March 17, 2004
Energy efficiency is not just for new buildings; building supers, owners, and tenants can employ basic-cost effective strategies to lower energy costs and the use of fossil fuels. Tom Sahagian, Project Manager at Powerconcepts, LLC, discussed some of these techniques this past St. Patrick’s Day at GreenHomeNYC’s March Forum “Energy Efficiency for Small Buildings.” Most of the strategies Tom discussed were no- or low-cost, and rarely involved big ticket items like a new boiler or hot water heater. Rather, he emphasized such things as building controls, insulation and envelope sealing, energy efficient appliances and lighting, and offered options that both tenants and building managers could do.
Specifically, Tom discussed the following:
- Burner tune-ups
- Steady state efficiency kit for boiler test
- Bi-level lights in hallways
- LED exit signs
- Occupancy sensors for lighting in common areas (e.g. laundry and compactor rooms)
- Lighting technology
- Timers for rooftop ventilation fans
- High efficiency, EnergyStar refrigerators and appliances
- Low flow showerheads and faucet aerators
- Energy management systems
- Boiler insulation
- Water pressure booster
- Boiler tune-up
- DHW recirculation control
- Apartment submetering
- Air conditioner covers
- Double-pane, low-emissivity, argon filled windows
Most of the strategies Tom spoke about are extremely simple. For example, a clean boiler room that is properly lit allows for better maintenance; and proper maintenance can improve the efficiency of the boiler. To maximize efficiency it is crucial to use tune-up instruments instead of tuning by eye. In addition, use of steady state efficiency kit to test oxygen levels and temperature of boilers and flues indicate when it is necessary to fix a boiler. Mr. Sahagian suggests using computer burner controls to program and tune boilers to optimize efficiencies. It is now possible to order burners with computer burner controls already included.
Condensing gas burners further improves the efficiency and operating cost of boilers by extracting the heat from the condensing water vapor before it venting it out the chimney. While there is a cost premium for condensing gas boilers, it will save money in the long run.
Domestic Hot Water (DHW)
The amount of energy used to heat water can be as great as the amount used to heat space, and therefore strategies to improve energy efficiency can have a significant impact. First, Mr. Sahagian advises to stay away from DHW Heaters that are not energy efficient and Energy Star labeled. Insulating pipes in unconditioned space can reduce energy waste as well. Also, the use of steam trapsâ€”a device that allows condensate and air to pass through, but not steamâ€”can improve system efficiency. Proper maintenance will ensure that traps do not leak and therefore it is beneficial to set-up a maintenance routine.
One measure that is very popular among tenants in NYC is the use of controls within living spaces to regulate temperature. Many New Yorkers only have the option to turn the radiator valve on or off, which means they are typically overheating their space when the radiator is on, and under-heating when the radiator is off. Thermostatic radiator valves offer a fix to radiator systems by automatically regulating the amount of heat passing through the radiator and into the apartment. The valves fit onto existing radiators and can be bought at hardware and home improvement stores. Whatâ€™s more, the valves tend to save lots of energy, since most apartments are generally overheated, with open windows to regulate temperature.
For systems that use fans as part of their heating or cooling system, fan coil thermostats can be retrofitted onto these systems as well. Fan coil thermostats allow for individual controls in each room and can control plug node, window air conditioning units, fan coil units, PTAC units and heat pumps. Newer models are wireless and battery operated, and therefore can be installed almost anywhere without wires running all over the apartment.
The vast majority of New York City buildings have centralized heat timer systems. Heat timers change the amount of time the boiler is on in an hour based on outside temperatures. Heat timers, used in conjunction with thermostatic radiator valves, are more efficient and less expensive than building management systems, which besides being expensive, are unable to balance out the systems. To maximize efficiency, the heat timer must be set-up properly.
Low flow showerheads cut water use, and consequently, the cost to heat water. These devices have a bad reputation due to the earlier versions disseminated decades ago. Today, however, there are showerhead designs that allow for good spray. In addition, faucet aerators further reduce water use and costs by mixing air bubbles with water to decrease the amount of water necessary to achieve the same pressure and feel.
Another strategy to decrease water and energy consumption is to buy front loading washing machines, as opposed to top loading. The front-loading machines use half (!) the water as their counterpart. They also require less detergent and are better for clothes.
Tiny building cracks and doorways that allow outside air to flow into buildings, leads to a chimney effect that pushes heated air up and out of the building through other cracks thereby wasting the energy used to heat the air and increasing energy costs. Properly sealing (caulking) doors and windows can stop this from occurring.
Tubular fluorescent fixtures are named according to the diameter of the tube (a.k.a. lamp); a T12 is a tubular lamp with a 12/8 (1.5 inch) diameter and a T8 is a tubular lamp with an 8/8 (one inch) diameter. T8â€™s are more efficient than T12â€™s, they have a short pay back period, and they fit into T12 fixtures. T5â€™s are even more efficient, but currently it is not possible to use them with existing fixtures, but are excellent for applications where the fixtures will be new as well.
Compact fluorescent lights (CFL) last ten times longer than standard incandescent light bulbs and use one-third the electricity. The longer a lamp is on, the greater the benefits of CFLs. They come in different designs, including ones for indoor and for outdoor use, and newer bulbs come in different colors (warm as well as cool) and fuller spectrum, so it doesnâ€™t feel like the old generation fluorescent lights.
Lights are usually on in apartment building stairwells and hallways 24 hours a day even when no one is using them. For safety (and perception of safety) reasons, people do not feel comfortable with the lights completely off when unoccupied and therefore are usually hesitant to install motion sensored lights that only turn on when someone is present. For these reasons, bi-level lighting is a great option. They are never completely off; instead, when noone is around they only use ten percent lumens and use 100 percent when people are sensed. There is a time delay so that maximum lighting levels remains on for approximately fifteen minutes.
Occupancy sensors as lighting controls can be retrofitted on to typical wall switches. The sensor turns on the lights when people enter a room and turns them off when no people are present. They work best when placed in a location that can view the entire room. If parts of a room are obstructed, it may be a good idea to install more sensors.
Tom Also Mentioned:
- Gas dryers are less expensive to run than electric dryers since electricity is more expensive than gas.
- Power strips reduce the electricity leakage of appliances that occur when the appliances are off
- Use EnergyStar air conditioners and refrigerators
- LCD panels for computers can reduce the electrical cost of computers and there is only a 3-4 year payback. (Plus, they look really cool!)
- Submetering offers the ability to keep people aware of their energy usage. Studies show that this feedback loop leads to a 20 percent reduction in usage.