Evaporative Cooler FAQ

What types of evaporative coolers are there?

Evaporative coolers range in size from small portable models to large ducted models for residential and commercial/industrial applications. Go to What is Evaporative Cooling to learn more about evaporative cooling and its benefits.

Can evaporative coolers be used in different climates?

Evaporative cooling is best suited for climates where the air is hot, and humidity is low. They may be a cost-effective option in some higher humidity areas. Use for spot cooling, garages, workshops, garden centers, auto shops, dog kennels, outdoor tents, horse stables, exercise areas, industrial plants, commercial kitchens, farming (i.e. poultry, hog, and dairy buildings), laundries, dry cleaners, and greenhouses.

Which is better – an evaporative cooler or an air conditioner?

That all depends on you. Evaporative coolers provide continuous fresh, cool air and are energy efficient to operate. Use an evaporative cooler for whole house cooling or combine an evaporative cooler with an air conditioning system.

How do I size a cooler?

Evaporative coolers are sized based on the amount of airflow needed or CFM (cubic feet per minute). There are two ways to size a cooler. See an example here.

One, you can calculate the cubic feet of an area by multiplying the length by the width by the height (L x W x H). Once you’ve determined cubic feet, multiply that number by an evaporative cooling climate factor for your area. Referring to a specification chart for a particular type of cooler, you can determine which model meets your needs. See Sizing a Cooler.

Two, determine the total square footage of your home referring to a square foot sizing guide. Please note, however, square foot ranges shown in any guide are based on ceiling heights of 8′ and other assumptions (i.e. desired room temperature and heat loads, etc.). Square footage sizing guides are approximations only. Since conditions vary from house to house, contact a salesperson or contractor for additional information.

How do evaporative coolers rid my house of indoor pollutants?

Evaporative cooling constantly exchanges the air instead of re-circulating it so stale, polluted inside air is replaced with fresh, filtered outside air that has been cooled.

Do evaporative coolers save energy?

An evaporative cooler uses 70% less power than air conditioning. The annualized energy savings make evaporative cooling a cost effective alternative to air conditioning.

How often should my cooler be serviced?

Regular maintenance will extend the life of your cooler and help avoid unnecessary problems associated with parts replacement. We recommend servicing your cooler three times throughout the year – at start-up, mid-season, and shutdown. Refer to your Owners Manual for the recommended maintenance schedule for your cooler. Check out this page for more information on how to maintain your unit.

Is it okay if I use soft water with my evaporative cooler?

Soft water may cause corrosion decreasing the effective life of your cooler.

I see scratches on my cooler. How can I get rid of them?

Should a scratch or any bare metal appear on your cooler, sand the area with steel wool to prepare the finish. Paint with standard spray paint or touch up paint available from a dealer.

What is a BLEED OFF KIT ?

The bleed-off helps your cooler function at its optimum. By continuously eliminating a small quantity of water from re-circulation, it reduces scale build-up and dilutes mineral concentrations. Consult your Owners Manual to determine the correct flow rate for your model.

You can also use a POWER-CLEAN® kit. This can reduce the amount of water used.

Is it important for my evaporative cooler to be level to operate properly?

Yes. When an evaporative cooler is mounted level, then the water within the pan is set at the appropriate level for the pump to operate efficiently. If the pump doesn’t have enough water to circulate, it will prevent the right amount of water from reaching the pads and will possibly create dry streaks. This would allow warm air to enter the evaporative cooler.

When I turn the fan on, no air is discharged. Why?

It’s possible the electrical power to the unit has been disconnected. Check fuses and/or circuit breaker. On portable or window coolers, make sure the cord is plugged in.

My evaporative cooler produces an unpleasant odor. What can I do?

Drain, flush and clean the reservoir. Make sure the cooler has a bleed-off. Clean or replace pads, if needed.

The cooler doesn’t seem to be cooling.

You could have inadequate exhaust. For every 1,000 CFM of air delivery, 2 square feet of unrestricted air relief is needed. Check the water distribution system to ensure there is adequate water reaching the pads. Clean and/or replace the distribution system if needed. Also, check the pads to make sure they aren’t clogged. If they are, clean and/or replace as needed.

I’ve heard about relief air. What is it?

As an evaporative cooler draws fresh outside air through the cooler into the home, hot stale inside air is exhausted out of the home. This is referred to as relief air. Generally speaking, a good relief design exhausts slightly more air out of the home than your cooler supplies.

How many windows and doors must I leave open?

It’s all based on the unrestricted exhaust air openings your home requires. For every 1,000 CFM of air delivery, allow 2 square feet of unrestricted air relief through windows or doors.

Are there other ways to exhaust air in my home?


VENTMATIC™ vents can be installed to exhaust air through your attic and out the roof vents. Remember to provide 2 square feet of relief for every 1,000 CFM of air delivery.

What is VENTMATIC™ ?

VENTMATIC™ is a brand name of ceiling vents that allows for air exhaust through an attic. This also cools down the attic temperature. When the cooler comes on, the air pressure automatically opens the barometric dampers. When the cooler turns off, the damper automatically closes.

How many VENTMATIC™ vents should I install?

At a minimum, install VENTMATIC™ vents in every major room. For maximum cooling comfort, install one VENTMATIC™ vent for every 500 CFM of air delivery.

How can I direct cooled air into various rooms?

Direct the air exhaust by changing the direction of the vents or opening windows or doors in different rooms. Remember to allow a total unrestricted area of relief of 2 square feet for every 1,000 CFMs.

Are thermostats available for evaporative coolers?


Thermostats are available for whole house coolers.

What can I expect the discharge air temperature to be from my evaporative cooler?

That depends on a number of factors. The discharge temperature is determined by the temperature and relative humidity of the incoming air. To determine the temperature of the air leaving the cooler, you will need to know the outside dry bulb temperature, the current outside wet bulb temperature, and the evaporative efficiency of the evaporative cooler (typically provided in product brochures under Performance Data). This should provide a guide to approximate discharge air temperatures.

What should I do if I won’t be using my evaporative cooler for a period of time?

Always drain the water from the cooler and start with fresh water if it has not been in operation for a week. If you are shutting down the cooler for an extended amount of time or the season, drain the water and clean the cooler. Cover cooler after cleaning.

What is a portable evaporative cooler?

A portable evaporative cooler requires no installation or wiring and can be used anywhere spot cooling is needed. Suited for residential and commercial applications, use portable coolers to cool rooms, offices, garages, workshops, garden centers, auto shops, dog kennels, outdoor tents, horse stables, exercise areas, industrial plants, commercial kitchens, farming (i.e. poultry, hog, and dairy buildings), laundries, dry cleaners, and greenhouses.

Where should I place a portable cooler?

The most important thing is to place a portable evaporative cooler where there is plenty of fresh air. The best position is adjacent to an open window or external door with additional openings on the opposite side of the room for relief air. This placement will provide the most cooling comfort.

How often should I clean a portable evaporative cooler?

Empty and replace the water reservoir at least once a week with fresh, clean water to reduce scale or mineral deposits from building up on the pad. At a minimum, clean your cooler (water system and filters) at least once during the season or more periodically depending on usage. This will help maintain the high performance of your cooler. Refer to your Owners Manual for required maintenance and scheduling.

Sunstar FAQ

Frequently Asked Questions

  • What is an ODS and how does it work? The ODS is an oxygen detection safety pilot system. It is designed to shut off the gas supply to the heater if the oxygen content in the room drops to 18% from a normal 21%+. In this event, the pilot flame actually lifts off the thermocouple cooling it down and causing the gas valve to close and the heater to shut off. Also, each ODS has a tamper-resistant pilot orifice assembly, so do not try to drill or clean out the ODS pilot with a hard object as you will damage it. Follow the cleaning instructions located below.
  •  How do I clean the ODS pilot assembly? If your pilot will not stay lit, try cleaning it. Use a can of compressed air, such as is used to clean a computer, to blow dust out of the pilot assembly. Sometimes just blowing air back through the pilot will get rid of the dirt.If that fails, turn off the gas supply to the heater. As indicated in Figure 5 below grab nut A with an open -end wrench and loosen nut B from the pilot tubing with another small adjustable wrench. Blow air pressure through the holes as indicated. This should blow out any foreign materials. To reassemble, tighten nut B by grabbing nut A with the open-end wrench. WARNING: When the heater is reassembled, always check for gas leaks. Apply a soap and water solution to all joints and watch for bubbles to check for gas leaks. Never use any open flame to check for gas leaks. 
    If that fails, you need to remove the orifice from the pilot burner cartridge using your wrenches to unscrew the orifice (Item A) and blow air through the pilot burner as shown in Figure 5. If the pilot burner remains blocked you will need to use a soft brush (pipe cleaner will also work) to dislodge a spider web or other obstruction. To prevent damage to this assembly, follow the instructions below for disassembly and assembly of the ODS for cleaning.
    WARNING: Never use needles, wires, or similar cylindrical objects to clean the pilot orifice. This will only damage the calibrated pilot orifice (about the size of the head of a pin) which controls the pilot gas flow. Simple rinsing with water and blowing air over it should clean the orifice.
  • How does this SunStar Corcho Model CK18 heater work again? (Applies to Manual ONLY) It’s slightly different than some 3-plaque heaters you may have seen previously. Instead of turning on the pilot and then one, two, and three plaques, the SunStar Corcho Model CK18 uses just two burner chambers and operates first on the single plaque burner. After the single plaque comes on, the double plaque is turned on giving you three full plaques of operation. If only two plaques are needed, then the double plaque burner may shut off leaving just one plaque burning.
  • Can a SunStar Corcho heater be converted to Natural or Propane Gas? No, each heater is specifically designed to work on either Natural Gas or Propane Gas. Each heater is certified only for use with the type of gas indicated on the heater nameplate (data plate). It is not designed for use with other gasses and is not convertible to use with other gasses.
  • Why doesn’t it need electricity? Each SunStar Corcho heater is equipped with a thermocouple incorporated in the ODS assembly. This is also the flame failure safety system. The heat from the pilot light warms the thermocouple and the dissimilar metals in the thermocouple react to the heat from the pilot flame and create a small amount of electricity (e.g. millivolts of electricity). This electricity from the heat is then used to energize a magnet in the gas valve to open it against the tension created by a spring in the gas valve. This allows gas to go to the burners. When the pilot flame is extinguished and is no longer generating heat on the thermocouple and, thereby, millivolts of electricity, the magnet de-energizes and the spring shuts the valve off. This is designed to turn off all the gas to the burner and pilot system. The use of this safety system and the gas fuel are the reasons that no electricity is needed to operate a SunStar Corcho heater. This product will still provide heat to your home even during power outages.
  • Can these heaters be installed in bedrooms or bathrooms? Only the model CK-6 (rated at 6,000 Btu’s) can be installed in a bathroom. Both the CK-6 and the CK-10 (rated at 9,500 Btu’s) can be installed in bedrooms. All other models are too big. The National Fuel Gas Code (NFPA 54) permits wall mounted installation of vent-free gas heaters of 10,000 Btu’s or less in bedrooms and 6,000 Btu’s or less in bathrooms. Please check with your gas supplier to determine if the installation of these heaters in bedrooms and bathrooms are permissible by your state and local codes.
  • Can this heater be installed in mobile homes? Yes, this heater may be installed in what’s termed “aftermarket” manufactured (mobile) homes where it is not prohibited by state or local codes. An “aftermarket” mobile home is defined as any type of mobile home that has already been sold to an end user or homeowner. It cannot be installed in a new mobile home on the dealer’s lot before it has been sold, but it can be installed in any mobile home after it has been sold (e.g. aftermarket). When installing this heater in a mobile home, the same safety rules of confined and unconfined spaces and clearance to combustible materials should be followed.