Painted Radiators

Silly_Dilly

We recently moved into a two hundred year year old, 2,300 sq. ft. home

that was extremely inefficient when we made the purchase. We have had

all of the widows replaced with energy star windows, insulated the

basement, and had a home efficiency company come in and help us plug up

as many leaks as possible. We have a radiant heating system that uses

oil delivered because we live in Maine where city oil or gas does not

exist. We still feel like we are paying way too much, almost another

mortgage per month in fact, and we are trying to figure out how to

further improve our efficiency to help cut down on some of these costs.

We

have radiators that have been painted with what seems to be many layers

of what looks like a standard interior white paint to match the walls.

The temperature of these when I take an infrared thermometer to them is

around 115 degrees Fahrenheit when they are fully producing heat. I have

read that the temperature should be up around 200 degrees. I was

wondering if this is correct and if so is it the paint layers that are

causing this drop in temperature? Also I have heard that putting a metal

sheet behind each radiator will help push more heat out into the room,

allowing us to keep the thermostat temperature down. Is there any merit

to this? I have also read that painting these radiators a dark color

such as black will allow them to radiate more heat. True or false? If

so, do I need to have them stripped first? So many questions I know, but

any help would be truly appreciated. Have a warm rest of the winter!

Brad White

The Color Purple

So long as the paint is in good shape and not flaking off or so thick it looks like the Michelin Man, I would not worry about the paint color. The only paint which reduces the radiant output are the metallic colors. They may knock the radiant effect down by ten percent or more.



There is a chart under resources I believe and certainly in Dan's books which will give you a better indicator. The last color is what counts. Terra Cotta for some reason will give you another two or three percent that I recall. An ideal is flat black but in actual testing, little difference in actual output. Besides, the Goth look is so ten years ago.



As for temperature, I presume you have a hot water system and not steam? If the system has outdoor reset or is still a gravity system (which can remarkably have the same effect), you may well have the lower temperatures. The key question is, "do they heat the house?"



Do not sweat tepid radiators if you are comfortable. Rejoice if you can.



When the system was original, indeed the radiators would be about 160 to 180F if hot water and 212+ if steam. (Even today, yes, steam would be 212+). But the hot water temperatures can and do vary.