What you were told was true in most cases, but specifically it depends on the room - if it's a typical US home bedroom, it's going to have one circuit in it, and that circuit is typically 15 amps, sometimes they'll be 20 amps, but that's less common. The Terminator 110's use about 1100 watts, which at household voltage (120v) comes out to just shy of 10 amps, so that's your problem - 3 devices that use 10 amps each, and one 15 amp circuit. Turn on two of them, and you'll trip the breaker.
Now, you can swap out the 15 amp breaker with a 20 amp, but this is BAD BAD BAD. The breaker is sized to the gauge of the wire, and the gauge of the wire directly relates to how much amperage can move down it before it basically catches fire (there's overhead to this, so 15 amps constant on a 15 amp circuit isn't going to cause problems, but running 20 amps over 15 amp wiring definitely will).
Make ***SURE*** to make it clear to the electrician that you're pulling 10 amps (at 120v) from each machine, 24x7 - this isn't a common load characteristic, so you want them to know not to cut corners when wiring for them.
Now for the good news - you do have a room that could run all three more than likely, and that's your laundry room. Things like the dryer use 240v power, and this effectively halves the amp draw, so if the A2 draws 10 amps at 120v, it draws 5 amps at 240v. Even better, a typical dryer breaker is 30amp at 240v, so technically you could run 5 A2's on it without issue, but you also won't be drying any cloths, unless you're using the hot air from the miners.
What I would recommend doing if you're going to have an electrician do something is look to have him run a new break and wire to the room at 240v. Typically I run 30amp breaks, since the best bang-for-the-buck PDU's are 30amps, and then a good rule of thumb for electrical wiring is to try not to exceed 80%, so 24-25 actual constant amps would be idea. You can certainly hit the limit at 30amps, but then I would recommend oversizing the wiring a gauge or two, just for good measure.
One other benefit of 240v is that the power supply will run more efficiently, so typically a couple percent less power consumption, and slightly cooler operation - so there really is no downside to doing 240v. The PSU's the Terminators come with are really designed to be run at 240v (they autoswitch to whatever voltage you're running), and virtually all ATX PSU's also run great at 240v.
Enjoy the miners - the A2's are a blast, at with 330MH, you can do some decent solo mining.