Hi
To lose weight through exercise it's important to understand how the body uses fuel during exercise. Short high intensity intervals (high heart rate stuff) predominantly uses sugars in the form of glycogen stored in the muscles and liver. To lose weight you need your body to burn fats. This requires that you exercise at lower intensity/heart rates for longer periods. You can do this on a turbo but as mentioned it gets to be boring, especially day after day.
If you can get out on a bike then you'll stay on it longer, if not I suggest not more than an hour on the turbo at a time, perhaps every other day and take something to distract you, DVD/CD/MP3 etc. You don't need to be working hard just turning the pedals briskly to the point of just able to sing to a tune/hold a conversation. If you can't you're working too hard! Take a drink, water!!! Anything else contains calories.
Split the session to make it interesting, warm up 10-15 minutes, 15 minutes at X heart rate/speed/cadence, then 15 minutes at Y and 15 minutes at Z followed by 5 minutes cool down.
To lose a pound of weight requires a deficit of 3600 calories and my estimate is that an hour on the turbo will burn 450-600 calories.