Energy Efficient Upgrades : HVAC Systems

Proper heating, ventilating, and air-conditioning (known in the trade as HVAC) are key to maintaining a comfortable, healthy and productive work environment. Collectively, these systems account for approximately 40% of the electricity used in commercial buildings. Improved heating and cooling performance along with substantial energy savings can be achieved by implementing energy-efficiency measures.

Whether you wish to improve the efficiency of your existing heating and cooling systems or are considering upgrading to a new system, the information on this page will help you to make informed decisions!

• Cooling and Heating Load Reduction
• Heating and Cooling Systems
• Control Systems
• Maintenance

Cooling and Heating Load Reduction

One of the first steps you should consider in your facility before upgrading your heating and cooling system is to reduce your load (i.e. how much heating and cooling you actually use). Reducing your facility's load allows existing systems to operate less frequently and newer systems to be designed smaller, thereby lowering operating costs. Common load reduction strategies include:

• "Tightening" your building shell and adding additional insulation to reduce leakage.
• Installing energy-efficient windows such as ENERGY STAR qualified windows.
• Upgrading lighting systems. Energy-efficient lighting systems emit less heat into conditioned space than older inefficient technology.
• Reducing solar gain (e.g., cool roofing and window tints) in cooling dominated climates, and in cold climates taking steps to increase solar gain.
• Selecting efficient office equipment and consumer electronics to reduce heat output.
• Controlling ventilation to improve occupant comfort and save energy.

Once you have addressed these areas, you can then make the most of your heating and cooling equipment dollars.

Heating and Cooling Systems

Heating and cooling systems are critical to most businesses, but also represent a large component of many facilities' utility expenses. Cooling systems, in particular, are typically very energy intensive and are almost always fueled by electricity. Their operation typically coincides with periods that are subject to peak and time of use charges. Heating and cooling systems have advanced significantly in design and efficiency. For example, today's air conditioners use 30% to 50% less energy to produce the same amount of cooling as air conditioners made in the mid 1970s. Even if your air conditioner is only 10 years old, you may save 20% on your cooling energy costs by replacing it with a newer, more efficient model.

Heating and Cooling System Tips:

• Consider implementing efforts to reduce heating and cooling load before selecting equipment.
• NEVER OVERSIZE! Avoid over sizing equipment at all costs. Over sizing equipment increases the capital cost at the time of the installation and the costs of operation of the equipment. Request that your HVAC professional conduct an Air Conditioning Contractors of America's (ACCA) Manual N Commercial Load Calculation to ensure proper sizing.
• When selecting a new cooling system, have your HVAC professional provide you a quote and specifications for a standard-efficiency and high-efficiency unit including lifecycle costs. If the lifecycle cost is less on the high-efficiency unit, purchase it.
• When purchasing Room Air Conditioners or Light Commercial heating and cooling units, select those units that are ENERGY STAR qualified.
• Consider energy recovery ventilation systems to reclaim waste energy from the exhaust air stream and use it to condition the incoming fresh air.
• In humid climates, consult your HVAC professional about supplemental dehumidification. By controlling humidity at your facility, you can increase occupant comfort and allow for further downsizing of equipment.
• Consider specifying economizers. Often available at a low incremental cost, these units draw in fresh air from the outside when the temperature outside is lower than the temperature inside.
• Install programmable thermostats and use automated settings to achieve savings.
• At a minimum, specify National Electrical Manufacturers Association (NEMA) premium motors on HVAC equipment, and consider specifying variable speed drives (VSD) on condenser and evaporator fans.
• In dry climates, consider evaporative coolers. These coolers use the evaporation of water to cool spaces, eliminating the need for energy intensive compressors.
• For facilities that have heat-generating processes such as cooking, or onsite distributed generation equipment, consider heat recovery as a way to capture free waste heat and use it to offset facility heating and cooling costs.
• For areas such as warehouses and garages, consider installing radiant heating . Radiant heating warms objects instead of the air, and requires less fuel. Radiant heat is also useful for warming exterior areas that require heating, such as patios and waiting areas.
• Many buildings are impacted by what goes on inside the building just as much as (and sometimes even more than) the weather conditions outside. That is why it is important to properly size equipment and consider the use of a demand controlled ventilation system coupled with economizers to meet the internal loads of the building, e.g., commercial kitchens, computer data centers, etc.

Heating and Cooling System Energy-Efficiency Resources

• ENERGY STAR Qualified Products: Heating & Cooling Efficiently
• EPA Indoor Air Quality (IAQ) Resources
• DOE EERE Consumer's Guide: Space Heating and Cooling
• American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE)
• Air Conditioning Contractors of America Resources
• FEMP Energy-Efficient Products: How to Buy an Energy-Efficient Commercial Unitary Air Conditioner
• Consortium for Energy Efficiency: High-Efficiency Commercial Air Conditioning & Heat Pumps
• Flex Your Power's Heating, Ventilation and Air Conditioning (HVAC) Systems

Control Systems

A great way to improve the efficiency of heating and cooling systems is to incorporate control strategies that ensure systems are used only when necessary. Common control strategies include ENERGY STAR qualified programmable thermostats, multiple zones, and CO2 demand sensors. These strategies can be specified on new heating and cooling systems and retrofitted to older systems as well.

• ENERGY STAR Qualified Programmable Thermostats: These simple, easy to install thermostats allow convenient night/weekend setback to save you money. Models range from $50 to $200 depending on the desired features and usually include manual overrides to ensure comfort for late night workers.
• Multiple Zones: By dividing your facility up into multiple heating and cooling zones, your system can deliver more efficient heating and cooling by eliminating inaccuracies from a central sensor point. In addition, building occupants in different areas can adjust the temperature to meet their actual needs. If your facility has many rooms or floors, multiple zones are recommended.
• Demand or CO2 Sensors: Most heating and cooling systems draw in ventilation air by assumed occupancy, however modern technology has sidestepped this by designing systems that actually can regulate the air quality of your facility by measuring the amount of CO2 present. The result is more energy-efficient operation and better air-quality.

Maintenance

Just like your automobile, your facility's heating and cooling systems need maintenance to operate efficiently. To improve efficiency and help ensure reliability and long life, consider the following tips.

• Engage a qualified HVAC firm in a maintenance contract with seasonal tune-ups. During these tune-ups, a technician should check combustion efficiency, refrigerant charge, and belt tension as applicable.
• Replace air filters regularly. Accumulated dirt and dust make your fans work harder. Clean or replace filters as recommended by your system's manufacturer.
• Clean the evaporator and condenser coils on your heat pump, air-conditioner, or chiller. Dirty coils inhibit heat transfer; by keeping them clean, you save energy.
• Inspect ducts and piping for leakage or damaged insulation. Leaky ductwork is one of the biggest contributors to cooling loss in buildings. Apply duct sealer, tape, and insulation as needed.
• Repair old valves and steam traps. These can waste hundreds of dollars and are low cost parts.

To learn more about maintaining your heating and cooling system visit ENERGY STAR's Heating and Cooling Maintenance Checklist and Duct Sealing information and Air Conditioning Contractors of America's Preventive Maintenance = $avings.