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Unread 11-12-2012, 12:39 PM   #36
Distribute/Sales/Install electric radiant systems
Warmsmeallup's Avatar
Join Date: Nov 2012
Location: Upstate, NY
Posts: 32
Let's first approach the primary heat idea. I'm guessing that the bathroom you did previously didn't have more than one window and one exterior wall so minimal heat would be fine. Does the area you wish to heat now with the line v. have more windows, exterior wall or doors? Keep all that in mind later if it isn't sufficient. I would NEVER just supply a heating element that covers the area and then guaranty primary without the loads in-hand.

Like I said, a watt is a watt. If the mats you purchased produce 15 watts and draw 6.5 amps @ 240v (approx 100sf) than so will a low voltage covering the same area. Ohm's law. I'm not sure where you're getting your calculations from.

Also keep in mind that we supply both low and line voltage systems. I don't have a preference, it's strictly what fits the application/budget of the client. If there's an open budget, we always suggest low v for the longevity of the element first. The low voltage advantage is the element, not the efficiency (accept for snow melting applications where low v is superior over all for longevity and efficiency). Line voltage elements (like toasters/ovens/water heaters) are not housewiring, they are something akin to a filament and are designed to last 10 years + due to the nature of the 'beast'. Some line v mfrs are now giving 25 year warranty's to keep up but you'll have a heck of time prooving it's the embedded element in 15 years.

The low voltage element is a just a single copper stranded THHN wire where low volts/high amps are used to create resistance/heat. Keep that resistance well below the wire's max capacity and it will last as long as housewire.

The low v transformers we use are AC/AC so the loss is about .3%. Insignificant. And, since the transformers get warm themselves, they make up for more than the loss if installed in the heated area.
Comfort Radiant Heating

"That which you manifest, is before you"
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