The weather forecast for July 10 said it all.  Vermont, for the first time ever, was at “extreme risk” for excessive rainfall, with flash flooding reaching nearly every corner of the state.  With damage from this 48-hour deluge still being tallied, historical comparisons are being made to Tropical Storm Irene, the August 2011 storm that caused three-quarters of billion dollars of flood damage in Vermont and claimed six lives.  

This latest storm was not a tropical storm, however; it just acted like one in slow motion.  It was primed with so much humid, Gulf air that it felt sticky just to be outside in 80-degree weather.  The high dew point above 65°F at night also made it hard to sleep.  These conditions not only juiced the atmosphere for torrential downpours, but also spurred demand for air conditioning – running day and night – before this epic storm wrung all that moisture out of its system.

Is Air Conditioning Becoming a Necessity?

Now that climate change is an ever-greater presence in our daily lives, air conditioning is becoming more of a necessity than an option in many parts of the world, including ours.  Heat – not floods – is the No. 1 weather-related killer in the United States.  One study found that greater use of air conditioning has actually reduced heat-related mortality in the U.S. by 75% since the 1960s.  

Globally, the number of AC units increased by 267% between 1990 and 2022.  The world is expected to add another billion air conditioners by 2030.  And for good reason.  With the onset of a new El Niño in the Pacific Ocean, global temperatures have gone on a tear this summer.  In just the first week of July, new all-time temperature records were set on five continents:

• South America (114.6°F)
• Europe (119.8°F)
• Australia (123.3°F)
• Africa (124.3°F)
• Asia (126.7°F)

Not to be outdone, North America tied the highest temperature ever reliably measured on Earth, with a 130°F reading in Death Valley on June 27.  

This means AC not only keeps people cool and comfortable, but can also be a true lifesaver in a rapidly warming world.

Unfortunately, air conditioners are themselves a source of global warming.  Air conditioners are now responsible for around 4% of global greenhouse gas emissions — and that figure is still rising.  The refrigerants in air conditioners, particularly hydrofluorocarbons, are potent greenhouse gasses, and the electricity used to run AC often comes from fossil fuels, at least for now.  

Think Twice Before Buying AC

Here in New England, 78% of homes in New Hampshire and 81% of homes in Vermont have air conditioning, based on 2020 census data.  (Most of them use window or wall units instead of central AC.)  These are still among the lowest penetration rates for air conditioning across the nation, however.  If you don’t already own an air conditioner, here are three simple measures you can take before you rush out and buy one.  

• Draw the blinds, shut off the stove.  For starters, you can make sure your blinds or shades are drawn during the hottest parts of the day, particularly if you don’t have insulated windows.  Try also not to run appliances like dishwashers, ovens, stovetops and dryers until later in the day, since they make spaces hotter and more humid.  
• Open the windows and turn on a fan.  You can also open windows to take advantage of natural air circulation, particularly at night.  And if that’s not enough, a fan can create fast-moving air to remove body heat with only about 1% of the electricity that an AC unit uses.  While the U.S. Environmental Protection Agency’s Excessive Heat Events Guidebook warns against relying on fans alone when the heat index is above 99°F, such stifling heat is still thankfully rare here in New England. 
• Adopt passive cooling measures.  If you are looking for a home, think about how much AC you really need.  There are lots of ways to cut down on artificial cooling demand – from adding more shade trees outside, insulation in the walls, and ensuring that windows are large and easy to open.  

Right-size Your AC Purchase 

• Consider an upgrade:  If you’re in a house that already has air conditioning, consider an upgrade to a newer, more-efficient model.  According to the U.S. Department of Energy, an AC unit from the 1970s uses twice as much energy as a newer model.  Even if your air conditioner is only 10 years old, you might save 20% to 40% on cooling costs by upgrading.
• Cool only the spaces that need it.  Whatever you do, try to limit cooling in spaces that are unoccupied (or rarely occupied like bathrooms) by closing doors and vents to reduce energy consumption and costs.  Of course, this process is easier to manage with window AC units that tend to use less electricity than central air conditioners. 
• Use smart thermostats wisely.  Smart thermostats can also help control when and how much you cool.  The hottest time of day is usually just before families start returning home from school and work, around the hours of 3 pm to 5 pm.  While you’re away from home, you can set your thermostat 5 to 10 degrees warmer than what would normally be comfortable for you when you’re at home.  As a rule of thumb, for each degree you set the temperature higher, you will typically save 1 percent in energy costs.  Some window AC units now also come with software that allows for a similar level of control.  
• Don’t crank the AC up too much.  Just because you set the temperature higher when you are away from home doesn’t mean you should crank up the AC even more when you get home.  It won’t make the room temperature drop any faster than if you set the thermostat at the cooling level you actually want reach.  
• Buy a unit that fits the space.  Also make sure you buy an AC unit that is appropriate for the space you wish to cool.  If the unit is too small, you may set your thermostat to a temperature that exceeds its cooling capacity, causing the system to run continuously at its maximum output, guzzling energy and shortening the life span of your system.
• Don’t go overboard.  Likewise, an air conditioner that is too large for the space it’s meant to cool may lower temperatures too fast, without also drawing out a comparable amount of moisture from the air, leaving the air feeling clammy.  That may cause you to turn the temperature setting even lower, driving up your electricity bill.  Large AC units can also turn on and off quickly as they reach the desired temperature level, producing a truncated cooling period known as short cycling.  This adds to the wear and tear on your unit, causing it to burn out faster.  Smaller units running at constant speeds typically provide the best mix of temperature and humidity control as well as reduced energy consumption.    

Think out of the Box

• Do your research.  For window AC units, the U.S. government’s Energy Star efficiency program has a helpful size guide.  If you want central air, you can consult an energy weatherization expert to do what’s known as a “Manual J Calculation,” which factors in everything from building size to insulation levels to give a measure of overall cooling needs.  Energy-smart models are almost always the better bet.  They may cost a little more upfront, but they bring significant savings over time.

• Consider a heat pump.  Better still, consider installing a heat pump that provides heating as well as cooling.  Heat pumps are far more energy efficient than electric- or hot-water baseboard heaters.  Some heat pumps now use natural refrigerants, such as hydrocarbons, ammonia, water, or carbon dioxide, as alternatives to HFCs that have high global warming potential.  This configuration yields environmental as well as financial benefits.
• Run your AC on solar power!  And to maximize these benefits in a complete home energy package, solar power is your best bet of all.  Depending on the size of your home and the type of heat pumps you install, the resulting energy savings will pay back the cost of that portion of a Solaflect Tracker’s amortized cost of service in as little as three years, and no more than 10 years, depending on your avoided utility costs.

Click on these links for more information on heat pumps and the payback times for home appliances using Solaflect Trackers.  While these singular purchasing decisions won’t ward off future heat waves or floods, working together we can make a difference in the fight against climate change.  Solaflect Energy is your home energy management partner.  We help you install clean and affordable solar electricity for a more resilient and climate-friendly future.  For more information email us, or call (802) 649-3700.