The question of opening refrigerator doors on Shabbat has been a matter of debate for many decades. In this essay we will outline the various approaches taken by the eminent Halachic authorities on this issue. We will discuss the situation in which the refrigerator light has been extinguished and thus does not pose a Halachic challenge. Our focus will be on the concern that opening the refrigerator door causes the motor to start earlier than it would have, had the door remained closed. Opening the refrigerator door allows warm air to enter, thereby causing a drop in temperature which will inevitably cause the motor to go on sooner.
It is important at the outset to delineate which specific halachic issues we are concerned with, and whether the issue involves violating a Torah or Rabbinic level prohibition. Rav Shlomo Zalman Auerbach, in an incredibly brilliant responsum (Minchat Shlomo no. 10) distinguished by incisive halachic insights and mastery of the of how a refrigerator operates, demonstrates that the possible concern is of violating a rabbinic prohibition and not a biblical transgression.
He notes that, in most refrigerators, metal is not heated until it glows. He explains that even though there are gases that are heated in the refrigerator cycle, heating these gases does not constitute an act of bishul (cooking). This is because the gases are not heated by a fire source (see Rambam's Commentary to the Mishna, Shabbat Chapter Four). Moreover, Rav Shlomo Zalman argues that heating a gaseous substance does not constitute bishul.
He continues to explain that even those (see Chazon Ish Orach Chaim 50:9) who rule that completing an electric circuit which powers an appliance constitutes a Biblical prohibition of boneh (building) or makeh b'patish (completing an item) would concede that causing the refrigerator motor to go on earlier does not violate these prohibitions. This is because boneh or makeh b'patish is violated only when turning on the electric appliance. The Chazon Ish (see letter published in Minchat Shlomo no. 11) explains that turning on an electric appliance constitutes boneh because one brings the appliance "from death to life." However, once the refrigerator is plugged in, the action cannot be described as bringing it from death to life by making the motor go on earlier. Moreover, since the motor will turn off by itself shortly after it goes on, only a rabbinic prohibition is violated. An action is biblically forbidden only if the resulting product is a lasting one (Shel Kayama). Thus, the only possible prohibition involved in causing the motor to go on earlier is the rabbinic prohibition to cause a current flow (see Teshuvot Beit Yitzchak 2:31). Accordingly, the issue of opening a refrigerator is a question of whether a rabbinic prohibition is violated, not a biblical prohibition. Therefore, the possibility of a lenient ruling is considerably greater since there is no concern in this situation of violating a biblical prohibition.
Opening the Refrigerator Door While the Motor is Running
Rav Shlomo Zalman Auerbach argues that opening the refrigerator while the motor is running should be unquestionably permissible despite the fact that the motor will remain on longer because the refrigerator door was opened. This is because opening the door merely preserves the status quo. It is analogous to the following halacha, recorded in the Shulchan Aruch (O.C. 277:2), that one may close the door that is opposite a fire. This isn't considered to be extinguishing because (see Mishna Brura 277:11) "even though the wind would have magnified the fire [had the door remained open] one does not violate the melacha (forbidden category of labor) of mechabeh (extinguishing a fire) since he did not perform any action, and if the fire will become extinguished as a result it, is of no concern to us." The Shulchan Aruch HaRav (287:1) explains that this action is not even considered "indirect extinguishing" (Gram Kibui). This is because he merely removed an impediment to maintaining the status quo (Meneat Monea). Similarly, opening the refrigerator door while the motor is running, merely removes an impediment to the motor continuing to run. Almost all Poskim believe that it is permissible to open the refrigerator door while the motor is running. (See Teshuvot Har Zvi O.C. 1:151; Igrot Moshe O.C. 2:68; and Teshuvot Yabia Omer 1: O.C. 21).
Opening the Door When the Motor is not Running - Rav Shlomo Zalman's Approach
The question of opening the door when the motor is not running, however, has engendered much debate. Rav Shlomo Zalman Auerbach rules that it is entirely permissible to do so. In fact, he writes that it is not right to be strict on this matter, as it will lead one to limit his Oneg Shabbat, enjoyment of Shabbat.
The lenient ruling is based on the fact that opening up the door will not immediately lead to turning on the motor. The inevitable time delay between the opening of the door and causing the motor to go on leads Rav Shlomo Zalman to classify this as a "Grama" - "Koach Sheini" (indirect action). It is analogous to the following classic case discussed in the Gemara (Sanhedrin 77b). An individual ties up another in front of a powerful stream of water stopped by a dam and releases the dam and thereby kills the victim. If the water killed the person immediately (see Rashi), then the perpetrator is to be punished with death because he killed directly (Koach Rishon). However, if the water didn't kill him immediately (ie. there was a significant time delay between the action of releasing the dam and the rushing waters killing the victim), the perpetrator is not subject to the death penalty because he has killed indirectly (koach sheini). Similarly, the opening of the doors and allowing the warm air to flow into the refrigerator will take at least a few seconds before it will effect the motor and cause it to go on.
It is not, however, sufficient to state that since he is only causing the motor to go on indirectly, that it is therefore permissible to open the refrigerator when the motor is off. This is because the Rama (334:22 and see Biur Halacha ad. locum. s.v. D'Gram Kibui) rules that Grama is permitted only in situations of great need. Rav Shlomo Zalman asserts, however, that since one's intention is merely to open the door and not to turn on the refrigerator's motor, Grama would be permissible in all situations even absent any unconventional needs. Moreover, he writes that since he is only causing the motor to go on earlier than it would have gone on without his opening the refrigerator door, (also see Minchat Shlomo 91:10) one may treat the act of opening of the door even more leniently than Grama. Thus, opening the refrigerator door would be permissible in all situations.
Opening the Refrigerator Door when the Motor is not Running- The Strict Approach
Many poskim concur with Rav Shlomo Zalman's lenient approach. Indeed, Rav Aharon Lichtenstein told this author that Rav Soloveitchik agreed with the lenient approach. Rav Moshe Feinstein (Igrot Moshe O.C IV: 74- Bishul -28) seems to fully accept Rav Shlomo Zalman's ruling (also see Igrot Moshe O.C. 2:68)- as does Rav Eliezer Waldenburg (Tzitz Eliezer 8:12 and 12:92). (See Encyclopedia Talmudit 18:663 note 13.)
Many eminent authorities, on the other hand, either rule strictly (Har Zvi O.C. I:151; Chelkat Yaakov 3:179; and Minchat Yitzchak 2:16) or at the least recommend that one to be strict if possible (Rav Yosef Henkin, Eidut L'Yisrael p. 122; Rav Ovadia Yosef, Yabia Omer I:O.C. 27). The problem is that once an action is performed routinely it cannot be classified merely as Grama (see Shabbat 120b and Rabbeinu Chananeil ad. loc. s.v. Rav Ashi and Bava Kama 60a and Rosh Bava Kama 6:11). Rav Shlomo Zalman responds that this applies only when one intends to create the resultant action. When opening the door one does not intend to turn on the motor.
Common practice in this country is to be lenient on this practice, although some people adopt the strict approach. In Israel, though, it is quite common in certain communities to be strict on this matter. In fact, the Shemirat Shabbat Kehilchata (10:12) counsels one who wishes to be strict to set the refrigerator on a timer, so that the refrigerator shuts off entirely at certain times and to open the refrigerator only during those times.
The Shemirat Shabbat Kehilchata (10:14) cautions that all opinions agree that it is forbidden to open a refrigerator in which a fan goes on when one opens the door and shuts when he closes the door. One must exercise caution when purchasing a refrigerator that it not be source of Halachic problems for use on Shabbat and Yom Tov.
A primary basis of the lenient opinion is that no Biblical prohibition is involved in the opening of a refrigerator door. However, opening an oven door is a more severe issue because opening the door causes cool air to enter the oven causing the fire to go on - a Biblical prohibition- unlike the question of opening a refrigerator door on Shabbat (see Encyclopedia Talmudit 19:669 and Rav Levi Yitzchak Halperin's Shabbat V'Kashrut B'Mitbach Ha-Moderni pp.335 and 339). Accordingly, it may be best to avoid using a lighted oven on Shabbat to keep food warm, since opening an oven is fraught with Halachic problems. One should consult his Rav for guidance regarding these issues.