Give yourself time to adjust. Your new bed probably feels different from your previous bed in many ways, and temperature is just one of them.
Reassess after one or two weeks.
Place the mattress' terry cloth cover directly on the mattress. It should be underneath all sheets and blankets.
This lightweight, terry cloth cover, which was provided with the mattress, allows just enough air flow between you and the mattress to make a significant difference in how warm you feel.
Make the rest of your sleeping environment a little cooler. Try lighter, or fewer, covers to compensate for the extra heat of the mattress.
Switch to a lighter weight blanket made of a breathable fabric such as 100 percent cotton, or sleep without a blanket. Turn down your home's thermostat a few degrees at night.
Place a quilted mattress cover on the mattress. A mattress cover made of 100 percent cotton is best for allowing air circulation.
Don't use a thick cover, however. If you have a large amount of fabric between you and the mattress' foamlike material, many benefits of the Tempur-Pedic mattress are lost because its foam cannot mold to your body effectively.
Insert a mattress pad specifically made to combat the Tempur-Pedic heat issue. That mattress pad should go between the mattress and any other bed coverings.
Available from several manufacturers, these pads optimize the airflow between the sleeper and the Tempur-Pedic material.