SweetNight CoolNest Ultra   Review

This Medium mattress performs best for average-weight and heavier side sleepers, who will sink into it enough for proper pressure relief. It's also decently supportive, so it's a good option for combination sleepers, but less ideal for dedicated back or stomach sleepers, who may need even better support. It's also not a good option for lighter side sleepers, since it's not conforming enough for people in that weight category and will put pressure on your arm and shoulder. 

This mattress's 2.5 cm (1.0 inch) upper comfort layer is made of memory foam infused with gel beads and phase change materials meant to help the foam conduct heat away from your body. The thin 1.0 cm (0.4 inches) lower comfort layer is made of 'Air Mesh', which, according to SweetNight, has a porous, 'mesh-inspired' design meant to improve air circulation. The 6.5 cm (2.6 inch) transition layer is made of gel-infused polyfoam with perforations for air flow. Most people will fully compress both comfort layers and also sink a little into the layer below, which creates an enveloping, contouring feel typical of memory foam. The firmer 28.0 cm (11.0 inches) support layer is made of polyfoam and has a scalloped shape meant to create zoning and help keep your spine aligned. 

The comfort layers are made of good-quality memory foam, which will help the mattress resist forming permanent indentations for longer. The support layer is made of good-quality polyfoam, which helps prevent sagging. The transition layer, however, is made of lower-quality foam, so it's a weak point in terms of durability.

This mattress's upper comfort layer is made of gel-infused memory foam that has a responsive feel, unlike regular memory foam. The gel beads are made of phase-change material meant to help the foam conduct heat away from your body. The thin lower comfort layer is made of 'Air Mesh', which, according to SweetNight, has a porous, 'mesh-inspired' design meant to improve air circulation. The transition layer is made of gel-infused polyfoam with perforations for air flow. The support layer is made of polyfoam and has a scalloped shape meant to create zoning and promote spinal alignment. 

Its body conformity performance depends on your weight. Average-weight and heavier people will sink in enough for comfortable side sleeping, but lighter individuals won't compress its foam layers enough and will feel uncomfortable pressure when side sleeping. 

You'll sink quite deeply into it overall, and the sleeping surface molds around you closely, creating an enveloping feel. 

This mattress offers decent support for most people, so whatever weight category you're in, it'll keep your spine quite aligned and is a suitable option for back/stomach sleeping. While it has a satisfactory performance, you might be more comfortable on a more supportive mattress if you always sleep on your back or stomach.

It has very good cooling. Its performance is particularly good during the first hour you're in bed, which makes it a good option if you often have difficult falling asleep because of the heat. It's slightly less cooling over eight hours, and while it'll keep most people comfortable, it's not ideal if you often wake up later in the night feeling overheated. 

Note: The behavior of our testing equipment is causing the Cumulative Energy Transfer line on the graph to have a smoother appearance at the four-hour mark, while most other mattresses' graphs have a stepped appearance, including the SweetNight CoolNest Pro and SweetNight CoolNest. With some mattresses, our PID controller adjusts its output when the mattress is saturated in heat. This results in a different power output during the last four hours of the cooling test, causing the smoother appearance of the graph and making the results over eight hours incomparable with other mattresses where the PID controller didn't adjust its output.

However, it's worth noting that this mattress's cumulative energy transfer is also lower (so its cooling is worse) during the first four hours of the test compared to other SweetNight models, despite being advertised as a more cooling mattress. We're currently investigating how aspects of our testing methodology, such as mattress compression, may be affecting the cooling results for this mattress, and we'll update the review in the future. 

This mattress has excellent motion dissipation. It does a great job of dampening movement, so your partner's smaller movements are noticeable. Bigger movements are mostly felt near the source instead of all over the mattress, and they dissipate very quickly, so you'll feel a brief shock, but the mattress doesn't wobble or bounce with movement. 

The sleeping surface responds slowly, which gives it a hugging feel, but may also make you feel constricted or stuck in place. Lower-end options from SweetNight, including the SweetNight CoolNest Pro and SweetNight CoolNest, are more responsive, likely because they lack the Ultra's slow-moving memory foam lower comfort layer. 

This all-foam mattress lacks a spring layer and includes a lot of low-resilience foam, so it's not bouncy. This makes changing sleeping positions feel more effortful.

Most of the foam layers have low resilience and an unbouncy feel. Although the upper comfort layer is a made of gel-infused memory foam, it's only slightly more resilient than regular memory foam. The thin lower comfort layer and transition layer are even slower-moving and give the mattress its slow-moving feel. The polyfoam support layer is much bouncier. 

This mattress has decent edge support. The sides sink significantly when you sit on the edge of the bed. However, they compress quite evenly, instead of forming a steep ramp. This helps reduce the feeling that you might fall out of bed if you sleep near the side. 

There's nothing reinforcing the mattress edges, which compress quite easily.