Can I replace sugar with honey in tea?
There is apparently evidence that some of the flavour compounds in honey deteriorate during heating:
http://www.ibrabee.org.uk/component/k2/item/1837-effect-of-heat-on-honey

The text suggests that honey should not be heated to more than 50 degrees Celsius (122 degrees Fahrenheit). So it might be wise to let the tea cool down a bit before adding the honey. Having said that, I usually put the honey in immediately after removing the tea leaves and it tastes fine to me. The flavour of the honey is clear and pronounced and I have never felt that anything was missing.