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. 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. 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 manufacturing 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
Analysis of the reasons why the manufacturers say the valve has been removed (and the implications)
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. They die off at high temperatures. It’s more economical to heat the small amount of water inside the washing machine than to use the inefficient hot water systems in many UK homes.
However, many people don’t use biological detergents. 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 but not necessarily for everyone as explained below.
Arguments in favour of cold fill only washing machines
- Modern washing machines hardly use any water on wash. So in cases where the water is supplied from a hot water tank or with a long pipe-run from the boiler a hot water valve would hardly fetch in any hot water. This is because hot water quickly 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 already 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 be up to a full bowlful of water. In effect this means twice as much water is heated than is used by the washing machine. 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. 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. This can cost more, take longer and add more wear and tear to the machine without a hot valve. Although limited hot water will get into the machine due to cooling in the pipes a boil wash only fills with hot water so this effect isn’t as bad and many people would get a reasonable amount of hot water in on a boil wash.
- 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. This adds 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
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. Many 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
Related: The following article used to be part of this one but has been moved to its own place – pros & cons of Cold fill verses Hot fill washing machines