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Getting More (Or Less) Out Of Your Steam Heat Radiators

October 11th, 2009

Steam heat systems are notorious for being hard to control, making rooms either too hot or too cold. Unfortunately, steam heat systems may distribute heat unevenly, making it impossible to adjust the system overall. Are there simple steps you can take to adjust the heat output in each room of your Boston steam-heated home?

Yes! You can adjust the heat output of a radiator by painting it. The type of paint you choose can either increase or decrease the heat output of the radiator by as much as 10%-20%. The paint will have no appreciable effect on the cost of operating the boiler but can make individual rooms more comfortable.

Radiators transfer heat to a room in two ways. First, radiators heat the air above the radiator. This heated air rises and moves into the rest of the room to warm it. This accounts for about 2/3 of the radiator’s heat output. Second, the surface of the radiator radiates heat. Painting the surface of the radiator either increases or decreases the radiator’s ability to radiate heat without changing the radiator’s ability to heat the air above it.

Metallic paints, those that have metal flakes in them, can give the radiator a fresh look of bronze or aluminum. You may be tempted to think that a metallic finish will increase the amount of heat transfer to the surrounding air, but you’d be wrong! Metallic paints reduce the radiator’s ability to radiate heat into the room. If a room in your home is too hot, a coating of metallic paint can help “adjust” the radiator by reducing it’s radiating capabilities.

Colored paints that have no metallic flakes in them have the opposite effect. They increase the radiator’s ability to transfer heat to the room. Painting a radiator with a colored paint will increase the radiator’s ability to radiate heat into the room. The efficiency of a radiator in a room that is chronically cold can be improved with a change of color.

You can also limit the “wasted” heat that is radiated toward a wall by painting the side of the radiator that faces it with a metallic paint, and painting the outward facing portions of the radiator with colored paint. This will increase the amount of heat that is radiated into the room, and decrease the heat that is “wasted” by heating up the wall behind the radiator.

It’s important to note that the last coat of paint on the radiator is the only one that has any effect on the radiator’s heat output. In other words, you can take a previously metallic-painted radiator, put a coat of colored paint on it and increase the radiator’s heating capacity. Likewise, you can decrease a radiator’s heating capacity by covering colored paint with metallic paint, so there’s no need to remove old paint on your radiator.

Finally, if you’re trying to improve the efficiency of your steam heat system, consider insulating the pipes that service each radiator. You may achieve some control by painting these pipes, but a build up of dust can easily undo even the most heroic effort!

Boston Standard Plumbing provides expert maintenance for steam heat systems. We can repair or replace radiators, service pipes, boilers, valves and other system components. Call us at 617-288-2911 for more information on your steam heat system.

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