Is the Copper Hybrid Medium good for side sleepers?

It is a medium feel, so lighter side sleepers may find it firm at the shoulder and hip. Heavier side sleepers usually get enough give from the copper foam layer.

Does the copper actually cool the bed?

Copper-infused foam is meant to draw heat away, but the effect is modest. The coil core and tight top do help it sleep cooler than a solid all-foam mattress.

How does it differ from a pillow-top hybrid?

The tight top is flat and low-profile with no extra soft layer on top. That means less sink-in softness and less chance of the top layer shifting or sagging.

Do I need a box spring?

A tight-top hybrid works on a solid platform, a slatted frame or a box foundation. A firm, flat base protects the coil unit and keeps the warranty valid.

How firm is medium in this line?

Spring Air's medium sits in the middle of its range, closer to medium-firm than plush. Back and stomach sleepers tend to find it supportive; side sleepers wanting a soft surface may want the plush version.