Which hot water system is considered to have the lowest installation cost?

The series loop system is recognized for its lower installation cost primarily due to its straightforward design and fewer materials required. In a series loop system, water is heated and then circulated through a series of connected units, such as radiators or convectors, in a single circuit. This means the same water can serve multiple heating units without the need for additional piping or complex connections, leading to significant savings on both labor and material expenses during installation.

Additionally, the system utilizes a simpler layout, which reduces the complexity involved in installation. Fewer pipes mean less time is needed to install, leading to lower labor costs. Since the water is not circulated independently through each unit but instead flows sequentially from one to another, there is typically a reduction in balancing and control systems required, further simplifying the processes involved.

In contrast, other options such as two pipe reverse return systems or radiant floor heating systems typically involve more complex designs with multiple piping routes, requiring more extensive labor and materials, thus raising installation costs. The single pipe system offers some cost-effectiveness but may not be as efficient as the series loop in terms of material usage and complexity.