I use misters on my HVAC units here at work. I went to this for the hottest part of the summer when the units just can't seem to keep up. It has it's upside and downside.

The upside is yes it does help improve the units ability to cool.

The downside is that (according to the HVAC contractor that takes care of my units) it can and will leave mineral deposits on the condenser coils. so you have to use cleaners on them to remove the buildup which can also deteoriate the fins themselves. I still use it but only during the very hot days of summer when the temps go above 100 deg.F. Usually the whole month of August in Oklahoma.

I find its easier to go to someplace like Atwoods or some other home and garden place and get what you need to build your own, if you are handy.

Thanks double_j_b - I've been looking around my area from time to time, we just have those Lowe's Home Impossible stores around here - Home Depot is way down the road...

I haven't seen much that I could adapt, so that's why I'm probably buying - _{that way I can play more golf right now}

The phase change induced by the transfer of heat from the Condenser coils to the water should dramatically increase the efficiency of the unit, considering the amount of heat you can remove, for the same pumping power.

Just yesterday I was contemplating using a rain-catching barrel, coupled with a switched valve.

Regarding the mineral deposits, would it still be an issue with rainwater?

Regarding the mineral deposits, would it still be an issue with rainwater?

Dunno - I would tend to think the area of the country you are in may be a factor - in researching several sites & discussions on this method, there was a lot of talk around what the effects of municipal water would cause regarding build-up & such

Although, my thoughts would be if the unit is outside, you can do periodic cleaning with solvents?

I am just putting one of these systems together....Probably spending about $170 total. The system breaks down like this...I tap into house water which I run through a T-Valve and then into a portable water softener (WaterStick $120). From the Softener I run into a Toro Mini-Irrigation Valve (it uses the lease energy, .09 holding amps at 24VAC). The output side of the Valve goes to a polishing filter (Pentek inline .05 micron). This filter actually removes the remaining setiment, chlorine and the salt or pottasium choride used to regenerate the softener. From the filter output I run 1/4" tubing to the AC unit where I have three .012" nozels situated about 4" in front of the fins (facing away from the unit). I use the 24VAC Cooling Call Thermostat lead to activate / deactivate the Toro valve. Fail-safe operation, clean, clean water. Looking forward to seeing how well this will work.

Let me know how it works out. I'd like to see some stats on temperature out put inside the house,with and without the unit and especially electricity savings, if there is any. It sounds good though.

What model Toro Mini-Irrigation valve did you use? I would like to build a similar system. Also how long to you think the WaterStick will last?

Hey cutiger, I was on the thread last year regarding misters for ac units. I live in NC and know about the humidity. The potential problem that I see is that the humidity here is so great that you're not going to get the flash evaporation that the web site talks about. More likely just hot wet air, since the air here is already pretty saturated with moisture.

Thanks for the good thoughts kramarat - the days do get brutal at times, heh? Those compressors are bangin' away trying to maintain....

_{Why don't I think that way when the Wife & I visit the Caribbean?}

Our hose nozzles have a setting for mist, and as I mentioned above I do sometimes spray down the unit when outside just fooling around and there is a perceptible difference in the house afterwards, and with the unit outside, although it only lasts until the next cycle time....

Hey cutiger, Not to be a smart ass, but if you've got you're thermostat in the house set at ,say 72 degrees, why would spraying water on your condenser make the inside of your house cooler. The compressor may not be working as hard, but I think you may have just worked up a sweat spraying all that water. I'm laughing because I did the same thing last summer. Sprayed water on the condenser, walked inside and felt a noticeable difference in the house, as I was patting myself on the back, I realized that what I thought I had accomplished didn't make sense. Hey, at least we're trying.

Thanks ozzb - sadly in elevation the condensate lines are about 6 feet below the unit outside...but that's a good idea!

I would look into those new ice box things there retrofiting to alot of these units, it makes ice at night then uses it at night to help cool the coils during the hotest part of the day, it is suppose to cut about 30 percent.

CUTiger,

I have used the mister setup and installed a solenoid to turn on the water when the unit came on. Even if the humidity was high the water contacting the coils would still adsorb significant amounts of heat. I measured the amps before turning on the water, then after and the drop was 3-4 amps! Not to mention the air temp coming out of the ducts was cooler. (i don't remember how much, I did this in the 80's!) My newest unit has more coils and the effect is smaller, but still significant in temps over 95 degrees.

At the maximum savings, too much water is wasted, so recirculate it or install a drip watering system to use the excess.

I sprayed WD-40 occasionally to combat the corrosion. I finally lost a compressor after 53 strait days of 100 degree plus days, which had nothing to do with the water misting system. (That day hit 113 degrees!)

At the price of energy now, I will most likely do this again this summer.

One other thing, I have installed a window unit in the area of the house that is occupied the most. Combined with that we turn off all lights when we leave the room and make sure un-necessary wall warts and phantom loads are unplugged. These items dropped our energy usage by 40%

Thanks Bill - the affirmation is great! I'm pretty much sold on the application & will be doing something this weekend

3-4 Amps reduction is mighty good to hear....and I agree that the air in the duct is cooler, although I never took any readings, it was just our preceptions.

Take care

I had been thinking about doing this same thing. However, our well water has lots of minerals and would certainly make a mess of the condenser. I was thinking of using some of the pads that you see in a swamp cooler. Run water through the pad...again like a swamp cooler. The water stays in the pad and so do the minerals, the condenser gets cool air. It's starting to get hot (and our neighbor cut down the tree that was shading our unit and the west side of the house! )...I might just try it this year.

Even with the worst water (minerals, etc.), have someone watch the electric meter turning when the unit is on; then have someone spray the unit with water and while this is happening, check the electric meter - it is quite amazing how much slower it will spin. Almost, have someone inside the house next to a return while the A/C is running, spray the outside unit with a waterhose and see if that person notices a difference in temperature. You'll be amazed.

Typically, you get a 22 degree difference in what is coming out of the vent vs. the current temperature. Physics is fairly simple, the outside unit is dispersing the heat, lowering the outside temperature (hence the cooler water hitting the unit), increase the 22 degree difference to somewhere in the 32 degree difference on my unit).

If your savings in electricity alone is in the neighborhood of $50 per month over a 4-5 month period each year, that is a savings of $250-$300 per year at a minimum, not taking into consideration the green savings that seems to be the buzz word right now. If your outside unit fails 5 years sooner, you still saved $1250-$1500 and then new unit won't cost that much. If you take that savings and invest in a home warranty, it becomes a wash and then all your systems would be covered - that is a thought.

Also, if you had to replace the unit 5 years earlier at no cost to you, you gain the effeciences of a newer system.

My thoughts would be to figure a way to take a 50 gallon drum that gathers rain water and once the temperature outside gets above say 85 degrees, it begins to drip on all sides of the evaporator coils. If there was a way to capture the excess water off of the bottom of the outside unit and recycle it back into 50 gallon drum that would be optimal.

As for cleaning the unit, if you take liquid tide (I've been doing it for years) and put it in an old spray bottle, mixing it 50/50 with water; spray it all over the outside unit, let it sit for about 10 minutes and then take your waterhose and spray it real well, being careful to not bend any of the coils, you'll have one of the cleanest units in the neighborhood. Does a real nice job.

Something I've been tossing around a little bit. It may not work or be to dang complicated to even attempt. But here goes. I live in Oklahoma city so I know heat and humidity, but I grew up In California (the land of the swamp cooler) now I know the humidity out here is quite high.....at times, not 100% all the time but 60, 40, even 25-30% a good portion of the time especially during the hottest part of the day. I havnt gotten around to making one YET and yes it will work tho not nearly as well as in the dry climates. But in my (cyber)travels I've seen more and more talk about 2 stage evaporative (swamp) coolers, seems you get considerably cooler air with "acceptable" humidity levels. I won't go into how they work (as I'm typing this on an iPhone) but should be fairly easy to build one or even go to a 3rd stage. But instead of using the cooled air for inside use it to precool it's own water which should compound it's cooling effect. Now take some of that chilled water and maybe use it to pre cool the refrigerant going into the condenser. Use 1 motor 1/2-3/4 hp for all 2or 3 swamp fans, you don't need 6000cfm. Plus the air at the very end of the system should be of a low enough humidity level to exhaust it directly into your attic or use an air to air exchanger and cool your attic which should help with keeping house cooler. What do you think. Now if I'm wrong or whatever don't be a jerk just explain why.