Q: My husband is a beekeeper. A hornet colony has built a sizable nest on the back of our house. What makes it unique is that the nest is flush on a window and you can see inside the nest. It is time for us to paint our house. My husband does not want to use pesticides because of the adjacent hives. Any ideas?
A: I think the bigger problem might be the hornets attacking and killing the honeybees.
Jennifer Berry, Apicultural Research Coordinator at UGA, says hornets and wasps will eat bees. They will certainly eat yellowjackets. See Hornet Eating Yellowjackets
Your heat lamp idea is good to deter a smaller nest but I think with this larger nest they would just move away from the window if you heat it up.
I’d get aerosol wasp and hornet spray and aim a 5 second squirt at the hornet nest opening. Your bees are not likely to come in contact with the insecticide.