Uhm, we just got two brand new AC units and the electricity cost compared to two similar units in our previous place (still fairly new units) dropped by about NT$1k a month. So our electricity bill is no more than about NT$2,500 a month now and considering that I work at home and have my computer on pretty much 24/7 and we’re not being stingy with using the electricity…
Anyhow, NT$500 a day, well, that depends, how far away from your place of work will you be living? I guess it would be easier in one of the big cities as public transport is better there, but only Taipei and Kaoshiung has MRT so far. Rental prices seems to have dropped slightly recently so NT$15k should get you a decent place, even a brand new place if you’re lucky. The water is never going to cost you more than NT$100 a month if you’re on your own and the Internet, well, it depends how fast you want it to go, the NT$1k price is for an 8-10Mbit connection depending on what service is available where you’re going to live.
If you stick to mostly local food, you’ll be fine, breakfast NT$50, lunch NT$50-100, dinner NT$50-whatever you want to spend…
If you cook then you might be able to get away cheaper if you want to eat western style food, although anything but sweet taiwanese toast is quite expensive here when it come to bread and cereals aren’t cheap at all. Oatmeal would be an affordable-ish bet and so would eating a lot of local fruit.
Don’t expect anything being like home and sometimes you end up paying stupid prices for things that you pay nothing for back home.
Things that are in general cheaper here imho is most fruit and vegetables, seafood, pork and chicken. Most other things are more expensive.