If the draw of pushy personal trainers and unbreakable contracts has left you lukewarm to the idea of joining a gym, consider a full-sized treadmill or elliptical exerciser for your home gym. Either can provide an exceptional cardiovascular workout, burning plenty of calories in the process. But before you delve into comparisons of individual models, you’ll need to decide between the two types of machines.

Consumer Reports turned to Neal Pire and Michael Bracko, exercise physiologists at the American College of Sports Medicine. Separately, they’ve seen hundreds of users make the most of their exercise equipment, and plenty more make their exercise equipment into expensive coatracks. Both note that either machine can be a great choice—provided you use it. They offered these five points to consider when choosing between the two for your home gym:

1. Size Up Your Space

“Before ever stepping foot in a store, I tell people to measure the space where they’ll use the machine,” Bracko says. Most treadmills and ellipticals in Consumer Reports' tests occupy 15 to 20 square feet of space. Ellipticals tend to be narrower, usually by 8 to 12 inches. “But if you need to do more than exercise in the space, consider a folding treadmill,” Bracko adds. Although it’s true that most of the treadmills in our reviews fold for storage, not all fold easily—and the action of unfolding your machine before each workout can create one more hurdle to overcome before using the machine.  

2. Test the Machines, and Yourself

Pire advises testing both types of machine, and your commitment, before buying pricey equipment. “January is a great time to get a trial membership at a gym, since they typically offer resolution deals,” he says. Once there, Pire advises using both machines to get a feel for what you like, but just as important, note how often you go. “If you find you make it there 3 to 5 times a week for a month or two, you can feel comfortable knowing you can make that same commitment after purchasing a treadmill or elliptical.”

Bracko notes the importance of using each machine extensively before deciding which is best suited for you. “I personally like ellipticals because the workout is engaging, but I’ve always found they bother my calves.” That kind of observation is hard to make with a brief trial in a sporting goods store, and neither machine is easy to return.

Check our treadmill and elliptical ratings: Once you've decided which exercise machine you want, check the results of our tests of treadmills and ellipticals for details on performance and features.

3. Consider Joint and Bone Health

If you’ve heard that the impact of a treadmill is bad for joints, think again. “Most of us walk all day long,” Pire says. “You can always find a way to walk or run on a treadmill without getting hurt.” Bracko adds that “if you’re relatively healthy, running is actually good for joints and makes bones stronger by building density.”

Both experts agree that elliptical machines provide a lower-impact workout, but that really only needs to be a consideration if you suffer from osteoarthritis or have an underlying injury, such as a torn meniscus. But there are other reasons to consider an elliptical, particularly for women. “The action of pulling back on the bars of an elliptical helps strengthen the thoracic spine,” Bracko says. “That’s important because it’s typically the first place women develop osteoporosis.”  

4. Think About Noise

“I always advise people not to skimp on their machine if they don’t have to,” Pire says. One reason for that is that pricier models typically offer sturdier construction that results in reduced noise. “You obviously need to consider noise if you live in an apartment or condo,” Bracko adds, “but you should also consider a quieter elliptical over a treadmill if you’ve got young kids in the house.” Anyone with young children at home knows how hard it is to make time to work out—the last thing you need is one more excuse not to get moving.

5. Ask the Pros

If you’re not married to either machine, consider asking a reputable dealer for help deciding. “Go to a store that really specializes in fitness equipment,” Pire suggests, “not a big box store with a sporting goods section.” Pire notes that pros will be thoroughly informed and can help you make a personalized decision based on your body and workout goals. And before buying, look at the warranty and service options offered. “I’ve heard too many horror stories about machines breaking,” Pire says. If you’re still on the fence, he suggests opting for the machine with the longest, most comprehensive warranty.