Air Conditioner Question - Misters

[WildBill]

I know that there is at least one AC professional on the forum.

Yesterday on my commute home, I heard an advertisement about installing misters on existing air conditioning units.

"The advertisement claimed that it only takes about 10 minutes to install, but it will save hundreds of dollars in electricity bills."

As usual, if it seems to be too good to be true, it usually is.

Does anyone have any knowledge or experience with these "misters".

[92f-fan]

I looked into misters years ago when my AC couldnt keep up in the summer.
NOT an HVAC expert but IF it works, its addressing the symptom, not the cause..

Very common cause is lack of insulation - both attic insulation and insulation around your ducts. If the AC is blowing cold in the attic but the air is getting heated by crappy ducts before it gets to the rooms, that causes issues. Ive owned 2 houses that had the flex ducts that the plastic cover split leaving basically an uninsulated hose in the attic delivering the cool air, and therefor cooling the attic not my house. Once I fixed the duct issues my AC issues went away. Also make sure you have good attic ventilation.

I started by replacing some of the ducts myself then finally had a contractor come in and cover the ducts in spray foam. Air comes out of my AC ducts at about 68 degrees on the hottest days ...

Sorry for going off topic but its how I fixed my issue.

[WildBill]

I looked into misters years ago when my AC couldnt keep up in the summer.
NOT an HVAC expert but IF it works, its addressing the symptom, not the cause..

Very common cause is lack of insulation - both attic insulation and insulation around your ducts. If the AC is blowing cold in the attic but the air is getting heated by crappy ducts before it gets to the rooms, that causes issues. Ive owned 2 houses that had the flex ducts that the plastic cover split leaving basically an uninsulated hose in the attic delivering the cool air, and therefor cooling the attic not my house. Once I fixed the duct issues my AC issues went away. Also make sure you have good attic ventilation.

I started by replacing some of the ducts myself then finally had a contractor come in and cover the ducts in spray foam. Air comes out of my AC ducts at about 68 degrees on the hottest days ...

Sorry for going off topic but its how I fixed my issue.

Thanks for your input. I don't have a problem. I just installed new units last year and they both work well. I was just wondering if I could save on electricity bills.

[JCole]

It seems like, depending on your local water, that it might very quickly scale up your unit, harming efficiency and probably shortening its life.

[JSThane]

Sounds like you're essentially turning a refrigerated air unit into an evaporative cooler. While the principle works quite well in west Texas and other arid places, I'm not sure that would be all that effective in humid climes.

[Bill O'Rights]

Sounds like you're essentially turning a refrigerated air unit into an evaporative cooler. While the principle works quite well in west Texas and other arid places, I'm not sure that would be all that effective in humid climes.

It's probably not a winning idea along the Gulf Coast.

[jimlongley]

Sounds like you're essentially turning a refrigerated air unit into an evaporative cooler. While the principle works quite well in west Texas and other arid places, I'm not sure that would be all that effective in humid climes.

The ones they are talking about in the ads enhance cooling by spraying mist on the condenser coils to cool the evaporatively. This is not the same as evaporative coolers which blow moistened air out to cool by evaporation. These misters are fine and dandy, but if we start going to stage 4 water restrictions as has been suggested may happen soon, it will likely be illegal to use them.

[WildBill]

Sounds like you're essentially turning a refrigerated air unit into an evaporative cooler. While the principle works quite well in west Texas and other arid places, I'm not sure that would be all that effective in humid climes.

The ones they are talking about in the ads enhance cooling by spraying mist on the condenser coils to cool the evaporatively. This is not the same as evaporative coolers which blow moistened air out to cool by evaporation. These misters are fine and dandy, but if we start going to stage 4 water restrictions as has been suggested may happen soon, it will likely be illegal to use them.

It sounds like I could turn my backyard into a swamp. How much water do you have to mist?

[jimlongley]

Sounds like you're essentially turning a refrigerated air unit into an evaporative cooler. While the principle works quite well in west Texas and other arid places, I'm not sure that would be all that effective in humid climes.

The ones they are talking about in the ads enhance cooling by spraying mist on the condenser coils to cool the evaporatively. This is not the same as evaporative coolers which blow moistened air out to cool by evaporation. These misters are fine and dandy, but if we start going to stage 4 water restrictions as has been suggested may happen soon, it will likely be illegal to use them.

It sounds like I could turn my backyard into a swamp. How much water do you have to mist?

Not very much in the overall scheme of things. The systems are set up to mist only when the condenser fan is running, so assuming that the whole AC system runs less because it's more efficient, then consumption is not high. I have yet to see a mister system that gives an estimate.

[ELB]

Seems like if this were really effective in most situations, it would already be an option on A/Cs to begin with.

[RPBrown]

In theory, the misters are a good idea. However, with the water in Texas, long term use of even 1 season can cause scale build up on the coils and virtually no way to remove it. The misters will lower pressures which lower power consumption but not for long. Once the scale starts to build up, the pressures and power consumption go back up eventually causing failure, either the coil or compressor.

I went to a customers home for her yearly spring inspection. Her son had installed a mister last year after I had done the inspection. The scale was so bad, the only option we had was to either replace the unit or the coil. She chose the unit.

Now, with that said, I have used a sprinkler on my own system OVERNIGHT, because I didn't have the correct motor after a failure. But this was at my own house and I replaced the motor the next day. It was either that or we went to a hotel. Not many hotels will take 4 dogs and we wouldn't leave them. The motor failed at about midnight and I wasn't going to pay a supply house an open up charge or have to go to the supply house that late.

So, no, I do not recommend a mister system.

[WildBill]

Seems like if this were really effective in most situations, it would already be an option on A/Cs to begin with.

I tend to agree with that.

The advertisement also stated that you could get a tax credit if you installed the system.

Thanks for all the feedback. I think I will leave well enough alone.

[JSThane]

Sounds like you're essentially turning a refrigerated air unit into an evaporative cooler. While the principle works quite well in west Texas and other arid places, I'm not sure that would be all that effective in humid climes.

The ones they are talking about in the ads enhance cooling by spraying mist on the condenser coils to cool the evaporatively. This is not the same as evaporative coolers which blow moistened air out to cool by evaporation. These misters are fine and dandy, but if we start going to stage 4 water restrictions as has been suggested may happen soon, it will likely be illegal to use them.

Ah, thank you for the clarification. The idea does make sense to me, but I'd never considered that application of it.

[WildBill]

Sounds like you're essentially turning a refrigerated air unit into an evaporative cooler. While the principle works quite well in west Texas and other arid places, I'm not sure that would be all that effective in humid climes.

The ones they are talking about in the ads enhance cooling by spraying mist on the condenser coils to cool the evaporatively. This is not the same as evaporative coolers which blow moistened air out to cool by evaporation. These misters are fine and dandy, but if we start going to stage 4 water restrictions as has been suggested may happen soon, it will likely be illegal to use them.

Ah, thank you for the clarification. The idea does make sense to me, but I'd never considered that application of it.

Is this the same type of mister that temporarily cools off the visitors at the Kemah Boardwalk?

[jimlongley]

Sounds like you're essentially turning a refrigerated air unit into an evaporative cooler. While the principle works quite well in west Texas and other arid places, I'm not sure that would be all that effective in humid climes.

The ones they are talking about in the ads enhance cooling by spraying mist on the condenser coils to cool the evaporatively. This is not the same as evaporative coolers which blow moistened air out to cool by evaporation. These misters are fine and dandy, but if we start going to stage 4 water restrictions as has been suggested may happen soon, it will likely be illegal to use them.

Ah, thank you for the clarification. The idea does make sense to me, but I'd never considered that application of it.

Is this the same type of mister that temporarily cools off the visitors at the Kemah Boardwalk?

Almost, but those are evaporatively cooling the visitors, while these are cooling the condenser coils.