I think it is 180 degrees at 5 or 10 minutes. I put my mail in the toaster oven at 200 for 10 minutes and I know that is above the recommend limit for food. (So figured it will work on mail too! Paper burns at 400 degrees. I saw some post that the 1918 flu - the biggest carrier was the mail! Not sure I buy that thought.)
Found the following regarding the H1N1 virus. There may be specific studies for Covid-19, but early on I just figured most viruses like this are going to be fairly similar in some regards. It has to do with their envelope rather than the actual virus.
They say 70 C which is 158 F.
Food safety issues (from WHO).
November 2005
The H5N1 avian influenza virus is not transmitted to humans through properly cooked food. The virus is sensitive to heat. Normal temperatures used for cooking (so that food reaches 70oC in all parts) will kill the virus. To date, no evidence indicates that any person has become infected with the H5N1 virus following the consumption of properly cooked poultry or poultry products, even in cases where the food item contained the virus prior to cooking.
I found another link specific to Covid-19. They said the same thing - normal cooking temperatures will destroy it.
They also say to wash clothing and towels at 140 degrees. But everything that I have read says that the washer and drier temperatures are too low to destroy it. BUT - the washing with detergent does break down the protective envelope to destroy the virus.
Just putting clothing into the drier MIGHT heat it up and dry it out (the envelope needs moisture), but I’m not sure I would depend on just that.