I am planning to install electric heat in a new log home. I have the choice of installing 120 or 240 volt circuits. What are the advantages and disadvantages of both. Also should I use Hydronic or standard baseboard. Also opinion on wall mounted thermostats or unit mounted. Also example to figure correct wite size.

A watt is a watt, so neither is any more efficient or cheaper to run.

240v circuits will let you run twice the amount of heat on a given circuit size. For instance, a 20A/120v electric heat circuit can have 1920 watts of heat on it. A 20A/240v circuit can have 3840 watts on it.

Wall mounted t-stats will do a better job of monitoring room temperature at a better level (typically 5' off the floor).

Wire size is figured like most any toerh circuit. 20A = #12, 15A = #14. For electric heat you can also use #10 wire on a 30A circuit, but #10 is pretty hard to work with in the small enclosures found in these heaters and also in wall boxes.

Hydronic baseboard heaters are MUCH safer, especially where kids are involved, but are also relatively MUCH more expensive to purchase.

I would just like to add, the hydronic units, in addition to being safer, can be more efficient than a standard heater of the same size wattage.

I have had good luck with these and satisfied customers, after having changed out the standard units for the hydronic units. They testified that they saved almost 15-20% of energy with the new units.

The concept is the heating element heats the fluid. After the heat element shuts off, the warm fluid continues to circulate inside the unit disspating heat long after the unit shut down and stopped using energy. This keeps the room warm longer and the heater off.

The quality of heat was better, did not seem as dry.

While initial cost is substantial, if you can fit it in the budget, I am sure you will be very pleased for years to come with the investment.

http://www.cadetco.com/show_product.php?prodid=1010

As Stan mentions, wall stats monitor room temp much better, and if you use programmable units, even better for savings. Be sure to install any wall stat on an inside wall in the room the unit heater serves.