A holiday is a special day for religious or cultural reasons - such as Christmas, Easter, New Year's Eve, and your country's Independence Day. Some holidays are also official days off from work, and others are not.
A vacation is when you take multiple days off from work/school to relax and/or travel. However, American English speakers call this a vacation and British English speakers call this a holiday:
My parents are on vacation in Asia. (American English)
My parents are on holiday in Asia. (British English)
There are several variable at play here, but generally speaking your microwave is more energy efficient than your stove. Of course, using a microwave is not nearly as classy and for large meals an electric stove would probably be a better option, but on average this modern marvel can save you a lot of energy.