What to choose - Evaporative or Refrigerated?

Hi,
As we have never been in a home that has a decent cooling system, we are a bit unsure of which will be better in terms of running costs, effectiveness and practicality.
We have had quotes from a few heating/cooling places for a gas central heating unit with add on refrigerated cooling for about $11,000 (I think it was a brivis heater with Lennox cooler) - of which the builder has said they will take $2,200 off the house cost, so we will be paying $8,800 for refrigerated cooling (the builder doesn't do refrigerated). We have also had similar quotes for an all-in-one heating/cooling unit by Hitachi - however our reservation is the cost of heating with an electric unit as in Melbourne we need more heating than cooling...
The builder will provide ducted evaporative cooling for approx. $4500 (which is probably overinflated) - however they have a promo at the moment for evaporative cooling for $1500 - which is very tempting.

Our concerns are:
* we plan on being in this house for 10 years + so we want something that is going to be useful long term
* we have a small child so we want something that will be effective
* we want the running costs to be as low as possible and are willing to pay a bit more if it means savings over the next 10+ years
* we are in Melbourne and I don't know which type of cooling is better for the climate here (I know evaporative isn't effective for humid days - but have had no experience with evaporative!)
* also our block backs onto a major highway, and having windows/doors open while running the evaporative may be an issue with noise

If anyone has any info/suggestions I'd love to hear them.

Thanks in advance.

When we built over in WA the builder put in an evap system. We had only ever used the normal split/ducted refrigeration setups and were surprised that on the hot sticky days the evap system was useless. A window had to be kept open otherwise you would hear the evap system start to make a bit of noise(airflow is needed).

Here in sydney we use daikin splits and could not be happier. When the new house goes up, we will either have a Daikin or Actron Air setup. unsure which one at this stage but leaning towards the Actron.

In Melbourne, we are fortunate that humid days are limited. We get them every now and then, but I don't think enough to worry about. If we were in Qld, you would never install an evaporative because it would be useless almost all the time.

We are installing an evaporative (South East Melbourne) because of low running costs and I like to have windows open (never like shutting the house up). Also, the evap cooling is very quiet (if you pick a good brand) so you barely notice that it's on.

I think as with all things, the choice comes down to personal experience.

good luck choosing!!

Amber

http://ourdreamhouse.blogspot.com/

Go for this, it may be possible down the track to convert it to Refridgerated. I would talk to your consultant, get the brand, and confirm it with them. I think it is Bonaire for memory.

Adrian B

I'm afraid that's pretty unlikely. Evap ducting is enormous - that method of cooling simply requires a large amount of airflow. The same size ducts won't be suitable for refrigerated cooling.

What you will find is that your heating ducts will be the right size - enquire about adding a refrigerated unit beside your ducted heating unit.

As far as running costs go, you won't beat evap cooling. They use a little bit of water, and run a fan all day - no chunky compressor to run.

Given the cheap cost of putting an evap in with your builder, I'd just let them go ahead and do it. It's great to have on in the evenings, and doesn't dry out your whole body if left on all day (incidentally, that's the best way to use them - not just when the house has heated up).

As others have said, they're really quite useless on a humid day - except to provide some airflow.

I'm building a new house at present - we're putting an evap in there (we have one now), but will also be putting in a split system (inverter) for those days when it's just too sticky for anything else.

If you can afford both an evap and a split - I'd go for that option. They both have their pros and cons on a pretty equal basis.

Our experience has been that evaporative cooling is near useless 90% of the time so personally I would steer well clear.

I suggest that you get a few reverse cycle inverter splits with a very high efficiency ratio. Try something like:

PANASONIC CS-HE9DKE / CU-HE9DKE with an EER of 4.93 or
MITSUBISHI SRK25ZDXA-S with an EER of 4.81 or
PANASONIC CS-TE9DKE / CU-TE9DKE with an EER of 4.49 or
PANASONIC CS-XE9EKE/CU-XE9EKE with an EER of 4.35 or
TOSHIBA RAS-10JKVP-E/RAS-10JAVP-E with an EER of 4.34

My understanding of EER is that it reflects the ratio of input power to output power. So the one at the top of the list would put out about 4.93KW of cooling for every 1KW of power supplied ie. nearly 500% efficient. This is possible because you are moving heat and not creating it. Cooling is the same process in reverse.

This will give you relativly cheap heating and cooling and be EFFECTIVE. I have found ducted gas heating to be a bit dry and seems to swing from hot to cold. The Inverter in the RC AC units listed should provide a more even heat or cool.

Most offices and shops use refrigerated AC and there is a good reason that they do. The only other heating system I would consider is Hydronic.

Good luck whatever you do.

3xb

we live in canberra and had evap cooling installed separately from heating due to duct size and layout of the house. We had a 2 storey home and only installed 3 ducts on the top floor ( our living room was open to the 2nd floor ) we opened a window where we wanted the air flow to go and it was great. Very inexpensive to run, we thinking of putting ducted evap in our new home now too.

For what its worth a different view point !

One of our recommendations for Melbourne is gas ducted heating with add-on air conditioning.
Gas heating is quite cheap to run and in Melbourne it is used for a good 4-6 months of the year at least. Then in summer simply turn on the a/c which runs through the same ducts as your heating.

An earlier poster said 90% of the time evap cooling is useless. This would only be the case in places where humidity is constantly high. In Melbourne we get about 5-7 days on average through the summer that your evap cooler won't work really well.

When it comes to cooling consider your lifestyle. A/C requires everything to be closed up, and you have to be able to afford to run it, otherwise its a complete waste of money. Evap requires everything to be open with constant fresh air and costs 10c an hour to run.

Hope this helps you to make an informed decision.

Thank you all for your replies.

We just couldn't go past the offer of evaporative for $1500, so (pending managers approval as the promo is finished, but have paid our deposit) we will be going with this option (it's at the promo price on the list of inclusions we have signed).
I don't think at this stage we could justify spending somewhere in the region of $10K on cooling - especially as the builder was only going to "refund" $2,200 for the included gas ducted heating to be removed.
If we were to choose one of the other options we would have gone for a gas heating/add on air con - mainly cos the cost of running the heating would be better compared to the electric all-in-one models, which were a similar price to install.
We have decided that should we find the evaporative ineffective we will add a wall mounted split system to the kitchen/meals/family later on, so that on days when the evaporative isn't coping we will at least have a large portion of the house cool.

Ray.

Thanks for this advice - I am reinstalling a ducted Breezair evaporative cooler. It worked fine in the single storey arrangement - and now we have added an extra storey I am about to reinstall it. I have been trying to get some advice on size of registers, ducts etc (without much luck, given that every air conditioner installer in Canberra is busy till March) - but your comments about directing the flow of air from upstairs by opening the appropriate windows gives me hope. I have been trying to get the ducting to the ground floor via a 16" duct (maximum that will get through the space allowed) and then through a few registers stuck in a bulkhead - I was worried that this wouldn't be enough cool air delivered downstairs - but by the sound of it - the size and shape doesn't matter too much, just so long as there is lots of air flowing around the house and out through open windows. This was the first bit of practical advice I have been able to get from any source.

Yes it will work amazingly well. Close all the windows upstairs, turn the cooler up to full fan speed and open some windows downstairs - that 2 - 3 thousand liters of air per second will take the easiest route out - which is to go downstairs! Enjoy!!