Evaporative is great except for blisteringly hot days

[Kim]

It's really hot today and we have evaporative cooling installed.  It does a great job until mid-afternoon, and then the challenge of the heat seems too great to keep the house cool. For anything except scorchingly hot days we love the cool, seabreeze feel of evaporative, and having the bi-folds and windows open.

We're thinking about installing a split-system in addition to the evaporative, but it feels like an expensive approach to keeping the house cool on those few hottest days of each year.

Has anybody else done this, or anything else to help out their evap system when it can't quite handle the blazing heat?

[Jason]

@Kim

Welcome to Workshop. It's great to have you join the community. 

I'm sure this will be a popular discussion. I know we faced a very difficult choice between evaporate cooling and air conditioning when we were renovating. I will be very keen to see what responses you receive from the Workshop community.

Jason

[Dan]

Hi @Kim,

We have evaporative cooling through the whole house on both stories. It does a great job of keeping the lower level cool but the 2nd story it struggles. So we have individual split systems in the 2nd story bedrooms and they work fantastically. Some units you can run 2 indoor systems from the one outdoor unit as well.

[ProjectPete]

My mother-in-law still has issues with her evaporative so she installed some splits. Fixes the problem but probably cheaper to install reverse cycle ducted by the time you do 2 or 3 splits.

I've got an amazing system. Doesn't struggle to heat or cool even on those 40+deg days. And they're cheap to run with their inverter technology, etc

[aussiblue]

I over specified my evap cooler when it was installed (11 outlets commercial units with a large motor) so on high speed (which I only rarely use on those very hot or humid days) I have a virtual tornado and it copes well in all Perth days. My issue is that I would like a thermostat control to automatically turn it of at night when it becomes too cold. They have thermostat in the US to retrofit to their swamp coolers but I can't find a source in OZ or even a US one that conforms to Oz electrical standards.

[bkedm]

Hi Kim,

If you dont do it already, the trick is to only have open the windows or doors in the area of the house you are using at that time.  Dont have all windows and doors open in the hourse.  Also, if the hot wind is coming from a particular direction, dont have those doors or windows open, this stops the hot area coming into the house.  Evap coolers dont cope with being turned on when the day is already hot, they are very effiecient when used from early in the morning.  The only days we dont use ours is on high humidity days.

I hope this helps.

[Jason]

Hi @bkedm, many thanks for joining the discussion. I'm sure @Kim will really appreciate your advice. 

Let me also extend a very warm welcome to Workshop. It's fantastic to have you join the community. I hope the site offers plenty of new ideas, information and inspiration for your projects. 

Jason

[Andy_Mann]

Brilliant post bkedm, we don't have evaporative, but what you say makes perfect sense.

I'm showing my ignorance here, but do ducted evaporative set ups have motor operated actuator valves, so that you can shut off unwanted rooms?

As others have done, installing splits would be great, & they'd be a hoot on humid days, but I can't imagine it would be a cheap move.

My suggestion if bkedm's suggestion doesn't fully fix the problem would be to upsize the 2nd floor ductwork. It's a project well within any DIYers skillset, & the money saved doing it yourself can go towards higher R-rated ductwork, which is more effectient. The thing is, unless you specify thermally effective ductwork when consulting for a ducted system, installers will put in the cheapest stuff that they can get their hands on to boost profits.

[aussiblue]

You can also install security outlets that empty the air into the attic space so you don't have to leave windows open. More importantly to me it increases the effectivness and efficiency of the system by keeping the air in roof space around the ducts and above the ceiling cool. Like these: (page 45 of https://www.metalflex.com.au/site-assets/Uploads/J2430-Metalflex-2017-18-Components-Price-Book-07031... and http://www.polyaire.com.au/products/grilles/security-relief-grille/ ) . I have just taken delivery of one for each room and hope to fit them in the next few weeks.  I will also add some more roof top (whirlybird style) and eve soffit vents (grill style) from Bunnings so the air can continually flow through the roof/antic space.  For the security vents to work the air must also be able to escape from roof space. 

I have also recently come across this innovative product out of Mt Isa Queensland that addresses:

a) the risk of water leakage into the dropper and onto your ceiling (believe me it does sometimes happens due to worn thin pads, poor installation, failed inlet float,  waters supply leaks, broken tiles or leaking flashings); and

b) the corrosion of the standard galvanised and colorbond droppers http://www.droppersolutions.com.au/ddk2.php  The dropper ducts do corrode (albeit it normally takes 20 plus years to do so).

Pity Dropper Solution have no distributors in WA yet (something for Bunnings to looks at carrying perhaps).

[Jason]

Great tips @aussiblue, many thanks for sharing. I'm sure many community members will find this information useful as we head into the warmer weather.

Jason