Meterial cost <$250, but you need a vaccume pump. Please see 泥猴 blog,he has full instrument for installation. I quoted for installing is $750 labor only if you ask someone do it.
The electric using is totally differient. before install, each month $170+/-, after install $75+/- during the winter, but if the weather is colder tha 0F, then it does not work, so need backup heating source.
