In Ontario - your designer is required to have his/her BCIN number as per this link… http://www.obc.mah.gov.on.ca/Page143.aspx
In additions, designers of radiant systems should also have their RHDT designations as per this link:
http://www.hrai.ca/designations.shtml
The LEED™ program in Canada is relatively new ( 2008 course were delivered across Canada )…I had the owner of one of Canada’s first LEED™ Homes in my class in 2007 ( it was registered under the U.S. program) and a LEED™ Home instructor in my class last week in Ottawa.
Message: regardless of what good information you harvest online…if your house follows protocol in Ontario you will need a certified designer who also has his/her BCIN number to obtain a permit.
Names of registered designers can be obtained online from the HRAI of Canada website.
Regards,
RB

Efficiency and cost of operation are not directly related.

There are places where electricity cost less per btu than propane (in fact the off-peak rate in my area is very close to the cost of natural gas). How "green" your electricity is depends on where it comes from though there is some merit in using what would be line losse etc. If you employ a gas-burning condensing boiler you are greener than electricity, save that converted from nuclear or hydro.

If electricity were the low-cost fuel, a modulating electric boiler gives one the option to change his mind and use propane later for instance.

You don't have to give up wood. It does resist heat but this is relative. The heat load of the room, subfloor insulation and floor coverings determine design water temperature. It takes some experience and a good design program to make it work.

I am using a free-floating laminated bamboo (how green is that!?) on one level of my own house and 3/4" oak on another. The difference was a few degrees in design water temperature and a slight penalty for system efficiency. Comfort will not be effected and my Dolly loves her wood.

Your questions are best put to a certified designer.

Maxxon gyprete is the industry leader (I poured my first in the Denver area circa 1987).

An independent design/contractor with factory software is your best bet.

you will place a pipe in floor under wood floor or in slab
You will place a piece of wire under wood floor or in slab
Both will be met with the same energy resistance. conductor issues.

Why electric radiant heating efficiency isn't effected by radiator R value:

With electric heat, it doesn't matter how hot the wire has to get to provide sufficient heat to the room - there is no place to lose heat to and it will always be ~100% efficient.
With other fuels, there is an efficiency benefit from operating at cooler temperatures (less heat out the exhaust or better COP) - so you want to minimize radiator R value.

I think hydronic is the right way to go for this project. I've talked to a few hydronic installers - one mentioned that he does not recommend gyp-crete due to moisture/expansion problems and instead recommends a light weight concrete. I am leaning towards light weight concrete for two reasons: 1) so far, no one has really convinced me of the benefits of gyp-crete over a light weight concrete and I have heard more issues with gyp-crete than concrete and 2) although I agree wood flooring is possible over the radiant, it seems to create a lot of additional work/worry/potential problems and is less efficient than a hard surface like concrete so why not do a light weight concrete and finish it as your flooring? Save on flooring cost and get a hassle free maximum efficiency flooring solution. This assumes you dont mind the look which I dont. If anyone disagrees with my thinking please let me know.

Light weight concrete is a generic term that covers many lighter than usual concrete. Much of it adds considerable resistance to ANY radiant heat source. Wood is not more work, worry or problem if normal care is taken.

Concrete is hard and without careful consideration-controlling the water temperature with outdoor reset-one could find the floors cold at times. Don't get me wrong, concrete is great for radiant floors but leaving out windows will do more for your radiant comfort and my Dolly likes window and wood so we will have both.

A good designer is the first step as Mr. Bean suggests.