Chapter 23
Housekeeping and Use of Domestic Facilities on Shabbath and Yom Tov.
CENTRAL HEATING
24.a. In countries with a cool climate, one may on Shabbath ask a non-Jew to turn on the heating, if one is troubled by the cold, since a person who is suffering from the cold is placed in the same category as someone who is ill. (See Chapter 38, paragraphs 4 and 8.)
24.b. 1) Where there are small children in the house, one may request a non-Jew to turn on the heating even when the cold is not intense enough to bother the adulta, since small children are naturally more sensitive to cold.
2) Once the heating is on, it is permissible for the grown-ups also to avail themselves of its benefit.
24.c. In any case, one should prepare, before Shabbath, any implements or materials needed for turning on the heating, so that the non-Jew can take them himself, as they are muktzeh and one will not be able to handle them on Shabbath.
25.a. It is forbidden to release air from a radiator on Shabbath by loosening the screw fitted for that purpose.
25.b. One should take care not to do this even after the heating system has turned itself off.

