Tell me more ×
Home Improvement Stack Exchange is a question and answer site for contractors and serious DIYers. It's 100% free, no registration required.
up vote 5 down vote favorite

I live in Phoenix where summer outdoor temperatures regularly exceed 110°F and humidity around 15% or lower is not uncommon. In this environment a mist system can easily pull the temperature down 20 to 30 or even 40 degrees in some cases. I've been toying with the idea of cooling my outdoor AC unit using mist, and did a little research.

There are several commercially-available systems to do precisely this such as this industrial unit and this residential one. But I wanted to get an idea of what other people think of these systems. In particular, I'm interested in the long-term effects of using these systems, especially with respect to mineral build-up and corrosion. The vendors of the commercial systems claim to have these factors under control, but I'd rather hear it from a neutral POV.

I'm not particularly interested in unfounded FUD or enthusiasm, and comments like, "if it works so well then we'd all be using it" are particularly unhelpful. Instead, I would like to know how these units actually fare in real-world usage. Also, bear in mind that this is Phoenix, not New Orleans; in the dry summer heat nothing stays wet for more than a few seconds. Factors like mold are an absolute non-issue.

share|improve this question
1  
Interesting question. Most window units work that way. The catch is it's using water from the air, rather than a well, so isn't coming along with the mineral deposit issue. – DA01 Jun 30 '12 at 4:53

1 Answer

up vote 3 down vote accepted

Mineral build-up is going to be dependent on your water. Do you have a Water Quality Report? Mine looks like this:

http://www.acwd.org/story_detail.php5?story_id=157

Hard water starts around 10 grains per gallon or 170 ppm. In other words, 1 liter of water will have 0.17 grams of calcium/magnesium. I didn't see any water usage estimates for coolnsave aside from 6 cents per day. Also, they sell a water treatment filter which could take some of the minerals out but there aren't any details provided.

The thermodynamics behind coolnsave are sound and the price is reasonable. Your best bet if no one here has any personal experience is to just try it yourself, keeping a daily inspection schedule for the first month to be sure you aren't coating your condenser with something that you can't remove.

share|improve this answer
Yes, my neighborhood has fairly hard water, but nothing like other parts of phoenix. A common component in all of these systems is a filter or treatment step. The CoolNSafe people use a filter that looks strikingly similar to the ones at home depot for use in mist systems. One site I looked at recommended spraying CLR on the AC unit and hosing it off once every 3 mo. – tylerl Jun 30 '12 at 7:11
CLR is often effective at removing deposits. But a condenser is a large investment and you want to be sure your water doesn't have anything that can ruin your condenser. If the water treatment is not effective and CLR does not work or there is some way that your water is especially corrosive to your condenser, the cost could be over $1,000 to repair. That's why I recommend you inspect it every day for a few weeks. Commercial installations have water quality professionals to analyze and maintain the water chemistry. – Philip Ngai Jun 30 '12 at 16:42
CLR is very corrosive, which is why they say to spray on and hose off immediately. Better than nothing, I suppose. But definitely not as good as good water treatment. – tylerl Jun 30 '12 at 18:23

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.