Evaporative cooler vs. air conditioner: Which is right for your home?
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Author
Andrew Blok
Electrification and Solar Writer and Editor
If you're shopping for a new cooling system, you've probably heard swamp cooler boosters touting their low cost and quick cooling.
Evaporative coolers (commonly called swamp coolers) do cost less to run than traditional air conditioners and are simpler in design. But for most of the country, they won't get the job done on their own.
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What are evaporative coolers (swamp coolers)?
An evaporative cooler works by pulling hot outdoor air through water-saturated pads. As the water evaporates, it absorbs heat from the air through the same principle that makes you cold stepping out of a pool on a breezy day. The cooled air is pushed into your home while warm air escapes through open windows or vents.
Because the only mechanical components are a fan and a small water pump, evaporative coolers use significantly less electricity than air conditioners. They also bring in fresh outside air continuously rather than recirculating indoor air.
Evaporative cooling adds moisture to the air. That's only useful if the air starts out dry. In humid climates, water won’t evaporate as well and the cooling effect nearly disappears.
Evaporative cooler pros and cons
Swamp coolers won't work in every situation.
Advantages:
- Lower electricity use: According to the Department of Energy, evaporative coolers use about one-fourth as much energy as central air conditioners.
- Lower upfront cost: Evaporative coolers are simpler to install than central air conditioning or heat pump systems.
- Continuous fresh air: Evaporative coolers constantly draw in outside air.
- No refrigerant: Swamp coolers don't use chemical refrigerants, which simplifies maintenance.
Disadvantages:
- Climate-dependent: Evaporative coolers don’t work in humid climates because they add humidity to the air and they can get less effective during wet seasons in dry climates. Opinions vary about swamp cooler performance as humidity rises, but common guidance says performance drops off significantly at 40% or 50% humidity. Because comfort comes down to personal preference, your mileage may vary.
- Water use: Evaporative coolers continually use water, which may be a concern in areas with limited water supplies or drought restrictions.
- Maintenance: Cooling pads need to be cleaned or replaced regularly or they can foster mold, which can be blown through your air.
- Outside air: When air quality is bad, swamp coolers introduce those pollutants into your home.
- Shorter lifespan: Evaporative coolers typically have a shorter lifespan than air conditioners, which can last up to 15-20 years with proper maintenance.
Evaporative coolers vs. air conditioners vs. heat pumps
They're the tree main cooling options. How do they compare?
How they work
Air conditioners and heat pumps both use a refrigerant-based cycle: they absorb heat from indoor air and release it outside. The difference is that a heat pump can reverse that process to heat your home in winter. An air conditioner only cools. Evaporative coolers skip the refrigerant entirely and rely on water evaporation.
Cooling performance
Air conditioners and heat pumps cool to a set temperature regardless of outdoor humidity. Because a heat pump and an air conditioner work identically in cooling mode, a heat pump with the same SEER rating (the standard measure of cooling efficiency) will cost the same to run in summer.
Evaporative coolers can perform well in the right conditions. In very dry climates like the arid Southwest they can drop air temperature rapidly and substantially. But that performance degrades quickly as humidity rises.
Energy efficiency
Evaporative coolers win on electricity use. Among refrigerant-based systems, heat pumps have a clear edge for homes that need both heating and cooling. A properly installed heat pump can deliver two to three times more heat energy than the electrical energy it consumes. For cooling only, air conditioners and heat pumps at the same SEER rating perform essentially the same.
Air quality
Air conditioners and heat pumps filter and recirculate indoor air, which can lead to stale air if the home isn't well ventilated. Evaporative coolers pull in fresh outdoor air continuously. That’s a genuine advantage unless outdoor air quality is poor (wildfire smoke, high pollen), at which point it becomes a significant disadvantage.
Heating capability
Only heat pumps handle both with a single system.
| Evaporative cooler | Central air conditioner | Heat pump | |
|---|---|---|---|
| Works in humid climates | No | Yes | Yes |
| Works in dry climates | Yes | Yes | Yes |
| Cools the home | Yes | Yes | Yes |
| Heats the home | No | No | Yes |
| Upfront cost | Low | Medium | Medium-High |
| Operating cost (electricity) | Low | Medium | Medium |
| Water use | High | None | None |
| Climate fit | Dry climates only | Any climate | Any climate |
| Typical lifespan | 5-15 years | 15-20 years | 15-20 years |
Is an evaporative cooler, air conditioner, or heat pump right for my home?
Choose an evaporative cooler if: You live in a dry climate. Swamp coolers are most common in parts of Arizona, California, Colorado, Nevada, New Mexico, Utah, and Wyoming. If monsoon season regularly pushes your summer humidity higher, plan on supplementing with an air conditioner or heat pump on the most humid days.
Choose a central air conditioner if: You're in a humid climate (the Southeast, Midwest, Mid-Atlantic, or anywhere with sticky summers). An air conditioner paired with an existing heating system is a common and cost-effective choice.
Choose a heat pump if: You want a single system for heating and cooling or you’d like to replace another heating system, either completely or partially. Modern heat pumps perform well even in extreme heat, and cold-climate models extend reliable performance well below freezing. Pairing any of these options with solar panels can help cover the electricity demand from any of these systems.
If you're looking at HVAC options, Palmetto's Comfort Plan. Like other HVAC leases, it let’s you skip the upfront cost of the equipment and installation, and instead make predictable monthly payments that also cover regular service and most repairs. To see how a new HVAC system can work at your home, connect with a Palmetto HVAC advisor for a no-commitment quote today.
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Frequently asked questions
What is the difference between an evaporative cooler and an air conditioner? An evaporative cooler lowers air temperature by evaporating water, which adds moisture to the air. An air conditioner uses a refrigerant cycle to remove heat and humidity from indoor air. Air conditioners work in any climate; evaporative coolers only work well where the air is dry.
Where do swamp coolers work best? In hot, dry climates where relative humidity stays very low, primarily Arizona, Nevada, New Mexico, Utah, and parts of Colorado and California.
Is a heat pump the same as an air conditioner? In cooling mode, they’re the same, but a heat pump can also heat your home in winter, while an air conditioner can only cool.
Can I use an evaporative cooler and an air conditioner together? Some homeowners in dry climates use an evaporative cooler for most of the summer and switch to air conditioning during the humid monsoon season. Only use one at a time..
How much does it cost to run an evaporative cooler vs. an air conditioner? In dry conditions, evaporative coolers use significantly less electricity, and cost less to run. Actual costs vary by unit size, climate, and local utility and water rates.
Disclaimer: This content is for educational purposes only. Palmetto does not provide tax, legal, or accounting advice. Please consult your own tax, legal, and accounting advisors.
