Heating Radiator & Baseboard Covers
Impact on Heating Efficiency, Cost, & Energy Savings Suggestions
RADIATOR BASEBOARD or CONVECTOR COVERS - CONTENTS: Why do we need covers on heating baseboards, convectors, or radiators? How much does adding a radiator cover affect heating costs?Do hot water heating baseboards need their covers? Can I replace the original manufacturer's cover on my wall-mounted electric heating convector unit? What is the benefit of adding insulation or a heat reflector behind a radiator or convector unit? Can I leave the covers off of my hot water heating baseboards? Where to get or how to build replacement covers for heating baseboards or radiators.
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Guide to radiator & baseboard or heating convector covers:
This article describes the types of heating radiators: hot water, steam, cast iron, heat convectors, baseboard heat, electric heating convectors, and we explain the diagnosis and repair of no-heat or leaks or other problems with heating radiators.
We explain the effects on heating output & distribution when a cover is placed around a conventional hot water or steam heating radiator, and we explain why covers are needed for proper functioning of hot water heating baseboards & convectors. We include sources of replacement baseboard covers & notes on where to buy or how to build a radiator cover.
Energy Saving Suggestions About Baseboard, Convector & Radiator Covers
Our photo at left above (at page top) shows a typical "one pipe system" steam cast-iron heating radiator behind a metal radiator cover. A single pipe delivers steam to the radiator and condensate from the cooling steam returns to the heating boiler via that same pipe.
Sketch at above right, provided courtesy Carson Dunlop Associates, shows the typical air inflow at the front of the radiator cover and outflow near the top as heated air rises by convection [Click to enlarge any image]. The CDA sketch points out that depending on its design, a radiator cover might actually reduce the heat output from the device! Yet in some cases (such as baseboard radiators and convector units, the cover is absolutely necessary for proper operation. We will explain this if you can stand reading-onwards.
In addition to cast iron radiators using hot water or steam as a heat source, we describe two other very common hot water heat distribution methods below.
How Much Do Radiator Covers Reduce Heat Output or Increase Heating Bills? Can Some Radiator Covers Increase Heat Output?
The two radiator cover sketches below are adapted from a now nearly-antique Steam Heat Book provided by ITT. The original text's explanation was confusing to non-heating experts so here we provide an explanation of the percentages of change in radiator heat output due to different radiator cover designs derived from the original data.
The original text did not cite a source for these percentages.
The percentages shown are translated as the additional surface added to heating column or tube radiation for each of the enclosure methods shown. You can see that in some designs the percentages by which you have to change (increase or decrease) the amount of heat radiation is reduced while in others it is increased.
While radiator covers are a popular way to modernize and improve the looks of steam or hot water radiators in a building, as Carson Dunlop's sketch above left and the sketches we adapted from the ITT book all show, most radiator covers will significantly reduce the heat output of the device.
If the percentage we show above each radiator cover design is positive (+ and shown in blue) that means that adding a radiator cover of that design actually reduces heat output while
If the percentage shown is negative (in red) that means that adding a radiator cover of that design actually increases the rated heat output.
Because adding a radiator cover in most of these designs slows the movement of heat out of the radiator and into the room, the rate of heat loss out through the building exterior wall is likely to be increased - also increasing your heating bills.
Below we show how to avoid this problem by adding solid insulation (usually foil-faced) behind the radiator and over the wall surface.
If the space between the radiator and the wall is too small to add much insulating board (less than1/2") or if adding insulation would totally block air flow in that area, you might prefer to install a foil reflector instead.
How to Make a Radiator Cover to Deliberately Reduce Heat Output
In field inspections we have not noticed a significant difference in the venting designs of covers over hot water radiators compared with electric convector units except in more extreme cases such as the radiator cover that we built for a Vassar College professor (left).
In the photo at left we show that we have enclosed the radiator on three sides and installed a louvered screen front. This was done deliberately to cut the heat output from this radiator.
Usually we like to use a very open screen material and have even used lattice with 1" openings so that we maximize airflow through the cosmetic screen of the cover (photo at left).
But in the example shown, a large cast iron radiator in an academic office was enclosed by shelving that we constructed deliberately to reduce heat output in a building where regulating heat among offices had proven difficult.
If the heat output is interfered-with on a hot water radiator, not much of a safety concern would be raised. But if we blocked heat output of an electric fan convector unit we might create an unsafe condition or even an electrical hazard or malfunction if internal components are overheated.
Adding Insulation or a Heat Reflector Behind Your Radiators
While you're at it, if your heaters are an older installation that was recessed into the building wall, you can greatly improve their heat output and perhaps significantly reduce heating costs if you move them forward to a flush-on-wall mount over a suitable insulating and/or heat reflecting board.
Carson Dunlop's sketch (left) demonstrates the improvement in heat output (and thus reduced building heating bills) from simply adding insulation behind heating radiators.
Thanks to Bearsville NY Architect Barry Price for the tip about bringing recessed radiators forward Feb 2010.
Utica Boilers provides a useful document - Utica Radiation Tables - that allows a homeowner or heating service technician to determine the heat output of a traditional cast iron radiator, measured in square feet of radiation for column, tube, and wall-type heating radiators.
Radiator Covers Over Electric Heat Convectors and Fan Boosted Convection Heaters?
Wall-mounted electric heating convectors with or without a fan to increase air movement, are produced and designed to work with the cover provided by the manufacturer.
Some readers have asked if it was acceptable to replace the manufacturer's OEM cover with an alternative. Sketch (left) of a generic wall mounted heating convector and its heating convector cover is courtesy of Carson Dunlop Associates.
You may be risking a fire if you put any cover of any kind over or even close to a wall-mounted electric convector heater. Using the DeLonghi CH15 CH15F instruction manual as an example, that document describes a portable electric convection heater that includes a blower fan. The heater can also be wall-mounted. But the manufacturer specifically states,
"Keep combustible materials, such as furniture, pillows, bedding, papers, clothes, and curtains at least 3 feet (0,9 m) from the front and top of the heater and keep them away from the sides and rear."
Do not buy or make or install additional or retrofit or "cosmetic" covers for heaters of this type without first getting an OK from the manufacturer. You're risking a fire.
As we mention at the DeLonghi wall panel heater citation in Technical Reviewers & References below, we do not recommend modifying or covering any OEM wall-mounted panel heater covers without checking with the manufacturer as well as reviewing the heater's installation manual.
Do We Really Need the Covers on Heating Baseboards?
The short answer is yes.
While heat will come off of an un-covered finned tubing baseboard heat system, it won't be working optimally because without its cover, it is more difficult for the baseboard to set up a convection current that draws cool air from the floor in at the baseboard bottom, delivering a flow of warm air current out of the top of the baseboard opening.
Quite often when we see that heating baseboard covers are missing, we also see that people walking near by or vacuuming, or just kids playing nearby have damaged the fins on the heating baseboard.
If significant areas of heating baseboard fins have been crushed, airflow over the heating pipe is reduced and heating costs are increased. Usually we repair these systems by installing new baseboard sections and covers.
Small areas of damaged baseboard fins might be un-bent manually or using a comb device intended for that purpose.
This article series answers most questions about all types of heating systems and gives important inspection, safety, and repair advice.
If you don't know what kind of heat your building uses, we explain how to figure out the answer at HEATING SYSTEM TYPES. If your heating system is not working properly, see NO HEAT - BOILER or NO HEAT - FURNACE.
Continue reading at RADIATOR or CONVECTOR INSULATION or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.
Try the search box below or CONTACT US by email if you cannot find the answer you need at InspectApedia.
Question/Comment: where to buy replacement covers for hot water (hydronic) heating baseboards
We manufacture Baseboarders - the most popular way to deal with problematic baseboard heater covers.
Quite often our product makes the difference between a fail or a pass when an inspection is conducted.
Address: Baseboarders Corp., 11765 Summit Crescent in Delta BC Canada V4E 2Z3
Telephone: 1 (800) 834-5672 - contact Jon Buss
We have added your company's contact information here for readers who need to buy replacement heating baseboard covers.
InspectAPedia is an independent publisher of building, environmental, and forensic inspection, diagnosis, and repair information provided free to the public - we have no business nor financial connection with any manufacturer or service provider discussed at our website. We are dedicated to making our information as accurate, complete, useful, and unbiased as possible: we very much welcome critique, questions, or content suggestions for our web articles. Working together and exchanging information makes us better informed than any individual can be working alone.
(Nov 2, 2011) Paul said:
Thanks for the Insulation tip! No where else I see that mentioned. I need to do 4 radiators and as it is the walls in the house don't have insulation. Thanks a million!
Glad to assist, Paul. Should questions arise don't hesitate to ask.
(Nov 15, 2014) Jim Johnson said:
Where can I find 1960's vintage Slant Fin baseboard covers?
Slant Fin sells compatible replacement covers.
Question: reader questions effects of radiator covers depsite research cited
(Feb 23, 2015) J in Boston said:
I'm not sure that I agree with your interpretation of the effect of the covers on heat transfer efficiency. The % the change in effective radiation area - these data are used in sizing the heat output of a boiler that is connected to the radiator system. With greater convective air flow caused by some of the radiator cover designs, the radiators actually radiate more heat into the room. If one added a bunch of those radiator covers to the system, then the boiler size might need to be increased to keep up with the improve heat transmission into the room. This might be a useful solution for systems in which the boiler is actually oversized - a common problem - and short cycles because the radiators do not emit enough of the heat and the system becomes pressured prematurely as the vents close.
Thank you for the discussion.
The data we cited came from research (see References) including data from the manufacturers and from textsbooks, not from the usual arm-waving that often is behind opinions in the trades.
But I certainly agree that radiation surface is not the whole story. Just consider a heating baseboard - a long flat small "radiator" in effect. If you take the covers off of the baseboard you'll stop the convective air movement from the floor up through the heater and thus it would seem clear that you'd impede its performance.
And I certainly agree too that in those ugly cases where heat output is excessive in a particular room or at a particular hydronic or steam radiator, occupants often build an enclosure to cool the heat output there. But it ought to be apparent that this is not the best solution; it'd be better to install a thermostatic radiator valve, for example.
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Questions & answers or comments about heating system radiator covers in buildings.
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Mark Cramer Inspection Services Mark Cramer, Tampa Florida, Mr. Cramer is a past president of ASHI, the American Society of Home Inspectors and is a Florida home inspector and home inspection educator. Mr. Cramer serves on the ASHI Home Inspection Standards. Contact Mark Cramer at: 727-595-4211 mark@BestTampaInspector.com
John Cranor is an ASHI member and a home inspector (The House Whisperer) is located in Glen Allen, VA 23060. He is also a contributor to InspectApedia.com in several technical areas such as plumbing and appliances (dryer vents). Contact Mr. Cranor at 804-747-7747 or by Email: email@example.com
 Dan Holihan, "Your Most Frequently Asked Questions About Cast-Iron Radiators – Answered! by Dan Holohan", http://www.oiltechtalk.com/pages/cast_iron.htm, retrieved 3/7/2013.
"Rv-4 One-Pipe Steam Radiator Valve", available from Armstrong International,
816 Maple Street, Three Rivers, MI 49093 USA, Tel: (269) 273-1415, Armstrong has offices in Beijing, China, Belgium, India and Mexico. Web search 12/27/2010, original source:
 Report 95-14, PB96-198163 Thermostatic Radiator Valve (TRV) Demonstration Project, contact NYSERDA. 17 Columbia Circle, Albany, NY 12203-6399 Toll-Free: 1-866-NYSERDA, Tel:(518)465-6252, Ext. 241. Web Search 12/27/2010, original source: http://www.homeenergy.org/archive/hem.dis.anl.gov/eehem/96/960509.html
 VariValve® Quick-Vent from Heat Timer, adjustable radiator and main line vent valves for one pipe steam systems, web search 12/27/2010, original source: http://www.heat-timer.com/enFiles/ProductDocument/literature/VariV056082C.pdf
 "Care & Feeding of Air Vents", Dan Holohan, Old House Journal Online, November 2004
 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, (see next item in this list). ITT Fluid Technology,
1133 Westchester Avenue
White Plains, NY 10604,
tel +1 914 304 1700 fax +1 914 696 2950 www.ittfluidbusiness.com
 Principles of Steam Heating, $13.25 includes postage. Fuel oil & Oil Heat Magazine, 389 Passaic Ave., Fairfield, NJ 07004.
DeLonghi Mica Panel Radiators can be wall-mounted and function similar to older designs of electric wall mounted heating convectors. We do not recommend modifying or replacing the manufacturer's covers on products such as this one and we do not recommend constructing home made covers to install over portable heaters of any type. Doing so risks a fire. Examples of fire and heat safety clearances for the DeLonghi electric panel heater are shown in this DeLonghi heater installation manual. - http://www.delonghiusa.com/index.php?product&nid=27
Thanks to reader Alan Pickles for ongoing discussion of the use of MDF radiator covers or pre-fab radiator covers with convection heaters 02/11/2010
Utica Boilers - The company's Utica Boiler Literature Page link: http://www.uticaboilers.com/product_literature.asp provides download links to current product information for the company's absolutely huge list of products.
Utica provides a useful document - Utica Radiation Tables - that allows a homeowner or heating service technician to determine the heat output of a traditional cast iron radiator, measured in square feet of radiation. - Original document source: http://www.ecrinternational.com/secure/upload/document/293.pdf
Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
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
Carson, Dunlop & Associates Ltd., 120 Carlton Street Suite 407, Toronto ON M5A 4K2. Tel: (416) 964-9415 1-800-268-7070 Email: firstname.lastname@example.org. The firm provides professional home inspection services & home inspection education & publications. Alan Carson is a past president of ASHI, the American Society of Home Inspectors. Thanks to Alan Carson and Bob Dunlop, for permission for InspectAPedia to use text excerpts from The Home Reference Book & illustrations from The Illustrated Home. Carson Dunlop Associates' provides extensive home inspection education and report writing material.
The Illustrated Home illustrates construction details and building components, a reference for owners & inspectors. Special Offer: For a 5% discount on any number of copies of the Illustrated Home purchased as a single order Enter INSPECTAILL in the order payment page "Promo/Redemption" space.
TECHNICAL REFERENCE GUIDE to manufacturer's model and serial number information for heating and cooling equipment, useful for determining the age of heating boilers, furnaces, water heaters is provided by Carson Dunlop, Associates, Toronto - Carson Dunlop Weldon & Associates Special Offer: Carson Dunlop Associates offers InspectAPedia readers in the U.S.A. a 5% discount on any number of copies of the Technical Reference Guide purchased as a single order. Just enter INSPECTATRG in the order payment page "Promo/Redemption" space.
The Home Reference Book - the Encyclopedia of Homes, Carson Dunlop & Associates, Toronto, Ontario, 25th Ed., 2012, 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. Field inspection worksheets are included at the back of the volume.
Special Offer: For a 10% discount on any number of copies of the Home Reference Book purchased as a single order. Enter INSPECTAHRB in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.
Special Offer: Carson Dunlop Associates offers InspectAPedia readers in the U.S.A. a 5% discount on these courses: Enter INSPECTAHITP in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.
The Horizon Software System manages business operations,scheduling, & inspection report writing using Carson Dunlop's knowledge base & color images. The Horizon system runs on always-available cloud-based software for office computers, laptops, tablets, iPad, Android, & other smartphones