05 – Mav’ir, Mekhabeh, and Electricity

01. Mav’ir

The Torah permits lighting a fire (hav’ara) on Yom Tov for tzorekh okhel nefesh (3:2 above). However, the Sages prohibited doing so (m. Beitza 4:7 and Gemara 33a), since creating something new is similar to performing a melakha. It is true that in order to cook and bake for Yom Tov, a fire is necessary. Nevertheless, since it is possible to light a fire before Yom Tov for use on Yom Tov, the Sages forbade lighting a new fire on Yom Tov (Beitza 33a-b; MT, Laws of Yom Tov 4:1; Rashba; SAH 502:1; MB ad loc. 1). Striking a match and turning on an electric light bulb are included in this prohibition (section 4 below).

Though lighting a new fire on Yom Tov is prohibited, adding fuel to an existing fire – whether wood, gas, or kerosene – is permitted. If an additional flame is needed to cook, a match or wood chip may be lit from an existing fire and then used to kindle a new flame. For these purposes, red-hot iron or red-hot coils are considered fire, as are smoldering coals. Therefore, one may light a match from them, as doing so is not considered creating a new fire.

Since lighting a new fire on Yom Tov is prohibited by rabbinic law and not Torah law, a non-Jew may be asked to light one for the sake of a mitzva or in a case of great need. For example, a non-Jew may be asked to turn on the lights or light a candle if the Yom Tov candles have gone out, the dining room is dark, and no pre-existing flame is available. Similarly, a non-Jew may be asked to turn on an electric heater if it is very cold.[1]

[1]. Beitza 33b explains that the prohibition of lighting a fire on Yom Tov is on account of Molid, meaning that the Sages prohibited creating something new on Yom Tov (Rashi; Ri’az; Ra’ah; Me’iri; Bartenura). Raavad and Sefer Ha-mikhtam maintain that the reason for this prohibition is because the newly created item is muktzeh, while Rambam (4:1) maintains it is because the fire could have been lit before Yom Tov. Rashba agrees with Rambam. It seems that Rashba thinks that the prohibition is rabbinic. Others explain that Rambam thinks it is a Torah prohibition, as the law pertaining to lighting a fire on Yom Tov is the same as that pertaining to makhshirei okhel nefesh, which can be prepared before Yom Tov (3:9 above). This is the approach of Taz 502:1 and those who follow its rulings. Since the vast majority of poskim think this prohibition is rabbinic, and the prohibition of asking a non-Jew to do melakha is also rabbinic, asking a non-Jew to light a fire is a shvut di-shvut (a double rabbinic prohibition), which is permitted for the sake of a mitzva or great necessity (Peninei Halakha: Shabbat 9:11).

Based on Rambam’s opinion that the prohibition of lighting a new fire is because it could have been prepared before Yom Tov, some say a fire may be lit on Yom Tov in the following two cases: if he was unable to do so before Yom Tov due to circumstances beyond his control (ones), or if he had lit a fire but it went out. The logic is the same as with makhshirei okhel nefesh (Birkei Yosef 502:1; Yaskil Avdi 4:27:2; Ḥazon Ovadia, p. 49). Others maintain that even if a person was unable to light a fire before Yom Tov, he still may not light one on Yom Tov. This position maintains that lighting a fire is comparable to creating a new kli. One may not do that on Yom Tov, even in a case where he could not have done it beforehand; see SA 509:2, SHT ad loc. 11, and elsewhere. Moreover, it should not be taught publicly that it is permissible on Yom Tov to take care of makhshirei okhel nefesh which could not have been prepared before Yom Tov (Minḥat Yom Tov 98:113; Minḥat Yitzḥak 4:99). Under pressing circumstances, when there is no neighbor from whom to “borrow” fire, one may rely on the lenient opinion. It is then proper to light with a shinui, which would render it permissible even according to the stringent approach. As for electric bulbs and appliances, it would seem that one may be lenient and turn them on with a shinui under pressing circumstances, even if they could have been turned on before Yom Tov, because aside from the aforementioned considerations for leniency, we can add the opinion that on Yom Tov, electric lights may be turned on even le-khatḥila (section 4 and n. 4 below). If one transgressed and lit a fire on Yom Tov, be-di’avad he may derive benefit from it (MB 502:4; as for benefiting from melakhot done on Yom Tov in a prohibited fashion, see ch. 8 n. 6 below).

02. Mekhabeh

On Yom Tov, a fire may be extinguished (kibui) only for the needs of okhel nefesh. Otherwise, it is forbidden. Even if all of one’s possessions are going up in flames, extinguishing the fire is prohibited as long as there is no danger to human life. Lowering a flame is also prohibited when there is no tzorekh okhel nefesh, as this of necessity involves extinguishing part of the flame (Beitza 22a; SA 514:1-2; Peninei Halakha: Shabbat 16:6-7).

In contrast, extinguishing a flame as part of food preparation is permitted. Therefore, raw meat may be placed upon coals, even though the juices dripping from the meat will initially put out part of the flame (Shabbat 34b; SA 511:4). Spices may also be put on the coals in order to infuse fruit with their flavor, even though initially the spices will put out part of the flame. Similarly, the flame under a pot of food may be turned down if it is so high that the food in the pot will burn. However, if a lower flame is available, the pot should be transferred there, thus avoiding unnecessary kibui.[2]

Let us say a fire is threatening to burn down one’s home, where he is planning to eat his Yom Tov meals. Alternatively, the fire is threatening to ruin the crockery and cutlery with which he is planning to eat the meals. May it be extinguished? Poskim disagree. Some prohibit extinguishing the fire, as doing so does not directly affect the food (Rif; Rambam; SA 514:1). Others permit it, maintaining that the permission to perform melakha for okhel nefesh includes the permission to protect the place in which one will eat and the crockery and cutlery with which one will eat. Therefore, as long as one does not have anywhere else convenient to eat besides his home, he may put out a fire which is about to burn it down. Similarly, if he cannot lay hands on other crockery and cutlery with which to eat, he may extinguish the fire which is about to ruin them (Mordechai; Ran; Rema 514:1; MB ad loc. 8). Since this is a disagreement pertaining to a rabbinic law, the lenient opinion may be relied upon when necessary.

[2]. The Gemara explains that it is permissible to extinguish a flame le-tzorekh okhel nefesh (Shabbat 134b; Beitza 23a and 32b). However, in Beitza 22a a disagreement is recorded between R. Yehuda and other Sages regarding the permissibility of extinguishing a burning branch that is threatening to burn food (or burn down a house). The Gemara there follows the view of the Sages that it is forbidden to extinguish the fire. This presents us with a difficulty. Why would it be forbidden to extinguish the fire under the food? Isn’t this a classic case of tzorekh okhel nefesh? Some answer that the Sages prohibited extinguishing the fire in order to save the house, but would agree that the fire may be extinguished to save the food (R. Sherira Gaon; Rid; Raavya; Mordechai; Yam Shel Shlomo; and many more). Others say that when the Gemara prohibits putting out the fire, it is talking about a case of an empty pot. However, if there is food in the pot that will burn, they would agree that extinguishing the flame is permitted (Tosafot and Ramban; AHS and Shtei Ha-leḥem understand Rif, Rambam, and SA 514:1 to agree as well). A third view maintains that extinguishing a flame is permitted only in a case where it happens as part of the cooking process, such as when meat is placed on coals and the juices from the meat put out part of the flame. However, extinguishing a flame in order to protect food from burning is not considered tzorekh okhel nefesh and is prohibited (Ra’ah; several Aḥaronim and MB 514:4 understand Rif, Rambam, and SA to agree as well). In practice, extinguishing a flame in order to prevent food from burning is permitted. This is the opinion of the majority of Rishonim; several Aḥaronim understand Rif, Rambam, and SA to agree as well. Furthermore, even those who prohibit extinguishing the flame would agree in this case that the prohibition is only rabbinic, because the person’s intention is not to produce coals (see Peninei Halakha: Shabbat 9:6).

If an existing flame is too high and the food is likely to burn, but a weaker flame is available to which it can be transferred, the food must be moved there to avoid lowering the flame unnecessarily (Rosh; Rema 514:1). If no weaker flame is available, some say that it is better to light a new fire rather than to lower the existing one (MA 514:3; MB ad loc. 6). Others maintain that it is better to turn down the existing flame (Igrot Moshe, OḤ 4:103; Yabi’a Omer 1:31:12). In practice, this position would seem to be correct, for two reasons. First, the extinguishing here is le-tzorekh okhel nefesh, and second, the uncertainty is on a rabbinic level, and the principle is that we are lenient in such cases. See Harḥavot.

03. Lighting a Fire for Heat, and Candles for Light and Atmosphere

Just as one may use fire to cook and bake, so one may to use fire to heat the house when it is cold. If the fire in a wood-burning stove is too small to properly heat the house, more wood may be added to make it hotter. If a heater uses kerosene or gas, one may add fuel to increase the heat it produces (SA 511:1). Even though heating the home is not tzorekh okhel nefesh, there is an accepted principle that once lighting a fire is permitted for okhel nefesh, it is permitted for other purposes as well (“mitokh”). This principle applies as long as the other purpose is something that most people find enjoyable (3:6 above). Heating a cold place falls into this category.[3]

Candles may be lit for a Yom Tov meal, even where the electric lights already provide enough light, because extra candles contribute to a joyous atmosphere and honor the festival. However, one may not light more candles than is generally accepted for this purpose. One who is afraid of the dark may also light a candle.

We have already seen that a new fire may not be lit on Yom Tov. Therefore, in all the cases mentioned above, the candles should be lit from a pre-existing flame. If it is difficult to bring the candles close to the pre-existing flame (as sometimes happens when a yahrzeit candle has burned down), one may light a match or wood chip from the pre-existing flame and use the new flame to light the candles. After lighting a candle, the match may not be put out, as doing so is not tzorekh okhel nefesh, and is thus prohibited on Yom Tov. Rather, the match should be put down gently and allowed to burn itself out.

Candles may be lit in the synagogue to honor the Shekhina that dwells there. As we said above, once lighting is permitted for okhel nefesh, it is permitted for other purposes as well, such as for a mitzva. One may light candles in a synagogue following Minḥa near the end of Yom Tov, even though they will burn only a short time on Yom Tov; this is not considered preparing for the weekday, since the Shekhina is being honored on Yom Tov, when they are lit (SA 514:5).

If one wants to light a yahrzeit candle in memory of his parents, he should light it before Yom Tov. Since there is no mitzva to light such a candle, and it serves no Yom Tov purpose, it is not proper to light it on Yom Tov. If one forgot to light the candle before Yom Tov, he should light it where it will provide extra light, whether for a Yom Tov meal or in the synagogue. If this is impossible, and he would be very upset were he not to light, he may opt to be lenient and light the yahrzeit candle anywhere, since there is a mitzva element in honoring the memory of one’s parents (BHL 514:5 s.v. “ner”).

[3]. If a gas tank runs out of gas, one may shut its valve and then open the valve to a new tank. However, le-khatḥila he should not connect a new tank, because of the issue of uvdin de-ḥol. Rather, a non-Jew should be asked to do it. In a time of pressing need, a Jew may connect the new tank (R. Shlomo Zalman Auerbach in SSK 13:11 n. 60; Hilkhot Mo’adim states in the name of R. Yosef Shalom Elyashiv that a Jew may open the new tank only if he was unaware that the old one was almost empty, and only if there is no non-Jew available to do it).

04. Electricity

Turning on an electric light or electric heater is included in the rabbinic prohibition on lighting a new fire on Yom Tov. Turning on an electrical appliance without a heating element is prohibited as well.[4]

Just as one may increase a flame to provide light or heat on Yom Tov, so too he may turn up the light of an incandescent bulb with a dimmer switch, or turn up the thermostat on an electric heater, on condition that turning up the light or heat increases the current to the same heating element. However, if it activates an additional filament, it is forbidden, as it is like lighting a new fire.

One may not use a microphone, telephone, or intercom on Yom Tov, as the Sages prohibited the use of sound-producing objects (see Beitza 36b). Moreover, doing so looks like a weekday activity and belittles the holiday. Nevertheless, one who is hearing impaired may use a hearing aid that rests on or inside the ear, since speaking near it increases the flow of the electricity only indirectly (grama). However, a hearing aid may not be turned on or off on Shabbat or Yom Tov (Peninei Halakha: Shabbat 17:3). On Shabbat, the volume of the hearing aid may not be adjusted, but on Yom Tov this is permitted, just as a flame may be raised or lowered when cooking.[5]

On Yom Tov as on Shabbat, one may not open a refrigerator if doing so will turn on a light. All methods used to deal with this issue on Shabbat are relevant to Yom Tov as well (ibid. 17:9).

[4]. Some poskim permit turning on an electric light on Yom Tov. Since the potential of the “fire” already exists within the wires, turning it on is the equivalent of adding fuel to an existing fire (AHS; Even Yekara 3:168; Mishpetei Uziel OḤ 1:19; Mayim Ḥayim §94). Alternatively, turning on an electric light is considered grama and is thus permitted (R. Zvi Pesaḥ Frank). However, the vast majority of poskim maintain that turning on an incandescent bulb is considered lighting a new fire (Oraḥ Mishpat §71; Aḥiezer 3:60; Tzafnat Pane’aḥ 1:273; Ḥelkat Yaakov 1:51; Yaskil Avdi 4:27; Tzitz Eliezer 1:20; Yeḥaveh Da’at 1:32; and many others). As for electrical appliances that do not contain a heating element, it is a little more complicated; even with regard to Shabbat there is disagreement about them. Some say that turning them on is prohibited because it is considered lighting a fire, and is thus a violation of a Torah prohibition on Shabbat (Rav Kook, Oraḥ Mishpat §71). Others say the Torah prohibition is that of Boneh (Ḥazon Ish). Many others maintain the prohibition is rabbinic, whether on account of Molid (Beit Yitzḥak), or uvdin de-ḥol (R. Yosef Eliyahu Henkin). Those who agree that the status is rabbinic include R. Shlomo Zalman Auerbach; Yabi’a Omer 1:20; Tzitz Eliezer 19:15. (This is explained in Peninei Halakha: Shabbat 17:2 and Harḥavot there.) In any case, when it comes to Yom Tov, when lighting a fire is itself only a rabbinic prohibition, turning on any electrical appliance – with or without a heating element – would be forbidden only rabbinically.

[5]. When a hearing aid is off at the start of Yom Tov due to circumstances beyond the wearer’s control (ones), some poskim allow it to be turned on, following the reasoning above in n. 1 for lighting a fire. Besides, some permit using electricity on Yom Tov, as explained in the previous note. Additionally, even according to the majority of poskim who do not allow it, some maintain that turning on an electrical appliance without a heating element is only rabbinically prohibited on Shabbat and Yom Tov. It is proper to turn on the hearing aid with a shinui, so that even those who are stringent would agree that there are grounds for leniency.

05. Grama and Turning Off Gas Burners

The Sages infer from the verse, “You shall not do any melakha” (Shemot 20:10), that the Torah prohibits the actual performance of a melakha; but if the melakha is done automatically, even if a person caused it to be done, it is considered grama, and it is not prohibited by the Torah. In cases of great necessity, one may use grama to achieve the result of a melakha. For example, if a fire is spreading, one may surround the fire with containers filled with water so that when the fire reaches them, the containers will burst open and the water inside them will pour out, putting out the fire (Shabbat 120b; SA 334:22). This ruling is followed in practice. On Shabbat grama is permitted in order to avoid a loss, in service of a mitzva, or for some other great need. Barring these circumstances, one may not cause melakha to be done on Shabbat (Rema 334:22).

However, when it comes to grama on Yom Tov, the poskim disagree. Some argue that the laws of Yom Tov are the same as those of Shabbat, while others maintain that on Yom Tov grama is permitted le-khatḥila, especially in the cases of Mav’ir and Mekhabeh, as they are prohibited only rabbinically on Yom Tov. In practice, one may be lenient concerning grama even without a pressing need. However, if there is no need, it is proper to be stringent.[6]

In the past, people who wanted to cook on Yom Tov would put enough firewood in the oven to allow them to cook what was necessary. This wood would be lit with a flame that had been prepared before Yom Tov. When the cooking was done, the fire would burn itself out, as the amount of firewood used was sufficient for the cooking and no more. Today, however, when we cook with gas burners, turning them off is problematic, as one is not allowed to directly turn off a flame on Yom Tov.

One possible solution is to use grama so that the flame is extinguished indirectly. For example, after the cooking is done, a full kettle of water can be placed on the burner and allowed to boil over. The overflowing water will put out the flame. Once it is out, the knob may be used to turn off the gas. The hot water remaining in the kettle should be used for making tea or washing dishes, so that it will not have been boiled up for no reason.[7]

A better, more convenient way of extinguishing the flame is by means of the Zomet Institute’s Holiday Gas Timer (“Chagaz”), a device invented specifically for cooking on Yom Tov. It involves a spring-operated mechanical timer. While it is on, gas flows through the pipes and feeds the flame; at the pre-set time, the gas supply is cut off, causing the flame to go out. Before one starts to cook, he sets the timer for the desired amount of time. When the time is up, the Chagaz simply cuts off the gas.[8]

[6]. Some maintain that grama is permitted even le-khatḥila on Shabbat as well as Yom Tov (Taz 514:10; Vilna Gaon 314:1; Shemesh U-magen 3:5). Others are lenient about grama on Shabbat only if being stringent will lead to a loss or the like, while on Yom Tov they permit it outright (Tosafot, Beitza 22a s.v. “ve-hamistapek”; Rema 514:3; Ma’amar Mordechai; SHT ad loc. 31). Others are lenient with grama specifically for lighting and extinguishing fires on Yom Tov (Aḥiezer 3:9; Ḥelkat Yaakov 1:60). Others are just as strict on Yom Tov as on Shabbat (MA 514:10; SAH ad loc. 9; Ḥayei Adam 95:5). Since the prohibitions of lighting and extinguishing on Yom Tov are rabbinic, I write above that one may be lenient whenever there is any need. However, if there is no need, it is proper to defer to the stringent opinion.

[7]. Some maintain that one should not do melakha indirectly on a regular basis, so the above solution may be used only on an occasional basis (SSK 13:13). However, the primary position is that grama is permitted on Yom Tov when there is a need. Therefore, one may cause the flame to go out by causing water to overflow onto it (Devar Yehoshua 2:84; Or Le-Tziyon 3:20:11; Yabi’a Omer 3:30). Netzer Mata’ai §9 maintains that shutting off the valve of a gas canister outside the house qualifies as putting out the fire indirectly and thus is permitted. Si’aḥ Naḥum 27:3 permits shutting off the main gas valve in the kitchen, on condition that there will be a delay of at least a few seconds before the flame goes out. He argues that cutting off the gas at a distance from the flame is comparable to removing wood that has been put in the fire but has not caught fire yet (which is permitted), and is not comparable to removing wood which has already started to burn on one side (which is forbidden). However, many prohibit extinguishing the fire by turning off the gas, whether inside or outside. These include Tzitz Eliezer 6:8-9; Yabi’a Omer 3:30; SSK 13:12 in the name of R. Frank. The reason is that the fire is being extinguished by removing its fuel, which they see as being comparable to cutting off part of a burning candle, which Rosh and SA 514:3 forbid. Furthermore, usually after the valve is turned off the fire goes out immediately, or is at least weakened immediately. Accordingly, Tosafot would agree the action is forbidden, as it cannot be classified as indirect. It seems to me that if there is at least a ten-second delay before the flame goes out, and the gas is turned off from a point which is at a distance from the flame, it can be considered indirect. It is also proper to use a shinui, thus rendering the action a shvut di-shvut.

According to Rema 514:3, one may place a lit candle in an area where there is currently no wind. Even if the wind sometimes blows there, and even though he hopes that the wind will blow out the candle, it is considered grama. However, MA and BHL prohibit this out of concern that the wind might begin blowing at the very moment he places the candle there, in which case he has directly extinguished the flame.

[8]. This device is even less problematic than ordinary grama, because before the gas is turned on, the length of time for which it will burn has already been set. Be-di’avad, if one forgot to set the timer before lighting the gas, he may do so afterward. Since the flame only goes out after a noticeable delay, it is considered indirect extinguishing, which is permitted on Yom Tov when there is a need. According to SA 514:3, one who wants to make sure that a candle does not burn all the way down may place it in loosely packed sand and then light it. When the flame reaches the sand it will go out. In contrast, one may not place a lit candle in the sand. Rema and most poskim (see MB ad loc. 20) disagree, maintaining that it is permitted to place even a lit candle in sand. In pressing circumstances, they may be relied upon.

06. Grama Devices and Alarms

Some rule leniently about devices and appliances whose functioning is barely distinguishable from regular devices but whose inner workings have subtle differences so that the devices can be considered to work via “grama.” Three different methods are used: 1) removing an impediment (hasarat ha-mone’a); 2) activation by means of a scanner; 3) activation by extending the present state (Peninei Halakha: Shabbat 17:18).

In practice, it would seem that if one’s action causes a device to turn on within a short time, as it normally does, then even if the appliance has been programmed to turn on in a grama-like way, one may not turn it on. The internal workings of the machine do not concern us; if it turns on in a way that looks normal, then that is not considered grama. Therefore, elevators and automatic doors may not be turned on via grama; since the goal is for them to function in the normal way soon after being turned on, it is not considered grama. Similarly, one may not travel using an electrical wheelchair or golf cart on Shabbat, even one that is specially designed for Shabbat use (such as a “kalno’it”), since it nevertheless operates in the way that one would operate a similar device during the week.

In contrast, if one’s action causes a device to turn on with a significant delay, and the device is designed with one of the three methods listed above – turning it on is considered grama. Such a device may be used when urgently needed on Shabbat, and when necessary on Yom Tov. These principles apply to arming a security system as well. If turning a key will cause the system to work via grama, and it will not actually arm itself until about five minutes later, that is considered grama, and may be done in a case of great need.

These laws are the same on Shabbat and Yom Tov. Therefore, one may not enter a room where an electrical mechanism turns the lights or air conditioning on automatically when someone enters. Likewise, if exiting the room will cause the lights or air conditioning to turn off, it is forbidden to leave. Turning the electricity or air conditioning on and off in this way is not considered grama. Rather, it is akin to turning appliances on and off with a remote control, which is the normal way to turn them on and off. It is irrelevant whether the normal way involves pressing a button or entering and exiting the room. (See Peninei Halakha: Shabbat 17:12 regarding a case of pressing need.)

07. Timers on Shabbat and Yom Tov

One may turn on lights before Shabbat and set a timer (“Shabbos clock”) to turn them off and then back on at the desired times. Similarly, one may use a timer to turn on an electric oven or fan, setting it so that the appliance will go on and off at the desired times.

If there is a need on Shabbat to change the start or end times, one may rely on the opinion of those who allow extending the current situation, but not shortening it. In other words, when the light is on, the timer may be adjusted to make the light stay on for longer, but may not be adjusted to make it turn off earlier. When the light is off, one may adjust the timer so that the light will stay off for longer, but not so that it will come back on sooner. In times of need, such as for someone who is sick, adjustments may be made which will make the light go on or off earlier, as doing so is grama, which is permitted on Shabbat only in pressing circumstances (Peninei Halakha: Shabbat 17:6 and n. 7).

Two factors allow for greater leniency on Yom Tov. First, lighting a fire on Shabbat violates a Torah prohibition, whereas on Yom Tov the prohibition is rabbinic (section 1 above). Additionally, according to most poskim, grama on Shabbat is permitted only in pressing circumstances, whereas on Yom Tov it is permitted for any need at all. Therefore, as long as there is some need, one may move the time forward on a timer. If a light is on, the timer may be adjusted so that the light will go off earlier; if the light is off, the timer may be adjusted to make it turn on earlier. Similarly, if there is any need, one may cause an oven to go on earlier by adjusting the timer – i.e., with a timer as long as it will not turn on for at least five minutes following the adjustment. As long as there is an external device with such a time delay, it is considered grama (Tzitz Eliezer 1:20:5; see SSK 13:31).[9]

[9]. Using a timer to turn on a dishwasher: See Peninei Halakha: Shabbat 17:10, where we explain that it is forbidden to turn on a dishwasher using a timer on Shabbat because the dishwasher will not actually go on until its door is closed. This means that the person who closes the door to the dishwasher after the dirty dishes have been loaded causes it to turn on (SSK 12:37). In pressing circumstances it is permitted, following the rules for grama on Shabbat (Responsa Me-rosh Tzurim §30). However, on Yom Tov this is permitted when needed, following the rules of grama on Yom Tov (section 5 above; SSK 12:37). This is all conditional on the dishes being needed for Yom Tov use.

08. Thermostats

If one set the thermostat of a radiator to a moderate temperature before Shabbat, but on Shabbat realizes that it is hotter than he had expected, he may lower the setting of the thermostat once it has switched the radiator off. Thus, he ensures that the radiator will remain off for a longer period of time, and the heating element will work for a shorter period of time. However, one may not lower the thermostat while the radiator is on. Doing so makes the radiator change its state sooner, from being on and heating to being off and not heating.

On Yom Tov as well, it is proper to lower the heat when the radiator has cycled off. True, grama is permitted for any need on Yom Tov, but in this case, there is a reasonable chance that if one lowers the thermostat, the heat will immediately switch off, which means that he has turned it off directly, not via grama.

If, during the course of Shabbat, one wants a radiator to stay on for longer, he must wait until the radiator has cycled on, and the temperature of the radiator has reached at least yad soledet bo (at least 160 degrees Fahrenheit or 71 degrees Celsius). Then he may turn up the thermostat so that the radiator will stay on for longer. However, he may not do so if the temperature is below yad soledet bo, as it would be a violation of Bishul. Once the radiator has cycled off, it is not permissible under any circumstances to turn up the thermostat, because doing so causes it to cycle on, and it may do so immediately, which means he has turned it on directly (see Peninei Halakha: Shabbat 10:3 and 17:7).[10]

In contrast, on Yom Tov, when there is no prohibition on lighting or cooking, one may turn up the thermostat on a radiator even if its current temperature is under yad soledet bo. Nevertheless, this must be done when the radiator has cycled on and is heating. Otherwise, adjustment may take effect immediately, which means he will have turned it on directly.

The laws pertaining to Shabbat and Yom Tov are identical when it comes to air conditioners and refrigerators with manual thermostats. When the compressor has cycled on, one may turn down the temperature, which will keep the refrigerator or air conditioner on longer. When the compressor has cycled off, one may turn up the temperature, which will keep the machine off longer (Minḥat Shlomo §10; SSK 23:24).

Of course, all of this assumes that there is no electronic display recording the temperature. However, if the thermostat is adjusted by pressing buttons to change the temperature, and this is shown in an electronic display (as is the case with many air conditioners), then it is prohibited, both on account of Kotev, and because each press of a button makes direct use of electricity.

[10]. This is the approach of SSK 23:24. At first glance, the case would seem to qualify as a davar she-eino mitkaven (which is permitted), as it is not certain that turning up the thermostat slightly will cause the heater to turn on immediately. However, the following distinction may be drawn. Davar she-eino mitkaven applies when the person undertaking the action intends to do something other than the melakha. In such a case, even though he may be happy with the resulting melakha, as long as it might not happen and he does not intend it to happen, the action is not prohibited. However, in the case of the radiator, he does intend to raise the temperature. Therefore, if the heat turns on immediately, it is not a davar she-eino mitkaven. He is considered to have turned on the radiator directly.

09. Incense and Cigarettes

According to the Gemara, one may not burn incense in order to perfume his home or clothing, because lighting a fire on Yom Tov is permitted only for something that most people enjoy (shaveh le-khol nefesh). Perfuming homes and clothing is done only by overindulged people. However, spices may be placed on coals to improve the flavor of the food being cooked on them. Even if the food would be tasty without the spice, anything that improves the food’s flavor is permissible. Since poor people would spice their food too if they had spices, it is considered shaveh le-khol nefesh. However, most people are not interested in perfuming their homes and clothes, as they consider it excessively self-indulgent (Beitza 22b; SA 511:4; see 3:6 above and n. 4).

Initially, some poskim were inclined to forbid smoking tobacco on Yom Tov because it entails Mav’ir. They maintained that since smoking was not so widespread, it could not be considered shaveh le-khol nefesh and was thus prohibited (MA 514:4; Korban Netanel, Beitza ch. 2, 22:10). Others disagreed, maintaining that smoking was indeed shaveh le-khol nefesh (Darkhei No’am, OḤ §9). In the course of time, smoking became more widespread. There was even a time when doctors thought that it was healthy and aided digestion. Therefore, most poskim were inclined to permit smoking cigarettes on Yom Tov (Pnei Yehoshu’a; R. Yonatan Eibeshutz; Pri Megadim, Mishbetzot Zahav 511:2; Ketav Sofer, OḤ §66; BHL 511:4).

In recent times it has become clear that smoking is extremely unhealthy, and that halakha forbids smoking altogether. Those who are already addicted must do their utmost to break the addiction. In fact, the percentage of smokers is decreasing and now stands at under 25% in Israel and under 20% in the United States. Since according to many poskim, the permissibility of smoking on Yom Tov was based on the reality that most men smoked, nowadays, when most do not smoke, some say that it is forbidden to smoke on Yom Tov, as it can no longer be classified as shaveh le-khol nefesh. Others permit smoking for those who suffer if they do not smoke. Since the motivation of smokers is not self-indulgence but the avoidance of suffering, and since everyone does whatever he can in order to avoid suffering, smoking can be considered shaveh le-khol nefesh. Additionally, it may be that shaveh le-khol nefesh need not require a majority of people, but only a significant percentage. Even though it is clear that smoking is harmful and smokers must try to quit, as long as they have not succeeded in doing so, they are not required to suffer specifically on Yom Tov (Tzitz Eliezer 17:21; Hilkhot Ha-mo’adim ch. 16 n. 1). In practice, le-khatḥila, smokers must try not to smoke on Yom Tov. One who finds this excruciating may rely on those who are lenient.

Since a fire may not be extinguished unless it is for okhel nefesh, smokers must be careful not to put out their cigarettes after they burn down. Rather, they should leave them somewhere safe, where they will burn out on their own. While smoking, people must also be careful not to knock off the ash at the end of the cigarette, because it is possible that this will extinguish ember contained in the ash. Rather, they must allow the ash to fall off by itself.[11]

[11]. Some say that one may not smoke on Yom Tov if there are letters on the cigarette paper, because incinerating the letters is considered Moḥek (erasing). However, in practice this is not a problem, as the paper burns up entirely (and Moḥek is limited to erasing letters in order to write others in their place). Besides, even if we considered the incineration to be Moḥek, it happens in an unusual way (with a shinui) and the smoker clearly has no intention (or ability) to write over the “erasure.” Thus it falls into the category of a psik reisha de-lo niḥa lei in a case of a double rabbinic prohibition, on which many are lenient (Peninei Halakha: Shabbat ch. 9 n. 2). Indeed, this is the ruling of Da’at Torah 514:1; Responsa Maharshag 2:41; and R. Shlomo Zalman Auerbach in SSK ch. 13 n. 34.

10. Bathing

Because of a variety of possible halakhic issues, many do not bathe or shower on Yom Tov. However, in a case of need, one may bathe in hot water as long as the water was heated in one of the following ways: before Yom Tov, on Yom Tov by the sun, or on Yom Tov using a timer. This is one of the differences between Shabbat and Yom Tov: on Shabbat one may bathe in lukewarm, but not hot, water, while on Yom Tov one may bathe in hot water (see Peninei Halakha: Shabbat 14:8).

Some are stringent, maintaining that there is no difference between Shabbat and Yom Tov, and on Yom Tov too one may bathe only in lukewarm water. Others are even more stringent, maintaining that it is rabbinically prohibited to bathe even in lukewarm water on Yom Tov as well as Shabbat. Some Ashkenazim follow this ruling. Nevertheless, in practice the halakha follows the majority of poskim who are lenient and permit taking a hot bath on Yom Tov. When not being able to bathe will cause serious discomfort, such as on Rosh Ha-shana, when Shabbat runs into Yom Tov, and in ḥutz la-aretz where Yom Tov is two days, it is proper to follow the lenient opinion in order to properly enjoy and honor the festival.

If one has a solar boiler (dud shemesh), he may bathe in water that was heated up on Yom Tov. One who does not have a solar boiler may turn on his electric boiler before Yom Tov. So as not to waste electricity, he may connect the boiler to a timer so that it remains activated only for the amount of time necessary.[12]

Unlike on Shabbat, on Yom Tov the hot water tap may be turned on, even if the water is boiling hot, and even if the heating element is working. This is because on Yom Tov there is no prohibition on cooking. However, one may not turn on an electric boiler on Yom Tov because doing so is considered lighting a fire. As we have already seen, it is forbidden to light a new fire on Yom Tov.[13]

[12]. The Sages forbade washing the entire body in hot water on Shabbat, even if the water used was heated before Shabbat, out of a concern that people would end up heating water on Shabbat (Shabbat 40a; SA 326:1). They also forbade washing most of the body in hot water, even one limb at a time. However, less than half of the body may be washed in water heated before Shabbat. The Gemara states that this enactment pertains to Yom Tov as well as Shabbat. The Rishonim disagree as to the reason. According to Tosafot (Beitza 21b s.v. “lo”) and Rosh (Shabbat 3:7), it is because washing the whole body is not shaveh le-khol nefesh, so it is prohibited by Torah law to warm up water for this purpose on Yom Tov. Rif (Beitza ad loc.) and Rambam (MT, Laws of Yom Tov 1:16) simply write that the ordinance pertains to Yom Tov. Ramban suggests that their reason is that even though heating water is permitted on Yom Tov, the Sages were concerned that permitting it in practice would lead people to engage in other prohibited melakhot (Ramban, Shabbat 40a).

If water was heated before Yom Tov, Rif and Rambam allow one to use it at home to wash his entire body. However, they do not allow doing so in a public bathhouse because of the above enactment. This is the opinion of the majority of Rishonim, including Ramban; Ran; Or Zaru’a; Hagahot Maimoniyot quoting Sefer Ha-Teruma; Raavya; Shibolei Ha-leket; Ri’az; Magid Mishneh; SA 511:2. Water that was heated on Yom Tov using a timer or a solar boiler is considered to have been heated before Yom Tov and may be used for bathing on Yom Tov (SSK 14:3; Ḥazon Ovadia, Yom Tov, p. 41).

In contrast, Tosafot, Rosh, Rid, and Itur maintain that even if water was heated before Yom Tov, one may not wash his whole body in it. Even though most Rishonim are lenient, Ashkenazic practice is to be stringent (Rema 511:2; Eliya Rabba; SAH; MB ad loc. 18). This is also the ruling of later poskim: Piskei Teshuvot 511:7 and Shemirat Yom Tov Ke-hilkhato 15:5. In their opinion, those who are stringent and prohibit using lukewarm water on Shabbat are equally stringent on Yom Tov as well (see Harḥavot to Peninei Halakha: Shabbat 14:8:1). However, we have already seen that according to Tosafot and Rosh, the reason for the prohibition to heat water on Yom Tov for bathing is because it is not considered shaveh le-khol nefesh. Following this understanding, it should be permitted nowadays to heat water on Yom Tov in order to wash the whole body, since most people shower every day or two, rendering bathing shaveh le-khol nefesh. The enactment would be limited to washing in a bathhouse, and would not apply to showering at home. This is the opinion of R. Shlomo Zalman Auerbach (SSK ch. 14 n. 21; Shulḥan Shlomo, p. 198 n. 3). R. Mordechai Eliyahu permits a hot shower but not a hot bath (Ma’amar Mordechai, p. 143). I ruled above in accordance with the lenient view, as that is the position of most Rishonim. Even according to Ashkenazic custom, it makes sense to be lenient, since the disagreement is on a rabbinic level and we are generally lenient in such disputes. On the other hand, I did not write that all Sephardim are lenient, because Or Le-Tziyon 3:21:1 permits bathing on Yom Tov only when the water was heated up before Yom Tov, but does not allow the use of water which was heated up on Yom Tov, whether by solar or electric boiler.

[13]. On Shabbat, turning on the hot water tap is forbidden, both when there is boiling hot water in the tank as well as when a heating element is boiling the water, because of the prohibition of Bishul (Peninei Halakha: Shabbat 10:23-24). In contrast, on Yom Tov one may turn on the hot water tap even when the heating element is working and will heat additional water which is not needed. Since it is impossible to use the hot water without having cold water enter the tank, and one needs the hot water, the whole process is deemed a Yom Tov need. Besides, it is possible that the additional water is considered to be heated up indirectly (grama), which is technically permitted (section 5 and n. 6 above). Moreover, there is no prohibition on Yom Tov of heating more water than necessary (as this is a case of marbeh be-shi’urim – we see this in SA 503:2 and SSK ch. 2 n. 22, which disagree with Shevut Yitzḥak, vol. 6, p. 94). In any case, there is no Torah prohibition involved, since guests might show up unexpectedly and make use of the hot water.

11. Specific Laws of Bathing

One may use liquid soap on Shabbat and Yom Tov. However, many are careful to avoid using bar soap or thick liquid soap, for two reasons. First, using bar soap or thick liquid soap resembles Memaḥek, since using a bar of soap smooths its surface and thick liquid soap is spread on the hands or body (MB 326:30). Second, when one uses these kinds of soap, it looks like he is producing something new, since the soap changes from solid to liquid (Ben Ish Ḥai, Year 2, Yitro 15). While according to many poskim this use is not technically prohibited, common practice is to be stringent and avoid using bar soap or thick liquid soap. Those who are lenient have an opinion to rely upon.

If a thick liquid soap spreads out upon being left on a surface, it is considered liquid, and all would agree that one may use it on Shabbat (Peninei Halakha: Shabbat 14:6).

A person may wash his hair with shampoo and conditioner. However, while shampooing, one must be careful not to pull out any hair. If a woman has long hair and always combs out her hair after showering, it is proper for her not to rinse her hair on Shabbat and Yom Tov, lest she violate a Torah prohibition by combing her hair (Peninei Halakha: Shabbat 14:3). If one is desperate to wash her hair and is positive that she will not be combing her hair afterward, she may wash her hair on Yom Tov.

A person washing his hair or beard must be careful not to squeeze out water from the hair. This is a transgression of Dash, since the squeezing removes water and soap that can then be used in the course of the shower. He may, however, towel his hair dry. Since he is not interested in the water that is wrung from the hair and absorbed by the towel, it is not a violation of Seḥita (Peninei Halakha: Shabbat 14:8).