.

However, many people don’t use biological detergents because at least one member of the family may be allergic to them and suffers irritation (Related – Biological detergents do not cause skin irritation) or simply because they prefer a non biological detergent. These consumers therefore don’t need the biological powder-boost benefit from cold fill washing machines. There is some truth in the idea that it is cheaper to heat the water in the machine though – although not for everyone as explained below.

Arguments in favour of cold fill only washing machines

  • Modern washing machines hardly use any water on wash, and a hot water valve would hardly fetch much hot water from the customer’s hot water supply in cases where the water is supplied from a hot water tank or with a long run from the boiler because it cools in the pipework and often takes a while to run hot
  • Manufacturers claim that in "most cases" it will be more economical energy-wise to let the modern washing machine heat the water up. Any hot water drained from the hot water cylinder is replaced by cold water from the tank in the loft. This cools the hot water in the cylinder and causes the boiler to have to reheat it. Drawing off hot water from such a system also draws more hot water into the plumbing pipe work between the hot water tank and the washing machine than is used by the washer. Unless drawn off quickly for other purposes this water cools down in the pipes and is wasted. The amount of water involved could easily be a full bowlful of water. In effect this means twice as much water is heated than is used by the washing machine and manufacturers argue that it's more economical to just draw in cold water and heat only the amount you need to use. This is a solid argument to me but again only relevant for people with a hot water cylinder or with long runs of pipe work from the boiler. People with a combination boiler near to the washing machine shouldn’t have this problem
  • A cold fill is better for biological detergent users and starting with cold water gives better wash results when using biological detergents. Flushing biological detergent into the drum with 60 degrees (and higher) hot water can kill off many of the enzymes that remove dirt and stains. However, you don’t need to remove the hot valve to not use hot water on 40 degree washes you just need to design the washer to fill only with cold for 40 degree washes
  • There is also a saving in manufacturing costs on the hot water valve, hot water hose and electrical wiring and internal hose connections which may   have helped reduce prices

Arguments against cold fill only washing machines

  • A hot valve is highly useful for boil washes to give a proper head start instead of heating to 90 degrees from cold. Manufacturers say that most people rarely (if ever) use the boil wash these days but washing machine manufacturers now recommend a boil maintenance wash once a month so this means everyone should be doing at least one boil wash a month, which will cost more, take longer and add more wear and tear to the machine without a hot valve
  • The ever increasing amount of people with solar powered, and other environmentally friendly or cheap hot water supplies want a hot valve, as do people never using biological detergent or using a lot of high temperature washes. However, these people are not yet in the majority, and unless the hot water is supplied at a high flow rate and runs hot quite quickly then very little of the economically heated water would be used anyway (as explained here – But do washing machines with a hot valve actually use much of our hot water anyway?)
  • If you used a lot of high temperature washes and have to heat it from cold it has an adverse effect on wash times adding extra wear and tear on the washing machine. However, the general increased wash times in modern washing machines is not solely due to losing the hot water valve. It’s as much a result of using a lot less water overall, which necessitates longer rinsing and wash labels rating wash performance forcing longer wash times to help achieve the "A" wash ratings. Increased wash times directly attributable to the missing hot water valve are likely to be relatively inconsequential on the average 40 degree wash

Solar-powered-heating Since washing machines first became cold fill things have changed. Now, more and more people are using environmentally friendly hot water supplies such as solar powered hot water and they are angry that their washing machines and dishwashers are not using any of what they consider to be “free” hot water.

I still want a washing machine with a hot valve

I still get people asking if I know of any washing machines with a hot water valve. My blog entry on the subject may be of help – I want a washing machine with a hot water valve

Article continued on next column

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  1. avatarM G Dat says

    Machine will be right underneath the boiler, with no hot tank so I .will be replacing my broken machine with a twin tub using only enough hot water to cover the amount of clothes in tub. Is this the nearest I can get to the best of both worlds? I do not use biological detergents.

  2. avatar says

    I’m surprised they still make twin tubs, to be honest they are rubbish now. Hoover and Hotpoint stopped making them years ago and the only ones I’ve seen are made of plastic. But yes, twin tub washing is very different to automatic washing machines.

  3. avatarBill Munns says

    For those with solar panels generating electricity, new technology such as the diverter switch from consumer unit to hot water cylinder immersion heater, this maximises unused power otherwise exported to the grid. There is much to gain on a nationwide basis. This continual topping up of hot water cylinders provides low cost (free in many situations) hot water, further reducing domestic carbon footprints.
    Washing machine manufacturers need to take this important development into account by fitting an eletronic valve to the water input, connected to a dial on machine that could allow adjustment of the incoming temperature. With today’s sophisticated electronic capabilities it shouldn’t be difficult to make this possible without detriment to the washing process. Washing machine makers could even claim money saving possibilities for their A Plus rated machines (when used with solar switched power)! That should help their sales and boost the development of switching technology.
    For anyone wishing to investigate this relatively new solar pv switch technology, Google “intelligent pv switches”. Their makers claim ROI in as little as 2 to 3 years.

  4. avatarGraham Aldred says

    Well done Andy of Whitegoodshelp !
    Having to buy a new washing machine (after10 years) I was taken aback to find that most were cold fill only. I am on the verge of returning the Beko model because there are so few programs that exploit the maximum spin and hoped to get hot and cold fill as well on any new one.
    I think your article on the merits or otherwise of cold fill only is excellent and persuasive. I have long pipe runs and washing mashines use so little water relatively that hardly any useful hot water ever gets into the machine. I am sure you are right, heat only the amount of water to the desired temperature on location, with an immersed element there are very few losses.
    But looking ahead it would be great to have a ‘box’ with with hot and cold feed in and a ‘water’ supply out to the washing mashine. The box would have a temp control just like a shower. or as you suggest have an option on the WM to allow the user to choose .
    Well done, good persuasive article, Thank you Andy

  5. avatar says

    Many thanks Graham, much appreciated. I try to look at issues in a balanced way. The main problem with cold fill only washing machines is that although the majority of people may find them adequate or even better, there are many people who find them less environmentally friendly and less economical. The answer is to design washing machines that adapt properly to the environment they are used in and give consumers the choice of whether to use a hot valve or not – many of whom would actually benefit :)

  6. avatarDiana says

    Hi Andy,

    I´m currently looking to buy a new washing machine and stumbled across your very useful article. If I buy a washing machine with hot and cold fill am I still able to only connect a cold fill hose?

    Apologies if this is a really obvious question but weirdly, my current choice of washing machine is a hot & cold fill washing machine.

    Thanks for your help.