Hydronic heating systems involve heated liquid being pumped through radiators, baseboard heaters, floors or even walls.
Similar to electric baseboards, hydronic heating systems facilitate zone heating as you can keep different rooms at different temperatures.
Though different from electric resistance heating, hydronic systems are ultimately still using electricity to generate heat, so all the same environmental realities apply. Heating the liquid in a hydronic system can be achieved in many ways:
- Tankless (on demand) water heaters
- Combination hot water tank and boiler
- Combination solar water heater and boiler
- Geothermal heat pumps
Hydronic radiators and baseboards will transfer heat in the same way as electric resistant heat sources. So for comparison shopping, efficiency of heat generation isn't as much an issue as installation cost and the lifespan of mechanical equipment.
One advantage to hydronic heating systems is the ability to convert to thermal solar in the future. Solar water heating is much less expensive than solar power generation (photovoltaic).
New homes can be made 'solar ready' which is very inexpensive, adds value for resale, and is worth LEED points. It is a simple matter of running a normal 4 inch plumbing pipe from your attic to your utility room.
By doing so, installing solar panels (thermal or photovoltaic) is a simple matter of fishing wires or tubes through the pipe rather than an expensive remodelling project involving opening walls. A bit of real estate is required in the basement as well for a storage tank.