I hear radiant heating systems are slow to react, the so-called lag-period and also tend to overheat. Is system design a factor in these cases?
The design of a radiant heating system along with other factors influence the response of the system. A properly designed system with specialized controls will substantially reduce or eliminate lag-periods and overheating. However, other factors can influence these processes and include the amount of insulation, exposure to sunlight, rapid climate changes, concrete slab thickness, boiler safety and support equipment and size, and owner operational preferences. Two common complaints about the performance of older radiant panel systems is the lag-time, the time it takes to change the room temperature once the thermostat calls for heat, and overheating, the rapid increase of room temperature due to the influx of solar energy (insolation) or the influx of body heat (a sudden increase in room occupancy). The lag time is a system response due to boiler output and the concrete mass to be heated. For example, a 6 concrete slab-on-grade will take longer to heat than a 1-1/2 slab on a wood sub-f
