A lot of people want to know if Calgon (or other similar anti limescale products) really work, and more importantly do washing machines really “last longer with Calgon” as their adverts insist they do?
The short answer is yes clearly the products must work as advertised but, and there’s a very big but – most people shouldn’t need them and the adverts are a bit misleading. This article is a balanced view from an experienced engineer originally published in 2001 on Washerhelp. It’s now been updated and moved here.
Here’s a warning about limescale which all manufactures give
"Too little detergent results in limescale on the heating element".
This clearly means that using enough detergent should not result in limescale on the heating element. Here’s a quote from a users guide to looking after your washing machine from Persil, which goes further -
“One of the things that can damage your washing machine is the build up of scale, particularly in hard water areas. But if you use Persil Automatic at the correct dosage you won’t need any additives to help protect your machine from scale”.
So all washing machine detergent already contains ingredients to soften the water and protect the washing machine from limescale. If you use a good quality detergent, and the correct dosage for the hardness of your water and the level of soiling on the laundry then you should not need to use anything extra. (This has now been backed up by recent research and testing by Which?)
Calgon just softens the water
However, it's always been advertised as a limescale preventer, which although technically it is, it’s implying it does something extra when it simply softens the water, the same as detergent does. One advantage could be that it would allow you to use less washing machine detergent in hard water areas, but this would only make sense if the combined cost of Calgon and the reduced amount of detergent was less than the cost of the full dose of detergent alone.
Can limescale really shorten a washing machine’s life?Yes there’s no dispute about that, the controversy over Calgon is does it really need to be used to save your washing machine from an early grave as they very strongly warn about in their ads? And does limescale really shorten a washing machine’s life as quickly as implied? Which? have recently submitted a complaint to the Advertising Standards Authority, asking it to investigate the claims made in Calgon’s adverts after finding that washing machines do not succumb to masses of limescale and break down if Calgon isn’t used.
In my experience limescale build up has always been a very slow process, causing problems only after ten years and over. So there’s also the issue of modern washing machines not really lasting long enough to succumb like they would in the past when they lasted twice as long. However, I have not worked in areas with very hard water.
Do not use in soft water areas
There could be many people using Calgon who have relatively soft water and could therefore be softening the water in their washing machine too much. This is because Calgon has often been advertised in areas with soft water, and their hard water checking tool was “faulty” (see next paragraph) for many years. Apart from being a waste of money, water which is too soft is not good for washing and can cause excessive soap suds, poor wash results, and even prevent detergent from being dissolved properly.
Check if your water is hard or soft
Calgon’s website used to have a post code checker tool which checked the hardness of the water in your area. I was initially impressed with this, and even considered linking to it but when I entered my own post code I received a full red bar pointing up to "hard", and the following message
"HARD – We recommend using Calgon in every wash to prevent limescale build up in your washing machine ."
As I know we have fairly soft water I sent them an email pointing this out and asking them to look into it. The tool was clearly “faulty” (at least with my post code) but even though they acknowledged receipt of my e-mail and claimed they would look into it, the erroneous advice was still there over 6 years later. Unfortunately I was left feeling they couldn’t be trusted to advise on whether you have hard water or not. They’ve now dropped this tool and just use a UK map with large red areas highlighted but when I contacted Yorkshire water to double check the hardness of my water they said post codes were an unreliable way of accurately determining water hardness.
Free water hardness test kits
Although Calgon have an online form you can fill in to send off for a free test kit might be able to get one from your water company (UK water companies). Ironically, when mine arrived, it was supplied by Calgon. It consisted of a small strip to dip into the water, which would indicate the hardness of the water. Sure enough, it showed my water is soft.
Summary regarding Calgon tablets (or similar products)
Products such as Calgon don't do anything that proper washing machine detergent doesn't do (as long as you use the correct amount) although they do -
- Help protect against under dosing
- Soften the water allowing you to use the amount of detergent recommended for soft water in a hard water area
The last effect could potentially save money if the money saved by reducing the amount of washing detergent is greater than the cost of the Calgon (or similar) tablets. I don't know of anyone that's done the appropriate tests to determine this but Calgon claim you could save up to 25% of the amount of detergent required. 25% is presumably the best case scenario, it depends how much the tablets cost compared to how much you save in detergent.
Is Clagon worth using? Why do some manufacturers recommend Calgon?
A few reputable washing machine manufacturers recommend Calgon. Calgon’s site lists 6, but because some of them are the same manufacturer making different brands (eg, Electrolux, Zanussi and AEG) there are only really 3. I was initially puzzled as to why because, if it was really so necessary and useful surely all brands would recommend it? But conversely, if it really was unnecessary, then surely no brands would recommend it?
I can only assume they are recommending it because they would rather people use Calgon tablets and be more likely to keep their washing machines free of limescale (and working) due to the fact so many people don’t use enough detergent even if it’s only effective for a small percentage of their customers.
Some people do indeed suffer from problems caused by limescale and I occasionally come across people who claim to have used good quality detergent and always used the right amount but still have limescale problems in their washing machines. This appears to contradict some of the advice in this article. There’s no way of knowing how accurate this anecdotal evidence is but in the interests of balance here’s a link to one such case – Limescale
Which? have carried out research that confirms a washing machine wouldn’t show any signs of limescale build up capable of damaging a washing machine’s heating element for at least 3 years.
In September 2011 Which also published an article in their magazine entitled, “Calgon’s own research matches Which? findings” where they reported that Calgon themselves have found it takes at least 3 years to show signs of significant limescale damage, by which time you would have spent £170 on Calgon (2011 prices). I think it’s safe to assume this is in hard water areas, so soft water areas would presumably never show any signs of breakdown due to limescale or the washer would be long since scrapped before it happened in most cases.