The Engineer Who Saved Shabbos: Kosher Refrigerators and Ovens


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By Rabbi Yair Hoffman for

He graduated from the University of Connecticut’s School of Engineering in 1989 with a degree in Mechanical Engineering and a love for helping people out.  He is the CEO of GE Appliances which employs over 12,000 people, among which are some very capable teams of engineers.  His name is Kevin Nolan and he has invested thousands and thousands of man-hours of his company to meet the Shmiras Shabbos needs of the Torah-observant community.

What this man and his three teams of engineers have done is nothing short of an engineering miracle.

Why did he do it?  Mr. Nolan told the Five Towns Jewish Times, “As a company we follow the zero distance philosophy, which means that we want to be zero distance to all our customers and consumers to learn about their needs, understand their expectations and to be able to develop relevant solutions.”

Mr. Nolan continued, “We saw a unique need in the Jewish community that only we could satisfy better than the competition. We came together as a big team and created a unique product that was specifically designed for this community. This is zero distance in action.”


For the Torah observant Jew, there are two sides to technology.  There is the fact that advances in technology can save us much time, money, and energy.  But sometimes, technology can cause the Torah observant Jew some serious halachic quandaries – particularly in regard to Shabbos observance.  The modern day keys to hotels is just one area where this applies.  As a child, I was once stuck in a restroom until Motzaei Shabbos because of an automatic light.  It was a relief to read later in life that Rav Reuvain Grozovsky zt”l had the same quandary.

GE Appliances CEO has accomplished two remarkable engineering feats.

  • They created an entire line of refrigerators that are fully Shabbos compliant reducing any possible question of chillul Shabbos – according to all Poskim.  Some of this line was introduced two years ago.
  • They created an entire line of ovens that can enhance Oneg Shabbos. This has just been introduced.

The oven has a Shabbos idle mode and requires a start button to be hit after a pre-Shabbos warning begins four hours before Shabbos. The refrigerator has a light that is always on during Shabbos but runs on less wattage. But before we get to a discussion of these two engineering miracles – let’s get some essential history and background.


Safe home refrigerators came into general household use in the late 30’s and 1940’s.  With the original refrigerators, that lasted into the late 80’s and early 90’s, there were some halachic concerns.  Four of Klal Yisroel’s leading gedolim addressed these concerns – The Chazon Ish zt”l, Rav Henkin zt”l, Rav Moshe Feinstein zt”l, and Rav Shlomo Zalman Auerbach zt”l.


When the refrigerator or freezer door is kept open, warmer air comes in. This could cause the compressor, which cools the air, to be turned on. Is doing this on Shabbos a Torah prohibition or a rabbinic prohibition? Is opening the door considered a direct action, or a grama, a secondary result of a primary action, which under certain circumstances would be permitted?

  • The Chazon Ish ruled that it is forbidden to open the refrigerator at all, whether the compressor is on or off. (Cited in HaPardes, Cheshvan 5719/1958)
  • Rav Eliyahu Henkin, zt’l, ruled that one can only open the refrigerator when the compressor is on and it is forbidden to do so when the compressor is off. This was also the view of Rav Elyashiv, zt’l, as cited in Mitbach K’halacha, page 303.
  • Rav Moshe Feinstein, zt’l, ruled that one can technically open the refrigerator even when the compressor is off, but it is preferable to wait and only do it when the compressor is on. (Igros Moshe, OC Vol. II #68)
  • Rav Shlomo Zalman Auerbach, zt’l, ruled that one can open the refrigerator door without a problem, whether the compressor is on or off. (Minchas Shlomo Vol. I #10)

In the United States, some followed Rav Henkin zt”l, others followed Rav Moshe zt”l, but the vast majority eventually followed the view of Rav Shlomo Zalman Auerbach zt’l. His three-fold rationale was based upon a combination of three factors:

  1. Causing the compressor to go on involved, in his view, only a rabbinic violation;
  2. Opening the door allowing surrounding air to enter was a grama on a psik reisha;
  3. The compressor did not always turn on.

On account of avoiding the negation of Oneg Shabbos, taking delight in Shabbos, Rav Shlomo Zalman allowed opening the door – even when the compressor was off.  The issue may be dependent upon whether Oneg Shabbos is a biblical Mitzvah or a Rabbinic one.  The Mishna Brurah in his Shaar HaTziun 242:1 writes that the Ramban holds that it is biblical, while the Sefer HaChinuch (#297) holds that it Rabbinic (as does the Beis Yoseph in Siman 487).


It is important to note that all of the early poskim agreed that it is a biblical prohibition to open the door if it will cause the inside light to go on, so the common practice is to loosen the light bulb, either permanently or before each Shabbos and yom tov, or to keep the switch covered so that it can’t be automatically released when the door is opened.


That was back then, however, when the only question was causing the compressor to turn on. Now, on account of the new technology of computer chips and sensors, there are numerous other issues:

  • Modern refrigerators have door sensors that detect every time the door is opened and report back to the computer.
  • Modern refrigerators have instantly reactive digital thermostats. The modern-day thermostats use a number of sensor technologies such as bimetallic mechanical or electrical sensors, electronic thermistors, semiconductor devices, and electrical thermocouples. These can and often do control the defrosting and cooling apparatuses instantly.
  • Manufacturers have now started using adaptive defrost controls where the heating coil of the defrost mechanism is directly connected to the temperature settings and thermostats. These controls measure compressor runtime and/or number of door openings and then automatically run the defrost cycle. For example, Maytag and Whirlpool models automatically run the defrost after four hours of compressor time.
  • The newer electronic damper controls are now controlled by heat sensors attached to computer chips. The controls of the damper, like the defrost cycle, are no longer mechanical – they occur with immediate repercussions when the refrigerator is opened.

The early thermostats in refrigerators were based upon mercury thermometers with electrodes inserted directly through the glass, so that when a fixed temperature was reached, the contacts would be closed by the mercury and the compressor would turn on. These were accurate to within one degree and were halachically more permitted.

Now, however, they are significantly more problematic.


In Israel, rabbanim and the engineers of Israeli refrigerator manufacturers have created Shabbos-mode overrides to address these problems. By and large, these do address the halachic concerns.  In America, initially, it was not so feasible.


There were, in recent years, two separate efforts to address the new technology issues.  One of the first organizations to do so, was the Star-K.  The Star-K worked with manufacturers to develop models with a “Shabbos mode.” These models addressed the issue of the defrost cycle, but they did not address a number of the other issues. In the early Shabbos Mode refrigerators, the computer was still constantly taking readings and electronic information. The Star-K approved Shabbos mode was relying on a leniency that a computer may be utilized as long as the digital display was not seen.

Other poskim, however, have questioned this leniency, some even stating that the use of a computer is either a biblical prohibition–of writing or of makeh b’patish.

This author reached out to Rabbi Avrohom Mushel from the Star-K. He explained that Rav Heinemann, shlita, spoke to Rav Elyashiv, zt’l, who said that as long as the refrigerator does not take any action that is no more than a grama when it takes in any information, then there is no violation being performed. Rav Heinemann is of the opinion that these are still considered a grama and are therefore not forbidden.

There are a number of debates as to what are the parameters and limitations of the term Grama.  Aside from this, when Rav Elyashiv, zt’l, was consulted by poskim in Eretz Yisrael, however, he indicated that a computer collecting information would be considered a serious problem, as a letter he had signed indicates.  The fact of the matter is that it was not uncommon for Rav Elyashiv to at times be quoted in a contradictory manner.

This author spoke to Rav Hershel Schachter, shlita, who held that recording the information on a computer would, under many circumstances, at least be considered ksiva miderabanan – rabbinically forbidden writing. He also felt that there may be issues of “davar shemiskaven–the person intends for it to happen” since it is beneficial for him–even on a rabbinic violation. Lehavdil bain chaim l’chaim, Rav Yisroel Belsky, zt’l, actually pushed to have timers on refrigerators. He would quote his grandfather, Reb Binyomin Wilhelm, who used to sell timers in his hardware store.  Rabbi Belsky sai that they called it “the Rav Henkin switch.”  He further told one of his talmidim who was concerned about the problem of the new refrigerators, “Until a timer comes out, open it with a shinui. When the timer comes out, purchase it.”

The Star-K models of ovens do have a one-time only opening policy, but unfortunately, this is not so well-known.  It is a Mitzvah, of course, to spread this information.


A few years ago, there was a timer that was marketed by Zman Technologies and is now off the market. It was a bold and noble attempt to address the halachic issues.  Alas, a number of people ended up with spoiled meat and broken refrigerators, including this author.

But, we all knew the risks.

The old timer essentially worked by shutting off the refrigerator for four 6-minute periods every hour. There was a green light which indicated when you could open the refrigerator or freezer and a red light indicated when you could not.  That timer contained a 40-year calendar for Shabbos and yom tov and did not need to be reset for the life of the refrigerator once it was installed.

There were a few flaws.  The product was lab-tested but it was not sufficiently field-tested. In many of the models, food in the freezers became soft by Motzai Shabbos and some of the refrigerators stopped working altogether. Also, use of the timer negated the warranty on many of the refrigerators.  The statement of Chazal (Mechilta 19:5) that, “kol haschalos kashos – all beginnings are difficult” was proven true once again. Another approach was needed.


Michael Gross, CEO of AJ Madison Home and Kitchen Appliance Store in Brooklyn, knew the Chief Technology Officer of GE Appliances and introduced Rabbi Ortner of the OU to him.  Eventually, Zman Technologies and the OU, approached Mr. Nolan who became the Chief Executive Officer of GE Appliances, and the rest was history.  Three teams of GE Appliances top engineers came on board: the oven team, the refrigerator team, and engineers assigned to develop the “Shabbos Keeper” plug-in.

Now, with the GE Appliances engineering teams on-board, all the old problems and all of the new problems have been entirely addressed.

Altogether, Mr. Nolan requisitioned some 75 to 100 engineering team members.  This, in itself, was a miracle.  The Shabbos Keeper was now to be manufactured for Zman Technologies by GE Appliances itself.  [It can be purchased either through Zman Technologies or through the GE Appliances website.]


The engineers achieved the impossible – a full override on every single sensor and computer signal – both on the refrigerators and the ovens.  Essentially, on Shabbos, the refrigerators go back to the way they were in the 1950’s – without the compressor problem.  All halachic issues were addressed.  Hisachdus HaRabbonim also joined in putting their stamp of approval on the product.  And the technology also involved a Shabbos and Yom Tov timer that works until the year 2050.

The ovens have a time cycle – essentially, making them into “dumb hotplates” that are kept not to go above a certain temperature.  They implement a time cycle system rather than a temperature sensitive system.  Different models, of course, have different reactions and, for now, one should get the specific Shabbos Keeper module for each particular unit. This is true for both electric and gas model ovens too. It should be known that the OU and Zman are continuously field testing the products.

For both the refrigerator models and the oven models, the inside light is always on for Shabbos, but dimmed.  Also, the override is complete – so even those who are adherents of the Chazon Ish’s view that the completion of a circuit on Shabbos even with no or minimal current electricity is forbidden will have no halachic issues.

The ovens have both hot starts and cold starts and there are five pre-programmable cycles. When it comes to Yom Tov – there are different time cycles that are programmed in it – up until the year 2050.  There is a one button shut-off that puts the oven into Shabbos idle mode.  There is no way to get around the button to get it to normal weekday mode – so the issues of shema yechateh b’gh’chalim has been addressed.  Although one may not press the button on Shabbos, the concern of Chazal was for stoking the flames to make the fire hotter – not for making it go lower.

The one button shutoff takes it back to Shabbos idle. The element is shut off. One can only cancel out the enhanced Shabbos mode, but not the idle mode.  It only goes back to the weekday  mode at the end of Shabbos.

How do they field test to make sure that there are no kinks in the system?  There is a way to artificially simulate a fast forward feature in order to better test the system.  They also incorporated more field-testing in real homes.


Also, for the caterers out there, GE is coming out with a Pro-Line in the spring – the Pro-Line will have 36 inch ovens as well as 48 inch ovens.  This can accommodate the eighteen by twenty-six inch full size sheet pans as well.  It won’t be available for Pesach yet, but this line will also have the Shabbos modes too.


The question of the day is whether or not one is obligated to purchase a fully Shabbos compliant refrigerator – now that it is available.  This author is the opinion that when one is purchasing a new refrigerator – there is an obligation to purchase one of the Shabbos compliant models made by GE  Does one have to get rid of the old refrigerator?  If one wishes, one can rely on opening it with a shinui and by taping shut the button near the door.  Many of the sensors are connected to that button and we have a situation of a safek – a doubt on what are probably Rabbinic issues.  But if one can afford it, it is certainly praiseworthy to replace the refrigerator. If one wishes to enhance their oneg Shabbos with piping hot food – one could purchase one of the new line of ovens as well.


For those who do wish to purchase any of the GE Appliances Enhanced Shabbos models, a special 5% discount has been arranged by this author with Drimmers – if you provide a special code. The 5% off code of their already discounted prices is “TYKNOLAN.” (Yes, it does stand for Thank You Kevin Nolan).  It is from Drimmers NJ (which delivers to New York too).  Their number is 866-589-8090.  The website is, and their email is [email protected]


The Torah community certainly owes a huge debt of gratitude to both Kevin Nolan and the GE Appliance engineering teams.  A certain tagline comes to mind:  GE – We bring good things to life

The author can be reached at [email protected]


  1. 1- I spoke to Rav Eliyashev re: the Star-K’s “Grama”, not seeing anything happening on the readout, etc. Rav Eliyashev said IT’S ALL POSHIT OSSUR.
    2-The Star-K’s other shabbos friendly gizmos for choilim, etc have the same issurim.
    3- I do have the GE Shabbos refrigerator which was very expensive.
    I told Rabbi Ortner from the OU, that it’s very not right from GE to only have the Shabbos mode on the very high-end refrigerators and stoves, if you have the technology make it available to the poor yeshiva leit-not everyone lives in the 5 towns. Yehuda Shain

  2. “THE NEW HALACHIC CONCERNS” for refrigerators (such as “door sensors that detect every time the door is opened and report back to the computer”, “instantly reactive digital thermostats”) are halachic “red herrings”.

    The “concerns” apply equally to many modern home security systems with motion sensors and video recording activations, that are of no halachic concern on shabbos. The same with smart air conditioning/purification systems etc.

    It is a shame when the general public is presented with misleading partial information that implies they are transgressing or acting improper, when that is not the case.

  3. Yehuda, you probably hadn’t visited in a while. The Shabbos Keeper is currently compatible with most of GE refrigerators in all price levels.
    I recently purchased a GE refrigerator that is compatible with the Shabbos Keeper. I am enjoying the benefits of their Oneg Shabbos. I wish I would have known they are coming out with ovens before I purchased my LG oven.
    We should all appreciate such an accommodation towards our community from such a huge corporation. Thank you Kevin Nolan and the GE team!

  4. “The “concerns” apply equally to many modern home security systems with motion sensors and video recording activations,”

    Good point. To follow the stringencies here means we can’t ever leave our homes on Shabbat. Security videos are just too common.

  5. A problem with quoting pasakim of people such as Rav Elyashiv is that their access to what really is occurring is limited. The metzius must be explained and from there they can make a ruling. The metzius will be explained differently by each person asking the question. As such, the answer can change from person to person. Therefore, rereading the article there is a quote saying Rabbi Heinemann asked Rav Elyashiv. Based on the information Rabbi Heinemann provided of how electronics operated, he was told it is fine. When the poskim of E”Y asked, they likely provided a different background to the electronics. This does not mean any of them are wrong or misquoting. This concept is no different than a machlokes in the mishna and one ruling tamei and one ruling tahar. There are various factors to consider and the weighting of each factor can change the outcome. Additionally, in E”Y they are more against technology than in America. That may have influenced Rav Elyashiv’s psak as well as he may have wanted to minimize the use of more modern appliances but understood that in America things are different.

    Also, if you don’t hold like Rabbi Heinemann, how do you live in the modern world? Smart electric meters note your use of electricity and many don’t realize how daily activities in the house impact its readings. Similarly, there are so many sensors in many devices. If someone has a Google Home, Amazon Alexa etc. device in their house what do they do? I am sure everyone with one will quickly say they unplug it for Shabbos but we know that does not always happen. In such cases are they silent and not move as it is always listening? We can go on and on with current technology.

    Many will claim to have ways around it but as time goes on, it will be more and more difficult to avoid. Think about all the hotel programs that will be back once Covid is over. How many electronic devices are triggered in such a location. This issue will be getting harder to avoid rather than easier.

  6. “pasakim of people such as Rav Elyashiv is that their access to what really is occurring is limited” belittles the intelligence and integrity of the posek.

    Do you think they simply shoot a psak without studying the mechanica and “mitzius”, blindly giving a psak on issurim d’oyraysa?

    There is no shame for them to say that they do not know how the device operates and therefore cannot pasken. If they weren’t totally comfortable in mastering the metzius, they would decline. When they pasken it is mutter, it means that they are certain.