Hot Water Fill Washing Machines
Another article explaining why for most people hot fill is a waste of time and money
All the time we get asked what machines have a hot fill and, to be perfectly honest, many engineers will struggle to understand why people want this feature as, in our opinion, it is a complete waste of time.
When we're asked about this we are often wondering, in most cases, why on Earth anyone would want a hot fill washing machine.
We are, as repair guys, sort of living in the past a little in this new found age of ecological awareness but, in the past the only machines that did a "proper" mixed hot and cold fill were old Hotpoint and Hoover washing machines (distinctly British and British made) but now with no washing machines made in the UK there is no hot fill washing machine on sale in the UK. Yet.
But these old machines were really pretty primitive and dumb. They just opened both valves and filled until the level was reached, there was no intelligence about them at all.
Later imports from Italy and beyond on occasion had a hot fill, mainly as they likely would sell less if it were omitted, but they only filled with hot water once, on one program only as did some of the Korean washing machines when they sported a hot fill valve. We explain more below.
Separating Myths From Facts
Most people think that a washing machine will fill from both the hot and cold at the same time, fact is that no current machine that we know of does this, period.
Old Hoovers and Hotpoint machines used to do so in the dim and distant past, but even they have not done this for many, many years and since both are now under Italian ownership it is also very unlikely that the feature will ever return.
You see hot fill is really pretty unique to the UK for some reason, outside of the UK there is very little, if any, demand for a hot fill. Manufacturers these days cater for either a European or global market, they are unlikely to change just for the UK.
The next point to make is that almost universally a machine that does have a hot fill capability will almost certainly only take hot water on the high temperature wash on the first fill after the pre-wash is completed. Obviously this is one of the least used programs, the most common in the UK being the 40˚C cottons wash, thus rendering the feature next to useless.
Modern Homes And Hot Fill
In the vast majority of modern UK homes the hot water is supplied either from a tank or from a combination or condenser boiler system.
This means that the water, whether it is stored or "instant" has to travel from the source to the machine itself via the home's pipework.
In reality with a modern machine this almost inevitably means that by the time that the machine has filled to level that all you've done is fill with the cold water that was lying in the plumbing and filling the pipes with that hot water that you thought you drew. This is a total waste of energy and, in the end the machine will continue and heat to the desired temperature anyway.
It also means that there will be almost no saving if indeed there is any at all, on time.
Actually, it can be seen as wasting energy as, after all what you've done is fill your pipes with hot water (that used energy to heat) only to have it dissipate away serving no purpose whatsoever. So really then, hot fill could cost you money, not save it.
Of course we have seen the argument over water that is heated via solar power and quite rightly too. But you see the same problem applies, you still have to get the water from the storage tank to the actual machine and, in any event, there's a whole load of hot water now filling your pipework that has just gone to waste.
Bear in mind that the newer the machine, especially the new A rated appliances, the intake of water is far, far lower than machines of old. A few litres of water is all they take.
Detergents And Clothing
If you use biological detergent (which we recommend you do) then if the incoming water is above 40˚C then you've just wasted the detergent. The high temperature will kill the enzymes and lower the efficiency with which the detergent will work. This may well apply for many other detergents as well as they are designed now for low temperature washing, not to work in an environment where the temperature is high and, unknown.
In short the technologies employed have changed and moved on just as they have in most areas of life and hot fill is really no longer required.
There's another problem though and one that many people probably will not consider.
There are a lot of fabrics now, especially expensive designer clothing, that must be washed correctly and, if too high a temperature is used then they are very likely to be damaged. This is known as "thermal shock" in many cases as, when the hot water hits the clothes then it can cause irreversible damage to the fibres of the garment. Again, this isn't good and damage is less likely if the temperature is gradually increased and may be avoided altogether.
Conclusion On Hot Fill
The simple conclusion is that, as you will probably now realise, that hot fill to a washing machine or even a dishwasher is that it is highly inadvisable in the case of dishwashers, pretty much a waste of time on washers and you certainly should not base your purchase decision on this feature.
But if you're really not convinced by the common sense and facts here, we expanded on this in a follow up article on why hot fill is still a waste of time in Hot Water Fill For Washing Machines Again that you can get from the link.
In that one there's an explanation of how you can do it, sort of right and some experiments that you can try at home that will demonstrate just how pointless it usually will prove to be.