What type of radiation transmits heat energy?
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.