Module 3: Energy Conservation

Identifying Options

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Stage Three: Load Reduction

Load reduction focuses on reducing the amount of work your HVAC system has to do. Most of this is due to the heat generated in your office space – known as your heat load. This heat load comes from several sources, including the outside environment and office equipment. Reducing the heat load in your office means that your air conditioning will not have to work as hard since the space will be cooler to begin with. Reducing the loads from the outside (heat in summer and cold in winter) is covered more in the section titled Building Envelope.

Office Equipment

In addition to being heated by the outside environment (the sun and hot summer air), your office space is also heated by all of the equipment running in your office, including computers, monitors, printers, copiers, and your refrigerator. Significant savings can be realized by turning off office equipment when it is not in use. Turning off a computer not only reduces the heat load in the office, it saves the amount of electricity that would have been needed to run the computer. Figure 11 shows potential savings from turning off a computer and large copier when not in use. Note that these figures only include the electricity cost of running the equipment. Additional savings would be achieved through a reduction in the load the air conditioning system has to handle. Lighting is another heat load on your space, but it was covered in Stage One of this module.

Figure 11 – Savings from Turning Off Equipment

Myth: Leaving computers on helps them last longer.

Reality: Today’s computers do not suffer from being turned on and off thousands of times. In fact, turning computers off when they’re not being used lowers the amount of dust buildup inside, which helps them last longer while saving you money.

Water heater

If you have control over your water heater, there are many opportunities for savings. You can turn the water heater on and off as water is needed, and insulate your tank and pipes. Whether you have such control or not, you can work to minimize your use of hot water

Turn off your water heater. Buy a 7-day thermostat (you can get one for about $30) to turn off your electric water heater at night and on weekends and to turn it back on one hour before your business starts up in the morning. If you have a big water heater, you can get even more aggressive and turn it off an hour or two before quitting time. The already-heated water will be sufficient for late-day needs. You’ll save anywhere from $10 to $50 per year with a water heater timer.

To optimize energy use of your water heater:

Minimize hot water use.
Provide hot water at the lowest temperature that is acceptable for the task. (See Figure 12.)
Insulate the tank and pipes.
Obtain hot water from the most efficient sources.
Perform periodic maintenance procedures.

Figure 12 – Recommended Hot Water Temperatures

Refrigerator

Purchasing a new refrigerator can save more than 50 % of the energy needed to run an older, less-efficient one. A typical new residential refrigerator uses about 800 kilowatt-hours per year and costs about $64 per year to run. This is less than half what you’d pay for the same size unit that is 20 years old.

If you are not prepared to purchase a new refrigerator, there are many no-cost things you can do to make sure your refrigerator is running optimally:

Keep the doors shut. Repeated fluctuations in temperature will damage your food quality and will cost you money.
Check the temperature settings. If your settings are lower than necessary, chances are you are wasting energy. The most common recommended settings are between –14 degrees and –8 degrees Fahrenheit for freezers and between 35 degrees and 38 degrees Fahrenheit for refrigerators.
Properly load your refrigerator. Overloaded units disrupt air flow necessary to cool the products efficiently, and allows deterioration to occur. On the other hand, under-loaded units waste energy. If you have partially filled units, consolidate them.
Properly position refrigeration units. Don’t put your soda display case right next to your deli bun warmer or in direct sunlight. Extra heat makes your refrigerator work harder to maintain the desired cool temperature. Make sure that there is enough ventilation for your refrigerator’s mechanical equipment. A 1-inch gap on the sides and a 4-inch gap at the back are recommended for refrigeration units to allow the condenser and fan to have access to a steady flow of air.
Clean the cooling coils. Dirt accumulation impairs heat transfer and lowers refrigeration efficiency and capacity.
Check the door seals. Tight seals and properly closing doors prevent warm air from entering the unit, which reduces cooling energy and prevents frost buildup. Use this rule of thumb: If you can easily slide a dollar bill into the seal, have the seal adjusted. The above actions can save you between $5 and $25 per year. These actions can also improve your product quality and extend the unit life. At no cost except a few minutes of your time, these actions are a bargain. Shorten defrost cycles. This is starting to get a bit technical. Fifteen minutes an hour isn’t perfect for everyone or for every season. If you’re in a dry climate or season, gradually decrease your defrost cycle time until you see hints of frost buildup on the coils. Back the setting up a bit, and you are optimized. This procedure, like others, can help extend the unit life.
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