When shopping for a new mattress, the bed’s motion isolation is often a secondary consideration. However, a mattress with good motion isolation can help you and your partner sleep better. But what exactly is motion isolation and why is it so important for couples to consider when buying a new mattress together?
Most of this year’s best mattresses for all types of sleepers will have strong motion isolation, as many high-quality mattresses are designed to isolate motion well. However, excellent motion isolation tends to be found in all all-foam mattresses, even the most budget-friendly ones, so you can find a bed that isolates motion well even if you’re on a tight budget.
Here, we’ll explain what motion isolation is and why it’s important to consider when shopping for a new mattress. We’ve also rounded up three deals on mattresses with great motion isolation ahead of this year’s Labor Day mattress sales and deals.
What is motion isolation?
Motion isolation refers to a mattress’s ability to prevent movements from a particular part of the bed from being transferred to other parts of the bed. This means that movements that occur on one side of the bed will not be felt on the other side. So, for example, if you are lying on the right side of a bed and someone comes over and sits on the left side, you will not feel it.
At Tom's Guide, motion isolation testing is included in how we test mattresses. We measure a bed's ability to absorb motion by placing an empty wine glass in the middle of one side of the bed, then dropping a 10-pound weight on the other side. If the wine glass doesn't fall or barely moves, that indicates the mattress has good motion isolation.
Why is motion isolation important when buying a mattress?
Have you ever slept and had your sleep disrupted by your partner staying up late? If so, it’s probably because your mattress has poor motion isolation. Motion isolation is important when you share a bed because it can absorb a partner’s restless movements, preventing them from tossing and turning and disrupting your sleep.
A bed with poor motion isolation can cause significant motion transfer, which can lead to sleep disruption and sleep deprivation.
Who needs motion isolation most?
If you share a bed, you'll definitely want to consider the bed's motion isolation when purchasing. Motion isolation is especially important for couples sharing a bed who have different body weights or sleep schedules. For example, a larger sleeper's movements may be easily felt by one partner, while someone who goes to bed later than their partner may disturb them at night when they go to bed.
A bed with good motion isolation can absorb your partner's movements and help minimize these disturbances. A bed with minimal motion transfer can also help those who sleep with a restless or combination sleeper, as the motion of their movements will not be transferred to the other side of the bed.
Which mattresses offer the best motion isolation?
The best memory foam mattresses tend to have good motion isolation. Their dense, slow-moving foam absorbs motion well and prevents motion from transferring to other areas of the bed. Memory foam mattresses also have an all-foam construction, meaning there are no interconnected springs to transfer motion.
Although springs tend to transfer motion, the best hybrid mattresses often include individually wrapped coils (meaning each spring is wrapped in fabric), which allows the coils to move independently and reduces motion transfer.
Which mattresses have poor motion isolation?
Traditional spring mattresses are arguably the ones with the lowest motion isolation. Their interconnected springs and lack of slow-moving foams mean that movements are easily transferred throughout the mattress.
Some hybrid mattresses may also have poor motion isolation, but others manage motion transfer by adding layers of slow-moving foam cushioning and wrapping their coils in fabric so they move individually and prevent motion transfer.
Latex mattresses can also be good or bad at isolating motion. Latex is naturally bouncy and responsive, which means it doesn't absorb motion as well as memory foam. However, some of this year's best organic mattresses have features that offset latex's motion transfer, like individually pocketed coils and quilted covers.
What are the disadvantages of motion isolation?
Motion isolation has many benefits, but a bed that absorbs motion perfectly also has some drawbacks.
For example, memory foam mattresses are great for absorbing motion thanks to their slow-moving foam construction. However, some sleepers may find that soft foam is too soft and lacks bounce and responsiveness. This is especially true for stomach sleepers (who need a firm, supportive surface) and combination sleepers (who need a responsive surface to help them change positions throughout the night).
Mattresses that absorb movement well are unfortunately also good at retaining heat. Their dense, slow-moving foam layers and lack of ventilating springs also mean that there is not enough air circulating through the mattress, resulting in a warm bed. However, many all-foam mattresses now come with special cooling features to offset their tendency to trap heat, such as cooling covers, breathable perforated foam and heat-dissipating gel infusions.