Imagine, you’re visiting the new, multi-purpose arena in Calgary for the first time to see the Flames face Auston Matthews and the Leafs on Saturday afternoon. You’re so mesmerized by the immense size of the entry doors you forget to empty all the metal from your pockets. After a third time through the metal detector you finally get the go-ahead to collect your things, which you mindlessly stuff into your pockets, forgetting you still have to show your ticket. The stadium staff member patiently waits for you to pry your phone from your pocket, open the app, and present your digital ticket. Another three tries with the scanner allows you to gaze upon the glass ceiling above—nothing but blue skies. 

You approach the edge of the stands in the first level of the arena to get a good look at the players warming up, noticing the temperature in the arena warming as you walk towards the rink. It’s not warm enough to remove your coat, but despite similarly gigantic doors swung wide open opposite you, the arena temperature is comfortable but not coddling. You assume arena operations staff wouldn’t turn on the heat with dual, 100-foot-tall doors wide open. But even with the doors closed, 20,000 people with heart rates more than double normal and breathing two-and-a-half-million-or-so hot breaths each hour warms an arena rather effectively without setting the thermostat.

The Audience-induced Greenhouse Effect

An audience at a hockey game is a living, breathing greenhouse gas emitter. The carbon dioxide emitted by the breaths of 20,000 fans turns an indoor ice rink into a greenhouse. The collective heat created by an arena full of fans seeks out the coolest area in the arena: the playing surface. That body heat (and any heat introduced to the arena from outdoors) forces the refrigeration system to kick on and keep the playing surface at a constant, cool temperature. At Keene Ice Arena in New Hampshire, one of the most environmentally friendly rinks in the United States, arena operations staff found a surface temperature of 7.2 degrees Celsius (45 degrees Fahrenheit) to be most efficient.

While rink refrigeration systems have become environmentally friendlier, even the friendliest only cut energy consumption in half or so. With 40 percent of hockey arena energy drawn by the refrigeration system, even the nicest of those systems is still responsible for roughly 170 metric tons of carbon dioxide being emitted annually. That would power 30 homes for a year in the United States, according to the Environmental Protection Agency’s website. Multiply that by 31 teams, and the lowest the NHL’s carbon footprint can get with arena doors closed is 5,270 metric tons of CO2 emitted annually. That’s the annual emissions equivalent of more than a half million gallons of diesel burned or 5.76 million pounds of coal burned.

With the survival of the human race at stake, and mass extinctions of animal species already occurring (dozens per day), it’s imperative that the people and corporations who can most afford and are most culpable for the climate crisis do the most to cut their carbon footprints. We’re well past the point of no return when it comes to preserving Earth’s environment. We can’t get back the ozone we’ve wasted, so any greenhouse gases emitted is already too much greenhouse gas emitted. And long after we, as a species, find a way to get our planetary energy needs fulfilled by renewable resources, the NHL will still be emitting greenhouse gases due to the refrigeration systems required to maintain the ice. That’s why in a previous editorial I floated the idea of opening the doors to NHL arenas so hockey—an outdoor game—can be played outdoors—sorta.

Harnessing the Power of the Polar Vortex to Play Hockey

Instead of forcing rink refrigeration systems to mitigate fans’ body heat, CO2 emissions, and a more than comfortable indoor temperature, why not keep some doors open to lower energy costs and emissions associated with maintaining the playing surface? There is a reason to do so that NHL owners might find convincing, too. They can expect energy costs to increase up to five percent per year, so NHL operating costs are only going up. And hockey fans won’t likely boycott over having to wear a jacket during some games.

Not all days are suitable for leaving doors and windows open, though. As of this writing it’s -27 degrees Celsius (-16.6 degrees Fahrenheit) in Calgary, so the doors to the Flames’ future arena wouldn’t be left open for a game. But on a Saturday afternoon with an average high of just above freezing in February and just below freezing in December and January, hockey games and fresh air could be enjoyed regularly throughout the season. And instead of the rink’s refrigeration system battling an arena temperature around 21 degrees Celsius (70 degrees Fahrenheit), NHL owners could save some money and the environment by opening the doors and playing in 10-degree weather (50 degrees Fahrenheit) while cutting climate costs in half. 

More than two-thirds of teams get something resembling winter during the NHL season. Retrofitting those 21 arenas to harness the power of the polar vortex to make the NHL environmentally friendlier should be the main objective of NHL owners looking to build new homes or renovate old ones for their teams. It will pay dividends, lowering energy costs and appealing to its fans’ environmental sensibilities…just like that eco-friendly, All-Star jersey scam.

Imagining Environmentally Friendlier NHL Arenas

Indoor/outdoor arena construction isn’t in its infancy. We, and by we I mean mostly American taxpayers, have been paying to put retractable roofs on baseball stadiums for decades. And now we have a blueprint for retractable walls, too.

The U.S. Bank Stadium doors weigh 40,000 tons, stand 95 feet tall at their highest point, and are covered with 30,000 square feet of glass. They are the tallest pivoting doors in the world and serve as a blueprint for making NHL arenas environmentally friendlier.

When the doors are open, the indoor arena can feel like an outdoor stadium, especially with the glass ceiling allowing natural light into the building. If an air-cooled condenser and rink refrigeration system could be installed under U.S. Bank Stadium, it would be a fitting, future home of the Minnesota Wild. It would also allow the Wild to increase ticket sales and accommodate members of its Warming House, a waiting list for season tickets.

It might not be feasible to retrofit the Vikings’ new home with rink refrigeration for hockey, but it is feasible for all new NHL arenas to incorporate U.S. Bank Stadium-inspired doors and ceilings. Air-cooled condensers should also be used in areas where winter makes an annual appearance, so outside air isn’t just coming through the open doors but being used to cool the refrigerant coils responsible for keeping the ice frozen. And before you hockey fans start complaining about watching an outdoor game in outdoor temperatures, remember, you can always close the doors. But you can’t take back the greenhouse gases emitted to satisfy your addiction or the climate change that results.