US Benchmarking

Hospitals are the 2nd most energy intensive building type in the United States according to the Commercial Building Energy Consumption Survey (CBECS).

The energy breakdown by end use in a US hospital can vary depending on several factors such as the hospital size, location, number of beds, operational practices, and energy efficiency of the facility, but for most large hospitals, heating energy is the largest single end use - by a wide margin. "Targeting 100!", a groundbreaking study of hospitals in the Pacific Northwest, helped many of us see the absurdity of this fact and show us a path to improve. According to Targeting 100!, healthcare buildings account for less than 1% of all commercial buildings, and 2% of all commercial floor space, yet account for 5.5% of commercial building energy consumption (EIA, 2012). The primary energy end uses in a hospital can be broken in to the following categories:

1. Space heating and cooling: Hospitals require a significant amount of energy for heating, ventilation, and air conditioning (HVAC) systems to maintain comfortable temperatures and air quality. Space heating and cooling typically account for a substantial portion of the energy consumption in hospitals.
2. Lighting: Hospitals operate 24/7 and require extensive lighting throughout the facility, including patient rooms, hallways, operating rooms, and other areas. Lighting can represent a significant portion of the energy usage.
3. Medical equipment: Hospitals rely on a wide range of medical equipment, including imaging systems, surgical tools, diagnostic equipment, and life support devices. These devices consume energy while in operation.
4. Water heating: Hospitals use hot water for various purposes such as patient care, cleaning, and sterilization. Water heating systems contribute to the overall energy consumption in a hospital.
5. Refrigeration: Hospitals require refrigeration for storing vaccines, medications, and blood products. Refrigeration systems can consume a notable amount of energy.
6. Plug loads such as computers and electronics: Hospitals have a substantial number of computers, servers, and electronic devices for administrative tasks, patient records, and other operational needs. These devices contribute to energy consumption.
7. Other support systems: Other energy-consuming systems in hospitals may include elevators, escalators, laundry facilities, kitchen equipment, and other support systems.

Figure 1: Average Hospital Baseline Energy Usage, Source: Targeting 100!

International benchmarking

The following chart compares hospital energy consumption between across various countries and regions. The study shows that comparatively North American hospitals use the most energy and German hospitals use the least, on average. The data is disaggregated where possible by electrical vs. natural gas utilization. The data in this chart was compiled from several sources available to the authors of this study as noted in the Y axis including (a) CADDET 1997 [9], (b), CBECS 2012 [10], (c) HTM 07-02 2015 [11], (d) Targeting 100! [12], (e) Gonzales 2018 [13], (f) TNO [X]

Figure 2: Benchmarking of International Hospital Energy Use

North American hospitals, which use a design approach similar to ASHRAE 170 and CMC Table 4-A, are the highest energy consumers internationally. UK hospitals, whose ventilation systems fall under HTM-03-01, use somewhat less. Hospitals in the Netherlands, Sweden, Switzerland, and Germany, whose ventilation system approach is governed by or similar to Germany’s DIN-1946, have the lowest energy consumption.

There are significant differences in international health care ventilation standards. Several papers have reviewed the variances between (1) ASHRAE-170 Ventilation for health care facilities (US), (2) DIN-1946 – VAC systems in buildings and rooms used in the health care sector (Germany), (3) HTM-03-01 Specialized ventilation for health care premises (UK), and (4) UNE 100713 Instalaciones de acondicionamiento de aire en hospitales (Spain). The comparison identifies the minimum (i.e. most permissive) ventilation requirements in six different requirement areas: outdoor air ventilation, total room air ventilation, supply air filter efficiency, room temperature, room humidity, and room pressurization. Results are normalized to common units, and compared.

Sources

Minimum Ventilation Requirements in Patient Areas: A Comparison of International Standards http://tinyurl.com/gt49bjr

Minimum Ventilation Requirements in Operating and Procedure Rooms: A Comparison of International Standards. http://tinyurl.com/hesathx

Benchmarking the US and UK Healthcare Ventilation Standards. http://tinyurl.com/jwr8lsf