Data from the US Energy Information Administration’s Commercial Buildings Energy Consumption Survey indicate that congregations in the United States spend about $1.00 per square foot (ft2) annually on energy. These expenditures include about 4.5 kilowatt-hours (kWh) of electricity per ft2 and about 41,500 Btu per ft2 of other energy sources, primarily for heating and hot water (figure 1).

Average energy use data

Figure 1: Energy consumption by end use

On the national level, although cooling and ventilation represent significant electrical loads in congregational buildings, miscellaneous plug loads—like amplified musical instruments, audiovisual equipment, and microphones—consume the most electricity in houses of worship. And where natural gas consumption is concerned, space heating is far and away the largest energy consumer.

A pie chart showing electricity end uses for congregational buildings in the US Census division: miscellaneous, 36%; other, 20%; cooling, 17%; ventilation, 16%; and lighting, 12%. The Other category includes refrigeration, office equipment, computing, heating, cooking, and water heating.A pie chart showing natural gas end uses for congregational buildings in the US Census division: heating, 77%; cooking, 12%; and water heating, 11%.

Congregational buildings are similar to commercial buildings, although facility specifics can vary. Your facility may have different occupancy levels, hours of operation, and needs depending on your worship schedule and other activities, such as community programs, daycare, soup kitchens, hostels, or computer training. In addition to a worship area and staff offices, your congregational building may include a cafeteria, bookstore, social and educational meeting rooms, high-end multimedia audiovisual systems, and capacity for thousands of congregants. You can implement some efficiency measures with little or no investment by managing these spaces. Often, improvements that require a larger initial outlay can pay for themselves quickly and, if planned well, can enhance the comfort of your building.

Quick fixes

Your congregation likely relies on members, volunteers, and paid staff to fund, operate, and maintain your buildings. Committees or multiple people within the congregation may oversee your budget and many of your building’s operations. Turning things down or off and properly maintaining equipment are quick fixes that members, volunteers, and staff can do. You should also simplify your building’s systems so they’re easier to operate.

  • Make controls for water, lighting, heating, and cooling accessible and usable by all.
  • Label all panels and switches.
  • Educate your congregation about your building’s energy usage.
  • Brief your congregation on how to use the systems you have and on the importance of turning things off and down.
  • Consider posting energy bills to raise awareness.

Turning things off

Turning things off seems simple, but remember that every 1,000 kWh you save by turning things off equals $120 off your utility bill (assuming average electricity costs of $0.12 per kWh). Turning things off is your congregation’s number one priority to save energy.

Lights Turn off lights when they’re not in use. Occupancy sensors can be cost-effective, but a less-expensive alternative is to post reminders to encourage worshippers and custodial staff to switch off lights. Be sure to turn off lights in parking areas when the lot isn’t in use or you don’t need light for security. Turn off lights in lobbies, entries, and vestibules that may already have plenty of daylighting.

Plug loads Plug loads are electrical devices such as computers, task lights, and fans that are plugged into electrical outlets and may continue to draw power even when the appliance is turned off. For maximum energy savings, unplug these appliances.

Have your staff switch computers to sleep-mode settings when no one is using the machines. The typical desktop computer, monitor, and shared printer draw about 200 watts, with the monitor alone drawing about 100 watts. Use smart power strips that will automatically turn off plug loads (such as monitors, printers, copiers, and audiovisual equipment) when they’re not in use. A smart power strip has an occupancy sensor or a programmable timer that turns equipment on and off. Other smart power strips, designed for computers, have a master outlet for the computer; when the computer is turned off, all other equipment plugged into the power strip is also turned off.

Vending machines Disconnect the ballasts for advertising lights in vending machines. Not only do the lights cost money to run, they also add heat to the refrigerated compartment. Turning off a vending machine light can save about $100 a year. For more information, see our article on vending machine energy savings.

Turning things down

Some equipment can’t be turned off entirely, but turning it down to minimum levels where possible can save energy.

HVAC temperature setbacks Use programmable thermostats to adjust temperature settings when educational, meeting, and office spaces aren’t in use. These thermostats are far more reliable than manually operating your heating system. Purchase thermostats that can program a week’s worth of regular meetings. For unscheduled activities, post clear operating instructions for members, volunteers, and staff.

Heating and cooling for occupancy Certain parts of a congregation, like your worship space, are only used during specific times of the day or week. Make sure that HVAC settings are at minimum levels during nonuse periods.

Water heaters Ensure that water heaters are set no hotter than 120° Fahrenheit (F) to avoid wasting energy. Bathrooms and kitchens used primarily during worship services are often good targets for lowering water temperatures.

Cleaning and maintenance

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 lower than 14°F or higher than 22°F, have a licensed technician inspect your air-conditioning unit.

Perform regular maintenance Your rooftop air-conditioning unit (RTU) will perform better if you do routine checks on a regular basis. Change filters on a monthly basis; change them more often if your building is next to a highway or construction site where the air is much dirtier. At the beginning and end of the cooling season, thoroughly wash the coils. Check them quarterly for debris and wash as necessary. And on a quarterly basis, make sure the panels are fully attached with all screws in place and verify that gaskets are intact so no air leaks out of the cabinet. Chilled air leaking out can cost $100 per RTU per year in wasted energy. For more information, see our article on packaged rooftop units.

Check airflow Hold your hand in front of 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 ductwork. Trim or move shrubs away from cooling equipment.

Direct airflow If you don’t use all the spaces in your building or have uneven occupancy and use, direct forced air to where it’s needed by closing and opening vents. If some rooms overheat while others are too cool, call in a qualified heating contractor to balance the distribution of conditioned air. Another way to balance warm airflow is to cover the metal discharge grilles in rooms that overheat or overcool.

Close vents Many older buildings have natural ventilation systems to remove hot air in the summer in place of air-conditioning. Close these vents in the winter, or they’ll exhaust air that your congregation has paid to heat.

Check your economizer Many air-conditioning systems use a dampered vent called an economizer to draw in cool outside air, when available, to reduce the need for mechanically cooled air. Have a licensed technician check, adjust, clean, and lubricate your economizer each year. One stuck in the open position will allow too much hot air in during the air-conditioning season and too much cold air in during the heating season. That can add up to 50% of your annual HVAC costs. If necessary, adjust the outdoor intake setting on your economizer.

Use desiccants for cooling If you’re in a humid region, use desiccants (drying agents) in the air-conditioning system to remove moisture from the incoming air. Air that has been dehumidified requires less energy to cool than humid air. Desiccants also contribute to a drier, cleaner, and more comfortable environment.

Water use and water heating Insulate your hot water pipes by wrapping the first 3 to 6 feet of hot water supply with pipe insulation. Fix leaky faucets, showerheads, pipes, and toilets.

Monitor and measure Use a device like a Kill A Watt to meter electricity usage in appliances and office equipment before and after turning them down and off to demonstrate and encourage savings. Visit your building in the very early morning hours to note temperatures, lights, and sounds; then take measures to reduce unnecessary overnight energy usage. You can monitor energy usage by reading meters morning and night or by using a data logger to record measurements of temperature, relative humidity, light intensity, and amperages.

Long-term solutions

Energy audits

A comprehensive energy audit can identify the most cost-effective improvements to congregational buildings and the energy-consuming equipment they contain. The Interfaith Coalition on Energy, an organization dedicated to working with congregations to reduce the costs of operating their facilities, provides energy audits to congregations. Other organizations familiar with the unique characteristics and energy requirements of congregational buildings are The Regeneration Project of California and its affiliate, Interfaith Power & Light, which has state-based programs.


Commissioning is a process in which engineers check and tune up building systems to make sure they’re operating appropriately and efficiently. If possible, choose engineers with expertise in commissioning congregational buildings. A quick solution is to reset your HVAC controls that, over time, may have been set to unnecessary levels. By consistently monitoring and maintaining your energy systems, studies have shown that you can reduce your energy consumption by 10% to 15%. Commissioning costs vary from $0.05 to $0.50 per ft2.


LED lights LEDs use far less energy, last multiple times longer than other light sources, and are more durable. They have fallen in costs in recent years and consume 85% less energy than older incandescent bulbs. You can purchase a 60-watt-equivalent LED bulb online for $3.50, and many utilities periodically sponsor sales or subsidies in hardware stores. Savings from a single bulb replacement can be as much as $45 per year. LED lights are also great for exit and other signs in your building, as well as holiday decorations. And they can last 15 years.

Fluorescent lamps If your building uses T12 fluorescent lamps, relamping with modern LED troffers and tubes can reduce your lighting energy consumption by as much as 50%. Adding specular reflectors, new lenses, and occupancy sensors or timers can double the savings. Paybacks of less than a year are common.

Daylighting Take advantage of daylighting where possible to reduce the need for electric light. But, proper design is critical to avoid glare and overheating. Light shelves, installed high on the inside or outside of a window, will shade and prevent glare in the bottom 6 feet of a floor, which is where most staff work. The shelves also reflect daylight up onto the ceiling, which indirectly illuminates a room (figure 2).

Figure 2: Increase daylighting with light shelves

Light shelves reduce glare and reflect sunlight onto the ceiling, distributing daylight further into the building.
Figure 3: Increase daylighting with light shelves

Daylighting sensors Install light sensors, a type of daylighting system, in offices, bathrooms, kitchens, and worship areas to turn on lights in the space only when daylight is insufficient.

Occupancy sensors Install occupancy sensors in bathrooms, utility closets, and other less-used spaces to control lighting in response to movement. Occupancy sensors may also be suitable for other building spaces, such as staff offices. In addition, you can use occupancy sensors to control plug loads. Plug-load sensors range from devices that control a single electrical outlet or piece of equipment to devices that control multiple outlets or a power strip; they can work together with other sensors. Built-in occupancy sensors can shut off plugged-in devices like printers, monitors, and copiers when nobody is in the area.

Smart lighting design in parking lots In its Lighting Handbook, the Illuminating Engineering Society of North America recommends that parking lots be lit at an average of 1 foot-candle or less of light, but most parking lots are designed with far more lighting than that. Using lower-wattage bulbs can actually increase the safety of your lot. An overlighted lot can be dangerous to drivers if their eyes can’t adjust quickly enough in the transition from highly lit to dark areas.

LEDs are well-suited to lighting parking lots. They have longer lifespans, are more efficient, and have dropped in cost. LEDs can cut energy consumption by 40% to 70% compared to high-pressure sodium lamps and can use less than half the energy of metal-halide lamps.

Photocells and timers Install lighting controls such as photocells or timers on outdoor lighting. A photocell control will turn on a light at dusk and turn the light off when the photocell detects daylight.


High-efficiency HVAC units A highly efficient packaged air-conditioning and heating unit can reduce cooling energy consumption by 10% or more over a standard-efficiency, commercial packaged unit. Select equipment that has multiple capacity levels (compressor stages) with good part-load efficiency. Don’t oversize your HVAC system if you don’t use all the spaces in the building or if there’s an imbalance in the amount of use spaces get. If your existing system is old enough, it may be cost-effective to replace it with a new one. A qualified energy auditor, preferably one who’s familiar with congregational buildings, can determine which measures are most cost-effective for your building.

Zoned HVAC An HVAC zone consists of a number of rooms that have a similar function and similar heating and cooling needs. Consider a separate HVAC system for more frequently used zones in the building that have a similar function and need, such as staff offices.

Demand-controlled ventilation For spaces that have large swings in occupancy, you can save energy by decreasing the amount of outdoor ventilation air supplied by the HVAC system during low-occupancy hours. A demand-controlled ventilation (DCV) system senses the level of carbon dioxide in the return air stream, and, using that as an indicator of occupancy, the system decreases the amount of outdoor air supplied to the space when carbon dioxide levels are low. DCV systems are particularly applicable to areas like worship spaces, meeting rooms, and cafeterias.

RTU controllers

If your building is cooled by RTUs, consider installing RTU controllers. These allow RTUs that are run on single speeds, for single zones, to operate in variable-speed modes. These controllers offer RTU energy savings of 25% to 50% for single-zone cooling with a capacity of 5 tons or greater. Simple payback periods are between one and five years.

Building construction

Insulation, secondary glazings, and weather-stripping Older congregational buildings are notoriously energy inefficient because they leak air to the outside (known as a building envelope). To tighten your facility’s building envelope, inspect or install insulation, secondary glazings, and weather-stripping. If your congregation’s buildings leak but are used intermittently, such as a small church used only for Sunday services, these measures may not necessarily be cost-effective. Work with a qualified energy auditor to determine which of these measures are cost-effective for your building.

Entries Entryways allow heating and cooling to escape your building when your building has high occupancy. To reduce losses, construct an interior divider, separating the entryway from the worship or common area of the building.

Windows Replacing windows is expensive. In cold climates, your congregation may find it cost-effective to replace old, single-pane windows with more energy-efficient (low-emissivity) windows. If new windows aren’t cost-effective, an alternative is applying window film, which typically costs between $1.35 and $3.00 per ft2 to install. Window film generally has a lifetime of 7 to 12 years, but it must be installed properly to avoid bubbles, cracks, or damage to your windows.

Window film isn’t appropriate for stained glass windows because they’re uneven. For stained glass windows, protective glazing such as laminated glass or polycarbonate will decrease drafts, but without proper ventilation and glazing may damage the stained glass. On plain-glass windows, use window treatments like drapes and shades and, on walls of south-facing windows, awnings or window film to block solar heat gain in the summer and reduce air-conditioning.

Cool roofs These aren’t suitable for all congregations, but if your roof needs recoating or painting, consider a cool roof—one that’s white or some other highly reflective color—to minimize the amount of heat the building absorbs. This change can often reduce peak cooling demand by 15% to 20%.

Landscaping Deciduous trees planted on the west- and south-facing sides of your building will shade windows, reducing solar gain and air-conditioning needs during the summer months.

Appliances and equipment

Purchases Upgrading old appliances to newer, more-efficient models can go a long way in reducing your energy consumption. Some common appliances you may want to replace are:

  • Freezers
  • Refrigerators
  • Dishwashers
  • Room air conditioners
  • Water heaters
  • Furnaces
  • Boilers
  • Ice makers
  • Washing machines

Look for the ENERGY STAR label on many appliances, and compare their energy usage to other models. The ENERGY STAR website has a listing of appliances and products that have earned the ENERGY STAR label. For computers, also look for the 80 PLUS label, which indicates that the computer has an energy-efficient power supply. Visit the 80 PLUS website for a list of suppliers.

Maintenance Disconnect unused equipment like refrigerators, freezers, and water heaters, and keep the appliances you do use in good condition. A refrigerator, for example, operates more efficiently when door seals are tight, condenser coils are clean, frost is removed, and airflow for exhaust heat is allowed sufficient clearance.

Water use and water heating

In addition to insulating hot water pipes and fixing leaks, consider installing sink and shower controllers that automatically shut off after a certain length of time. Low-flow faucets and showerheads can also help conserve energy used to heat hot water.

Explore new ways to heat and cool

If you’re planning a comprehensive renovation of your heating and cooling system, consider some energy-efficient alternatives.

Geothermal heat pumps Also known as ground-source heat pumps, these systems rely on the thermal stability of the ground to heat and cool a building. Because the ground temperature below the frost line remains relatively constant throughout the year, it can be used as a heat source in the winter and a heat sink in the summer. The first costs of a geothermal heat pump can be slightly higher than those of other systems, but the life cycle costs are often lower. The energy consumption of geothermal heat pumps can be 25% to 50% less than that of traditional heating and cooling systems.

Evaporative cooling An evaporative cooling system uses the natural cooling of evaporation, a tactic that’s especially effective in warm, dry climates. It typically uses less than 25% of the energy of a vapor-compression air-conditioning system. First costs may be higher than for a vapor-compression system, but paybacks can be rapid—six months to five years, depending on climate.

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