A very important component of green building operations is conserving energy. Energy efficiency includes selecting efficient equipment, operating it wisely, and encouraging persons who use your building(s) to avoid wasteful practices.
Frankly, churches do not have a great reputation for energy efficiency. Church buildings tend to be built with a focus on the initial cost of construction rather than a long-range focus on operational costs. Lights are often left on in rooms that are not being used. Heating and air conditioning systems are often setup so that large areas must be conditioned even when only a few persons are gathering for a meeting.
ENERGY STAR Portfolio Manager
We encourage churches to use the EPA’s ENERGYSTAR® Portfolio Manager to rate the energy efficiency of their facilities. You will need to enter slightly more than a year of energy bills and information like your weekly operating hours and gross square footage. Portfolio Manager is a free tool in which all data is entered online. You can setup your account by going to www.energystar.gov/benchmark and choosing to create a Portfolio Manager login.
Portfolio Manager will compare the energy performance of your church to other places of religious worship. It uses daily temperature data collected by NOAA (National Oceanic and Atmospheric Administration) for each zip code as part of the score calculation. Typically, it takes Energy Star 20 to 30 days after the end of a month to obtain the temperature data from NOAA and upload it into the software. Therefore, after you upload a new energy bill it may take some time before it influences your score.
After you enter 12 months of energy use data and information about your facilities, you will receive an Energy Star score that ranges from 1 to 100. These scores are percentile ranks. Therefore, a score of 60 means that the church demonstrated greater energy efficiency than about 60% of the other places of worship that are part of EPA’s sample.
As churches take action to improve energy efficiency, Portfolio Manager can be a great tool to evaluate the impact of those changes because weather data is incorporated into the scores. As you do this, be aware that one of the characteristics of percentile ranks is that they have unequal units along their scale. This means that the difference between the 40th and 50th percentile ranks is smaller than the difference between the 1st and 2nd percentile ranks. Therefore, percentile ranks in the middle of the distribution tend to overemphasize differences in performance and percentile ranks at the ends of the distribution tend to under emphasize differences in performance. If you start with a score of 40 and make relatively modest improvements in energy efficiency, you may see significant changes in your Energy Star Score. If you start with a score of 95, it will take larger energy conservation measures to create significant changes.
Heating and Cooling Systems
We encourage churches to evaluate their heating and cooling systems. We recommend you inventory these systems recording efficiency ratings like EER and SEER values. Use resources like EPA’s Building Upgrade Manual to evaluate and prioritize changes. Time should be invested in evaluating if systems are working properly. Research indicates that even with new facilities investing in a commissioning process to evaluate HVAC functioning can pay dividends. Those with larger buildings and low ENERGY STAR scores are excellent candidates for implementing an extensive retrocommisioning process in which systems are tested and adjusted in an existing building to insure they are functioning optimally.
Churches should educate themselves about new technologies that improve energy efficiency. For example, replacing single speed motors with variable speed motors can improve the efficiency of ventilation systems. Energy recovery systems that capture conditioned temperatures from air flowing out of a building and use it to cool or heat incoming fresh air can save significant energy. For large rooms where occupancy numbers vary, carbon dioxide (CO2) sensors can be used to supply the amount of fresh air needed based on the occupancy of the room at a given time. Modern computer-based building management systems/ building automation systems/energy management systems (BMS/BAS/EMS) can provide integrated ventilation and lighting control with the ability to make adjustments based on scheduled activities in specific spaces. Wireless sensors are widely available for these systems that do not require running extensive wiring through building walls.
Churches may want to contract with a third-party to conduct energy audits of their facilities. Frankly, the quality of these audits vary greatly based on who is conducting the audit. A good format to follow is one that conforms to ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers) standards. ASHRAE’s Level I audit includes a review of energy bills and a brief visual survey of the building. Low-cost, no-cost, and capital improvements are identified to increase energy efficiency.
The ASHRAE Level II audit builds on the level I audit with a more detailed examination of energy use within the building. It includes careful evaluation of operation and maintenance practices. ASHRAE Level III focuses on more rigorous analysis and implementation of the capital intensive products identified in the prior audits.
Part of the cost of these audits is the time required to gather utility bills, information about existing equipment, and building operations practices. You may be able to reduce the cost of these audits by demonstrating that you already have an Energy Star score for the building and have collected relevant data about existing equipment.
Significant innovations in the energy efficiency of lighting systems have occurred over the past decade. We strongly encourage churches to research and try new products. In some cases the payback in energy savings can be quite dramatic. For example, if you have an older building with T12 fluorescent lamps with magnetic ballasts, converting to T8 lamps with electronic ballasts usually increases the quality of light while producing large energy savings. It is mainstream knowledge now to replace standard incandescent bulbs with compact fluorescent bulbs. The use of occupancy sensors to turn off lights in unoccupied rooms can produce great savings. New lighting technologies like LED lamps hold great promise. These bulbs use less energy, reduce maintenance due to longer bulb life, and reduce HVAC costs by producing less heat.
We encourage you to be assertive in adopting new technologies, but to test new products prior to widespread installation. For example, when compact fluorescent bulbs first were introduced the quality of many of the bulbs was quite poor. If you purchase low quality motion detectors, you are likely to receive reports of lights going off in occupied spaces. Some of the current generation of LED bulbs provide very low lumens (light). There are many great new products. We encourage you to use them, but only after testing on a small scale.
Energy Efficient Equipment
We recommend that churches implement policies that require the purchase of equipment like copiers, TVs, computers, and kitchen appliances that have demonstrated high energy efficiency. For example, some churches require the purchase of products with an ENERGY STAR label if the product is from a category rated by ENERGY STAR. We encourage you to walk through your building and examine what is plugged into electrical outlets. If you have vending machines on your property gather information about their energy usage. If you find electric space heaters plugged-in next to desks, seek to adjust your HVAC system so that these are not needed.
Green Approaches to Roofing Materials
The roofing materials you select can have an impact on the environment and the energy efficiency of your buildings. Dark, nonreflective surfaces absorb the sun's warmth. Throughout most of the world, energy savings can be achieved by using light, reflective roofing materials. Studies have found significant savings even in northern U.S. cities like New York City. Cool roofs can increase heating costs in the winter in cold climates. Yet, the increases are typically minimal because during winter the sun is low in the sky, it tends to be more overcast, and snow sometimes covers roofs. The savings achieved during the summer typically far outweigh any winter costs.
During the summer in southern U.S. cities, installing a light colored, reflective roof can result in a dramatic decrease in roof temperature. For example, one study conducted in Texas found that the average summer roof temperature was 43 degrees F lower when a black rubber roof was replaced with a white vinyl roof (Konopacki & Akbari, 2001).
Another solution to this issue is to install a green roof. New roofing technologies permit the installation of native or adaptive plants on roofs. This can be an expensive option, but it can provide additional insulation and beauty.
The consequences of using dark materials on exterior surfaces can extend beyond your property. In urban areas, the combined effect of dark surfaces can produce the Heat Island Effect. This can result in annual mean increases of 5 degrees F in cities. The added cooling cost and pollution produced in the summer for a large city can be quite dramatic.
Q: How do we obtain an ENERGY STAR score if we have multiple buildings on the same site that are not physically connected?
Konopacki, S. & Akbari, H. (2001). Measured Energy Savings and Demand Reduction from a Reflective
Roof Membrane on a Large Retail Store in Austin. Heat Island Group,