Per usual, our Full Site covers this subject in greater detail. A starting point is our page about electricity . If you're moving from America you'll need step down transformers and adaptor plugs and still a lot of your stuff won't work here. If you're moving from continental Europe, you're likely only to need adaptor plugs, and your gear will work just fine. Most shaving sockets also support 110 VAC with the 2 pin international shaving plug.
Many hotel rooms provide hair dryers.
Even so, all sorts of problems relating to hardwired phone systems could arise, so better consult our phone page . Whatever the regulations say, Ireland is still a very smoky place. Although only a quarter of the populace smokes, they have the run of the pubs and restaurants. This is a seldom enforced rule, but gradually the non-smoking areas are getting more common. The Irish are a tolerant lot, and among the things tolerated are smokers.