{"id":508,"date":"2026-09-23T14:19:04","date_gmt":"2026-09-23T06:19:04","guid":{"rendered":"http:\/\/www.thietkewebbmt.com\/blog\/?p=508"},"modified":"2026-09-23T14:19:04","modified_gmt":"2026-09-23T06:19:04","slug":"is-a-bimetal-thermometer-waterproof-4db5-824d91","status":"publish","type":"post","link":"http:\/\/www.thietkewebbmt.com\/blog\/2026\/09\/23\/is-a-bimetal-thermometer-waterproof-4db5-824d91\/","title":{"rendered":"Is a Bimetal Thermometer waterproof?"},"content":{"rendered":"

Hey everyone, it\u2019s Jake here from the bimetal thermometer supply side. I get so many questions from customers, new and returning alike, and one that\u2019s been popping up nonstop lately is: \u201cIs a bimetal thermometer waterproof?\u201d Let me just cut to the chase first\u2014this is such a common concern, especially for people buying these for outdoor use, food processing, HVAC that deals with moisture, even marine applications. And honestly, I see why it\u2019s confusing, because \u201cwaterproof\u201d means different things to different brands, right? I\u2019ve had to explain this to so many folks over the years, and I thought I\u2019d break it down in plain talk, no stuffy engineering jargon that makes your eyes glaze over. Bimetal Thermometer<\/a><\/p>\n

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First, let\u2019s start with what a bimetal thermometer actually is, just to set the stage (quick, I promise). Unlike a digital thermometer that uses a sensor and a display, bimetal ones work on two different metal strips bonded together\u2014like, say, steel and copper, or steel and brass\u2014each with a different rate of expansion when heated or cooled. When the temp changes, one strip grows more than the other, making the whole coil (that\u2019s the curved part inside the case) twist, which moves the needle on the face. Super simple, no batteries needed, which is a big plus for a lot of users. Now, all that mechanical movement means there are tiny gaps, seams, and parts inside the case\u2014so when water gets in, what happens? It\u2019s not just the temp reading that gets messed up; it can corrode the metal strips or the coil over time too. That\u2019s the root of the waterproof question, right?<\/p>\n

Here\u2019s the thing: not all bimetal thermometers are created equal when it comes to water resistance. I see a lot of suppliers slap \u201cwaterproof\u201d on their cheap, entry-level models, and that\u2019s just marketing fluff. For our part, we categorize our thermometers based on IP ratings\u2014you\u2019ve probably seen that term, right? IP stands for Ingress Protection, and it\u2019s an international standard that tells you how well something is sealed against solids (like dust) and liquids (water). The first number is solids, the second is liquids. So if a model has an IP65 rating, that means it\u2019s dust-tight (6) and protected against low-pressure water jets from any direction (5). If it\u2019s IP67, that means it can even handle being submerged in up to 1 meter of water for 30 minutes.<\/p>\n

Let me give you real-world examples, because that\u2019s what matters. If you\u2019re buying a bimetal thermometer for something like a home water heater, or a greenhouse that gets splashed with rain, or a food truck that wipes down equipment constantly, an IP65 model will do the job. It\u2019s sealed well enough that splashes, hose-downs, light rain, even being left in a damp outdoor shed overnight won\u2019t hurt it. But if you need it for submerging\u2014like a well sensor, a marine engine that\u2019s partially immersed, or a process in a factory where it\u2019s fully submerged in water during operation\u2014you want at least IP67, maybe even IP68 if it\u2019s going deeper than 1 meter long-term. Our IP68 models are tested to go down to 5 meters, so they\u2019re totally fine for extended submersion.<\/p>\n

Wait, but what about the old myth that all bimetal thermometers are naturally waterproof? No way. The entry-level, no-name models we see sometimes\u2014those cheap ones you pick up at a big box store for $10\u2014they usually have a thin plastic case and a tiny O-ring that\u2019s basically just a rubber band. Leave that out in a rainstorm, and water will seep in within an hour. The coil will rust, the needle will get stuck, and the temp reading will be all over the place. We test every single model we sell, though\u2014before it even gets to our warehouse, we do what\u2019s called a water ingress test: we spray the unit with water from every angle for a set time, or submerge it, then check if the inside is dry and the reading is accurate. If it fails, we send it back to the factory no questions asked.<\/p>\n

I also get questions about cleaning. Let\u2019s say you have a bimetal thermometer for commercial kitchen use\u2014you need to wash it down with soap and water, right? An IP65 model is totally safe for that. You don\u2019t need to submerge it, just wipe it off, maybe rinse it a little. But don\u2019t blast it with a pressure washer, that\u2019s way higher pressure than what IP65 is rated for. I\u2019ve seen customers do that and blow the seal right out of the case, which then lets water in. For anything over-the-counter, light cleaning is fine, but pressure washing is a no-go unless it\u2019s a heavy-duty IP68 industrial model made specifically for that.<\/p>\n

Another big use case: HVAC technicians. A lot of them use bimetal thermometers for duct work and pipe measurements. Those spaces get super humid, sometimes there\u2019s condensation on the pipes. We always recommend our IP54 models for that\u2014IP54 is dust-protected (no heavy dust, just enough to keep light dust out) and protected against splashing water from any direction. That\u2019s perfect for HVAC, because you don\u2019t have to submerge it, just handle it around damp pipes. I had a tech tell me last month that he\u2019d been using our IP54 model for 2 years, wiping it off every week, and it still reads within 0.5 degrees of the actual temp\u2014way better than the cheap one he had before that died after 6 months.<\/p>\n

Wait, what about cold environments? A lot of people think waterproofing stops working in cold weather, because rubber seals get brittle. That\u2019s a good point. We use special, cold-resistant O-rings for all our models rated for temps below 0\u00b0C (32\u00b0F). I\u2019ve had customers use our IP67 thermometer for ice fishing, leaving it out in -20\u00b0C (-4\u00b0F) all day, and it works fine\u2014no water seepage, no seal cracking. The key here is to make sure the model is rated for both water resistance and the temp range you\u2019re using it in, because if the seal fails due to cold, the waterproofing goes out the window.<\/p>\n

I should also clear up a common mix-up: water-resistant vs. waterproof. A lot of suppliers use these terms interchangeably, but they\u2019re not the same. Water-resistant means it can handle some moisture, but not submersion or heavy exposure. Waterproof means it\u2019s sealed enough to handle full submersion or sustained water exposure. That\u2019s why we always make sure our product descriptions are clear\u2014no vague \u201cwaterproof\u201d claims. If a model can\u2019t be submerged, we say \u201cwater-resistant, suitable for splashes and rain.\u201d If it can go under water, we specify the IP rating and the maximum depth\/time.<\/p>\n

Let me give you a bad example, just to make it real. A few years back, a customer bought a bimetal thermometer from a random online supplier, said it was waterproof, and used it to check the temp of his fish tank. Within a week, the inside of the case was fogged up, the needle was stuck, and it read 5 degrees lower than actual. He sent it back, and we took it apart\u2014turned out the O-ring was thin, not compressed right when assembled, so even small amounts of water got in. That\u2019s why we source all our parts from reputable manufacturers, not the cheapest knockoff. Our O-rings are made of Buna-N or silicone, both super durable against water, and we test each unit twice before shipping.<\/p>\n

Another thing: what about the stem? The metal part that goes into the liquid or the surface you\u2019re measuring. That\u2019s usually stainless steel, right? Which is corrosion-resistant, but not immune to salt water. Wait, hold on\u2014salt water is way harsher than fresh water. If you\u2019re using a bimetal thermometer for marine applications, salt water can corrode the stem over time, even if the case is waterproof. Our marine-grade models have extra-thick 316 stainless steel stems, which resists salt corrosion way better than 304 stainless. That\u2019s a big difference I tell people\u2014don\u2019t just rely on the IP rating for water; if it\u2019s salt water, make sure the metal parts are compatible too. I once had a fishing boat captain use a regular 304 stem model in the ocean, and after 6 months, the stem had a tiny pinhole where salt got through, even though the case was sealed. Switched to our 316 model, and he\u2019s had it for 3 years no problem.<\/p>\n

Now, let\u2019s get back to the original question: is a bimetal thermometer waterproof? The short answer is: only if it\u2019s built to be. If it\u2019s an entry-level, no-name model, probably not. If it\u2019s a model with a clear IP rating, matched to your use case, yes\u2014up to the limits of that rating. And here\u2019s a pro tip for buying: don\u2019t just buy whatever\u2019s cheapest, or whatever says \u201cwaterproof\u201d in big letters. Think about how you\u2019re going to use it. Are you just dealing with occasional splashes? IP54 or IP65. Are you going to submerge it briefly? IP67. Are you using it in salt water or full submersion? IP68 with 316 stainless steel.<\/p>\n

I get it, if you\u2019re not super technical, IP ratings can seem confusing at first, which is why our team is always here to help. We don\u2019t just sell thermometers\u2014we help people pick the right one for their job, so they don\u2019t waste money on something that\u2019ll break after a month. Last week, a small food processing plant contacted us, needing thermometers for their vats of hot sauce that get washed down every night. We recommended our IP65 models, which are perfect for splashes and hose-downs, and they\u2019ve been ordering 50 units a month since. That\u2019s the stuff we love\u2014helping customers get exactly what they need, no guesswork.<\/p>\n

At the end of the day, bimetal thermometers are great for all kinds of applications, but their water resistance depends entirely on how they\u2019re built. A good, quality model with the right IP rating and compatible metal parts will handle way more water exposure than a cheap one with a fake \u201cwaterproof\u201d claim. If you\u2019re in the market for a bimetal thermometer and you\u2019re worried about water, don\u2019t overthink it\u2014just tell us what you\u2019re using it for, and we\u2019ll point you to the right model. No hard sell, no jargon, just straight answers.<\/p>\n

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If you\u2019re looking to source bimetal thermometers for your business, or you have questions about which model is right for your specific use case, feel free to reach out to our team for a procurement consultation. We\u2019re here to help you find a solution that works for your needs and your budget.<\/p>\n

Temperature Sensor Accessories<\/a> References:<\/p>\n

    \n
  1. International Electrotechnical Commission. (2013). IEC 60529: Degrees of protection provided by enclosures (IP Code). Geneva, Switzerland: Author.<\/li>\n
  2. American Society of Mechanical Engineers. (2020). ASME PTC 19.3: Thermometers and temperature elements. New York, NY: Author.<\/li>\n
  3. Underwriters Laboratories. (2021). UL 873: Standard for safety for temperature indicating instruments. Northbrook, IL: Author.<\/li>\n
  4. NATIONAL SANITATION FOUNDATION. (2022). NSF\/ANSI 2: Food equipment materials. Ann Arbor, MI: Author.<\/li>\n<\/ol>\n
    \n

    Chongqing Haichen Instrument Co., Ltd.<\/a>
    Chongqing Haichen Instrument Co., Ltd. is one of the most professional bimetal thermometer manufacturers and suppliers in China for over 20 years, featured by good service and competitive price. Please rest assured to buy high quality bimetal thermometer for sale here from our factory. For customized service, contact us now.
    Address: No.11 Gusheng Road, Caojie Street, Hechuan District, Chongqing City, P.R. China
    E-mail: sales@hcsensor.com
    WebSite:     https:\/\/www.hcsensor.com\/<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

    Hey everyone, it\u2019s Jake here from the bimetal thermometer supply side. I get so many questions … Is a Bimetal Thermometer waterproof?<\/span>Read more<\/a><\/p>\n","protected":false},"author":9,"featured_media":508,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[471],"class_list":["post-508","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-industry","tag-bimetal-thermometer-44c4-8287ec"],"_links":{"self":[{"href":"http:\/\/www.thietkewebbmt.com\/blog\/wp-json\/wp\/v2\/posts\/508","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.thietkewebbmt.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.thietkewebbmt.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.thietkewebbmt.com\/blog\/wp-json\/wp\/v2\/users\/9"}],"replies":[{"embeddable":true,"href":"http:\/\/www.thietkewebbmt.com\/blog\/wp-json\/wp\/v2\/comments?post=508"}],"version-history":[{"count":0,"href":"http:\/\/www.thietkewebbmt.com\/blog\/wp-json\/wp\/v2\/posts\/508\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/www.thietkewebbmt.com\/blog\/wp-json\/wp\/v2\/posts\/508"}],"wp:attachment":[{"href":"http:\/\/www.thietkewebbmt.com\/blog\/wp-json\/wp\/v2\/media?parent=508"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.thietkewebbmt.com\/blog\/wp-json\/wp\/v2\/categories?post=508"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.thietkewebbmt.com\/blog\/wp-json\/wp\/v2\/tags?post=508"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}