All You Need to Know About In-Slab Heating
The main goal of hydronic slab heating is to heat the slab efficiently and supply the right amount of heat to the desired space above the slab (actually six to eight feet air space above the floor). Following are some of the important factors that we have to take into consideration in order to increase the performance of in-slab hydronic heating system.
- Insulation: Insulation is strongly recommended below the slab. Theoretically, the utilization of insulation sheer provides haze barrier as well as reflective layer above the insulation will make sure that the major part of the supplied heat will make its way to the designated area, that is six-eight feet area above the slab.
- Planned Slab Size vs Heated Space: A slab depicts a thermal mass. It will not only absorb the heat but will also transmit it. In hydronic slab heating, if only a section of slab is heated, it is understood that some of the heat is lost to the areas that are not being heated and hence the heat will not reach intended space. It may be acceptable in some cases, but if it is not acceptable, then it is recommended to place the thermal breaks into slab floor. This idea could be considered either by homeowner, designer, or builder.
- Slab Thickness: In a hydronic heating system, heat is effectively transferred from hydronic system into thermal mass. Volume of thermal mass and the time taken to transfer the heat are directly proportional to each other. So, greater the volume of thermal mass, longer the time taken to transmit the heat. But the best part is that once the thicker slab is heated, it will give off the heat into 6-8 feet above the floor or a longer period of time.
- Tubing Size: As we all know, concrete has particular absorption rate. Changing the tubing size will have a major impact on the overall system efficiency. In this case, bigger is not better. Larger diameter tubing will require more powerful and larger circulator. Larger circulator means increased size and cost of hydronic slab heating system and moreover, this might fail to generate desired performance.
- Manifold Placement: Usually, manifolds are either hidden on a wall or sometimes located in an easily accessible place. Overall, care must be taken to ensure that all manifolds and electrical wires are safely located.
- Tubing Position within the Slab: It is important to see that tubing is not located at the bottom of the slab because in this case, there are chances of these not being fully wrapped when the concrete is poured. This will impact the process of heat transfer into the slab and significantly reduce the system efficiency.
- Heat Source (Boiler vs Geo): Even though geo heat pumps generate much less hot water than boiler, both geo pumps and boilers should be fine for hydronic slab heating system. If all the guidelines are adhered during the construction, there will be an efficient and effective transmission of heat.
Nonetheless, hydronic slab heating is the best way to reduce the energy consumption. It is an ideal option to consider for heating the places and maintaining the temperature. If done properly, it can be efficient and beneficial in long terms.