Hey All,
I can't find clear cut answer (maybe due to different models), but in general does Evaporative Cooling Increase Humidity?
I've got Bonaire Summer Breeze if it matters
Cheers
Does Evaporative Cooling Increase Humidity?
Godric on 10/01/2022 - 22:24
Comments
Yes. Evaporative cooling works by increasing humidity to decrease temperature.
Ah okay,
I was reading different threads like this one where you get yes & no answers -> https://www.quora.com/What-does-air-conditioning-do-to-humid…
Yep, big difference between evaporative cooling and refrigeration, but both are forms of air conditioning
Yeah fair enough was getting mixed up, cheers
kind of right but wrong conclusion.
The end result is an increase in humidity but in the increase in humidity is not the cause of the temperature decreaseThink of it in terms of human sweating.
sweat through the pores of our skin. heat is taken away from our body to evaporate the sweat, so the body cools down.
The water evaporates so it increases humidity. This is not perceivable unless you are in an enclosed space.When humidity in the surrounding air increases, the rate of evaporation drops, thus making it harder to cool the body through evaporation
I have been running Evap cooling for 15+ years now. The quick answer is yes, it does increase humidity, but it's all about how you use use. Evap is incredibly cheap to run compared to refrigerated (like cents per hour). We run the fan / vent mode until it gets hotter outside than in, before switching to cooling mode. In WA this is usually around 10-11am. As a general rule, if it is cooler outside than in, run it on vent instead of cooling and humidity wont be an issue.
It only works because of the generally dry climate in most parts of Australia but have you counted the cost of water into the equation? But the ongoing cost difference is negligible if you start from scratch, evap doesn't work very well once temp goes around 40 and it will take ages to get there. If you have to fork out $3k for new install then a 7kw split can easily beat an evap cooler in keeping half the house cool. And you can save the roof space for solar.
Have you seen any recent analysis of running costs. I remember they used to advertise as being much cheaper, but have heard of people very disappointed with the running costs recently.
Refrigerated systems have become a lot more efficient in recent years, and don't run at full power all the time, so it is difficult to estimate comparitave costs just on specifications. I'd be interested to know what the cost difference is now, but haven't found a good analysis.
Also water costs have risen substantially and power potentially dropped if you have PV.I'm not saying the evaporative isn't cheaper, just that I don't know.
I currently have both, tend to use the evap in milder weather and to bring the outside air in at night, and the refrigerative on really hot days or when only one room needs to be cooled.
I’ve been using 2-3 Lg split systems this year and haven’t noticed any huge spike in electricity costs over the times I had evap cooling only
The fan on an evap unit uses between 250w on low and 750w on high. A modern inverter split system would be in the same range once the area is cool, although it won't cool as big an area.
Do you need the windows open if using just the fan?
Yes and I don't really recommend it. Doesn't work well in humid weather or at night.
We live in Geelong and have on occasion had condensation building up on the floor tiles because of it, also a musty smelling walk-in-robe due to the dampness and lack of ventilation.The only benefit is that we can leave it on cooling the whole house, as much as we want, and not worry about the cost.
I could only recommend it to someone living in a dry climate like central Australia, Mildura, etc. where it would be great.We got it because when I went to a specialist and asked them to quote for ducted air-con (we already have ducted heating) they told us that evaporative was way better, that it's what everyone is getting.
Depends where you live and if your house is subject to moisture problems. I have had evaporative in both my last two houses and it has been wonderful. No moisture issues at all. Canberra
Exactly. If you live in a place that is hot and dry they are fine. Hot and humid… not so much. In Brisbane for example, hot nights are usually humid so I suspect it is not very effective, or possibly even makes you feel worse (more humidity without any cooling effect).
Had this in a place we rented a while back, and I didn't like it at all for the exact reason that it massively increased the humidity inside.
On really hot days it was effectively useless in terms of improving comfort
Are Evaporative Coolers susceptible to Legionnaires Disease ?
Not if they have been double-vaxxed and had their booster.
OH can you get vaxxed for Legionnaires Disease ?
😪
Evaporative systems are very common in WA and I've never known anyone with Legionnaires in my 40 odd years here.
No because they dump water in the tank when you turn the system off. The pads will then dry off naturally. There shouldn’t ever be any still/stagnant water.
I can't find clear cut answer
O.o
Do you like 7up?
Check the humidity where you live. It averages around 50% in Perth during the summer and evaporative works well. Different story in Brisbane.
Are you in Perth?
Seems like many houses there have evaporative AC there. Cheap to install and run.
Yep, in Perth. You see them everywhere.
Don't bother with Evap cooling. Pay the extra money to get split system(s) installed
And solar to power it. The cooler unit on the roof unusually take up space that could be used for solar panels, plus the big outlets in the ceiling loose a lot of heat in winter.
That reminds me. I need to 'block' my evap cooling vents
Not if it's on your southern roof
Southern roof is quite effective for solar in Australia, only about 20% worse than north.
@md333: If you have a northern roof and a southern roof, you would be daft to put your evap cooling box on your northern roof and solar on your southern one though.
Also there is a wide range of latitudes in Australia! If there is a 20% difference in far north Queensland there is going to be a much bigger difference in southern Tassie.
@Quantumcat: Sure, but if you don't have space on other directions, solar still works quite well on a south roof.
Approx 20% difference was for Perth, so won't be as good in Hobart. South is as good as north in Darwin.
This is how evaporative coolers work:
Think of it in terms of human sweating.
sweat through the pores of our skin. heat is taken away from our body to evaporate the sweat, so the body cools down.
The water evaporates so it increases humidity. This is not perceivable unless you are in an enclosed space.When humidity in the surrounding air increases, the rate of evaporation drops, thus making it harder to cool the body through evaporation.
In those situation, sweat starts forming beadsAn evaporative cooler will not work when the weather is humid (like Melb the last few weeks, or darwin and carins 365 days)
Thanks for info everyone (Y)
Also whilst i'm here, the 'fan' function on the Evap, that's literally all that mode enables, just the fan and no evap function is that right?
Yep, which is perfect for when it's cooler outside.
Bad for when it is smokey
ah right good to know,
cheers
I have been using evaporative cooler for few years in Melbourne and has been fine even with 38 degree days. Selecting evaporative cooler depends on house size as well. For a 29sq built house I went with second largest size and it cools down the house much faster as compared to lower sized models at my friend's place with similar built area. Also while using evap cooler one need to open sufficient windows for air circulation. Each unit come with recommended window opening size.
Also while using evap cooler one need to open sufficient windows for air circulation. Each unit come with recommended window opening size.
This is something I like better about evap compared to split systems. With split systems you need to keep everything closed so you don't lose the cool/let heat in. The air then gets stale and you feel hotter with no moving air and stale air. Evap lets you have lovely breeze and fresh air constantly. It is like being outside on a lovely cool spring morning.
Looking at the specifications alone as you have to start somewhere my breezair evaporative unit has 7 cooling pads, 1100watt motor and says that it offers up 14.5 kW of heat removal when running full blast and using my powerpal connected to my electricity meter I've managed to find that the breezair uses between 500 and 600 watts of energy running on minimum. Compare this with the two split units I have of 7 and 8 KW Mitsubishi Electric units that use 3.2 and 3.5 KW of electricity to create that heat removal of 15 kilowatts and the difference in electricity price is clear. However when they're both running on idle the specifications of the Mitsubishi unit says that they both use 570 watts each. Making their idling cost together twice that of the breezair. The cost savings claims is very well founded and that's with an older evaporative than the newer Mitsubishi electric equivalent heat removal
So purely on an electricity running cost the breeze air unit cools a whole house for about 1/6 of the price of the two splits cooling half the house assuming a nice dry day below 38 C.
Now the Direct Drive Brazier units use less electricity but they're also more unreliable breaking down more so than the belt driven however the benefit of the evaporative is it you can use it to blow stale out of the house and certainly recirculating stay aware isn't it healthy for you as having water cool incoming air assuming the air quality is good so there are a few times when you want to run the evaporative and there are a few times when you want to run the split but make no mistake the split will cost you more even with the cost of water ah there's nothing wrong with that it's a different mode of cooling the other advantage is it the Spitz off a heating as well I'm currently automating my home to try and have the two units switchover according to air quality temperature humidity and maximum day temp the latter proving difficult to obtain programmatically..
Oh God! This reminded me of when I worked retail. Our shop had E/AC and management insisted on running it, even when it was hot & humid out. Staff & customers were nearly wiping out on the stupid, wet tiles. We were actually told to run around with a sponge mop to try to dry the tiles! I told the manager that if anyone was injured, I was going to support them if they made a claim.
Yes.
Also it doesn't work well in humid weather.