Furnace | Heating, Efficiency, Maintenance

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class="drawer d-flex flex-column open"> <div class="left-rail-section-content"> <div class="topic-left-rail-header text-truncate bg-gray-50 position-relative text-right d-flex align-items-center"> <div class="tlr-title px-20 py-15 text-left"> <em class="material-icons text-gray-400 d-lg-none" data-icon="toc"></em> <a class="font-serif font-weight-bold text-black link-blue" href="https://www.britannica.com/technology/furnace">furnace</a> </div> <button aria-label="Close" class="js-sections-close-button btn-link btn-sm btn d-lg-none position-absolute top-0 p-10 right-0" > <em class="material-icons font-26" data-icon="close"></em> </button> </div> <div class="section-content pl-10 pr-20 pl-sm-50 pr-sm-60 pl-lg-5 pr-lg-10 pt-10 pt-lg-0 bg-gray-50 clear-catfish-ad"> <div class="toc mb-20"> <div class="font-serif font-14 font-weight-bold mx-15 mb-15 mt-20"> Table of Contents </div> <span class="toc-extra-link selected link-gray-900 mt-15"> Introduction </span> <a class="toc-extra-link link-gray-900" href="https://www.britannica.com/technology/furnace/additional-info">References & Edit History</a> <a class="toc-extra-link link-gray-900" href="/facts/furnace">Related Topics</a> </div> <div class="tlr-media-slider pb-10 mb-30"> <a class="section-header link-gray-900 font-serif font-14 font-weight-bold mb-10 mx-10" href="https://www.britannica.com/technology/furnace/images-videos">Images</a> <div class="slider js-slider position-relative d-inline-flex align-items-center mw-100 "> <div class="slider-container js-slider-container overflow-hidden d-flex overflow-hidden text-nowrap ml-15"> <a href="https://cdn.britannica.com/52/4252-004-DBD42104/furnace-Mont-Louis-France.jpg" data-href="/media/1/222589/7480" class="media-overlay-link d-inline-block mr-5"> <img loading="lazy" src="https://cdn.britannica.com/52/4252-004-DBD42104/furnace-Mont-Louis-France.jpg" alt="Solar furnace at Mont Louis, France" height="50" /> </a> </div> <button disabled class="prev-button 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in the Amon Carter Museum of American Art. Catalog entry: The historian Mason Locke Weems, commonly known by his clerical title, Parson Weems, pulls back a curtain to point at 6-year-old George Washington. Bearing an adult head and holding an axe, George gazes blankly up at his father, Augustine, who questions his son while holding a partially cut cherry tree. All of this takes place in front of a 20th-century brick building, which Wood modeled after his own home in Iowa. The scene illustrates the fable of Washington and the cherry tree, which Weems invented in 1806 for the first president's biography. Wood playfully suggests the artifice of the tale here, presenting the story in the manner of a costumed stage play rather than a real event. Amid the action, two Black figures pick cherries in the background, a reference to Washington' slaveholding past and a reminder of of what often gets left out in historical mythmaking." width="200" height="200" /> </a> </div> <div class="card-body ilf-content"> <a class="font-weight-semi-bold d-block mb-5 font-16 ilf-title" href="/story/did-george-washington-really-say-i-cant-tell-a-lie" >Did George Washington Really Say, “I Can’t Tell a Lie”? </a> </div> </div> <div class="imagelink-with-image-on-the-side card card-horizontal tlr-img-with-side-link ml-15 link-gray-900 mb-10" > <div class="position-relative card-media" style="flex: 0;"> <a class="ilf-image position-relative" href="/story/who-was-the-woman-behind-the-statue-of-liberty"> <img loading="lazy" src="https://cdn.britannica.com/61/93061-131-ABCDE075/Statue-of-Liberty-Island-New-York-Bay.jpg?w=200&h=200&c=crop" alt="Statue of Liberty in front of the skyline of Manhattan, New York City, New York." width="200" height="200" /> </a> </div> <div class="card-body ilf-content"> <a class="font-weight-semi-bold d-block mb-5 font-16 ilf-title" href="/story/who-was-the-woman-behind-the-statue-of-liberty" >Who Was the Woman Behind the Statue of Liberty?</a> </div> </div> <div class="imagelink-with-image-on-the-side card card-horizontal tlr-img-with-side-link ml-15 link-gray-900 mb-10" > <div class="position-relative card-media" style="flex: 0;"> <a class="ilf-image position-relative" href="/story/6-important-mughal-emperors"> <img loading="lazy" src="https://cdn.britannica.com/09/172209-131-02E18D09/Shah-Jahan-watercolour-gold-ink-paper-1690.jpg?w=200&h=200&c=crop" alt="Shah Jahan. Taj Mahal. Mughal architecture. Emperor Shah Jahan fifth Mughal Emperor (reigned 1628-1658) India, Himachal Pradesh, Basohli or Jammu and Kashmir, Mankot, circa 1690 Drawings; Opaque watercolor, gold, and ink on paper (see notes)" width="200" height="200" /> </a> </div> <div class="card-body ilf-content"> <a class="font-weight-semi-bold d-block mb-5 font-16 ilf-title" href="/story/6-important-mughal-emperors" >6 Important Mughal Emperors</a> </div> </div> <div class="imagelink-with-image-on-the-side card card-horizontal tlr-img-with-side-link ml-15 link-gray-900 mb-10" > <div class="position-relative card-media" style="flex: 0;"> <a class="ilf-image position-relative" href="/list/8-of-the-largest-empires-in-history"> <img loading="lazy" src="https://cdn.britannica.com/11/191611-131-E5041420/Watercolour-uprising-Decembrist-Karl-Ivanovich-Kollmann-St-1825.jpg?w=200&h=200&c=crop" alt="Title: Senate Square, St. Petersburg, December 14, 1825: repression of the troop mutiny - watercolor by Carl Ivanovitch Kollman, 1825 depicts Decembrist uprising clashing with cavalry, with spectators watching. 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Saint" width="200" height="200" /> </a> </div> <div class="card-body ilf-content"> <a class="font-weight-semi-bold d-block mb-5 font-16 ilf-title" href="/list/8-of-the-largest-empires-in-history" >8 of the Largest Empires in History</a> </div> </div> <div class="imagelink-with-image-on-the-side card card-horizontal tlr-img-with-side-link ml-15 link-gray-900 mb-10" > <div class="position-relative card-media" style="flex: 0;"> <a class="ilf-image position-relative" href="/story/from-sport-to-spectacle-the-history-of-the-super-bowl"> <img loading="lazy" src="https://cdn.britannica.com/94/188294-050-BE037BD2/analysis-game-results-Super-Bowls-teams-wins-MVP-NFL-football-infographic.jpg?w=200&h=200&c=crop" alt="Data analysis of the Super Bowl's "winningest" teams, game locations, MVP winners by position, teams with the most game losses. football, sports, infographic" width="200" height="200" /> </a> </div> <div class="card-body ilf-content"> <a class="font-weight-semi-bold d-block mb-5 font-16 ilf-title" href="/story/from-sport-to-spectacle-the-history-of-the-super-bowl" >From Sport to Spectacle: The History of the Super Bowl</a> </div> </div> <div class="imagelink-with-image-on-the-side card card-horizontal tlr-img-with-side-link ml-15 link-gray-900 mb-10" > <div class="position-relative card-media" style="flex: 0;"> <a class="ilf-image position-relative" href="/story/how-does-wi-fi-work"> <img loading="lazy" src="https://cdn.britannica.com/18/197118-131-00A7D6AF/Computer-Code-Binary-Internet-Password-Data-Technology.jpg?w=200&h=200&c=crop" alt="Binary Computer Code, Binary Code, Internet, Technology, Password, Data" width="200" height="200" /> </a> </div> <div class="card-body ilf-content"> <a class="font-weight-semi-bold d-block mb-5 font-16 ilf-title" href="/story/how-does-wi-fi-work" >How Does Wi-Fi Work?</a> </div> </div> <div class="imagelink-with-image-on-the-side card card-horizontal tlr-img-with-side-link ml-15 link-gray-900 mb-10" > <div class="position-relative card-media" style="flex: 0;"> <a class="ilf-image position-relative" href="/list/6-deadliest-earthquakes"> <img loading="lazy" src="https://cdn.britannica.com/41/166941-131-E27FD3A6/Yingxiu-school-China-Sichuan-earthquake-May-2008.jpg?w=200&h=200&c=crop" alt="earthquake. Heavily damaged school in the town of Yingxiu after a major earthquake struck China's Sichuan Province on May 12, 2008." width="200" height="200" /> </a> </div> <div class="card-body ilf-content"> <a class="font-weight-semi-bold d-block mb-5 font-16 ilf-title" href="/list/6-deadliest-earthquakes" >The 6 Deadliest Earthquakes Since 1950</a> </div> </div> </div> </div> </div> </div> <button class="drawerToggle btn position-sticky border btn-xs btn-white btn-circle rounded-sm d-none d-lg-flex " type="button" aria-label="Toggle Drawer"> <em class="material-icons font-18 text-blue" data-icon="keyboard_arrow_left"></em> </button> </div> </div> <div class="col"> <div class="h-100 ml-0 pr-lg-0 "> <div class="h-100 grid gx-0 gx-lg-20"> <div class="h-100 col-sm"> <div class="h-100 infinite-pagination-container d-flex flex-column position-relative"> <div class="position-absolute top-0 h-100 w-100"> <div class="toc-sticky-header d-none d-lg-none bg-gray-50 px-10 px-sm-30 position-sticky w-100 "> 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Please refer to the appropriate style manual or other sources if you have any questions. </div> <div class="label mt-20 mb-10">Select Citation Style</div> <select class="js-citation-format-select form-select"> <option selected value="mla">MLA</option> <option value="apa">APA</option> <option value="chicago">Chicago Manual of Style</option> </select> <div class="citation font-serif border rounded p-15 mt-20" data-authors="The Editors of Encyclopaedia Britannica" data-authors-initial="The Editors of Encyclopaedia Britannica" data-title="furnace" data-published-date="19 Jan. 2024" data-url="https://www.britannica.com/technology/furnace" > <div class="citation-text"></div> </div> <button class="js-copy-citation-button mt-20 btn btn-xs btn-outline-blue border shadow-sm pr-10" > <em class="material-icons md-icon ml-n10 my-n5 mr-5" data-icon="file_copy"></em> <span class="js-citation-status-text">Copy Citation</span> </button> </div> </div> </div> <div> <button class="js-share-modal-button js-modal btn btn-sm btn-link gtm-topic-tool font-weight-bold btn-link" data-modal="[data-topic-id=222589] .md-share-modal"> <em class="material-icons mr-5 ml-n10 my-n5 md-icon" data-icon="share"></em> Share </button> <div class="md-share-modal size-lg d-none qa-share-modal"> <div class="md-modal-body"> <div class="h2 font-serif d-flex align-items-center pb-15 border-bottom"> <em class="material-icons text-blue mr-10" data-icon="share"></em> Share </div> <div class="label my-20">Share to social media</div> <div class="md-social-toolbar-circle d-flex align-items-start inverted" data-value="share" title="furnace" data-url="https://www.britannica.com/technology/furnace" > <a class="social-icon facebook justify-content-center d-flex align-items-center align-self-center" data-provider="facebook" href="https://www.facebook.com/BRITANNICA/" target="_blank" rel="noopener"><span>Facebook</span></a> <a class="social-icon x justify-content-center d-flex align-items-center align-self-center" data-provider="x" href="https://x.com/britannica" target="_blank" rel="noopener"><span>X</span></a> </div> <div class="label pt-20 mt-20 mb-5 border-top">URL</div> <a class="font-serif text-truncate d-inline-block" href="https://www.britannica.com/technology/furnace">https://www.britannica.com/technology/furnace</a> </div> </div> </div> <div> <button class="js-feedback-modal-button js-modal btn btn-sm btn-link gtm-topic-tool font-weight-bold btn-link" data-modal=".md-feedback-modal"> <em class="material-icons mr-5 ml-n10 my-n5 md-icon" data-icon="message"></em> Feedback </button> </div> <div> <button class="qa-external-website-modal-button js-modal btn btn-sm btn-link gtm-topic-tool font-weight-bold btn-link" data-modal="[data-topic-id=222589] .md-websites-modal"> <em class="material-icons md-icon ml-n10 mr-5" data-icon="link"></em> External Websites </button> </div> </div> <div class="md-feedback-modal size-lg d-none"> <div class="md-modal-body"> <div class="h2 font-serif pb-15 border-bottom"> Feedback </div> <form method="post" action="/submission/feedback/222589"> <div class="my-20"> Corrections? 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Let us know if you have suggestions to improve this article (requires login). </div> <div class="type-menu"> <label for="feedback-type" class="label mb-10">Feedback Type</label> <select id="feedback-type" class="form-select mb-30" name="feedbackTypeId" required> <option value="" selected="selected">Select a type (Required)</option> <option value="1">Factual Correction</option> <option value="2">Spelling/Grammar Correction</option> <option value="3">Link Correction</option> <option value="4">Additional Information</option> <option value="5">Other</option> </select> </div> <label for="feedback" class="label mb-10">Your Feedback</label> <textarea id="feedback" class="form-control mb-30" name="feedback" maxlength="3000" rows="7" required></textarea> <button class="btn btn-blue" type="submit">Submit Feedback</button> </form> <div class="success-messaging d-none mt-30"> <div class="title">Thank you for your feedback</div> <p>Our editors will review what you’ve submitted and determine whether to revise the article.</p> </div> </div> </div> <div class="md-websites-modal size-lg d-none"> <div class="md-modal-body"> <div class="h2 font-serif pb-15 border-bottom font-weight-bold"> External Websites </div> <div class="pb-20"> <ul class="list-unstyled mt-20 lh-lg"> <li><a class="external" href="http://www.bbc.co.uk/history/british/victorians/launch_ani_blast_furnace.shtml" target="_blank" rel="noopener ">British Broadcasting Corporation - The Blast Furnace</a></li> </ul> </div> <div class="md-websites-ebk-title">Britannica Websites</div> <div class="md-websites-ebk-subtitle">Articles from Britannica Encyclopedias for elementary and high school students.</div> <ul class="list-unstyled bps-topic-web-sites lh-lg"> <li><a class="external" href="https://kids.britannica.com/students/article/furnace-and-boiler/274463" target="_blank" rel="noopener">furnace and boiler - Student Encyclopedia (Ages 11 and up)</a></li> </ul> </div> </div> </div> </div> <div class="toc-header-marker"></div> <button class="ai-ask-button btn border-2 js-header-ai-ask-button d-none btn-sm btn-outline-red-400 border-red-400 mr-0 mr-lg-10 ml-5 ml-sm-10 ml-lg-0 p-10"> Ask the Chatbot a Question </button> <div class="md-byline module-spacing "> <div class="font-serif font-12"> <span class="written-by text-gray-700"> Written and fact-checked by </span> <div class="editor-popover popover p-0"> <a class="d-block p-20 qa-editor-popup gtm-byline font-12 byline-contributor" href="/editor/The-Editors-of-Encyclopaedia-Britannica/4419" > <div class="editor-title font-16 font-weight-bold">The Editors of Encyclopaedia Britannica</div> <div class="editor-description font-12 font-serif mt-5 text-black">Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree. They write new content and verify and edit content received from contributors.</div> </a> <div data-popper-arrow></div> </div> <span class="btn btn-link editor-link p-0 qa-byline-link gtm-byline font-12 byline-contributor text-decoration-underline"> The Editors of Encyclopaedia Britannica</span></div> <div class="last-updated font-12 font-serif"> <a class="byline-edit-history" href="https://www.britannica.com/technology/furnace/additional-info#history" rel="nofollow">Article History</a> </div></div> </div> <button class="d-flex d-lg-none btn btn-outline-blue border rounded-sm shadow-sm mobile-toc-button gtm-mobile-toc-inline-button d-none d-sm-block js-sections-inline-button module-spacing btn d-lg-none"> <em class="material-icons mr-5 ml-n10 my-n5 md-icon" data-icon="toc"></em> Table of Contents </button> <div class="d-flex d-sm-none flex-row"> <button class="d-flex d-lg-none btn btn-outline-blue border rounded-sm shadow-sm mobile-toc-button gtm-mobile-toc-inline-button js-sections-inline-button module-spacing"> <em class="material-icons mr-5 ml-n10 my-n5 md-icon" data-icon="toc"></em> Table of Contents </button> <button class="ai-ask-button btn border-2 ai-ask-button btn border-2 module-spacing btn-sm js-inline-ai-ask-button btn-outline-red-400 border-red-400 p-10 ml-5"> Ask the Chatbot a Question </button> </div> <div class="js-qf-module qf-module px-40 px-sm-20 py-15 mx-auto module-spacing font-14 bg-gray-50 rounded"> <div class="facts-list mt-10"> <div class=""> <div class="js-fact mb-10 line-clamp clamp-3"> <dl> <dt>Related Topics: </dt> <dd><a href="/technology/refractory" topicid="495715">refractory</a></dd> <dd><a href="/technology/blast-furnace" topicid="69019">blast furnace</a></dd> <dd><a href="/technology/electric-furnace" topicid="182618">electric furnace</a></dd> <dd><a href="/technology/cupola-furnace" topicid="146714">cupola furnace</a></dd> <dd><a href="/technology/reverberatory-furnace" topicid="500397">reverberatory furnace</a></dd> </dl> <button class="js-more-btn d-none btn btn-unstyled font-12 bg-gray-50" aria-label="Toggle more/less fact data"> <em class="js-content link-blue">(Show more)</em> </button> </div> <div class="text-center"> <a class="btn btn-sm btn-link p-0" href="/facts/furnace"> See all related content </a> </div> </div> </div> </div><span class="marker before-article"></span><section data-level="1" id="ref1"><span class="marker PREMOD1 mod-inline"></span><p class="topic-paragraph"><strong><span id="ref154705"></span>furnace</strong>, structure in which useful heat is produced by <a href="https://www.britannica.com/science/combustion" class="md-crosslink autoxref " data-show-preview="true">combustion</a> or other means. Historically, the furnace grew out of the <a href="https://www.britannica.com/technology/fireplace" class="md-crosslink autoxref " data-show-preview="true">fireplace</a> and <a href="https://www.britannica.com/technology/stove" class="md-crosslink autoxref " data-show-preview="true">stove</a>, following the availability of <a href="https://www.britannica.com/science/coal-fossil-fuel" class="md-crosslink autoxref " data-show-preview="true">coal</a> for heating. A coal furnace is made up of several elements: a chamber containing a grate on which combustion takes place and through which ashes drop for disposal; a chimney to carry away smoke and provide a <a class="md-dictionary-link md-dictionary-tt-off eb" data-term="draft" href="https://www.britannica.com/dictionary/draft" data-type="EB">draft</a> of air; another source of air supply to help burn volatile gases and hydrocarbons; and a <a href="https://www.britannica.com/science/metal-chemistry" class="md-crosslink autoxref " data-show-preview="true">metal</a> surface over which the hot gases pass and which transfers heat to circulating <a href="https://www.britannica.com/science/water" class="md-crosslink autoxref " data-show-preview="true">water</a> or air. Coal furnaces are still widely used in <a href="https://www.britannica.com/money/industry" class="md-crosslink autoxref " data-show-preview="true">industry</a>, where they are usually equipped with mechanical stokers.</p><div class="one-good-fact-module"> </div><span class="marker MOD1 mod-inline"></span><span class="marker PREMOD2 mod-inline"></span><p class="topic-paragraph">Chemical <span id="ref154706"></span><a href="https://www.britannica.com/science/energy" class="md-crosslink " data-show-preview="true">energy</a> is transformed into heat by burning fuels such as coal, <a href="https://www.britannica.com/science/wood-plant-tissue" class="md-crosslink autoxref " data-show-preview="true">wood</a>, oil, and hydrocarbon gases. Electrical energy is transformed into heat in an electric furnace or an electric burner (<em>see</em> <a href="https://www.britannica.com/technology/electric-furnace" class="md-crosslink " data-show-preview="true">electric furnace</a>). Solar radiation energy is used in the solar furnace (<em>see</em> <span class="link-blue media-overlay-link asmref" data-href="/media/1/222589/7480">photograph</span>), a device for concentrating large amounts of <a href="https://www.britannica.com/science/solar-energy" class="md-crosslink autoxref " data-show-preview="true">solar energy</a> into a small area. Nuclear energy is transformed into heat energy in atomic reactors, so that these function as furnaces in <a href="https://www.britannica.com/technology/nuclear-power" class="md-crosslink autoxref " data-show-preview="true">nuclear power</a> stations. Furnaces may apply their heat to other devices, as boilers, ovens, and kilns, or they may apply it directly to material in the course of being processed, as in steel production.</p><span class="marker MOD2 mod-inline"></span></section> <span class="marker end-of-content"></span><span class="marker after-article"></span></div> <div id="chatbot-root"></div> </div> </div> </div> <div class="ai-dialog-placeholder"></div> </div> </div> <aside class="col-md-da-320"></aside> </div> </div> </div> </div> </article> </div> </div> </div> </div> </main> <div id="md-footer"></div> <noscript><iframe src="//www.googletagmanager.com/ns.html?id=GTM-5W6NC8" height="0" width="0" style="display:none;visibility:hidden"></iframe></noscript> <script type="text/javascript" id="_informizely_script_tag"> var IzWidget = IzWidget || {}; (function (d) { var scriptElement = d.createElement('script'); scriptElement.type = 'text/javascript'; scriptElement.async = true; scriptElement.src = "https://insitez.blob.core.windows.net/site/f780f33e-a610-4ac2-af81-3eb184037547.js"; var node = d.getElementById('_informizely_script_tag'); node.parentNode.insertBefore(scriptElement, node); } )(document); </script>  <script> window.ap3c = window.ap3c || {}; var ap3c = window.ap3c; ap3c.cmd = ap3c.cmd || []; ap3c.cmd.push(function() { ap3c.init('ZO4siT4cLwnykPnzZWJtd3Byb2Q', 'https://engage.email.britannica.com/'); ap3c.track({v: 0}); }); ap3c.activity = function(act) { ap3c.act = (ap3c.act || []); ap3c.act.push(act); }; var s, t; s = document.createElement('script'); s.type = 'text/javascript'; s.src = "https://engage.email.britannica.com/app.js"; t = document.getElementsByTagName('script')[0]; t.parentNode.insertBefore(s, t); </script> <script class="marketing-page-info" type="application/json"> {"pageType":"Topic","templateName":"DESKTOP","pageNumber":1,"pagesTotal":1,"pageId":222589,"pageLength":224,"initialLoad":true,"lastPageOfScroll":false} </script> <script class="marketing-content-info" type="application/json"> [] </script> <script src="https://cdn.britannica.com/mendel-resources/3-133/js/libs/jquery-3.5.0.min.js?v=3.133.9"></script> <script type="text/javascript" data-type="Init Mendel Code Splitting"> (function() { $.ajax({ dataType: 'script', cache: true, url: 'https://cdn.britannica.com/mendel-resources/3-133/dist/topic-page.js?v=3.133.9' }); })(); </script> <script class="analytics-metadata" type="application/json"> {"leg":"A","adLeg":"A","userType":"ANONYMOUS","pageType":"Topic","pageSubtype":null,"articleTemplateType":"SMALL","gisted":false,"pageNumber":1,"hasSummarizeButton":false,"hasAskButton":true} </script> <script type="text/javascript"> EBStat={accountId:-1,hostnameOverride:'webstats.eb.com',domain:'www.britannica.com', json:''}; </script> <script type="text/javascript"> ( function() { $.ajax( { dataType: 'script', cache: true, url: '//www.britannica.com/webstats/mendelstats.js?v=1' } ) .done( function() { try {writeStat(null,EBStat);} catch(err){} } ); })(); </script> <div id="bc-fixed-dialogue"></div> </body> </html>

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