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Prudent RVer says:

LEDs Don't Make Good Space Heaters

 I sell LED products throughout the USA and Canada. Recently, I had a strange complaint from a customer in Ottawa. "I turned on my lights to warm my coach, but it didn't do any good. You need to do something about your LED products to fix that problem."

Patiently I explained, "LEDs are not supposed to produce a lot of extra heat. That is why they save so much on power. The halogen bulbs I replaced in your motorhome used 80% of the electricity they burned to produce so much extra heat you could use them to warm your rig. You gave up that advantage when you switched to LEDs."

She replied, "Oh, but how can I heat my coach now?"

Incandescent bulbs reach a temperature of 600 degrees Farenheit to make the tungsten filament glow. Halogen bulbs must achieve a surface temperature of over 1,000 degrees to operate properly. That means that between 75% and 85% of the electrical power used in an incandescent or halogen goes to creating the heat needed to create their light, and that heat radiates out from the bulbs. Bulbs get hot enough to cause third degree burns if you are dumb enough to touch them barehanded.

Another friend complained when she ordered that every halogen in her Country Coach be replace with LEDs that she liked a lot of light. Her reason for installing the LEDs was that whenever she came in and turned on the halogen lights, her husband turned on both air conditioners to cool things down -- even in the winter when they were in Wyoming.

Think about that. Not only is 85% of the power you pump through the bulbs wasted to create heat, but then you must run your air conditioner to remove that heat so you can enjoy the cool in you well-lit coach. The true factor is that LEDs allow you to use less than 10% of the power required to run with incandescents.

Fluorescents are only a little better. They are maybe three times more efficient than incandescents, but that still means 50% of the power creates heat. And those ballasts can create a wild assortment of high-frequency AC noise on your DC power lines. My customers complain of non-working refrigerators and air conditioners when the ballasts go bad.

If you wonder why LEDs are so much cooler, it is because they are 85% efficient at converting electrical power into light. They simply don't need to pull as much current as incandescents or halogens or fluorescents to produce the same amount of light.

But LEDs do produce some heat. That 15% inefficiency becomes heat, and it turns out that LEDs must be properly cooled to operate and should not exceed 188 degrees Farenheit at the semiconductor junction or they will fail. Well designed LEDs are warm, but you can touch them without fear of being burned. Correct LED design uses metal heatsinks to pull the heat that is generated away from the semiconductor.

Remember, when searching for the best LED solutions to light your coach or boat, don't expect a Space Heater Bonus in the deal.

And if someone asks why you bought both LEDs and a Space Heater, tell them the Prudent RVer told you to.

copyright Sam Penny, July 26, 2010