Energy Efficiency Calculators and Tips for your Office Building or Residence

Oct 3, 2018

By Ilina Talwar and Katy McSurdy

At Nexant, we’re celebrating Energy Efficiency Day 2018 on October 5th! Check out this campaign hashtag, #EEDAY2018, and on our social media channels: @Nexant_Utility for Twitter and Nexant LinkedIn.

In honor of Energy Efficiency Day, we have collected numerous tools and ideas to improve energy efficiency in your home, office, or building. These resources can help reduce your energy consumption, increase cost effectiveness, and decrease carbon emissions. Check out these online calculators to start saving.

Energy Efficiency for Commercial Buildings

Heating and Air Conditioning

Properly maintained heating and cooling systems are essential for conserving energy and saving money. HVAC systems primarily operate during peak hours and account for 40% of the electricity used in commercial buildings.[1] Regularly perform maintenance checks and updates to ensure your system is running efficiently and has a long shelf life. Check out these HVAC calculators for air cooled chillers, boilers and heat pumps that estimate a product's lifetime energy cost savings.

Commercial HVAC and Programmable Thermostat


Updating your lighting system has many benefits including improving productivity. Having the right brightness and illumination can help boost morale and create a better work environment. LEDs (light-emitting diodes) are one of the most efficient lighting options. According to the DOE, “By 2027, widespread use of LEDs could save about 348 TWh (compared to no LED use) of electricity: This is the equivalent annual electrical output of 44 large electric power plants (1000 megawatts each), and a total savings of more than $30 billion at today's electricity prices.” Georgia Power Company has a tool for comparing savings on 4 different types of bulbs including LEDs.

Compact fluorescent bulbs are another good option. The Department of Energy’s Compact Fluorescent Lamps Calculator measures cost savings when you replace existing incandescent bulbs with compact fluorescent light bulbs. CFL’s are 75% cheaper to operate and last 10 times longer.[2] Making this change along with implementing an effective lighting design strategy is an easy way to reduce your electricity usage.


If your appliance is more than 10 years old replace it with a more efficient model that will consume less energy. Some states and utilities even provide tax incentives and/or rebates for replacing old equipment. The Appliance Energy Calculator helps you calculate the cost of using your appliances/electronics in your home. Once you know how much energy and money is spent, you can choose to limit your usage or upgrade to a new model. Here’s an online calculator from ENERGY STAR for refrigerators.


Often, commercial buildings face a “split incentive” problem where the owner assumes the full cost of efficiency upgrades and the tenant receives the benefit through reduced operating expenses. The Building Upgrade Value Calculator evaluates energy investments in commercial properties and helps to solve this issue by taking into account flexible lease terms.


Investing in energy efficiency might seem costly but in the long run it saves you money and returns a positive cash flow. Use the Cash Flow Opportunity Calculator to help plan strategic upgrades for your equipment and manage your finances. By estimating future savings, the tool can evaluate if and when you should buy new equipment as well as analyze the impact of interest rates on your budget.

Evaluating and understanding your existing equipment is the first step towards making smart decisions. Make use of the online calculators to help you decrease your electricity usage and save money.

Energy Efficiency for Your Residence

Understand Your Electricity Usage

Knowing how your daily routine affects your electricity usage and its associated cost is the first step towards making smart decisions. There are various tools online such as the Appliance Energy Calculator by the US Department of Energy that can help you calculate how much it costs to use the appliances and electronics in your home. Once you know how much energy and money you are using, you can decide to use it less, or buy a new model that uses less energy.

Invest in Programmable Thermostats

Programmable thermostats can help you save 10% to 30% on your heating and cooling bill. All you need to do is to adjust your temperature settings so that it consumes less electricity while you are sleeping or away from home. You can even up the game by using a Smart Thermostat that can be controlled remotely and alert you if the temperature setting is not right.

Replace Old Appliances with ENERGY STAR Models

Is your appliance more than 10 years old? If yes, it’s time to replace it with an energy efficient model that will use less energy. Make use of online calculators that can help you estimate your savings by upgrading or replacing a particular appliance. For instance, here’s one from ENERGY STAR for refrigerators. Some states and utilities also provide tax incentives and/or rebates for replacing older appliances with energy efficient models.

Slay All Vampire Energy LoadsIdentify Vampire Energy Loads

Identify the appliances that are using electricity when not in use and quietly draining the dollars from your wallet. Typical suspects include cell phone/desktop/laptop/chargers, music systems, TVs, coffee machines, game consoles, etc. So how can you slay these vampire energy loads? First, unplug appliances that you do not use often, like the TV in the guest room. Second, use smart power strips that automatically switch off power when appliances are not in use. Finally, use the “sleep mode” button on devices such as laptops and computers. These baby steps can turn into significant savings. You can calculate the vampire loads here to see what your charger is costing you.


Consider “Off-Peak” Use of Appliances: Off Peak Load Reduction

Many utilities provide incentives and rebates for using appliances during off-peak hours, when energy costs less to use. A simple routine change such as running your dishwasher before going to bed instead of just after lunch can help you save on your electricity bill.

Maintain Your HVAC

"Tune-up" your heating, ventilating and air-conditioning (HVAC) system with an annual maintenance contract. Even a new ENERGY STAR qualified HVAC system, like a new car, will decline in performance without regular maintenance. A contract automatically ensures that your HVAC contractor will provide pre-season tune-ups before each cooling and heating season. You save energy and money, and your system may last years longer with minimal costs for yearly maintenance fees.