Can someone please let me know if hydronic electric baseboard heaters are really more efficient than regular electric baseboard heaters. Example of hydronic electric baseboard [url]http://www.hydrosil.com/[/url] These types of baseboards with fluid in them tend to be a lot more expensive. Thanks in advance

First off, my apologies if I don't use the right verbiage here or ask dumb questions. I am finding my skills as a network engineer do not translate well into residential electrical! My old clunky analog dial 'comfort zone' style thermostat crapped out, and I bought a Aube TH110 digital thermostat that is compatible with baseboard heaters. The new thermostat is a four-wire unit - red/black for LOAD and red/black for 240 VAC. However the old thermostat used only two wires. I see in the junction box that there are [I]three [/I]pairs of wires. Each pair in the box in black/white. When I attach the pair used by the old thermostat to the new one's 240VAC wires, the display comes to life but it will [I]not control the heater[/I]. The original electrician put all the white wires together with a wire-nut; not sure what that accomplishes. He had one black going to the red from the old thermostat, and another black going to the black for the thermostat. I a kind of out of my element here, but an determined to figure this out. And advice? Should I just bag the whole thing and call an electrician? Thanks!