Combination systems are typically designed to deliver what percentage of the calculated heat loss for a building?

Combination systems are typically designed to deliver between 95% to 105% of the calculated heat loss for a building. This range allows for flexibility and ensures that the heating system can adequately meet the demands of the building under various weather conditions and usage patterns. Designing a system to this percentage provides a buffer to account for heat losses due to factors such as inadequate insulation, drafts, or changes in occupancy.

Options indicating 120% or any higher percentage, like 200%, would create an oversizing scenario, which can lead to inefficiencies, increased operational costs, and discomfort due to frequent cycling of the heating equipment. On the other hand, a design of 90% might be insufficient to maintain comfortable conditions, particularly during severe weather. Therefore, the optimal design falls within the range of 95% to 105%, ensuring reliability and efficiency in heating performance.