Unmasking the thermal behavior of single-zone multi-room houses: an empirical study

Ozan Baris Mulayim, Mario Berges

Abstract: In single-zone multi-room houses (SZMRHs), temperature controls rely on a single probe near the thermostat. This practice often results in temperature discrepancies that cause both thermal discomfort and energy waste. Automatic vent registers, among other similar solutions, have faced adoption barriers due to installation, cost, and maintenance constraints. Utilizing per-room sensors with smart thermostats (STs) to control based on average temperature has gained acceptance by major ST manufacturers and demonstrated initial potential to diminish thermal discomfort. This paper empirically characterizes temperature discrepancies in SZMRHs and studies their effects, particularly with respect to thermal comfort and demand response (DR). Our aim is to leverage room-level data sourced from 1000 houses across the United States and two real-world testbeds to identify the shortcomings of SZMRHs and to diagnose the deficiencies via parameter identification. We discover that comfortable DR durations (CDRDs) for rooms are typically 70% longer or 40% shorter than for the room with the thermostat. When averaging, rooms at the control temperature’s bounds are typically deviated around -3°F to 2.5°F from the average. Moreover, in 95% of houses, we identified one or two rooms experiencing notably higher solar gains compared to the rest of the rooms, while 85% and 70% of houses demonstrated lower heat input and poor insulation, respectively. This study serves as a benchmark for assessing thermal comfort and DR services in the existing housing stock, while also highlighting room-level retrofitting needs. Our approach sets the stage for more granular, precise control strategies of SZMRHs.