The only way you will lose more weight is if you find an activity and stick with it. Where you can do more activity (home or gym) is where you will lose the most weight. A gym has several advantages: a variety of exercise options, equipment and a social environment. However, the gym can be intimidating or inconvenient. Some people may spend 20 minutes driving to and from the gym - time that could be used to work out at home. Others will go to the gym and socialize.
Even if you cant set time aside for a 30-minute workout, you can fit a considerable amount of physical activity into your life. Gardening, housework, walking and riding a bike are examples of activities you can do at home to burn calories. If you're short of time, split it up by walking for 10 minutes, three times a day.