Here's a wee dig at the 'Rug Doctor' carpet cleaning machines you can hire from all your favourite supermarkets etc. Damn! even I've used one of these in a past life. Anyway, as I'm now a professional carpet cleaner (no laughing in the cheap seats!) I find these machines to be unsuitable for the purpose of carpet cleaning for the following reasons:
The suction is very poor so they leave your carpet wetter than it should/could be (this may lead to brown rings (no not those type!) on light coloured carpets- especially wool carpets).
The detergent you buy with it is 9-9.9 pH this is quite high in alkalinity terms, especially if you have a wool carpet which is unsuitable for this type of fibre.
There are no 'pre-spray' solutions supplied with it; all carpets should be presprayed with an appropriate solution in order to 'loosen' up the dirt, especially where a carpet is heavily stained, e.g. near doorways/traffic walkway areas etc. Otherwise, by just using the water extraction method of this machine you will only achieve a 'superficial' type cleaning- that's ok if you just want a quick spruce-up, say after a party etc.
The water is not hot (50 degrees) as professional machines are, so, again it fails the test on this aspect. It is, in my humble opinion, seriously ineffective at being a carpet cleaner ( water extraction machine).
I don't like the colour (red).
On the upside it is reasonably cheap to hire - £29.00 for a couple of days -and the detergent at say a tenner for a litre is ok.
A monkey could use it.
But if you want a good deeeeep carpet clean the only way is 'professional' (then I would say that..). Seriously, we guys in the trade know the shorty comings of the 'Rug Doctor' type machines, but 'Joe public' are unaware that they are being taken for a ride due to their ignorance of what true carpet cleaning is all about.
Anyway, I could go on, but I'd better get off my soapbox. Thanks for listening/reading