Halakhah for Beitzah 2:5
בֵּית שַׁמַּאי אוֹמְרִים, לֹא יָחֵם אָדָם חַמִּין לְרַגְלָיו, אֶלָּא אִם כֵּן רְאוּיִין לִשְׁתִיָּה. וּבֵית הִלֵּל מַתִּירִין. עוֹשֶׂה אָדָם מְדוּרָה וּמִתְחַמֵּם כְּנֶגְדָּהּ:
Beth Shammai say: One may not heat water for his feet (on yom tov) unless it is fit for drinking. [The Torah permitted (what is necessary for) eating, but not lighting a fire for bathing.] And Beth Hillel permit it. [For since lighting a fire was permitted for purposes of eating, it was also permitted for other purposes so long as some benefit is to be derived therefrom. And the halachah is that one may wash his face, hands, and feet with water that was heated on yom tov eve, but not his entire body, yom tov being decreed against by reason of Shabbath. And with water that was heated on yom tov eve, one may wash his entire body on yom tov.] One may make a bonfire (on yom tov) to warm himself thereby.