Watts: Understanding Power Equivalents

James Watt contributed so many engineering advancements in the late 1700s that we named the “watt” after him: a single unit of power. The Scottish engineer and inventor patented the first steam engine in 1769 and the association of watts with the power required for, well, running cool stuff, has been around since. Today, we’re most familiar with the rated wattage of home light bulbs and kitchen appliances. However, wattage (and decreasing how much you need) is critical to the energy use in commercial and industrial facilities as well.

Most of us are aware that our facility’s electricity use is measured in kilowatts and that we’re billed based on kilowatt hour consumption. Many of us also understand which equipment has the greatest impact on our electricity costs (old boilers, rows of outdated, fluorescent lighting). However, fewer of us know what a kilowatt actually is – or what uses that amount of energy.

What’s a watt?

Measuring power demands in wattage and calculating savings in kWh helps businesses understand the resulting financial savings from lowering energy use. But watts, on their own, can quickly become intangible. What good, after all, is a single watt?

We broke down a few common comparisons to illustrate the relationship between wattage and power requirements for day-to-day applications.

What can one watt do?

• To be honest, not much. A single watt doesn’t usually hold enough power to be useful.

What can 100 watts do?

• Power a laptop
• Power an LCD Monitor
• Power a ceiling fan

What can 1,500 watts power?

• Space Heater
• Vacuum
• Clothes Iron
• Hair Dryer
• Electric Oven

Energy use in watts: at home and at work

Consider the simple household incandescent light bulb. An incandescent light bulb uses 60 watts. 17 of these light bulbs require about one KW of electricity. If 17 of these bulbs are left on for an hour, the homeowner would consume one kWh.

Please note: If you currently have incandescent light bulbs in your home or incandescent or fluorescent fixtures at work, you should really consider LEDs which use 10x less electricity

A typical electric space heater uses 1,500 watts or 1.5 kilowatts. That consumes one kWh for every 40 minutes of use. According to the Energy Information Administration, the average American household consumes about 10,000 kWh per year.

Let’s translate some numbers

One of our largest, single projects for a hospital covered 10 buildings and is saving the healthcare network over 14,000,000 kWh annually. What does this mean in terms of watts and kWh?

To produce 14,752,000 kWh it would take:

• 3 wind turbines running for a year
• 4 rail cars worth of coal
• 24,148 barrels of oil

Equivalents + calculation source: epa.gov

Saving that amount of energy (annually):

• is the equivalent of taking 2,021 cars off the road
• equals the amount of energy saved if 10,105 cars switch to being hybrid from conventional
• allows for 1,195 houses to use electricity for a year (energy providers want to optimize what exists so that power can go farther without needing to make more energy than we already do)

Equivalents + calculation source: Fairbanks Energy internal data

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How to decrease kilowatt hours (kWh) in commercial/industrial facilities

High wattage across equipment can quickly increase utility costs in commercial and industrial buildings. Many commercial and industrial energy users – universities, hospitals, manufacturing, warehouses, etc. – consume millions of kWh per year. Efficiency projects designed for large commercial and industrial facilities focus on reducing their energy usage. The (resulting) conserved electricity is measured in kilowatts (kW) and annual kilowatt hours saved.

Follow these steps to evaluate current wattage demands in your own facilities and find ways to decrease energy use.

1. Audit and evaluate facility for existing high-wattage products

2. Replace outdated lighting fixtures with LEDs

3. Retrofit or replace air handlers and rooftop units

4. Optimize building automation and control systems

5. Improve airflow management (data centers)

6. Consult an ESCO or professional engineering firm to discuss current energy demands and custom solutions for lowering utility costs

Depending on the building type, upgrading inefficient lighting to LEDs can reduce utility bills by 15-20%. Replacing or retrofitting old rooftop units (RTUs) can sometimes reduce electric bills (not to mention the gas savings) by nearly one-third. Combined with utility incentive dollars, these annual savings can result in efficiency projects that pay for themselves in 1-3 years.

Fewer kWh, lower bills

Higher wattage appliances, fixtures or equipment demand more energy to match the wattage required of its application. High wattage lighting fixtures and HVAC system components can quickly bloat annual energy bills.

Not everyone owns a building that needs to save millions of kWh annually. Some equipment has a high wattage and simply requires lots of power to run. But others can be replaced with more efficient, upgraded models or optimized in their larger systems to only run and use power if truly needed.

The best way to reduce kWh usage and a utility bill is by retrofitting or replacing inefficient equipment and/or optimizing a space specifically to lower the energy needed to run a building at any given time.