What can lead to discrepancies between estimated and actual energy use in homes?

Discrepancies between estimated and actual energy use in homes often arise from inaccurate assumptions and unforeseen occupant behavior. When energy modeling is conducted, the assessment typically relies on standard profiles and typical usage patterns to project energy consumption. However, real-life factors such as individual occupant habits, preferences, and lifestyle choices can significantly alter energy consumption patterns.

For example, if occupants tend to keep windows open instead of using air conditioning, or if they operate appliances more frequently than average, the real energy usage could vary widely from the predictions made during the design phase. This unpredictability in human behavior, along with assumptions that may not hold true in practice – such as the degree of occupancy, the amount and types of equipment used, and the interaction of occupants with the home’s energy systems – contribute to these discrepancies.

Therefore, it is this combination of assumptions that may not align perfectly with actual usage, along with the unique behaviors of occupants, that explains why the correct answer focuses on these factors. Other options, such as careful planning, improved insulation, and regular maintenance, generally contribute to a more efficient energy system but do not directly account for the human element that affects energy use variability.