What type of radiation transmits heat energy?
Heat energy is transferred by Infrared type of radiation.
Radiation which can be detected as heat occurs in the infrared range of the electromagnetic spectrum.
see a process below.
If we are talking about heat energy in specific it relates to light .
yes, light , it would be more correct to say
We see something because of light coming from it , but we can't see something that emits light of some other (which is either too high or too low) frequency or wavelength , whatever! other than those of visible spectrum.
this is the reason the sky appears dark at night though a lot of radiations are there from distant stars , galaxies and cosmic background radiations .
Coming to main question, it is infrared radiations that cause heating , don't wonder that its not gamma rays or x-rays or even ultraviolet rays just because if you focus gamma rays to say steel pan , it would make a hole in it .
Electrical appliances like ovens , microwaves do use infrared radiations to cause heating
Hope this info. helps you at least a little.