I purchased an evaporative cooler from one of the big box home & garden stores, and installed it on the northeast side of my greenhouse. It sat on a concrete block pad (I placed/leveled a few concrete blocks on the existing dirt ground) outside the structure. I also attached it to 2 hanging chains/hooks for additional support. The unit's cooling outlet poked through a small side window into the structure. The water resevoir (on the outside) was automatically refilled using a floatation on/off device connected to a tube which connected to my greenhouse water faucet. I did have some issues with the tubing leaking at the stepdown connection (from garden hose size hose to 1/4 inch tubing.) I have a greenhouse controller connected to an outlet specific for "cooling" and just plugged the evaporative cooler's electric plug into the special outlet. My controller was able to turn on/off the unit (by supplying power or removing power from the outlet) as needed with my set temperature requirements. It probably brought the temperature down by 10 (maybe 15) degrees at most. It also blew cooling/humid air which was a nice benefit--the plants in its direct path were cooler than the ambient temperature. Unfortunately, algae grew in the resevoid and the unit's pump it died after the first winter (likely froze since the resevoid was outside the structure) even though I attempted to weatherize it (guess my weatherization wasn't effective.) After it died, I just left it in place, but covered it on the inside with plastic to prevent cold air leaks in the winter. It was rather inexpensive to purchase and to operate. And, because I was able to self-install (and I'm very much NOT an HVAC installer type) I am considering another one to replace it.

The more open the air channels are, the more air it will move and the better it will work. If debris clogs up half the orifices, the pads may still look good but give inferior performance. Nick, this sounds like the performance of lungs which are "compromised"! --Stitz--

Gary: Window AC's are cheaper than portables, but require a large cutout in the polycarb, while the portable ones need only a 4 - 5" hole and we could add one next to the existing heater vent, where we reinforced the walls with aluminum sheet metal. Then, sealing it off for winter would be simple. Dcharch: The only live plants in my GH in summer are aquatics and they are under lights anyway. All of the tank lights will soon be connected to a single timer with a built-in bypass swtich, so I'll be able to turn them all off/on during the day if needed, with a single flick. So giving my GH a lot of shade in summer won't be an issue for any plants, and closing it all up if I really feel the need for some genuine chill, would be as simple as turning off the the power to the intake vents and exhaust fan and sliding the storm panel up in the door. When he installed the lines for the vents/fan, my husband put a switch on the main line, to avoid the need to fiddle with the thermostat. The roof vents would of course, remain open, because I can't reach them without a ladder, but with the ceiling fans pulling cold air up, it wouldn't take all that long for them to close on their own. As long as the cold air is directed at the smaller tanks, which are set above the big ones, even if just for those few hours on the relatively few days each year they might need it, could be just that extra edge- and if just one small tank that doesn't overheat has a spawn of a particularly valuable species in it; alive and growing, they would pay for the AC and the cost to run it all summer, let alone at most- 150 hours a year. In any case, the lattice shade fence is under construction and will be up by the end of the weekend, just in time for me not to especially need it this year. The portable AC will very likely be bought anyway. My husband was looking at them with me and mused about how nice it would be to AC the curtained off section of the garage where parks my rival for his affections. Another good reason to go for a portable: they are on wheels, and even I can roll one out of the garage and into the GH, all by my old, arthritic self. So it's likely there will be a portable AC here anyway, just in case. But I really am so close to not needing one. Again: all I can do is see how well the extra shade will do the job next summer. But I admit that having the ability to chill it would be a nice security blanket. Kind of like the stand-by generator. Always gratefull when it's not needed, and even more so that it's there, ready to crank up when it is.

Important Feature Considerations for Window Swamp Cooler and Window AC Energy Efficiency Window evaporative air cooler is an energy efficient method of cooling a home. Compared to air conditioners, they have no chemical and use about 15%-35% of the electricity used by air conditioners. However, they do require a constant water supply. They may, therefore, prove not efficient in areas experiencing water restriction or drought. They are also not as effective as air conditioners when it comes to cooling the air in various weather conditions. Climate Considerations Window Swamp Coolers work best in hot and dry climatic conditions, such as in desert regions. This is because they function by adding moisture to the air making your home have a more comfortable feel. In humid regions, swamp coolers can only lead to excess humidity giving room to the growth of mold or mildew. Air conditioners are effective in almost all climatic conditions but they can also make the air dry. It, therefore, makes their use more effective in humid areas. Using air conditioners in dry climate could make the air too dry and might lead to eye and skin complications. Costs Window air conditioning gadgets cost somewhere between $345 – $1,190. They normally come complete with a DIY manual. On the other hand, window swamp coolers are priced between $400 – $1000. They require no professional help to install. CO2 Emissions Window mount swamp cooler tends to have reduced levels of CO2 and greenhouse gases emissions when compared to air conditioners. This is because swam coolers utilize the use of water to cool the air. Air conditioning units on the other hand use cooling or refrigerant chemical. When this chemical is converting into gas or liquid, it emits CO2 and greenhouse gases. This becomes harmful to the environment as well as the air we breathe. Noise Window AC tend to produce more noise compared to window evaporative cooler. The noise in air conditioners occurs when the condenser is working to convert the chemical into either gas or liquid. Installation Window unit swamp coolers will need no professional services to install in most situations. Window air conditioning units, on the other hand, might need the help of a professional or a detailed DIY manual. Maintenance Forwindow air cooler to function properly they require maintenance daily, monthly, and yearly. This also involves changing the pad when necessary and controlling the water. Most of the maintenance jobs are DIY. You can also do a professional yearly service of about $100. The swamp cooler units require more concentration in maintenance compare to air conditioners. Ait conditioners are meant to be serviced yearly. The yearly maintenance includes changing the filter, charging the chemicals, and cleaning. The cost to the yearly servicing is about $70 – $100. Air conditioners have parts that are prone to failure. These parts can lead to an additional yearly cost of about $250 and $ 2,000. It, therefore, makes them more expensive in terms of maintenance.