Ducted Evaporative A/C - Is it as bad as some say?
Discussion
Mods - Please dont move this thread away from here as it's an Australia specific thing.
We're looking at a "new" house, built in 1990 that has ducted evaporative A/C. Our current house has reverse cycle A/C in the lounge room only and we use a portable reverse cycle unit, ducted through a hole cut in the glass, in the master bedroom.
The new house has ducted evaporative A/C with the big box on the roof and basic vents in the ceiling of every room. From what I read, these systems only work if the door and windows are open and they dont work on a humid day.
But what does that really mean for a house in perth (Hillarys)?
One a hot day we open windows and are met with a wall of hot air so surely opening the windows is counter productive in terms of temperature reduction?
I quite like the idea of needing to have the windows open and the resulting fresh air that could be blowing through the house.
I'm an engineer so I understand the theory of each system, I'm here seeking practical experience of these systems and how they make you "feel" rather than what a temperature gauge tells me the temperature in the house is.
We're looking at a "new" house, built in 1990 that has ducted evaporative A/C. Our current house has reverse cycle A/C in the lounge room only and we use a portable reverse cycle unit, ducted through a hole cut in the glass, in the master bedroom.
The new house has ducted evaporative A/C with the big box on the roof and basic vents in the ceiling of every room. From what I read, these systems only work if the door and windows are open and they dont work on a humid day.
But what does that really mean for a house in perth (Hillarys)?
One a hot day we open windows and are met with a wall of hot air so surely opening the windows is counter productive in terms of temperature reduction?
I quite like the idea of needing to have the windows open and the resulting fresh air that could be blowing through the house.
I'm an engineer so I understand the theory of each system, I'm here seeking practical experience of these systems and how they make you "feel" rather than what a temperature gauge tells me the temperature in the house is.
I have this in Canberra and its amazing. This is because its very dry here. I like this much better than normal air cond because of exactly what you said about having constant fresh air replacing relatively stale air from the house.
Stupidly cheap to run as its basically a big fan and water. About 10c per hour. Takes about 30 minutes for you to fully start feeling the effect of the cooling air but once its running then will keep temp at a very reasonable 24 to 27 degrees even when its 40+ outside. On a hot day I would turn it on from around 11am and run it until we go to bed and cost basically $1 for the day. Some people will even leave it running 24/7 when its really hot. Depending on the size of the system, our house is 300+m2 and it completely cools the whole house.
Depending on the humidity in Perth, the effectiveness of this solely relies on low humidity. The lower the better it works fine when its 50+% but not when its 70% or more.
You don't open every windows and doors. You just need to open maybe 2 or 3 windows about 15cm wide to let the hot air out. You direct the airflow by opening and closing windows in different part of the house. Because it is a pressurised system, no hot air will come in from the windows if you don't have it open too wide.
If Perth is dry then its a perfect system to have. I think a normal air cond will struggle on a 40+ day. This won't.
Stupidly cheap to run as its basically a big fan and water. About 10c per hour. Takes about 30 minutes for you to fully start feeling the effect of the cooling air but once its running then will keep temp at a very reasonable 24 to 27 degrees even when its 40+ outside. On a hot day I would turn it on from around 11am and run it until we go to bed and cost basically $1 for the day. Some people will even leave it running 24/7 when its really hot. Depending on the size of the system, our house is 300+m2 and it completely cools the whole house.
Depending on the humidity in Perth, the effectiveness of this solely relies on low humidity. The lower the better it works fine when its 50+% but not when its 70% or more.
You don't open every windows and doors. You just need to open maybe 2 or 3 windows about 15cm wide to let the hot air out. You direct the airflow by opening and closing windows in different part of the house. Because it is a pressurised system, no hot air will come in from the windows if you don't have it open too wide.
If Perth is dry then its a perfect system to have. I think a normal air cond will struggle on a 40+ day. This won't.
Edited by onny on Thursday 30th January 03:53
I’m not sure on the windows open aspect, but as a FM for buildings etc, we had Cooltech Eco-Cooler evaporative system in Risby on one of our buildings.
Aside from pad maintenance, water supply being the right temperature, it was quite efficient, minimal maintenance, ductwork cleans /checked every 6 months from memory; one lot on system start in the spring time, and one on shutdown in late Autumn and the running costs of a reasonable sized fan,
Aside from pad maintenance, water supply being the right temperature, it was quite efficient, minimal maintenance, ductwork cleans /checked every 6 months from memory; one lot on system start in the spring time, and one on shutdown in late Autumn and the running costs of a reasonable sized fan,
We put Evap in to our house (in Vic) as it only had a split in the main room.
Split has never been on since then. The Evap is working away right now - as above it draws air in from outside so effectively pressurises the house and the hot air doesn’t come in. Few windows and the sliding door open a crack and off you go.
It might struggle tomorrow though because of the high humidity - I came home a few years ago and the OH had it going on a humid day and the tiled floors were wet!
When we put ours in I asked about ducted refrigerated systems and the bloke said a) it would be too cold, and b) evap would be fine 99% of the time.
It might be worth ringing a local installer for advice. Chances are if they offer it for install it will be fine for the weather over there.
Split has never been on since then. The Evap is working away right now - as above it draws air in from outside so effectively pressurises the house and the hot air doesn’t come in. Few windows and the sliding door open a crack and off you go.
It might struggle tomorrow though because of the high humidity - I came home a few years ago and the OH had it going on a humid day and the tiled floors were wet!
When we put ours in I asked about ducted refrigerated systems and the bloke said a) it would be too cold, and b) evap would be fine 99% of the time.
It might be worth ringing a local installer for advice. Chances are if they offer it for install it will be fine for the weather over there.
Agree with everything said, although I do prefer refrigerated! , I have evaporative on my house as that is what it was built with, and the configuration of windows makes a split system unachievable.
I have one large sliding window open, on the non-windy side of the house! So the south side, when it is hot.
Just got home at midnight, My house was 31 about 15 minutes ago when I put the machine on, It is now. down to 26
Melbourne tends not to have as many really hot days in a row, like Perth does. It is also very dry heat in Perth.
A few years ago, it was hot and humid in Melbourne for 4 or 5 days in a row, it struggled then.
HiIlarys would be near the water to, so a little bit of respite as opposed to inland anyway.
I have one large sliding window open, on the non-windy side of the house! So the south side, when it is hot.
Just got home at midnight, My house was 31 about 15 minutes ago when I put the machine on, It is now. down to 26
Melbourne tends not to have as many really hot days in a row, like Perth does. It is also very dry heat in Perth.
A few years ago, it was hot and humid in Melbourne for 4 or 5 days in a row, it struggled then.
HiIlarys would be near the water to, so a little bit of respite as opposed to inland anyway.
Really depends on the part of Australia...
Adelaide, Canberra - it would work great. Low relative humidity levels. The MILs one in Adelaide works well up to a point. If the temperature is above 40+ you notice it is less effective based on the way evaporative cooling works. That said, it is still good!
I don't think I have ever seen one on a house in Sydney/Brisbane!
Adelaide, Canberra - it would work great. Low relative humidity levels. The MILs one in Adelaide works well up to a point. If the temperature is above 40+ you notice it is less effective based on the way evaporative cooling works. That said, it is still good!
I don't think I have ever seen one on a house in Sydney/Brisbane!
I’m in Perth and given Hillary’s is pretty windy you might be ok for having a less humid area and better airflow for ‘window open’ evenings.
I’m 10kms north of Hillary’s for reference - I had evap ducted and now have reverse cycle and whilst evap ducted is fine most of the year, get it over 37 here in Perth and it struggles. Reverse Cycle is amazing in comparison.
So in short, fine for most of the year, you’re in a better place for it than most but when you really really want to be cool it’s not great.
I’m 10kms north of Hillary’s for reference - I had evap ducted and now have reverse cycle and whilst evap ducted is fine most of the year, get it over 37 here in Perth and it struggles. Reverse Cycle is amazing in comparison.
So in short, fine for most of the year, you’re in a better place for it than most but when you really really want to be cool it’s not great.
When we first moved to Perth we rented a big two storey house with ducted evap, it was OK but the only thing I found was that it tended to leave everything in the house kind of damp and sticky. As others have said it is cheap to run. We later moved to a house with ducted, zoned reverse cycle and that was good, except in Winter when heating the outside unit would freeze up!
Stef
Stef
Well, we've been in the house for a week now and the evaporative A/C is probably best described as an "air cooler" compared to reverse cycle A/C. Whilst the air feels cool if you stand under a duct, walking inside on a hot day doesnt give that same cool feeling that reverse cycle does - It just feels a little cooler than outside.
We've not experienced any of the damp feelings others mention but have been ensuring windows are always open when the system is running. That in itself is a bit of a pain because we have to spend a few minutes opening and closing all the windows at various times throughout the day as we come and go.
Time will tell next summer, I guess. Fingers crossed we dont have many humid days until then.
We've not experienced any of the damp feelings others mention but have been ensuring windows are always open when the system is running. That in itself is a bit of a pain because we have to spend a few minutes opening and closing all the windows at various times throughout the day as we come and go.
Time will tell next summer, I guess. Fingers crossed we dont have many humid days until then.
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