Heat emitters in hydronic heating systems are designed to deliver heat to the conditioned spaces of a home. They are what make the spaces you inhabit feel warm and cozy. The selection of emitters for each heated space depends on whether you are building a new home or retrofitting an existing home, which level of the home you are heating (basement, first floor, etc.), the aesthetics of the emitter, cost, efficiency, heat storage capacity, operating temperature and several other factors. The following are a few of the most common types of emitters.

Slab on Grade or Basement Slabs

For new concrete slabs, whether poured on grade or in a basement, the best choice is to turn the poured slab itself into the heat emitter by embedding loops of flexible tubing into the concrete. Because the slab is very massive, it becomes not only an emitter but also a thermal storage element. The tubing is layed out in a precise pattern that creates the desired heating effect in the room. Insulation must be installed first to act as a thermal barrier between the warm floor and the cold earth around the slab. Insulating the perimeter of the slab is also very important to prevent heat loss. Existing slabs and basements can also be retrofitted by insulating and pouring another slab on top. This technique is a great option if you can afford to lose 5 to 6 inches of head room.

Wood Framed Floors

For wood framed floors there are many options for radiant heat emitters. A pour over material can be used over the wood subfloor to create a relatively thin, lightweight slab. In this case, smaller diameter tubing is embedded in the poured floor to reduce the overall thickness of the slab which can range from 1 to 1.5 inches. Pour over floors are popular in bathrooms, but some people use this technique throughout the upper floors of their home. Eventhough poured floors are relatively lightweight compared with a regular concrete slab, they do add considerable dead load to the floor structure. It is important to design appropriately for this added load. This technique may not be appropriate for existing homes that were not designed to handle the additional load. If you are unsure about whether your structure can handle the additional weight, you must consult a structural engineer.

Special flooring material with a track for embedding tubing is also available for wood framed floors. These materials usually incorporate a formed aluminum sheet on their surface to distribute the heat from the tubing throughout the floor. These systems are flexible and easy to install, but are more expensive than conventional subflooring materials. This material can be installed in new construction or incorporated into an existing home during remodeling if the floor covering is being replaced.

Tubing can also be installed under existing wood framed floors. This technique is most often used to retrofit an existing home with radiant heat. Formed aluminum fins are used to fasten the tubing to the underside of the subfloor. The fins help distribute the heat uniformly over the floor surface. An insulation barrier with a 4 inch air gap must be used beneath the tubing. This arrangement creates a warm air pocket that evenly heats the floor above. Because the heat must travel through the subfloor and floor covering to reached the heated space above, higher temperatures must be used with under floor installations.

Cast Iron and EuroStyle Radiators

Aside from radiant floor panels, there are other options for hydronic heat emitters. Cast iron radiators are still in use in many systems and are often an efficient and cost effective option if they can be reclaimed and reused. EuroStyle radiators are available in baseboard, wall-hung, room-divider and towel-drying models. These elegant radiators integrate well with the interior architecture using minimal space and offer consistent temperatures.

High-Temperature Baseboards

Fin-tube baseboard heaters are also a popular option because of their low cost and ease of installation. The baseboards are comprised of a copper tub with aluminum fins inside an enclosure. As hot water passes through these finned tubes, natural convection draws cool room air into the bottom of the enclosure and exhausts warmed air out the top.

Choosing the Right Heat Emitter

Selecting the best heat emitter to work with your hydronic heating system is often simple and straightforward, but not always. There are several factors that affect this choice. Mixing several different types of heat emitters in the same system can increase the complexity of the mechanical package and distribution system. We can sort through this complexity and design a custom heating system for your new home or remodeling project. Please contact us for a custom heating system quotation.