What is radiant in floor heat?

Radiant in floor heat acts in a similar way to sunlight. Heat from the warm floor surface is radiated outward through air at the speed of light. In fact a warm surface is emitting energy in all directions but we cannot see it.
While everyone has experienced radiant from the sun, other good examples are a campfire or wood stove. Which are great forms of radiant heat but often it is very difficult to be at the proper temperature; often you must stay yards from source of heat...

What is floor heating and warming? 

Floor heating often can provide all your heat requirements in a modern  home ( Some exceptions are very cold climates, walls with  large window area or  extensive hardwood floors that limit floor temp to 78’, In such cases additional heat may be required from wall or ceiling heat, radiators or fan coils).With floor warming floor heat is your primary heating system, with a secondary system coming on only as required for fast response, or on very cold days (Note: some older homes that are not insulated well and have poor windows etc., may not be able to get enough heat from in floor alone, and will require additional heat from an existing system, wallor ceiling panels or hydronic fan coils or radiators.)

Where can I install it?

The best location for radiant panels are in the floors but radiant may also be installed  in walls and even ceilings. Great for  shops, garages and greenhouses, also snow melting driveways and sidewalks (Never shovel again!)

 Energy Sources

One of the great benefits of hydronic in floor heat is that any energy source can be used, with the ability to change to a different energy source relatively easily. - Or another heat source can be added with most of the existing system remaining intact. All systems can have optional indirect domestic hot water heating.

Natural gas /propane
High efficiency (modulating, condensing often called mod/con) these units are a relatively new design. Some units available with modulating and condensing features with rated efficiencies better than 95%
Note: to reach these high efficiencies specific design and mechanical room layouts are required, certain conditions are required to actually attain condensation and the resulting energy savings.  If your system is incorrectly designed or installed the efficiencies may at times drop to around 85%.
Conventional boilers are available to around 85% efficiency ratings and are considerably cheaper than condensing units.
Note:  specific design and mechanical room layouts are required to prevent Thermal shock and or condensation that could ruin a new boiler within a few years. Correctly installed conventional boilers are very reliable and can easily last 25 or more years.
There are high efficiency and conventional combination units available that can also heat domestic hot water. Although these units cost more the installation can be much simpler resulting in significant labour savings.

Electricity
electric boilers
Combo (with Domestic Hot Water combination) is expensive but greatly simplifies installations resulting in lower installation costs.
Note: A standard electric hot water tank only provides about 10,000 BTU which is only capable of heating a relatively small area - several would be required for a typical home. Most are not certified for this purpose.

Oil boilers are available

Heat Pump

Air to water heat pump. These units can save about 50% or more of heating and dhw costs.
Daikin Altherma, Offers a new to North America state of the art air to water Heat pump with optional DHW and solar assist. Draws heat from the air for the ultimate in energy efficiency. These systems should approach geothermal efficiencies in certain warmer climates of Canada at a much lower cost.
http://www.youtube.com/watch?v=cPIjuNFPeKM

Geothermal heat Pump. Drawing heating and cooling from the ground using ground loops in drilled vertical Holes or buried horizontal trenches. Also loops can be installed in ponds, lakes or ocean.  Geothermal can cut heating costs well above 50%. These installations should be considered the ultimate in energy efficiency.  High costs for drilling boreholes or laying ground loops generally requiring 1/2 acre or more of land can limit widespread use of this system.

Wood
Can be used as primary home heating and can used in combination with backup boiler that will automatically provide heat when required.

Solar
A typically installation primarily will be used to supplement Domestic Hot Water, providing about 50% of dhw energy( it will provide most or all dhw requirements in summer and supplement dhw energy  in winter)
Generally with a typical installation unless you are in an area with a lot of sun in the winter, solar can only supplement Home heating in spring and fall.