Hi everyone,
My builder starts my townhouse next month, and I need to work out what sort of cooling to go with.
I don't want evaporated cooling, as it only cools and need a heating system too.
It's either 2 split systems. One up and one down stairs, or a ducted refridgerated system,
Has anyone seen deals on the latter? Not cheap I'm aware of that. But cheaper would be better.
Can anyone provide feedback on their cooling systems, what's so good/bad about them?
Thanks
I agree with this. AC is expensive to run, ideally you want to cool as little of the house as possible and close off the rest. Note that heating works much better, particularly on gas as this will cost far less to run.
So depending on your using you might be better off getting a ducted heating system anyway. This also opens up the evaporative option.
Installation costs are mute because its going into a new install. Also most new ducted systems have zones so you can turn sections on and off as you see fit . It's what I have currently, 14.1kw system, 4 separate zones and sensors in each if the 4 zones, so as each area hits the ideal temp it shuts down that zone and reduces fan speed to the remaining zones.
Ducted is generally more efficient as well, and adds more value to the dwelling.
Doesn't matter how many sections you turn off or on, you are still powering a 14kw system 100% of the time; I'd hardly call that efficient! Remember, the fans aren't what's chewing the juice…that's the compressor/heat exchanger system that you cannot avoid running.
OTOH, if you have 2x 7kw systems you have the option of running either (50%) or both for your full 14kw of cooling. I've had a couple of homes with ducted systems, I've never been happy with them long term.
I'm not sure I'd agree about adding value to the place either…if I'm looking at a property & it has a ducted system, all I'm thinking is how much it's gonna cost to replace it…then I subtract that from the offer! ;)
Incorrect. The higher end models adjusts the compressor load in relation to zone choice and temp. Mine for example when set to the master bedroom draws less then 700w at the 20a breaker. The beauty of zones is that you can cool specific portions of the house without having to use extra power to cool the unused rooms. With say two split systems you are going to have waste since you won't have heads positioned in every room, and means that you cannot cool specific rooms effectively.
This will still depend how it is done though. With your system do you have an intake for every outlet? It will scale to the number of intakes and thermostats you have.
4 thermostats, 1 in each zone, Intake is in the central of the house, bought specifically so I can run it I. The bedroom for fatigue management.
How much did your system cost Copie?
Not that much I think, around 6400 installed, it was specked and installed when I built is place.Actron air.
See, to my way of thinking that $6400 buys at least half a dozen installed splits…any one (or two) of which will be cheaper to run than even the most energy efficient mode of your 14kw compressor.
Then you have fulgy wall warts all over the house. And you would be buying basement air cons, not Aus made.
splits system are cheaper to run. i had ducted air con before it was not cheep to run and if i just want office cool in day time i had run it for whole house. In the end i put splits system in bed room and in office and cut power bill buy around 70%. cople they are not good to look at but they cheeper to run.
The older systems maybe, zoned systems cuts down the amount of wasted energy.
Another point to note is that reverse cycle is one of the most cost efficient ways to heat a home except for gas.
My bill for an example is 128 per quarter, that's with a 1.5kw system, AC is run 24/7, server rack never turned off etc. I'm also on the peak system so I pay 50c per kwh during peak time.
Reading the op he is already getting some kind of ducted heating, he should look into the cost difference between reverse cycle and the straight heating.
I tend to live inside the house, so I'd rather have a few compressors I'm not gonna see outside the house & a cheap power bill than be running a 14kw compressor all of the time regardless of some fairy tale about magic giant adjustable compressors chewing less juice than smaller units when the thermostat zone pixies wave their wands. Just curious, how did you get from 14.1kw to 1.5kw?
I'm also yet to see a ducted system that is reliable long term, IME they're complex, finicky things; especially once you start introducing multiple points of failure. Then, once they crap themselves you end up with a huge dead box in your roof space & splits anyway, or perhaps a huge repair bill with an even more unreliable system. Been there, done that…now can't afford the T-shirt! KISS principle Copie, simple things don't break down as much. ;)
As nikey said, most people are only in 1 or 2 rooms of their house for any appreciable period in a given day…running a single huge compressor to cool a single room is just wasteful.
As for the 'basement systems' thing…well, let me just say I've had just as good a run out of my cheap Mistral, Gree & Aldi (Stirling) units than the Kelvinator & Samsung units I paid top dollar for. I didn't know anybody actually manufactured splits in Australia?
I didn't neg you. The 1.5kw system I refer to is solar system. They aren't any more complex then a split system, infact they are exactly the same except the output is fed into ducts where split is pushed out of the head.
Modern aircons adjust the compressor output relevant to the temp set and fan level, therefore your power consumption varies.
how the f is your electricity so cheap? Live in the sticks?
Live in Newcastle, not sure tbh, Mean I'm not frugal by any stretch, ill have a look at the bill more closely later.
Stewballs, please learn how air conditioners work, specifically inverter models. Just because a unit has a maximum cooling capacity of 14kw doesn't mean the compressor is running flat out all the time, even in a non inverter setup. Sheesh, this is basic stuff.
We did the research for our house. Running cost for evaporative was 12 cents an hour whereas refrigerative cooling was way more.
When I lived in Singapore, I was constantly sick from the refrigerated air because it was recycling air through the office. Refrigerated is exactly that…like being in a fridge. I spent heaps on acupuncture each week in Singapore to recover from the internal imbalances that the refrigerated air had on my respiratory system.
We have evaporative which still cools the home without the health impact I suffered from working in a refrigerated environment. If you plan to do both heating and cooling from the same vents, make that decision early because it is a special type of ducting they use that can withstand the cooling and heating. Otherwise, if you go heating first, then cooling later when you can afford it, you will end up with two sets of ducts running through your roof, and two types of vents cut out of your ceiling.
Evaporative cooling is also pretty much useless in humid climates; it will actually increase the ambient humidity in the home making the environment stuffy without any appreciable drop in temperature. Evaporative is only useful in distinctly hot, dry climates. For many people, it's not so much about dropping the ambient temp per se, as much as it is about dehumidifying the air that makes AC useful.
Now, as far as illnesses go…well, it's nice that you've had your chi restored and all that; but if whatever you had wrong with you was cured by acupuncture then it couldn't have been too serious. In fact, I don't believe you could really blame the AC for it at all if a placebo fixed you up! ;)
Frankly, I'd be more worried about evaporative cooling for bugs than refrigerated; clearly you haven't heard of a little bug called legionella, which causes Legionnaire's Disease. This genuine risk makes proper maintenance critical & thus running costs for evaporative cooling higher than your 12c/hr estimate.
If your building is to commence shortly, it may be too late to be making any serious changes, but if it's not, and you haven't already done so, you'll be doing yourself a huge favour by having as much energy efficiency built in as possible. Even simple things such as roof colour can make a huge difference to the temperature inside.
On a sweltering day when the energy grid goes into overdrive and power cuts occur, you'll be thankful that you did, and likewise, when you receive your electricity bill.
It is possible to build so that no aircon (or minimal) is required. Probably too late for that though.
I'd probably go the split system if I wasn't a cheapskate. Ducted may be expensive to repair. You can cool only certain zones, but the houses I've been in with ducted installed… they just don't seem to cool as well after a while, and (I believe) it would have to take more power to shove the air around all the ducting.
I don't like split systems much either. Because you need to get someone else to install and repair them. I'd rather have small window types for a few hundred $. Sure they're not as asthetically pleasing and make more noise. But you can cool only the rooms you use, and when they break, no week-long suffering in sweltering heat waiting for an installer, because everyone is installing at the same time. You just pull it out, screw a new one into the same space, and plug the cable into the standard power point - and it's cooling your house again in a couple of hours.
Agreed. None of us likes to pay such exhorbitant fees for split installs.
That said, it is a one-off expense you can mitigate by shopping around; I've had them down as low as $300 for a simple swap-out or $450 for basic new install. Use the coupon code CASH for a discount! :)
To save $$$ on cooling, install shade cloth (eg, nice looking shade sails, a some car vendors have, to keep their display vehicles cool) to protect the side(s) of the home getting hit by each day's hottest sunlight.
A friend - from the Sub Corp - told me he saves > 30% -each- Summer, in cooling costs.
Dunno why the neg, it's good advice.
Hmmm. I'm not sure I want a split system in every room, that's a lot of compressors around.
It's not too late to change my mind about what system to use.
The builder includes a 9 point heating system, which I would asime costs $2-3k?? Then we have to supply a cooling option. 2 splits may cost $3k. We are up towards the costs of a refrigerated system I think? Plus I don't want remote control clutter… We could get zone controls but then makes things dearer. I have Coldflow based around the corner.. Will see them tomorrow I think. Still not sure :(
We lived in a horrible, asbestos-government-housing-type house with no insulation. We had a 1.5 horsepower window rattler type (like I mentioned above). Admittedly the house is small - but even so, 3 bedrooms, dining, kitchen, lounge and hallway were brought down to a comfortable level - most of the time - by blowing the cool air into other rooms of the house using some cheap fans. Not ideal I know. It depends on how much convenience is worth to you. But just so you know, you don't need a split system in every room. If bedrooms are all off the lounge room for instance… one mounted there may do the lot. (Fans are dirt cheap to run.)
You're not likely to do this of course, being a new home. But you are on ozbargain too…
i know that feel been there before.
3 bedrooms, dining, kitchen, lounge and hallway were brought down to a comfortable level - most of the time - by blowing the cool air into other rooms of the house using some cheap fans.
Nothing wrong with this, I do it myself quite frequently. I only install splits in strategic places, no point wasting power when you can leverage the cooling you already have!
Not ideal I know.
Saving money is always ideal IMHO!
But just so you know, you don't need a split system in every room.
Agreed, 110%! :)
what part of Aus are u going to be in?
Melbourne
If I was to do it again I would run a ducted system.
I recently built a double storey house with only Gas ducted heating. Not I have to add splits in all the bedrooms upstairs and have one big one downstairs(open plan living). I am thinking about doing a single compressor unit with multi split heads in the bedrooms to minimise the compressors outside.
But the downsides of ducted cooling is that they are a little more expensive to install and the reverce cycle heat is not as good/cheap as gas.
Depends on what you want from your house and how much you have to spend.
Also remember that in Melbourne 90% of your climate energy costs come from heating.
Get some quotes.
Gas heating should be about 3K installed to 8 points. The ducts would be too small for add on cooling if you decide to do it later on.
Reverse cycle ducted aircon, 8-15k installed depending on how big the system is.
Also remember that in Melbourne 90% of your climate energy costs come from heating.
This is ringing alarm bells for me, do you have a source for this information?
WOW great discussion, personally i'd go for evap, and then of course you would need a seperate heater, but looking at the above, it would work out cheaper on both install and running costs, something to keep in mind with the increasing electric prices.also cheaper to maintain and or/repair
this is what we currently have (also in Melbourne) i have also previously tinted windows which worked really well about $500 for 9 windows (3 doors size), and fitted a whirly gig in the roof to remove heat from the loft space.
if you do go for refrig, strongly consider Daikin, one of the best buy all accounts, check out
productreview.com.au for reviews, you may also wants to look at the siddons solar hot water system
I'm really surprised that no one has mentioned how fast split systems are compared to ducted. We have a ducted system, and by the time it cools the house down enough, it's been running for almost 2 hours…. With a split system at our last house, I used to wait 15 minutes.
If you have the room, I'd say +ve for the splits…
Must of been a shitty ducted system. Mine can cool the entire house to the set temp in <10min with the fan on high.
For Melbourne, an evap system will keep your house comfortably cool for all but a few days a year with ~10% of the operating costs. In my opinion evap offers a much more pleasant environment to be in (windows open, fresh air), as compared to the stuffy dry cool offered by a refrigerative system. I've been cold in a friends house operating on evap only and it was 42 degrees outside (western Victoria, dry heat).
Legionella is not a risk with modern evap coolers (notice how all the legionella outbreaks you have heard about are linked to cooling towers, which is the evaporator for a large scale refrigerative system). Do some reading on this if you're not sure.
Comments on ducted using more power than splits because the compressor is bigger are incorrect. Modern systems run on variable speed drives, which adjusts the speed & power output of the motor to suit the mechanical load. The mechanical load is based on the amount of heat that needs to be pumped (hence AC's are called heat pumps in cold climates). A larger system will be inherently more efficient (better motors, compressor etc), however there are some inefficiencies introduced to the system running at non-optimum speeds. As a rule of thumb these will cancel each other out.
For whatever system you choose, get it correctly sized.
We just had a 41 degree day in Melbourne. We had our evaporative cooling on and you wouldn't have known it was so hot outside. We still think our investment in evaporative cooling was a good one. We purchased from Coldflow and their service was so excellent that many years after buying and installing, we got a phone call reminder to service our evaporative cooler.
Hi Berger, I am An Conditioning Engineer, The type of the shading devices to be installed at your new premises is one of the main factors in deciding the type AC requirements. Important fact External Shading devices are much more effective than internal shading devices. Adelaide is located 30degress S latitude for solar azimuth calculations, in this case assuming one your windows is facing North, your typical glass windows will have a solar heat gain factor of 5.89W, usually adding around 545 W or 0.5 Kw, with an external shading device you can reduce this drastically to 45W only! Lets say you have 10 windows large in total facing north only, this was you will hit around 600 W, account for cooling load which is always the worst case scenario, a 10Kw Cooling and 8Kw heating load would suffice for the whole house, ducted reverse cycle AHU. Cost ~$7000
I am currently building and I have gone with ducted reverse cycle.
Main reasons, big open plan house with 4 BR and media room, 10 outlets and six zones, all controled from central location (Ipad).
I have also got ceiling fans installed at same time, and will put solar panels on roof….. Run aircon during day whilst sun shining and fans will minimise need to run flat out all the time
Do this at my current location and power bill is the same all year round..
There is nothing worse than not being able to cool or heat a house because of cost… Comfort at home is my main priority.
Nice discussion.. I am told that the you have to keep the windows open with evaporative cooling and a bit concerned the risks of doing that at night. Some tell me that house smells damp due to the way the evaporative cooling works. Love to hear the feedback from those using it.
I prefer splits to ducted, primarily because if you're only going to be either upstairs or downstairs you only need to run one of the splits at any given time.
If you have a ducted system with a single large compressor you've got no alternative but to run that 100% of the time regardless of how much area you're actually cooling or heating.
Plus, initial installation costs are usually much lower for a couple of splits vs the outright purchase price & more labour intensive install for ducted.