Is a cold fill washing machine economical to run?
Hello,
I am new to the world of washing machines and have recently read a great deal in a short time. I am buying a machine for a housing association. I read around and it seems that the consensus is that boiler fed machines are inefficient because most of the water is cold as it has been sitting in the pipes.
I eventually settled on a Miele pw6065. It has a hot inlet and a cold inlet so this confused me; because with my limited knowledge the hot fill made me think it was boiler fed, or partly at least. I contacted the merchant and they said that it cannot be compared to the old, inefficient boiler fed machines and this can run off cold only or hot feed only or both feeds.
Considering my concerns about the inefficiency of hot water feed, it seems that the best way to connect it would be just cold water feed. Obviously I don't know what i am talking about so any advice would be gratefully received.
Thanks
Solution Summary
AI-generated from this discussion
This thread was marked as solved. Here's a summary of the problem and the fix, generated from the discussion below.
Cold-fill likely most economical for Miele PW6065 in typical domestic use
- The problem
- The user was choosing a Miele pw6065 for a housing association and wanted to know whether using its hot inlet would be economical, or whether it should be connected to cold fill only.
- Likely cause
- No appliance fault was reported. The discussion supports that hot-fill washing machines can be inefficient in many UK domestic installations because modern machines use little water, so the hot supply may not reach the machine before it has nearly filled, especially with long pipe runs from a stored hot-water system.
- What fixed it
- The accepted advice was that cold fill is usually the more efficient choice in a typical domestic setup. The Miele pw6065 having hot and cold inlets does not automatically make it economical to use hot fill; any benefit depends on the property layout and hot-water system. It was also noted that some Miele machines only use the hot valve on high-temperature programmes, so it may offer little benefit for mainly 40°C washes.
- Checks to try
- Machine model identified as Miele pw6065
- Machine has both hot and cold inlets
- User confirmed the advice fully answered the question
2 Answers
Yes hot water can be very inefficient in domestic washing machines. Especially in the UK where many houses have hot water stored in a large cylinder in the airing cupboard upstairs. I have a very comprehensive article about the subject which explains everything in detail. If particularly interested the comments contain many other interesting details and arguments but there were so many comments I had to trim a lot down and close them. Here is the article Cold fill verses Hot fill washing machines
In a nutshell the main problem is that by the time the washing machine starts to get fed hot water it is almost full anyway because they don't use much water any more. Hot water drawn into long pipe runs quickly cools down and is wasted. For example in my house if I want hot water (even at the bathroom sink) it takes around 1 minute before the tap supplies anything but cold water. Downstairs at my washing machine it is even worse. Therefore as I have a modern washing machine it is totally inefficient at using hot water.
Having said all that, if the washing machine was sophisticated enough it could deal with this, but it would not be an easy problem to solve and would considerably increase the cost of washing machines. Manufacturers don't currently think it's a problem worth solving.
Some washing machines may be very close to the hot water supply and not really subject to much of a pipe run between washing machine and water supply. Others may have combination boilers which might be set up efficiently and start to supply hot water to the washing machine quite quickly. These washing machines could utilise hot water and it would help to reduce running costs. Basically washing machine manufacturers decided to design for the lowest common denominator and they just got rid of the hot water valves. This means that most people will get a more efficient machine, but some people, especially those with solar heated hot water, will not benefit from their hot water supply.
Some Miele washing machines do have a hot water valve. There may even still be some other brands that have a hot water valve. Most of them if not all of them though only use the hot water valve on the very hot water settings such as boil wash or anything over 60°. Therefore if you are mostly washing on 40° washes, in my opinion and in my experience, hot water valve is next to useless for most people.
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Dear Andy,
Thanks for your reply and the links that you supplied.
Very helpful and totally answered my question.
Cheers
Ray Purchase
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