Comments from another article have ventured into the subject of whether you can connect a dishwasher to the hot water instead of cold. This doesn’t appear to be a clear-cut yes or no answer and there is conflicting advice even from dishwasher manufacturers with some claiming it’s more economical, and others saying it’s better to run a dishwasher using cold water.
Most dishwashers in the UK are supplied with a cold fill hose and with instructions to connect it up to the cold water supply. Most people do connect it to a cold water supply and they work perfectly well.
Many dishwashers can be connected to a hot water supply though and if so it should say so in the instruction book. However, if you do connect a dishwasher to the hot supply you should use a hot fill hose, which is designed for use with hot water. I’m not able to emphatically say that connecting a cold water hose to a hot water supply is running any risk. All I know is that fill hoses have always come in red or blue, or with a red stripe or blue stripe and sold as either hot or cold hoses. If this is pure marketing spin I wouldn’t be too surprised but I’ve never really thought much about it until just now. It is reasonable to expect that the individual requirements for carrying hot and cold water are different enough to require specialised hoses.
What are the pros and cons of connecting a dishwasher to a hot water supply?
Presumably it saves electricity as dishwashers wash at high temperatures as well as using high temperatures for the last rinse to aid drying. However, I can’t help wondering why if using hot water is so much more efficient they aren’t all coming with recommendations to use hot water and advising cold can be used if preferred instead of the other way round.
If the water is over 60 degrees it can damage the filtration system built into dishwashers so don’t use hot water if this is the case. My understanding is that hot water should only be set to 60 degrees anyway, which is the optimum setting for a hot water supply in most homes. If it’s much hotter the water is not only dangerously hot but it’s so hot you can’t use it for anything much without adding a fair bit of cold water. This begs the question, what’s the point of heating water up to such a high temperature only to cool it down with cold before it can be used? An exception to this rule may be for people using solar powered hot water where they can heat to higher temperatures at no extra cost. However, the potentially dangerous temperature consideration is still relevant depending on the age and abilities of the people who may use it.
Hot water supplies may not have the same water pressure as cold especially if supplied through a hot water cylinder in the airing cupboard. Hot water hoses are more prone to kinking too to you would need to ensure the hose isn’t under any physical strain as when hot water runs through it, the hose can go soft and develop a kink.
Hot water can bake some food onto plates and make it more difficult to clean.
My dishwasher has a 50 degree wash cycle. If the water inlet temperature is already 60 degrees this programme may be compromised.
If you want to check your dishwasher can use hot water but don’t have the instruction book you may be able to download one here – download instruction manual for washing machine or other white goods appliance