{"id":11542,"date":"2020-01-26T03:42:12","date_gmt":"2020-01-26T03:42:12","guid":{"rendered":"https:\/\/essential.construction\/cnstrctr\/glossary\/fan-coil-unit\/"},"modified":"2026-11-03T10:08:34","modified_gmt":"2026-11-03T17:08:34","slug":"fan-coil-unit","status":"publish","type":"glossary","link":"https:\/\/essential.construction\/academy\/glossary\/fan-coil-unit\/","title":{"rendered":"Fan Coil Unit [FCU]"},"content":{"rendered":"<p>A fan coil unit (FCU) is a simple HVAC terminal unit made up of a fan and one or more heating and\/or cooling coils, with a filter and controls, in one cabinet. The fan draws room air across the coil, which is fed with chilled water, hot water or refrigerant from a central plant, and blows the conditioned air back into the space. FCUs serve a single room or zone and are common in hotels, apartments, offices and schools.<\/p>\n<h2>Main parts<\/h2>\n<ul>\n<li><strong>Fan and motor<\/strong> &#8211; multi-speed or variable-speed (often EC motors).<\/li>\n<li><strong>Coil(s)<\/strong> &#8211; cooling, heating or both; some units use an electric heating element instead of a hot water coil.<\/li>\n<li><strong>Control valve(s)<\/strong> &#8211; modulate or open\/close water flow to the coil.<\/li>\n<li><strong>Filter<\/strong> &#8211; cleans the recirculated air.<\/li>\n<li><strong>Drain pan and condensate drain<\/strong> &#8211; collect water from the cooling coil.<\/li>\n<li><strong>Controls<\/strong> &#8211; a room thermostat or controller, often tied into the building automation system.<\/li>\n<\/ul>\n<h2>2-pipe vs 4-pipe fan coils<\/h2>\n<table>\n<thead>\n<tr>\n<th><\/th>\n<th>2-pipe<\/th>\n<th>4-pipe<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Piping<\/td>\n<td>One supply and one return, carrying either chilled or hot water<\/td>\n<td>Separate chilled and hot water supply and return<\/td>\n<\/tr>\n<tr>\n<td>Heating and cooling<\/td>\n<td>One mode at a time for the whole system (seasonal changeover)<\/td>\n<td>Any unit can heat or cool at any time<\/td>\n<\/tr>\n<tr>\n<td>Cost<\/td>\n<td>Lower<\/td>\n<td>Higher, more piping and valves<\/td>\n<\/tr>\n<tr>\n<td>Comfort<\/td>\n<td>Can struggle in shoulder seasons<\/td>\n<td>Best zone control<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h2>Common configurations<\/h2>\n<ul>\n<li>Horizontal concealed, above the ceiling and ducted to diffusers<\/li>\n<li>Vertical floor or wall-mounted cabinet (console) units<\/li>\n<li>Ceiling cassette units<\/li>\n<li>Vertical stacked units with integral risers, common in high-rise hotels and residential<\/li>\n<\/ul>\n<h2>Fan coil unit vs air handling unit<\/h2>\n<p>An <a href=\"https:\/\/essential.construction\/academy\/glossary\/air-handling-unit\/\">air handling unit<\/a> is larger, usually central, and conditions outdoor air as well as return air for many zones through ductwork. A fan coil unit mainly recirculates air in one room or zone. In fan coil buildings, ventilation air usually comes from a separate dedicated outdoor air system or energy recovery ventilator, ducted into the space or to the FCU return.<\/p>\n<h2>Installation and maintenance tips<\/h2>\n<ul>\n<li>Provide an <a href=\"https:\/\/essential.construction\/academy\/glossary\/access-panel\/\">access panel<\/a> big enough to change filters and service valves, motor and drain pan.<\/li>\n<li>Slope the condensate drain, trap it where the manufacturer requires, and provide a secondary drain pan or overflow switch where needed.<\/li>\n<li>Flush the piping before connecting the coils, and insulate chilled water piping and valves to prevent condensation.<\/li>\n<li>Check fan noise at the speeds the units will actually run, and balance water flow during commissioning.<\/li>\n<\/ul>\n<h2>Related terms<\/h2>\n<ul>\n<li><a href=\"https:\/\/essential.construction\/academy\/glossary\/air-handling-unit\/\">Air Handling Unit (AHU)<\/a><\/li>\n<li><a href=\"https:\/\/essential.construction\/academy\/glossary\/heat-pump\/\">Heat Pump<\/a><\/li>\n<li><a href=\"https:\/\/essential.construction\/academy\/glossary\/variable-frequency-drive\/\">Variable Frequency Drive (VFD)<\/a><\/li>\n<li><a href=\"https:\/\/essential.construction\/academy\/glossary\/ductwork\/\">Ductwork<\/a><\/li>\n<\/ul>\n<h2>Related templates and guides<\/h2>\n<ul>\n<li><a href=\"https:\/\/essential.construction\/academy\/tutorials\/introduction-to-mechanical-and-electrical-systems\/\">Introduction to Mechanical and Electrical Systems<\/a><\/li>\n<li><a href=\"https:\/\/essential.construction\/files\/construction\/quality\/hvac-design-quality-checklist\/\">HVAC Design Quality Checklist<\/a><\/li>\n<li><a href=\"https:\/\/essential.construction\/files\/design\/autocad\/general-details-hvac-systems\/\">General Details &#8211; HVAC Systems<\/a><\/li>\n<\/ul>\n<h2>Frequently asked questions<\/h2>\n<h3>What does a fan coil unit do?<\/h3>\n<p>It heats or cools a single room or zone. The fan pulls room air through a filter and across a coil supplied with chilled or hot water (or refrigerant), then delivers the conditioned air back to the space, controlled by a local thermostat.<\/p>\n<h3>Is a fan coil unit the same as an AC unit?<\/h3>\n<p>Not exactly. A commercial fan coil unit has no compressor of its own; it relies on chilled and hot water from a central plant. In homes, the indoor section of a split air conditioner or heat pump is sometimes also called a fan coil, because it is a fan blowing across a coil.<\/p>\n<h3>What is the difference between an AHU and an FCU?<\/h3>\n<p>An AHU is a larger central unit that usually brings in and conditions outdoor air and serves several zones through ductwork. An FCU is a small local unit that mostly recirculates air in one room or zone. Many buildings use both: an AHU or DOAS for ventilation and FCUs for zone temperature.<\/p>\n<h3>Do fan coil units provide fresh air?<\/h3>\n<p>Usually not on their own. Most FCUs recirculate room air. Fresh air is supplied by a separate ventilation system, either ducted directly to the space or connected to the FCU&#8217;s return so the unit conditions it before supplying it.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>A fan coil unit (FCU) is a simple HVAC terminal unit made up of a fan and one or more heating and\/or cooling coils, with<\/p>\n","protected":false},"author":1,"featured_media":2482,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"glossary-categories":[473],"glossary-tags":[519,520,521,522,523,524,525,492,526],"class_list":["post-11542","glossary","type-glossary","status-publish","has-post-thumbnail","hentry","glossary-categories-division-15-mechanical","glossary-tags-commercial-mechanical","glossary-tags-condo-mechanical-unit","glossary-tags-cooling","glossary-tags-fan-coil","glossary-tags-fan-coil-unit","glossary-tags-fcu","glossary-tags-heating","glossary-tags-mechanical","glossary-tags-residential-mechanical"],"_links":{"self":[{"href":"https:\/\/essential.construction\/academy\/wp-json\/wp\/v2\/glossary\/11542","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/essential.construction\/academy\/wp-json\/wp\/v2\/glossary"}],"about":[{"href":"https:\/\/essential.construction\/academy\/wp-json\/wp\/v2\/types\/glossary"}],"author":[{"embeddable":true,"href":"https:\/\/essential.construction\/academy\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/essential.construction\/academy\/wp-json\/wp\/v2\/comments?post=11542"}],"version-history":[{"count":1,"href":"https:\/\/essential.construction\/academy\/wp-json\/wp\/v2\/glossary\/11542\/revisions"}],"predecessor-version":[{"id":20371,"href":"https:\/\/essential.construction\/academy\/wp-json\/wp\/v2\/glossary\/11542\/revisions\/20371"}],"wp:attachment":[{"href":"https:\/\/essential.construction\/academy\/wp-json\/wp\/v2\/media?parent=11542"}],"wp:term":[{"taxonomy":"glossary-categories","embeddable":true,"href":"https:\/\/essential.construction\/academy\/wp-json\/wp\/v2\/glossary-categories?post=11542"},{"taxonomy":"glossary-tags","embeddable":true,"href":"https:\/\/essential.construction\/academy\/wp-json\/wp\/v2\/glossary-tags?post=11542"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}