A building’s rate of heat loss is affected by how that heat is replaced. Identical buildings, heated differently, can have significantly different rates of heat loss. Buildings with hydronic heating have consistently lower heating energy use than equivalent structures with for example, forced-air heating systems.
Hydronic systems do not typically affect room air pressure when running, forced air systems do. This can result in pressure differential leaking heat at every envelope egress opportunity. It was found that air leakage rates averaged >25% higher and energy usage averaged >30% in the same identical homes with forced-air heating.
Temperature stratification is where warm air tends to rise toward the ceiling while cool air settles to the floor. The temperature differential can be highly significant. Stratification is worse in high ceilings. Maintaining comfortable air temperatures in the occupied regions of rooms that have a high degree of temperature stratification, leads to significantly higher air temperatures near the ceiling where it can lose much of its energy.
Hydronic systems transfer the majority of their heat energy by thermal radiation, reducing air temperature stratification. Much of the time heat can be maintained at lower air temperatures when an occupied space is radiantly heated. The net result is comfort as well as energy savings.
Zoned hydronic systems also allow owners to purposely keep some low use locations, at lower temperatures, which also lowers heat loss and reduces fuel consumption.
Hydronic systems have a long life expectancy with nominal but regular maintenance. In the case of the DSH system, the system requires a simple flush every 5 years and solar panel cleaning. Pumps are designed to last for many years.