Washing machine

Do Washing Machines Need Hot Water?

When washing machines offer washes up to 90°C, some do wonder whether their washing machine uses hot water from the mains or if it heats the water itself.

The majority of washing machines will only be connected to the cold water supply and will heat it during the wash cycle. Others will take water from both the hot and cold supplies. The best way to find this out, if you didn’t install the washing machine yourself, is to look at the manufacturer’s specifications in the booklet that came with your machine. If you can ask the person who fitted it, they will know whether it is only connected to your cold supply.

Older Machines

If your washing machine is older, then consult the booklet that came with it. If your booklet has gone walkabout, then see if you can find out online, or easier still, pull out the machine far enough to see how many connectors there are on the back. There will be a red and blue pipe if your machine takes in water from your hot supply and cold supply.

Newer machines

Modern machines are being manufactured to eco-friendly standards (see the most economical washing machines in the UK here), so will only use the cold supply. Only using water from the cold supply is said to save you money in the long run by not using your heating system. Many people actually use gas to heat their homes and water, so could argue that using gas to heat water is cheaper than the electricity used for the washing machine to do it. There is a little bit of controversy over this subject.

Why just cold?

With the world trying to clamp down on energy usage and the environment at the forefront of many people’s focus, more and more are turning to low temperature washing. Manufacturers are producing ‘cold supply only’ machines to help to create more a eco-friendly product, but also to reduce the cost of manufacture. It is cheaper to produce a machine which only has one inlet and no need for a hot water valve.

Machines that do have both hot and cold supplies only use the hot supply when washing above 50°C, so this change in manufacture is not all that detrimental when the average wash is at 40°C.

Are hot supply machines still being made?

They are relatively difficult to source, but are still produced by some manufacturers. The problem with a hot fill washing machine is there eco rating, they will normally be classed as B or lower and can be quite pricey.


So, do washing machines need hot water? Well… it all depends upon your energy supply in the home. If your home is completely run off an electricity supply, then it would make no real difference to your bill as both heating water and your washing machine heating would yield similar costs. If you have a gas supply for your heating, it could be cheaper to use a hot and cold fill washing machine.

If you rarely run a wash cycle past 30-40°C then you probably don’t need to worry about getting a double supply washing machine for your laundry.