A SWR of 1:1 is easy with a dummy load but as a radiator its efficiency is very poor.
Some antennas can be matched to a good SWR and still be poor radiators.
SWR is not a measure of antenna effectiveness or efficiency its a statement of
how well the load is matched to the source.
So where does the energy go, mostly heat. the comment I hear often, I I can
measure no warming, completely missing that all that copper or aluminum
will radiate heat well.