What's a good carpet cleaner to rent?
All carpet cleaners work on the same principle - hot water and detergent injected under pressure into the fabric, the detergent breaks down grease and dirt and the dirty solution is extracted out by powerful vacuum.
The important thing isn't so much the machine but the detergent. All the detergents that are available to the public are weak and not all that effective. Much better to go to a janitorial supplies company and get a commercial grade carpet cleaning powder - as well as being a cleaner these include odor neutralizers, sanitizers, optical brighteners, fabric conditioners etc.
If you do this check with the hire company first as they may only let you use the detergent they supply. When you hire the machine go for the biggest one as this will have a more powerful vacuum and so extract more water. It will also have a larger reclaim tank (where the dirty water goes), some of the smaller machines need emptying every few minutes.
As for how easy they are to use - the operation of them is very simple but it is quite physically demanding work and if it's a hot day you'll end up sweating a lot.
You can replace your furniture immediately but if it has wooden or metal legs or castors then place a piece of baking foil or small square of plastic underneath the legs to prevent damage to the furniture and staining of the carpet.
Carpets can be walked on immediately without causing damage and if you use a powerful machine then nylon carpets will be dry in 1 to 3 hours (depending on the weather) and wool carpets, which retain more moisture, will be dry in 2 to 6 hours. To speed up drying times allow as much ventilation as possible (open doors, windows etc).
Before cleaning anything spot check a small inconspicuous area first as some colours may run - especially dark green, dark blue, red and gold. If your carpets are wool then make sure they're well secured right the way around the edges, if not then they'll shrink when you wet them.
If you're cleaning upholstery, chairs, mattresses etc then do so outside if possible. The hand tool attachment you use tends to cause a lot of overspray and if you're not very careful you'll get water on the walls and other furnishings. Plus being outside gives you more room to work and the items will dry quicker.
A good idea is to quickly go over each area once and then go over it again more thoroughly a few minutes later. This will give you a better result - a bit like cleaning a shirt for example, rather than dip it in the water then hang it out to dry you'd allow it to soak a while before cleaning.
Once you've cleaned an area then go over it again but this time with just the vacuum (ie no cleaning solution), this will remove excess moisture and speed drying times.
If there's any particular marks or stains then tell the hire company or janitorial supplies as there's a whole range of different products that will often remove marks and stains.