Hydronic basedboard heating systems can be purchased at The Home Depot, Lowe's, eBay or Amazon.com. Hydronic baseboard heaters can be filled with either oil or water. When filled, electrical current is used to warm the fluid that then radiates heat into the room.
Hydronic systems are more energy efficient than electrical baseboard heaters that use a series of metal fins to radiate heat, because the fluid retains heat longer than the metal. However, hydronic models do take longer to heat up. The units also require electrical wiring and plumbing skills for installation, but they do not require any duct work. Models offered for sale vary in price and wattage.