Hospitals in the U.S. use an average of 27.5 kilowatt-hours (kWh) of electricity and 110 cubic feet of natural gas per square foot (ft2) annually. In a typical hospital, lighting, heating, and hot water represent about 72 percent of total energy use (Figure 1), making those systems the best targets for energy savings.
In order to better manage your building's energy costs, it helps to understand how you are charged for those costs. Most utilities charge commercial buildings for their natural gas based on the amount of energy delivered. Electricity, on the other hand, can be charged based on two measures—consumption and demand (Figure 2). The consumption component of your bill is based on the amount of electricity, in kWh, that the building consumes during a month. The demand component is the peak demand (in kilowatts) occurring within the month or, for some utilities, during the previous 12 months. Demand charges can range from a few dollars per kilowatt-month to upwards of $20 per kilowatt-month. Because it can be a considerable percentage of your bill, you should take care to reduce peak demand whenever possible. As you read the following energy cost-management recommendations, keep in mind how each one will affect both your consumption and demand.
All of the conservation measures discussed for the short and longer term represent good investments. Most will not only save money but also ensure the comfort of your facility's patients and staff.
Many hospitals have tight facility budgets, so low- or no-cost reductions in energy expenditures are especially important.
Although it may seem like a simple measure to take, remember that every 1,000 kilowatt-hours (kWh) that you save by turning things off equals US$100 off your utility bill (assuming average electricity costs of 10 cents/kWh).
Lights. Turn off lights when they are not in use. Occupancy sensors can help, but a less expensive alternative is to train staff to turn off lights when they leave unoccupied rooms.
Computers. Computers are used intermittently in laboratories and offices and should employ sleep-mode settings or be shut off when the machines are not in use. The typical desktop computer, monitor, and shared printer draw about 200 watts, with the monitor alone drawing about 100 watts. "Smart" power strips with built-in occupancy sensors are available to shut off plugged-in devices like printers and monitors when no users are present.
Air-handling units. There may be large fan systems serving areas unoccupied at night—such as the cafeteria, educational areas, or offices—that can be shut off.
Some equipment cannot be turned off entirely, but turning it down to minimum levels where possible can save energy.
Operating-room air-handling setbacks. Many operating rooms have air-handling units that draw 100 percent of their supply from outside air, which needs to be heated or cooled depending on the season. In these rooms, install occupancy sensors or manual switches that will reduce the operating speed of the supply and exhaust fans when the rooms are unoccupied but will continue to maintain air-pressure relationships.
Room temperature setbacks. Not all rooms in a hospital are occupied 24 hours a day. Such rooms should have programmable thermostats that turn temperatures up in the cooling season and down in the heating season during hours of no occupancy.
You are charged three times for every drop of warm or hot water used or wasted—once for fresh water entering the facility, a second time for wastewater being disposed of, and again for the energy used to heat the water.
Review maintenance procedures. Many obvious water leaks simply go unreported. Ensure that leaks are found and repaired promptly.
Enlist the janitorial staff. Some faucets are not turned completely off. A vigilant janitorial staff can report any leaks immediately and make sure that all faucets are shut off.
Making sure that your HVAC system is regularly cleaned and serviced can help to prevent costly heating and cooling bills.
Check the economizer. Many air-conditioning systems use a dampered vent called an economizer to draw in cool outside air when it is available to reduce the need for mechanically cooled air. If not regularly checked, the linkage on the damper can seize up or break. An economizer stuck in the fully opened position can add as much as 50 percent to a building’s annual energy bill by allowing in hot air during the air-conditioning season and cold air during the heating season. About once a year, have a licensed technician check, clean, and lubricate your economizer's linkage, calibrate the controls, and make repairs if necessary.
Check air-conditioning temperatures. With a thermometer, check the temperature of the return air going to your air conditioner and then check the temperature of the air coming out of the register nearest the air-conditioning unit. If the temperature difference is less than 14° Fahrenheit (F) or more than 22°F, have a licensed technician inspect your air-conditioning unit.
Change filters. Filters should be changed on a monthly basis; they should be changed more often than this if you are located next to a highway or construction site where the air is much dirtier.
Check cabinet panels. On a quarterly basis, make sure the panels to your rooftop air-conditioning unit are fully attached with all screws in place, and also check to see that gaskets are intact so no air leaks out of the cabinet. If chilled air leaks out, it can cost US$100 per year in wasted energy per rooftop unit.
Clean condenser coils. Check condenser coils quarterly for debris, natural or otherwise, that can collect there. Thoroughly wash the coils at the beginning or end of the cooling season.
Check for airflow. Hold your hand up to air registers to ensure that there is adequate airflow. If there is little airflow or if you find dirt and dust at the register, have a technician inspect your unit and duct work.
You should also consider longer-term solutions. Although the actions covered in this section require more extensive implementation, they can dramatically increase the efficiency of your facility without compromising patient care or comfort. Ask your local utility's representative for more information about initiating such projects.
Commissioning is a process in which engineers observe a building and perform a tune-up to ensure that its systems are operating appropriately and efficiently. Studies have shown that continuously monitoring a building's energy systems can lead to reductions of 10 to 15 percent in annual energy bills. For the typical 100,000-ft2 hospital, that's equal to about US$35,000 in savings per year! Savings typically result from resetting existing controls to reduce HVAC waste while maintaining or even increasing comfort levels for occupants. Commissioning usually costs between 5 and 40 cents/ft2.
Look for Energy Star–qualified commercial food service equipment when making new purchases. Dishwashers, fryers, griddles, hot food–holding cabinets, ice machines, ovens, refrigerators, freezers, and steam cookers are all now available in energy-efficient models. Energy Star–rated steam cookers use about 2 gallons of water per hour compared to the 25 to 30 gallons used by standard models, and their improved design, components, and insulation make them about 60 percent more energy efficient. A combination oven, operating in moist heat mode, can consume 30 to 40 gallons of water per hour, while an Energy Star model reduces water use to about 10 to 15 gallons per hour by spraying a water mist on the heat exchanger, saving more than 100,000 gallons per year. Replacing a 2.6 gallon pre-rinse spray valve, used to remove food particles from dishware, with a 1.6 gallon low-flow model can save about 66,000 gallons per year when operated three hours per day. You may save as much in energy costs as in water costs, depending on your water heater type and utility costs.
For more ideas about efficiency opportunities in the kitchen, see Managing Energy Costs in Restaurants.
Take advantage of daylighting where possible to reduce the need for electric light—proper design is critical to avoid glare and overheating. If your facility uses T12 fluorescent lamps, relamping with high performance T8 lamps and electronic ballasts can reduce your lighting energy consumption by 35 percent. Adding specular reflectors, new lenses, and occupancy sensors or timers can double the savings. Paybacks of one to three years are common. Compact fluorescent lamps (CFLs) can replace incandescent lamps in many applications, reducing energy use by two-thirds and saving up to $20 per lamp per year. Light-emitting diode (LED) exit lights that consume only 2 watts represent a great energy savings over incandescent fixtures, and they are easier to maintain because of their long service life.
Hospitals have many rooms that are used periodically, such as restrooms, storage rooms, break rooms, and offices. For work areas, a combination of occupancy sensors, time switches, and local override controls can accommodate people who arrive early or stay late.
Water and sewer costs can average over 20 percent of a hospital’s total utility costs. Utility incentives may be available for some of these retrofits.
Install low-flow faucet aerators. Installing a 1.5 gallons-per-minute low-flow aerator (which costs about $10) on a faucet that is on one hour per day will save around $300 per year in energy costs.
Replace older fixtures with low-flow faucets, showerheads, and toilets. Low-flow showerheads can save about 4 gallons of water per person, per day. The U.S. Federal Energy Management Program found that using low-flow faucets and showerheads allowed the Portland, Oregon Veterans Affairs Hospital to save about $17,000 annually, with a payback of less than one year.
Install water-saver kits on autoclaves and sterilizers. A continuous supply of cold water is often routed down the drain to cool the high temperature condensate even though these devices tend to be run intermittently each day. In 41 laboratories across its campus, Colorado State University installed water-saver kits to monitor the temperature of the drain line and inject cold water only when needed. The university achieved annual water savings of over 15 million gallons, annual cost savings of over $59,000, a 1.4-year payback, and a return on investment of 72 percent.
Laundry systems consume large amounts of energy to heat water. Following are some options to consider that are more energy-efficient.
Use ozone laundering. This method performs better than traditional technology on some stains—including Betadine and blood—but worse on others. It saves energy, requires less detergent, and uses much less water. Although this technology does have a different cost structure than the conventional methods (an ozone generator is required, and the system needs more maintenance), a two-year payback period is often possible. It is important to select a vendor that has an effective maintenance support network.
Reduce temperatures. Hospital laundry can be safely washed at lower temperatures. The common practice of laundering in water at 160° Fahrenheit (F) is outdated. Modern detergents and bleaches allow hospital laundry to be effectively washed at 120°F.
Recycle water and heat. Another efficient laundry system uses a storage tank or pit to extract the heat energy from the washer's wastewater to preheat incoming raw water. Additionally, final rinse water can be recovered in a holding tank and used for the first wash cycle of the next dirty load. Microfiltration systems remove particles as small as 0.5 microns from laundry wastewater so that the water can be reused. This not only saves heat energy but also cuts down on your water bill.
Cogeneration systems provide both heat (for space or water heating) and power. They have more applications and offer more savings potential for hospitals than for any other class of commercial building. Some hospitals are installing advanced incineration systems to destroy medical waste. Capturing and using the waste heat from incinerators can be cost-effective in some cases. The University of Michigan saved $400,000 in yearly steam bills by coupling medical waste incinerators with cogeneration.
Laundry and kitchen operations can all benefit from heat-recovery systems. Waste heat from boiler exhaust stacks can also be effectively recovered and used to preheat boiler makeup water.
A water-side economizer evaporatively cools water in a cooling tower and delivers it to a building’s chilled water coils via a flate plate heat exchanger. In northern climates, the opportunity for free cooling with a water-side economizer typically exceeds 75 percent of the total annual operating hours, whereas in southern climates, such free cooling may only be available during 20 percent of the operating hours. Typical payback periods from energy savings range from 2 to 5 years.