It is forbidden to use electricity on Yom Tob, such as to turn lights or other appliances on or off, just like on Shabbat. Although some authorities ruled leniently in this regard, and permitted the use of electricity on Yom Tob, Halacha does not follow this view. It is likewise forbidden to use a telephone on Yom Tob. Unfortunately, there is a misconception that Yom Tob resembles Hol Ha’mo’ed and does not have the same restrictions that apply on Shabbat. This misconception results from the special dispensation granted by the Torah allowing cooking and carrying through a public domain on Yom Tob. But these are exceptions to the rule; in all other respects, Yom Tob is similar to Shabbat. It is thus forbidden to turn on or off electrical devices, and to use a telephone, on Yom Tob, just as on Shabbat.
However, Halacha does treat Yom Tob more leniently with respect to the issue of "Amira Le’nochri" – instructing a gentile to perform forbidden activity on one’s behalf. Thus, for example, if a light is needed in the room where the Yom Tob meal is being held, or it is needed to generally enhance the atmosphere in the home for Yom Tob, one may ask a gentile to turn on the light. Turning on electric lights on Yom Tob is forbidden only Mi’de’rabbanan (by force of Rabbinic enactment), and asking a gentile to perform a forbidden activity is likewise forbidden only Mi’de’rabbanan. This situation thus involves what we might term a "second degree" Rabbinic prohibition, which is permissible for the purpose of a Misva, such as the Misva of Simhat Yom Tob (rejoicing on Yom Tob). Hence, if light is needed to enhance the enjoyment of Yom Tob, one may ask a gentile to turn on the lights.
Similarly, one may ask a gentile to light a match when this is necessary for the enjoyment of Yom Tob, such as to light the stove for cooking, or if one smokes on Yom Tob and needs a match for his cigarette.
If one’s home is uncomfortably warm on Yom Tob, he may ask a gentile to turn on a fan or air conditioner. Regarding Shabbat, Hacham Ovadia Yosef (in Yabia Omer, vol. 7, Orah Haim 38) allows asking a gentile to turn on an air conditioner if the heat is especially oppressive.
It goes without saying that one may not press the buttons in an elevator on Yom Tob, as this involves the use of electricity. Additionally, however, Hacham Ovadia rules that one should preferably refrain from using elevators altogether on Shabbat and Yom Tob, even without pressing buttons, as in the case of the so-called "Shabbat elevators." He writes that one should especially avoid descending in an elevator unnecessarily, as one’s presence in a descending elevator can affect the electricity used by the elevator. Ill patients, elderly people, and women who are pregnant or have recently given birth may ride elevators on Shabbat and Yom Tob (without pressing any buttons), but others should avoid elevators, if possible.
Summary: It is forbidden to use electrical devices or appliances, or telephones, on Yom Tob, just as on Shabbat, but one may ask a gentile to turn on a light or strike a match when this is necessary for the enhancement of Yom Tob. One may also ask a gentile to turn on the air conditioning if the house is uncomfortably warm. One should preferably avoid riding elevators on Shabbat and Yom Tob – even without pressing buttons. People who are ill or weak may use elevators (without pressing buttons) on Shabbat and Yom Tob, but others should preferably not ride elevators, especially for descending, unless it is necessary.
