How to Diagnose, & Repair Heating System Noise Problems
InspectAPedia® -
How to find and fix heating system noises
Heating System Noises & Building Temperature-Change Noises
Heating System Noise & Sound Isolation methods
Heating System Noise Cause Diagnosis List & Articles
Troubleshooting heating system noises traced to chimneys and vents
Troubleshooting heating system noises traced to thermal expansion/contraction
Questions & answers about how to diagnose and fix heating system noises, rattles, bangs, hisses, clanking, and other sounds
Diagnosing heating equipment noises: this noise control article discusses the diagnosis and cure of heating system noises, including heating equipment noise, heat piping or ductwork noises, radiator noises, steam pipe banging, and steam radiator vent noise control. We describe just about every single noise that might come from or have to do with building heating systems. We describe the noise, where that noise usually originates, and what to do about it.
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Heating System Noises & Building Temperature-Change Noises
In this NOISE / SOUND DIAGNOSIS & CURE article series we discuss how to locate the source of, identify and correct various building sounds and noises indoors or on occasion, noises from outside that penetrate indoors at annoying levels. Separately at SOUND CONTROL in buildings we provide a series of detailed articles on reducing unwanted building noise levels through building design, insulation, sound isolation, and noise barriers. For the broad topic of controlling plumbing noises in buildings see Sound Control for Plumbing.
Curing or controlling noises traced to building heating systems is divided naturally into two topics that should to be addressed in this order:
Identify the source and cause of noises traced to the heating system or its components. Some heating system noises are normal and are thus not a worry.
But other heating system noises (rumbling, buzzing, banging) might be a sign that the heating system needs repairs, that it is not operating efficiently (costing more than necessary for heat), or the heating system may be unsafe. To rule out heating system operating problems, review the Heating System Noise Cause Diagnosis Articles we list just below.
Isolate heating system noises, or prevent heating system noise transmission through the building. Once we are confident that the heating system noises themselves are normal, we can focus on keeping those noises out of the rest of the building. You will still need to identify specific heating system noise sources, since some noise control steps focus on specific heating system installation details.
Once those noise and sound problems have been addressed, normal building noise transmission and sound control measures, such as sound insulation, can be applied to the room where heating equipment is located. See Heating System Noise & Sound Isolation
Watch out: while adding sound control barriers and insulation around a mechanical room be sure that you do not interfere with proper combustion air supply or you risk making the heating system work poorly or you may make it unsafe, risking carbon monoxide production and even death.
Heating System Noise & Sound Isolation
Examples of steps that reduce noise transmission from heating systems include
HVAC Duct noises: review and fix loose HVAC duct components, check that vibrations from the mechanical systems are not being picked up and carried through the building by metal duct vibration.
HVAC Ducts & Privacy: Sound from any source can also be transmitted between building areas through the ductwork itself. The author, politely smooching his girl friend in her family basement rec-room,was jolted by her father's sudden loud voice: "Joanne! time to come upstairs!!" - her dad just shouted down through the air ducts into the basement, leaving the couple to wonder if their private sounds had been transmitted up to Joanne's parents' bedroom.
Oil piping vibration transmission: as we cite at Heating System Noise Cause Diagnosis Articles, clamping heating oil piping to the underside of floor joists converts the floor above to a speaker cone to transmit vibrations from the oil burner into the space above.
Mechanical room sound isolation: once specific sound sources have been addressed, what remains is the isolation of mechanical room sounds from the rest of the building. See the sound control articles beginning at NOISE / SOUND DIAGNOSIS & CURE
Heating System Noise Cause Diagnosis List & Articles
Heating systems and building heat as a source of indoor noises and sounds include air bubbling in piping, shrieks (bearings), bangs (puffbacks), rumbling (air noise, mechanical noise), grinding noises, and other mechanical noises.
For warm air heat see FURNACES, HEATING and DUCT SYSTEM DEFECTS. Steam heat can also produce (normal) hissing sounds as air escapes from steam radiator valves.
Since heating system malfunctions that result in un-wanted noise may also produce smells, see ODORS & SMELLS DIAGNOSIS & CURE.
All heating systems can cause creaking or popping noises as heating system and piping or ductwork expand (and contract) through the heating cycle, though meticulous installation or repair can usually stop those sounds.
Troubleshooting Noisy mechanical system components and moving parts
Blower fans and air handlers: can induce vibration into building HVAC ductwork if a vibration isolator or vibration dampener is not installed. See VIBRATION DAMPENERS for a discussion of devices used to isolate noises produced by HVAC air handlers such as air conditioners and furnaces.
Bubbling or rumbling heating system noises in hot water heating piping can be caused by air in the heating lines. If the amount of air becomes excessive the heating system may be unable to circulate hot water and extra steps to bleed unwanted air will be required. See AIRBOUND HEAT SYSTEM REPAIRS
Buzzing sounds and vibration at oil or gas fired heating boilers, furnaces or water heaters can be caused by a variety of problems such as a control cover touching a relay switch, control unit transformer failures, bad motor bearings, or loose mounting hardware. Buzzing and similar vibration sounds may also be traced to fuel oil piping that is not properly mounted, is in contact with building surfaces, and is transmitting vibrations from the heating appliance or oil burner to the building. We also trace buzzing sounds to a failing low voltage transformer such as the transformer that may power zone valves, thermostats, and some other heating system components.
Buzzing heating system controls & relays: our photos below illustrate how a trapped aquastat relay buzzing problem can happen. Our measuring tape is stretched across the two steel ends of the aquastat control. The red arrow points to a relay in this control. You can see that there will be very little clearance between the relay's moving head and the an aquastat control cover that is pressed tightly in place.
If the control cover is lightly touching the relay switch the control may simply buzz when the relay is trying to move. On some controls this clearance is so tight that the relay or is trapped solid so that it cannot move - leading to a no-heat servicer call. Simply pulling off the cover to let the relay move freely can immediately discover and "fix" this buzzing heating control problem.
So if you notice that the control cover on your aquastat (or on a cad cell or stack relay) has been bent slightly convex, or has been left slightly ajar (our photo, above right) think twice before jamming it on tightly. Thanks to oil heat service technician Bob at Bottini Oil for this service tip.[3]
Circulator pump noises: circulator pupms on hot water hydronic heating systems range from quiet to producing a mechanical whine or hum, or if failing bearings, grinding, or if failing electric motor, humming and vibrating. In our experience Taco-brand circulator pumps are usually so quiet that we can tell that the circulator pump is running only by feeling for a temperature change the pipes entering and leaving the pump. - see Circulator Pumps & Relays
But if a circulator pump and hydronic heat piping contain unwanted air, cavitation in the pump itself due to the presence of air can make a pump abnormally noisy as well as making a bubbling or gurgling sound in the building hot water heating pipes, baseboards, or radiators. See air Bleeder Valves for a catalog of air purging procedures for hot water heating systems. See Air Scoops Purgers Separators for an explanation of the equipment intended to get rid of un-wanted and noisy air in hot water heating systems.
Clanking heating system pipes or sharp snapping noises may be heard as a normal consequence of expansion of metals during the heating cycle. These noises can often be eliminated or reduced
by careful routing of piping and by allowing room around heating pipes for expansion, but probably not eliminated in the case of hot water baseboards. See BANGING HEATING PIPES RADIATORS
Hissing heating system sounds such as air escaping from
radiators or the piping where air bleeder valves are installed are normal but should be brief and uncommon. If you constantly hear air
hissing from radiator bleed valves double check that you understand what kind of heat you have - hissing from bleeder valves on steam
heat radiators as heat is coming up in the building is normal. See RADIATORS.
Oil burner noises: could be normal motor noise or could be a sign of serious and even dangerous heating system conditions - see both OIL BURNER NOISE SMOKE ODORS and OIL BURNER INSPECTION & REPAIR for details. Additional noises at the oil burner may be due to a problem with the oil burner fuel unit (oil pump) such as a bad or slipping coupling between the burner drive motor and the fuel unit. Air in the heating oil supply piping can also cause noises in the fuel unit. Those problems are detailed at OIL BURNER FUEL UNIT.
Oil piping noises: buzzing or vibrating sounds may be transmitted from an oil burner fuel unit through flexible copper oil lines to the building, especially if the oil lines are hard-mounted to the basement ceiling (the bottom of floor joists for the floor above. See OIL TANK PIPING & PIPING DEFECTS
Radiator Noises: Watch out: If the radiator continually makes noises (whistling or wheezing) at the steam vent, there is a problem that needs to be fixed: a bad steam vent, steam piping problem, steam pressure set too high, or boiler oversized for the heating distribution system. See our diagnostic articles at RADIATORS and see BANGING HEATING PIPES RADIATORS
Steam pipe noises: see BANGING HEATING PIPES RADIATORS for the causes and cures of banging, clanging, hammering steam pipes as well as sounds from hot water heat piping.
Steam radiator vent hissing or other noises: steam vents should quiet down after steam has entered the radiator and the radiator and its vent have become hot. See Steam Vent Noise.
Whining, grinding humming: bearings in electric motors or other mechanical devices (whining, grinding, vibrating, maybe humming)
Zone valve noises: sometimes a zone valve motor makes a small grinding or whining noise when the motor is operating. In many cases that's normal. If the heating zone valve motor is getting louder we suspect it's failing.
Troubleshooting heating system noises traced to chimneys and vents
Heating flues, chimneys: Noises associated with heating system exhaust, including
Chimney noises: see Chimneys & Chimney Fires. Watch out for roaring freight-train sounds - indicating an immediate emergency - a very dangerous chimney fire may be happening - call the fire department and get out of the building. Wind blowing over a chimney can produce howling or whistling sounds - see Wind Noises
Draft inducer fan noises, usually on oil-fired heating equipment. See Draft Inducer Fans for details.
Troubleshooting heating system noises traced to thermal expansion/contraction
Thermal expansion/contraction: Noises associated with thermal expansion or contraction of heating system components
Hot water baseboard piping or radiator piping makes creaking or crackling sounds as the piping expands or contracts, particularly where piping passes through tight openings in walls or floors.
Heat Loss in buildings, how to determine and calculate heat loss from a building (or heat gain in a cooling climate), how to evaluate building insulation, & how to insulate buildings
Humidity: moisture changes can also cause creaking or ticking noises in buildings. See How Low Should You Keep Indoor Humidity to Avoid a Mold Problem discussed at HUMIDITY CONTROL & TARGETS INDOORS
Questions & Answers regarding this article
Questions & answers about how to diagnose and fix heating system noises, rattles, bangs, hisses, clanking, and other sounds.
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Additional technical contributors & reference sources for this article are listed below.
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[1] Acoustical Society of America - http://asa.aip.org/ Elaine Moran, ASA Office Manager, Suite 1NO1, 2 Huntington Quadrangle, Melville, NY 11747-4502
516) 576-2360, FAX: (516) 576-2377 email: asa@aip.org.
ASA is an excellent source of noise and sound standards. Quoting from the associations history page:
"From the Society's inception, its members have been involved in the development of acoustical standards concerned with terminology, measurement procedures, and criteria for determining the effects of noise and vibration. In 1932, The American National Standards Institute (ANSI), then called the American Standards Association, appointed the Acoustical Society as sponsor of a committee, designated as Z-24, to standardize acoustical terminology and measurements. The work of this committee expanded to such an extent that it was replaced in 1957 by three committees, S1 on Acoustics, S2 on Mechanical Shock and Vibration, and S3 on Bioacoustics, with a fourth, S12 on Noise, added in 1981. These four committees are each responsible for producing, developing a consensus for, and adopting standards in accordance with procedures approved by ANSI. Although these committees are independent of the Acoustical Society, the Society provide
s the financial support and an administrative Secretariat to facilitate their work. After a standard is adopted by one of these committees and approved by ANSI, the Secretariat arranges for its publication by ASA through the American Institute of Physics. The ASA also distributes ISO and IEC standards. Abstracts of standards and ordering information can be found online on the ASA Standards Page. More than 100 acoustical standards have been published in this way; a catalog is also available from the Standards Secretariat (631-390-0215; Fax: 631-390-0217). The Society also provides administrative support for several international standards committees and acts as the administrative Secretariat (on behalf of ANSI) for the International Technical Committee on Vibration and Shock (TC-108)." - http://asa.aip.org/history.html
Developments in Noise Control, NRCC, National Research Council, Canada, suggestions for noise control, sound transmission through block walls, plumbing noise control, noise leaks, and sound control advice. Web search 01/17/2011, original source: https://www.nrc-cnrc.gc.ca/eng/ibp/irc/bsi/90-noise-control.html
[3] Thanks to Bottini Fuel service tecnician Bob for discussing the buzzing aquastat relay problem, 4/18/2012. Bottini Fuel is a residential and commercial heating oil distributor and oil heat service company in Wappingers Falls, NY and with offices in other New York locations. Bottini Fuel, 2785 W Main St, Wappingers Falls NY, 12590-1576 (845) 297-5580 more contact information for Bottini Fuel
[4] Thanks to audiologist Cheryl P. Harllee, licensed hearing specialist, for discussing noises and noise problems in preparation for this article. Ms. Harllee can be located at the Village Hearing Center, 249 U.S. Highway One, Tequesta FL 33469 561-744-0231
Thanks to reader Sue Hazeldine, from the U.K. for discussing how she tracked down a whistling chimney noise to an antique hanging sign on the building exterior - 01/19/2010.
[5] Thanks to reader Michael Anderson, 8 May 2009, for discussing clicking sounds coming from air conditioning equipment.
[6] Thanks to reader Erna Ross who described loss of sleep due to a hissing noise at her home 06/15/2008.
[7] Marpac, produces white sound generators, a product that they identify as the Marpac sound conditioner. Marpac can be contacted at http://www.marpac.com/ or contact the Marpac Corporation,
P.O. Box 560 Rocky Point, NC 28457 Phone: 800-999-6962 (USA and Canada) Fax: 910-602-1435 1-910-602-1421 (worldwide), 800-999- or email: info@marpac.com
[8] Sound Oasis sound conditioners are produced by Sound Oasis: http://www.sound-oasis.com/ email: info@sound-oasis.com or 1-866-625-3218
[9] Barrier Ultra-R super high-R building panels, produced by Glacier Bay, use Aerogel and are rated up to R-30 per inch, or in Barrier Ultra-r™ panels, R-50 per inch. The company also produces acoustic panels that are Ultra-db resistant and lightweight. Unlike the appliance insulation panels discussed in the original Q&A above on miracle insulation, these Areogel based panels will continue to retain some, though reduced insulating value if punctured, performing at perhaps R-9 per inch. The product is used in marine refrigerators, but in the future may be available as a residential construction product. The company is researching specialized products in medical, transportation, and aerospace applications. Contact: Glacier Bay, Inc., 2930 Faber Street, Union City, CA 94587 U.S.A., (510) 437-9100, Sales and Technical Information - sales@glacierbay.com
[10] Tremco, Tremco Global Sealants Division, 10701 Shaker Blvd., Cleveland OH 44104 - see www.tremcosealants.com/
Noise - a Health Problem - http://www.nonoise.org/library/epahlth/epahlth.htm - quoted below
Racket, din, clamor, noise. Whatever you want to call it, unwanted sound is America's most widespread nuisance. But noise is more than just a nuisance. It constitutes a real and present danger to people's health. Day and night, at home, at work, and at play, noise can produce serious physical and psychological stress. No one is immune to this stress. Though we seem to adjust to noise by ignoring it, the ear, in fact, never closes and the body still responds - sometimes with extreme tension, as to a strange sound in the night.
The annoyance we feel when faced with noise is the most common outward symptom of the stress building up inside us. Indeed, because irritability is so apparent, legislators have made public annoyance the basis of many noise abatement programs. The more subtle and more serious health hazards associated with stress caused by noise traditionally have been given much less attention. Nonetheless, when we are annoyed or made irritable by noise, we should consider these symptoms fair warning that other things may be happening to us, some of which may be damaging to our health.
Protective Noise Levels - 1979, basis for many local noise ordinances and codes - http://www.nonoise.org/library/levels/levels.htm This publication is intended to complement the EPA's "Levels Document,"* the 1974 report examining levels of environmental noise necessary to protect public health and welfare. It interprets the contents of the Levels Document in less technical terms for people who wish to better understand the concepts presented there, and how the protective levels were identified. In that sense, this publication may serve as an introduction, or a supplement, to the Levels Document.
[13] "Measurement of Highway-Related Noise", US Department of Transportation, Federal Highway Administration, http://www.fhwa.dot.gov/environment/noise/measure/chap8.htm
Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
Our recommended books about building & mechanical systems design, inspection, problem diagnosis, and repair, and about indoor environment and IAQ testing, diagnosis, and cleanup are at the InspectAPedia Bookstore. Also see our Book Reviews - InspectAPedia.
The Home Reference Book - the Encyclopedia of Homes, Carson Dunlop & Associates, Toronto, Ontario, 2010, $69.00 U.S., is available from Carson Dunlop. The Home Reference Book is a bound volume of more than 450 illustrated pages that assist home inspectors and home owners in the inspection and detection of problems on buildings. The text is intended as a reference guide to help building owners operate and maintain their home effectively. InspectAPedia.com ® author/editor Daniel Friedman is a contributing author. Field inspection worksheets are included at the back of the volume.
Domestic and Commercial Oil Burners, Charles H. Burkhardt, McGraw Hill Book Company, New York 3rd Ed 1969.
National Fuel Gas Code (Z223.1) $16.00 and National Fuel Gas Code Handbook (Z223.2) $47.00 American Gas Association (A.G.A.), 1515 Wilson Boulevard, Arlington, VA 22209 also available from National Fire Protection Association, Batterymarch Park, Quincy, MA 02269. Fundamentals of Gas Appliance Venting and Ventilation, 1985, American Gas Association Laboratories, Engineering Services Department. American Gas Association, 1515 Wilson Boulevard, Arlington, VA 22209. Catalog #XHO585. Reprinted 1989.
The Steam Book, 1984, Training and Education Department, Fluid Handling Division, ITT [probably out of print, possibly available from several home inspection supply companies] Fuel Oil and Oil Heat Magazine, October 1990, offers an update,
Principles of Steam Heating, $13.25 includes postage. Fuel oil & Oil Heat Magazine, 389 Passaic Ave., Fairfield, NJ 07004.
The Lost Art of Steam Heating, Dan Holohan, 516-579-3046 FAX
Principles of Steam Heating, Dan Holohan, technical editor of Fuel Oil and Oil Heat magazine, 389 Passaic Ave., Fairfield, NJ 07004 ($12.+1.25 postage/handling).
"Residential Hydronic (circulating hot water) Heating Systems", Instructional Technologies Institute, Inc., 145 "D" Grassy Plain St., Bethel, CT 06801 800/227-1663 [home inspection training material] 1987
"Warm Air Heating Systems". Instructional Technologies Institute, Inc., 145 "D" Grassy Plain St., Bethel, CT 06801 800/227-1663 [home inspection training material] 1987
Heating, Ventilating, and Air Conditioning Volume I, Heating Fundamentals,
Boilers, Boiler Conversions, James E. Brumbaugh, ISBN 0-672-23389-4 (v. 1) Volume II, Oil, Gas, and Coal Burners, Controls, Ducts, Piping, Valves, James E. Brumbaugh, ISBN 0-672-23390-7 (v. 2) Volume III, Radiant Heating, Water Heaters, Ventilation, Air Conditioning, Heat Pumps, Air Cleaners, James E. Brumbaugh, ISBN 0-672-23383-5 (v. 3) or ISBN 0-672-23380-0 (set) Special Sales Director, Macmillan Publishing Co., 866 Third Ave., New York, NY 10022. Macmillan Publishing Co., NY
Installation Guide for Residential Hydronic Heating Systems
Installation Guide #200, The Hydronics Institute, 35 Russo Place, Berkeley Heights, NJ 07922
The ABC's of Retention Head Oil Burners, National Association of Oil Heat Service Managers, TM 115, National Old Timers' Association of the Energy Industry, PO Box 168, Mineola, NY 11501. (Excellent tips on spotting problems on oil-fired heating equipment. Booklet.)
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