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AIR CONDITIONING & HEAT PUMP SYSTEMS
BACKDRAFTING HEATING EQUIPMENT
BACKUP HEAT for HEAT PUMPS
BANGING HEATING PIPES RADIATORS
BLOWER FAN OPERATION & TESTING
BOOKSTORE - InspectAPedia
BTU USAGE MONITORS
CARBON MONOXIDE - CO
CIRCULATOR PUMPS & RELAYS
DIAGNOSTIC GUIDES A/C / HEAT PUMP
DIAGNOSE & FIX HEATING PROBLEMS-BOILER
DIAGNOSE & FIX HEATING PROBLEMS-FURNACE
DIRECT VENTS / SIDE WALL VENTS
DRAFT HOOD, GAS HEATER
DRAFT REGULATOR, DAMPER, BOOSTER
DUCT SYSTEM & DUCT DEFECTS
ELECTRIC MOTOR DIAGNOSTIC GUIDE
FAN, AIR HANDLER BLOWER UNIT
FLOODED HEATING EQUIPMENT REPAIR
FLUE SIZE SPECIFICATIONS
GAS BURNER FLAME & NOISE DEFECTS
GAS PIPING, VALVES, CONTROLS
GEOTHERMAL HEATING SYSTEMS
HEAT PUMPS, DIAGNOSIS, REPAIR
HEATING COST SAVINGS METHODS
HEATING OIL PIPING TROUBLES
HEATING OIL TANKS
HEATING SYSTEM NOISE DIAGNOSIS
HEATING SYSTEM TYPES
GAS LP & NATURAL GAS SAFETY HAZARDS
MANUALS & PARTS GUIDES - HVAC
MIXING / ANTI-SCALD VALVES
MOTOR OVERLOAD RESET SWITCH
NOISE, HEATING SYSTEMS
ODORS FROM HEATING SYSTEMS
OIL FILTERS on HEATING EQUIPMENT
OIL FILL PIPE LEAKS
OIL SPILL CLEANUP / PREVENTION
PLASTIC PLEXVENT ULTRAVENT RECALL
PUFFBACKS, OIL BURNER
RELIEF VALVE LEAKS
RESET SWITCH, HEATER PRIMARY CONTROL
RESET SWITCH, ELECTRIC MOTOR
RESET SWITCH, STACK RELAY
SAFETY, HEATING INSPECTION
SAFETY RECALLS CHIMNEYS VENTS HEATERS
SOLAR HEATING SYSTEM DESIGNS
SOOT on OIL FIRED HEATING EQUIPMENT
STEAM HEATING SYSTEMS
THERMOSTATS, HEATING / COOLING
VIDEO GUIDES: HEATING SYSTEMS
WINTERIZE A BUILDING
WOOD-OIL COMBINATION HEATERS
WOOD STOVE OPERATION & SAFETY
ZONE VALVES, HEATING
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.
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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 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.
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.
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,
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?
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 the More Reading links shown below.
Suggested citation for this web page
Green link shows where you are in this article series.
Frequently Asked Questions (FAQs) About Heating Baseboard, Convector & Radiator Covers
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.
We have added your company's contact information here for readers who need to buy replacement heating baseboard covers.
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(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.
Questions & answers or comments about heating system radiator covers in buildings.
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Technical Reviewers & References