The electrical code in your area should tell you how to properly install this. I would suggest a 30A breaker (as opposed to a 25A) as it will give you more leeway if it surges when it turns on and some flexibility if you ever need to replace the appliance with something larger. As far as the wiring goes I believe 10 gauge wire is rated for 30 Amps. (Make sure both the breaker and wire are rated the same). I am also guessing you will need 10-3 as opposed to 10 - 2 as you will probably need the extra wire.
You should also take note of the master breaker in your home. Older homes often have a 100 Amp breaker. If you run an electric oven and have a clothes dryer already, you will probably need to upgrade the services from your provider and install a new circuit breaker panel with a 200A master.