Wattage is one thing, where it goes is another. A heat
gun for soldering puts that wattage into a low flow air
stream for high temperature - temps that will melt any
cheapo consumer hair dryer.
Consumer dryers are made to prevent faults such as
inlet obstruction from burning lawsuit-happy American
idiot consumers. Probably internal bypass-air paths,
probably internal temperature switches that limit max
temp in fault conditions.
You can get cheap heat guns but these are often too
big for such work. The Nice Ladies In The Lab had tiny
ones with adjustable nozzles and probably only a couple
of hundred watts, for rework.
Might be best off looking on ebay for "surface mount
heat gun" and wait for the fluke low price buy-it-now.