When a dryer goes around but doesn’t produce even warm air, something has interrupted the heat source. Run the dryer for a couple of minutes, making sure you don’t have the dial or controls on a non-heat setting such as “Fluff” or “Wrinkle Release.”
With an electric dryer, jno heat may mean that the circuit breaker or fuse that controls the power has blown; reset or replace this. Be aware that a dryer may have two breakers or fuses. The motor will run when one works, but the heating element requires both.
With a gas dryer, check the gas valve behind the dryer to be sure the gas supply is turned on. Also make sure the house’s main gas valve is turned on.
Most modern dryers have electronic ignition instead of a pilot light. If yours has electronic ignition and isn’t heating, call a qualified repairperson.
On an older dryer, make sure the pilot light is burning. If it isn’t, relight it. You can find directions in your owner’s manual, and pilot light instructions are often mounted next to the pilot light on the burner, too. For more about dryer repairs, see the links below.