I lost about 20 lbs doing at home exercises, when I was plateauing with just diet, and since I do a mix, but they really good when on tight schedule, and definitely as effective as the gym if by gym you mean treadmill/elliptical. When it comes to weight lifting it is different because you need someone to spot you and the weights are relatively expansive. What kind of workout are you looking for, and usually are you on a tight schedule, are you more team or solo? all these questions can help pointing you in the right direction
I've lost 26lbs and dropped from a size 12 to a 4/6 (depends on the brand) without stepping into a gym. I started with Jillian Michaels DVDs, which got me into using weights and the like, but have moved on to workouts on my Nike Training Club app (uses dumbbells and medicine ball, some call for a box for stepping/jumping on), and want to start New Rules of Lifting soon. For cardio I run 3 days a week and still do Jillian's Kickbox FastFix for 20 minutes on strength days. I do need to invest in some heavier weights - no room at home for a bench or full barbells, but doing what I can (and making progress) with dumbbells so far. If you've got the space, check Craigslist or yard sales for equipment. Check your library for New Rules Of Lifting - he's got several books out, all start with that same title but one is for Men, one for Women, one for Abs. At 44, I'm in better shape now than I was in my 30's, and feeling great! Wow, I am thoroughly impressed!!! Makes me want to get up off this chair and put that dvd in. Thanks