The Best Tent AC and Evaporative Coolers

/

The best AC or evaporative cooler for tent camping is hard to find.  There are two main options: 1.  Build a 5 gallon bucket evaporative cooler -OR- 2. Buy a dual vent portable AC.  There are now very compact, but pricey, portable AC units designed for camping.

AC units can work great but they have a couple challenges:

1.     They take a lot of power – get ready to buy or borrow a generator.  1000-1500 watts AC is a common power requirement.  Generators start around $400 and go up from there.  Honda EU2200 and EU3000 generators are favorites for their low noise level and reliability.  But they aren't cheap – the smaller EU2200i goes for about $1,000.  Then you need fuel – about 1 gallon per 8 hours of run time.  Thankfully that’s only about 3-4 gallons for a week (8 days at 3 hours day for 24 hours run time).  Don’t forget a proper fuel canister and containment basin (both required at Burning Man). 

2.     The only off the shelf AC unit that works easily with a tent is a dual vent portable model.  Expect to pay around $350 or more.  Also the tent needs to have dual vent ports (The No Bake Tent has these.) You will also need additional air intakes for the tent so it doesn't collapse – with filters to keep out dust (the No Bake Tent also has two of these 4x12” ports that take standard 4x12” register filters).

Notice the Dual round Vent Ports on the back - One fresh air intake and one hot air output.  There's also a second rectangular air intake.

Notice the Dual round Vent Ports on the back - One fresh air intake and one hot air output.  There's also a second rectangular air intake.

You can't tell from the front if the AC has dual ports

You can't tell from the front if the AC has dual ports

Here is one AC that meets the basic requirements: https://www.homedepot.com/p/Whynter-Eco-Friendly-11-000-BTU-Dual-Hose-Portable-Air-Conditioner-with-Dehumidifier-ARC-110WD/204146581

Here is one designed for camping and that comes with optional batteries: https://www.zerobreeze.com/collections/mark-2-portable-ac-for-tents

Once you have a generator, fuel, and a portable dual vent AC you are set.  You can make a normal tent cool enough to sleep in (but probably not take an afternoon nap on 100ºF plus days), or to make a No Bake Tent cold at any time of day (Thanks to the dual layer heat reflective material the No Bake Tent starts off about 30ºF cooler than a normal tent at midday – and heats up much less quickly in the sun so you won't have to run your AC nearly as much).

But wait – what if I don’t want to spend $1000 plus dollars to stay cool?

Enter option #2 – The Evaporative or Swamp Cooler

Evaporative and Swamp coolers are the same thing with different names.  They take warm air and run it through a wet membrane.  This causes liquid water to phase change into water vapor which cools the air.  In dry climates the difference is dramatic – up to  30ºF cooler.  This isn’t a cold as an AC, but the swamp cooler uses a lot less power.  Commercial swamp coolers use about 1/10th the power of a similarly sized AC.  Homemade swamp coolers can use as little as 1/50th the power of an AC.  You can make a 5 gallon bucket cooler for as little as 70 bucks and some elbow grease.

There are a couple tricks to making a swamp cooler work with a tent:

1.     You must draw outside air into the swamp cooler anytime it’s running - so leave the swamp cooler outside the tent. Then use one of the ports on the tent for the cold air to flow into the tent.  If the swamp cooler is inside your tent it mostly won’t work (unless you have a fresh air intake rigged up).*

2.     You must open vents on the opposite side or the top of the tent.  Swamp coolers only work when you are turning over the air inside the tent.  Aim to replace the air every 3-5 minutes or faster.  The tent should inflate slightly (i.e. show positive pressure like a balloon) when the swamp cooler is running.  Adjust the vents in your tent to achieve this. Start by closing all of the vents and watching the tent inflate.  Then start opening vents until the inflation is just barely noticeable – this is the ideal amount of venting for your swamp cooler.

Where can I get plans to make a 5 gallon bucket evaporative cooler?

There are a lot of plans out there, but perhaps the best are from a burner who goes by the name FIGJAM.  Follow the directions closely - even small deviations can make the design fail. Check out this post on eplaya for details: https://eplaya.burningman.org/viewtopic.php?f=280&t=33842&start=1560#p869218

What about other Evaporative Coolers and ACs?

Unfortunately we haven't found any evaporative cooler that are specifically designed for camping tents.  You can buy a commercial swamp cooler and rig up tubing to take the cold air into the tent - just make sure it's air tight.  You could also rig up a window AC unit - again the trick is to manage the air intakes and outputs.  So get your MacGyver skills ready. 

*A small personal sized evaporative cooler will work for a while in your No Bake Tent - until the humidity rises too much. All evaporative coolers work by taking dry warm air, adding water vapor to drop the temperature through the magic of phase change, and delivering cool humid air. Once the supply of low humidity air is gone you’ll have to open a window to draw in fresh warm dry air. This helps but isn’t nearly as effective as a evaporative cooler as described above.

We compiled this chart for you to better understand your options:

Tent Cooling Options              
  Ready off the Shelf   Cost (5)   Needs Generator   Needs Water   Power use per hour  
Dual Vent Portable AC Yes   $350-500+   Yes   No   1050-1500+ watts AC  
Single Vent Portable AC  Maybe (1)   $350-500+   Yes   No   1050-1500+ watts AC  
Window AC Yes with caveats (2)   $125-200+   Yes   No   1050-1500+ watts AC  
Commercial Swamp Cooler Yes with caveats (2)   $150-300+   Maybe   Yes (3)   100-300+ watts AC  
Homemade Evaporative/ Swamp Cooler No   $70-100   No   Yes (3)   1.5-3+ Amps 12v DC (equals 18-36+ watts)  
                     
  How much solar power needed to run? (6)   Can be run on a battery?   Works in the Desert?   Works in Humid places?   Might cause tent collapse? (4)  
Dual Vent Portable AC 1300+ watts (13+ 100 watt panels)   No   Yes   Yes   Low  
Single Vent Portable AC 1300+ watts (13+ 100 watt panels)   No   Yes   Yes   Med-High Risk (1)  
Window AC 1300+ watts (13+ 100 watt panels)   No   Yes   Yes   Low Risk  
Commercial Swamp Cooler 130+ watts (1 100 watt panel plus a smaller 30-50 Watt panel plus batteries)   Maybe (9)   Yes   No (8)   No Risk (7)  
Homemade Evaporative/ Swamp Cooler 30-50 Watts (1 30-50 Watt panel plus battery)   Yes (10)   Yes   No (8)   No Risk (7)  
                     
Notes                    
1. May need to have an additional improvised intake vent added if it isn't a dual vent model  
2.  Will need to have improvised venting or set up added to work properly  
3.  Between .5 and 2 gallons of water per hour depending on model  
4.  Air Conditioners work by drawing in air - this can cause negative pressue to form inside the tent. For example let's say 2 cubic feet per second is drawn into the AC unit.  Part of that air is cooled and sent back into the tent - 1 cubic foot, the remaining air is sent outside - 1 cubic foot. The 1 cubic foot of hot air that was expelled has to be replaced.  If the tent is well sealed and air cannot get in then tent might start to be sucked in.  If the pressure becomes too great the tent might collapse.  Dual hose AC units avoid this in part be sucking in outside air.  Single vent AC units do not do this.  You MUST have additional air intake.  The No Bake Tent has 2 4x12" filter pocket vents to allow fresh filtered air in.  This reduces the negative pressure inside the tent.  Depending on the power of the AC you use you may need to partially open a window.      
5.  Cost doesn't include power source (i.e. generator and gas, solar panels and batteries)  
6.  Assumes a 80% conversion rate - i.e.. 100 watt panel nets 80 watts after transmission and conversion power losses.  
7. Evaporative/Swamp Coolers create positive pressure so there is no risk of the tent collapasing.  They also will prevent dust from entering thr tent when they are unning due to the positive pressure.  
8.  Evaporative/Swamp Coolers work by adding humidity to the air - which can be quite nice in low humidity environments like the desert.  
9. Would need many large deep cycle batteries or the ability to recharge regularly
10. One 100+ Ah deep cycle battery will last 8 days of 3 hrs a day use

Let us know if you have better solutions in the comments below!