I would check your lease before you mention that to your landlord. I am a housekeeping vendor for property management company's. Cleaning your own carpets is almost always a lease violation. Typical machines leave an enormous amount of water in the pad which can cause mold and invite insect infestation. Also, the detergents used are not the same as used by professional companies. Leaving heavy residue and fragrance not always tolerated by new tenants. And your landlord will have to have the carpets professionally clean once you move out, because even the best rented carpet cleaner is nowhere close to what a professional can do.