AirBnb May Have a Climate Change Problem

Transient visitors like the ones highlighted in this real-world example may use two or three times the resources of full-time residents.

Have you ever been in a relationship where the person you thought you knew turns out to be someone completely different? Did your demure, sweater-clad Midwestern girlfriend turn out to have a meth addiction and a secret desire to test-fire a Taser at you? Did Mr. Right turn abusive, steal your bank account, and donate his life savings to QAnon?

That's how I feel about AirBnb now. The company, which I used to defend vigorously as a way for middle-class homeowners to underwrite much-needed energy upgrades, may be enabling wasteful energy, water and data consumption among its more irresponsible guests.

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As a disclaimer, let me note that this story is anecdotal, zooming in on a single long term AirBnb rental. But perhaps it's a tale that will encourage a deeper look at how AirBnb can adjust to reduce the ability of guests to use excessive resources.

Meet the Guzzlers

A family member of mine recently experienced an eye-opening encounter with some AirBnb guests. The unwelcome surprise revolved around resource consumption. But more than just hearsay, she was able to document the environmental thrashing doled out by these guests, thanks to the presence of numerous smart wifi products.

Here's the scenario: A month-long rental to a family of four, plus an occasional mother-in-law and two dogs, plus one overnight by an extra guest. Let's call them The Guzzlers, for the sake of accuracy and anonymity. But these are real people, and all of the data I'm going to show you is raw and unadjusted. I’ll be contrasting their energy, water and other resource use to that of the owners, a family of three.

The Guzzlers rented a small, one-story southeast home in May 2021, during the shoulder season, just before the heat of summer. They arrived in three large vehicles, two SUVs and a pickup truck, with kids, barbecue grill, and luggage in tow, planning to migrate from the Midwest to Florida. So you can’t blame their behavior on Florida.

Things immediately went south.

Exhibit 1: Cooling the Neighborhood

Let's begin with the big ticket resources: heating and cooling the rental house. In most places in the United States, HVAC accounts for the largest source of CO2 pollution in a home. And when people rent, especially if utilities are included in the cost, they tend to use heating and cooling with wild abandon. A study of apartment renters at Harvard, for example, found that renters in general use more energy per square foot than owners.

AirBnb’s HVAC footprint, however, may be even more extreme, because it throws in the factor of transience. I’ll touch more on this later, but I can tell you from years of experience as an AirBnb host that I’ve almost never had a guest turn the thermostat up or down when leaving the property for the day. Most don’t even turn off the lights.

Let’s return to The Guzzlers.

This traveling AirBnb family consumed 292 hours, 12 minutes of cooling in May 2021, compared to 98 hours, 13 minutes of cooling by the owner/occupant in May of the previous year (and 4 minutes of continuous fan operation).

What do we know about their behavior? How did this happen? With data from an Awair air quality monitor in the home, correlated with a Sensi smart thermostat, the host was able to determine that these guests were cooling the home almost continuously, and at night they opened windows or doors to the outside, humid air.

This could have been prevented with the lock down feature of the Sensi thermostat, but the guests specifically requested more access to the HVAC controls (granted by the owner), after heavily hinting (after their arrival) that their children might have seizures if the temperature was not cool enough. The host set the bottom limit of the thermostat at 68 degrees Fahrenheit—much lower than the normal 73 degrees used by her).

The Sensi has the ability to send an alert to your smartphone under certain conditions; for example, when humidity hits 70 percent. In total, the host began to get humidity warnings in the middle of the night, when the house hit 91 percent. This humidity level is impossible with the A/C running constantly, unless the house has either flooded or some of the windows and doors have been left open to the 100 percent humidity outdoors.

Continuous Fan Operation: A Losing Proposition

Along with operating the electric split system cooling 24/7, The Guzzlers also manually turned on the air handler fan and left it on all month for continuous operation. This added a large energy footprint to the HVAC system, with a negligible impact on indoor comfort, other than possibly increasing the level of filtration (more changes per hour through the MERV 11 filter). And of course this means the filter, which normally encounters only one-tenth of the numbers of cycles, will need replacing in a fraction of its normal lifespan. The filters require resources to produce and also cost about $20 apiece.

According to inspect.com, running a 500-watt whole-house A/C fan continuously works out to about $43 per month, or about $520 per year. The Guzzlers ran the recirculating fan continuously for 420 hours, not quite full time, so the extra energy added up to about $30 for the month for the fan alone.

The Bottom Line. The AirBnb transient guests produced about three times the CO2 pollution from cooling as the owner did in the same month of the previous year. In the first two weeks of The Guzzlers’ stay, they racked up an electric bill of $268, compared to the previous year’s monthly bill of under $100.

Not all of this power consumption, however, can be blamed on HVAC misuse. Other behavior added to the bill. For example, let’s look at domestic hot water consumption.

Exhibit 2: The Personal Laundromat: Hot Water Blues

I’m a big fan of Aquanta technology. It’s a smart, wifi-enabled controller that works on most electric hot water tanks. It so happens that one was installed on the Rheem hot water tank in our case study house. As an extra perk, it includes a rudimentary leak sensor that’s strapped to the tank. Things have to get pretty wet for it to go off.

The Guzzlers made it happen. Not once, but repeatedly.

On the day that she broke the washing machine, early in her month-long stay, this guest told the host she had just finished doing four loads of laundry. Let me pause for a moment:

Q: Who goes on vacation and does four loads of laundry in a single day?

A: Possibly more people than you think, especially if you limit the number of linens available.

In my personal experience as a host, AirBnb guests tend to use every piece of linen that you leave out. If you have two guests and two bedrooms, you’ll find both beds have been slept in. If you have two guests for a weekend and leave out eight towels, they’ll use every towel before they leave. And inevitably, they use the towels to remove makeup, stain them with hair dye or blood. Many end up unusable. The same is true of sheets, pillowcases, and blankets.

In this case study, the host thought she had figured out a way to reduce the amount of laundering and destroyed linens, by limiting the available towels and sheets. The guests simply found a workaround. With access to the washer-dryer they kept a regular cadence of wash underway. They used or took all of the reserves of laundry soap by the time they departed.

Perhaps coincidentally, the washing machine leak grew worse. The host offered the guests a $200 stipend to cover their laundry costs for their stay, rather than replacing the unit. They agreed, but then continued to use the leaking washer, triggering repeated flooding alerts in the laundry room on the Aquanta app. When asked to stop, they refused to stop, arguing that traveling to a laundromat would be too inconvenient.

Of course, some of that hot water usage came from showering and dishwashing. While the host can’t quantify those “silos” precisely, I know from long experience with guests, and many anecdotal comments from other hosts, that guests tend to shower frequently, and take long 15 to 20 minute showers. This is especially troubling (and costly) in areas where fresh water is precious, and droughts are getting worse, like California and Arizona.

The Bottom Line. This case study, plus anecdotal reports, suggest that AirBnb guests rarely practice water conservation, let alone minimize their use of heated water.

Exhibit 3: A Firehose of Data Usage

The Guzzlers used more data in one month than the full-time telecommuting homeowners use in five months. They exceeded the plan cap by 180 gigabytes, which would have incurred a charge of $10 per 50 gb, or $30 extra, but the cable provider waives one month of data excess per year.

It's important to note that online data has a CO2 footprint. Fast Company notes that the transmission of 1 GB of information takes an estimated 13kWh, a kWh creates about .92 lbs of CO2. For the month of mainlining data, The Guzzlers used about 1.6 terrabytes of data. That's 1600 gigabytes multiplied x .92 lbs, resulting in 1,472 lbs. of additional CO2 pollution dumped into the atmosphere by these AirBnb guests.

Where did all that extra data usage come from? To quote the host “I don’t even know how it’s possible to use that much data. I work at home, stream movies, listen to music. These people managed to blow the top off our data plan in a way that I didn’t even know was possible.”

Which begs the question: Is this host the exception? Do most families consume huge amounts of data every month? Is this host just exceptionally data frugal? None of the above. According to Statista.com, in 2020, Internet data usage for a family “soared” to about 400 Gb per month in March, from a more typical average of 190 Gb per month.

The Bottom Line. Some travelers, including our sample family, consume three to four times the data of an average household while traveling under the AirBnb umbrella.

Other Excesses: A Thousand Cuts

In my experience, much of the excessive resource consumption enabled by AirBnb occurs in less obvious ways. These are problems that are very familiar to hoteliers, but often shocking to AirBnb hosts. Amateurs expect that their guests will share their eco-conscious behavior and priorities. But that’s often more wishful thinking than reality.

Toilet Paper: If you leave it, they will wipe. A common thread on some AirBnb forums is “how much toilet paper should I leave for guests?” Why? Because, like Internet data, travelers seem to rip through TP at an unfathomable pace.  It’s not uncommon for a family of four to tear through 32 rolls of TP in a long AirBnb weekend. What’s the CO2 footprint? At 1.8 grams of CO2 produced to create one sheet, 500 two-ply sheets per roll, that’s about 2 pounds of additional carbon pollution per extra roll. That may not seem like a big deal, until you remember that 292 million AirBnb guests traveled in 2019.

Cleaners. High-Impact Pollution. Since the pandemic, AirBnb has asks hosts to upgrade their cleaning protocols. That means that even well-intentioned hosts who normally use green cleaners now are expected to apply strong chemicals that wipe out any living thing on a surface. These chemicals have a much higher CO2 footprint. Here are just three bullet items from AirBnb’s “enhanced” cleaning instructions. All of them incur additional environmental costs:

  • Use disinfectants approved by your local regulatory agencies for use against COVID-19.
  • Spray high-touch surfaces in each room with an approved disinfectant spray.
  • Wash all dishes and laundry at the highest heat setting possible.

Grilling: A Dirty Amenity. Let's talk about grilling and barbecues for just a moment. Guest behavior has led many AirBnb hosts to consider providing grilling equipment and fuel as an essential amentity of AirBnb rentals now.

However, research by Eric Johnson in 2009 found that a single session of grilling using propane emits the equivalent CO2 pollutants as driving a compact car 8 miles, and grilling with charcoal nuggets spews enough pollution for 22 miles of driving.

Let's dive a little deeper. Grilling in the United States is emblematic of another huge Climate Change contributor: meat consumption. Of course it's not AirBnb's role to convert guests to meat-free diets, but they provide a carefree, conservation-free environment in which to normalize that vacationer tradition.

AirBnb’s Response

AirBnb has largely dodged bad press about its crushing environmental footprint, in part because their marketing materials encourage hosts to use eco-friendly cleaners, and they often tout statistics like one from 2018, suggesting that “88 percent of hosts incorporate green practices into hosting.”

But AirBnb has been criticized for taking no meaningful role in reducing the vast, polluting impact of the property “sharing” that it enables. It’s not that they couldn’t. Perhaps they don’t want to risk alienating guests by requiring people to adhere to reasonable standards of resource conservation. In fact, they’ve changed their procedures so that it’s virtually impossible to simply restrict or remove guests because they use resources irresponsibly.

As a case in point, let’s look at the end scenario that played out with The Guzzlers.

It became apparent to the host, after a couple weeks, that this family was consuming huge amounts of resources, and engaging in activities that could damage the house. She approached AirBnb, hoping to terminate their reservation quickly.  

In AirBnb’s protocols for removing guests, however, the company has now created "ambassadors" to play the role of judge, jury and mediator. As a host you have to argue your case, and you may even have to supply documents to “prove” that a guest has broken house rules. This also assumes that your house rules are specific enough to include provisions for vast usage of resources. The guest then gets a chance to tell her story. You can end up in an unwanted mediation with a hostile squatter in your home—which is what happened with The Guzzlers.

In my research, I could find very few hosts who write eco-conscious rules into their house rules. For short term stays, ejecting bad actors may not be as crucial, but for long-term stays, AirBnb has created a situation where even an extreme CO2 polluter can not be evicted easily. The excess resources they use also can mean the difference between a profitable rental and a net loss for the host.

AirBnb has come under repeated fire from hosts for their frustrating policies with regard to removing problem guests. The problem is, in my long experience as a host and landlord, that once you encounter a "red flag" renter, you need to get them off the property as soon as possible. Most will only get worse, the longer you let them stay.

Ultimately, my case study host had to cut a compromise with AirBnb, and allow The Guzzlers to stay about an extra week beyond the cutoff date she asked for. During that time they continued to use huge amounts of resources, park vehicles in the middle of the lawn, leave windows open while running the A/C, and send a flurry of hostile messages to the host, to the point where, unable to get a response from AirBnb, she had to delete her account to protect herself.

AirBnb’s Tipping Point

Unless AirBnb drastically alters its model to wrap sustainability into every transaction, their operation is likely to face increasing scrutiny for its environmental impacts.

Certainly not every guest creates as great a pollution footprint as The Guzzlers, but it’s safe to say most do not tread lightly on local ecosystems. Under the current rules, hosts can only do so much to limit resource waste. Some action that they can take is obvious: installing low-flow fixtures and faucets, timers on showers, hot water tanks with limited capacity and occupancy sensors for lighting. But without AirBnb's leadership and collaboration, even these changes will not flatten the resource waste curve. I tend to agree with other critics who note that AirBnb is "checked out" on sustainability. But it's a situation they could correct.

Here are 5 changes that might allow AirBnb to remain a viable form of short term rental.

  1. Subsidize smart technology. AirBnb can use some its vast wealth to offer rebates for hosts on smart monitoring equipment—sensors that monitor water usage and leaks, hot water controllers, smart thermostats for heating and cooling, to name just a few.
  2. Offer bonuses for energy efficiency. In the category of carrots, rather than sticks, offer guests an AirBnb-funded kickback of 10% when they keep overall energy/water usage below a certain threshold.
  3. Enable eco-eviction. Put power back in the hands of hosts. With real time monitoring, canceling a reservation can be triggered when a guest exceeds the bounds of reasonable resource use.  Enforce good eco-citizenship.
  4. Discourage CO2 intensive amenities.  It’s time for AirBnb to do more than just talk and “listen.” They need to take a stand. Call out the problems with grilling. Market the advantages of bidets over paper-using toilets. Ditch the chemical cleaner protocols. 
  5. Become advocates for energy efficiency, frugality and responsibility, not just in words but in deeds. This is not a PR problem. It’s a deep structural flaw in AirBnb’s current business model.

Technology can’t fix behavior. You can put the most efficient mini-split cooling in a rental, but if the guests sleep with all the windows open, they’re going to waste energy. They need to know that if they choose to behave like locusts on this precious planet Earth, they’ll need to do it somewhere else, not while renting with AirBnb.

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