Ducted Air con zoning question

Hi guys,
Since we moved into our new home 4 months back,we are now looking at getting a ducted air con. I was looking at 3-4 zones but one of the installers told me that if I had 2 zones, one for beds and one for living areas, it should be sufficient.
I wanted to get a 3rd zone for my master bed so that during night when we only use this room, I don't need air going in the other 3 bed rooms and hence less energy will be used as the cooling requirement will be lower.

But the installer tells me that whether i go for a separate zone for my master bed, the power consumption will not be less as more air will be pumped out of the only 1 of the 9 outlets open during night and it will get loud because of the air flow.

Is he talking crap or am i making a logical error? Mostly only 1 bed will be used for next 2-3 years so it made sense to me to have this bedroom in its own zone to save energy costs. Someone pls clarify this.

The comments about noise sounds about right to me we sometimes shut some vents down and the remaining vents are noisier

Some systems, such as the Actron ESP+ are able to vary the speed of the internal fan and adjust the compressor loading when fewer zones are active.

With a more traditional unit you can get some improvement in effectiveness by closing the doors to the empty rooms - but you can get a whistling sound or other noise

Paul

I have my master bedroom on the same zone as the living areas

I'm getting an LG 5 zone installed in my new house (yet to be finished) and the way they've set it up is as follow's.
Constant Vents - Living Room (2 vents)
Zone 1 - Kitchen/Dining (2 vents)
Zone 2 - Home Theatre (1 vent)
Zone 3 - Beds 3 & 4 (1 vent per room)
Zone 4 - Bed 2 (1 vent)
Zone 5 - Master Bedroom (2 vents)

The 5 zones can be turned on or off at will, but in case they all get closed, the 2 constant vents in the Living area (connected to the Kitchen/Dining as open plan living) will allow the air to flow therefore not blowing all the ducting apart. If I have the Dining/Kitchen zone on too that makes 4 vents in the one area.

It seems to me and from my own Fujitsu ducted system you have either been mislead or misunderstood. There will always be two or three outlets open, as Sir Snagger said, so the ducting remains intact. Ive a smallish home with a 10Kw 6 outlet 3 zone system, with the kitchen/dine and adjoining lounge always on, and have the 3 bedrooms independently zoned. Some companies will suggest day/night zoning, which is useless if you want to use a bedroom during a hot day.

Im happy with my setup, but these things do suck up the electricity, so unless you want a bank-breaking bill, dont just turn it on and forget it. Look at other ways to cool your home (heavy drapes, roller shutters etc etc) so its not solely reliant on A/C

This is the model I (think I'm) getting installed in my house - http://lgairconditioning.com.au/air-conditioner/b36awy-763

We've just had an Actron ESP+ system installed and we've got it zoned:

Main living/dining/kitchen/playroom (open plan) - Zone 1 - 5 vents
Clinic - Zone 2 -2 vents
Media -Zone 3- 1 vent
Study - Zone 4 - 1 vent
Main bedroom - Zone 5 -1 vent
Beds 2, 3, 4 - Zone 6 - 1 vent each

We don't have any constant zone, the system allows me to run only one room if I like without a 'rushing' of air through that vent ... so at night in summer I can run just the bedrooms without wasting energy having an unused zone on.


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Sent from my mobile device so please excuse my typing missed cakes.

Can anyone confirm the Actron systems are actually more efficient at part load? The fact that they can lower capacity and fan speed is one thing (comfort and convenience), but does the end user actually save in running costs, particularly with the premium they are paying on the initial outlay.

Keep in mind with any zoning all outlet air must recycle to the return air, if it travels through an area that is turned off then there is not much point turning that area off.

Zones give options, but many get too caught up on having too many options. Ducted air takes up to hours to heat or cool, it is climate control not an on/off appliance. Most can zone a house in one to three zones and have plenty of flexibility and an efficiently designed and running system.

Good example from the old days still works today as a good base, day (living) and night (beds).

Our system has only just been installed, so can't compare electricity bills, but with all the research my DH completed he kept coming back to Actron and effiency was high on our list of musts.

A good installer will set up the layout to achieve best results as well. Like you said with return air ... one supplier zoned ours as I listed above, but had one return air near the kitchen only. Not very efficient when running other ends of the house. Where as the supplier we went with designed the layout with three return air allowing each end of the house to be able to function well (we have a long house - if that makes sense).


Edited: typo ... I really like my Actron but I don't lust over it

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Sent from my mobile device ... please excuse the typing missed cakes.

What happens if you turn the A/C on, forgetting you have all zones closed?

Seems like a disaster waiting to happen

If I read it right, it might not be able to close all the vents. Always needs one opened. That would be a programming thing which would be easy enough to do, or I may be wrong

You can't turn them all off at once, the system is pretty smart and won't let you turn the last zone off. .


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Sent from my mobile device so please excuse my typing missed cakes.

Each zone is a labelled button, all I do is press the zones we want opened and a little red light goes on, if I want that zone off I press it again and the little red light goes off. As a default it won't let you turn off the last zone, so if I want to run only the master bedroom and only study is lit up, just press master bedroom first and then study to turn that one off.




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Sent from my mobile device so please excuse my typing missed cakes.

we were in the US for several years and they have no zones- just vents that you can open or close off- where as in our Aussie home we had 5 zones and was always worrying about the different rooms.

We are about to start building a house. We will have ducted air conditioning.

Looking at the traditional way ducted air conditioning is set out, it occurs to me that there are two weaknesses in terms of efficiency. One is the fact, that even though the various rooms and areas have ducts bringing the conditioned air into them, there is only one return vent, usually mounted in the ceiling of the second floor (in a 2 storey home).

The weakness I see with this is, that if I want to have just one zone on, as for example at night when I would only want to condition the Master Bedroom ( and any other bedrooms that were occupied), then I can set the air conditioner to bring air into just those rooms (if, of course, it has a separate zones option on the control), however, that same air then has to travel through a section of the rest of the house to get back to the return vent and in doing so looses a tremendous amount of the heat (or in summer - cold) that it had.

Why can’t certain rooms, for example the bedrooms and the Home Theatre, have not just a vent to admit the conditioned air but also a return vent to take the air DIRECTLY back to the main unit through insulated ducting and hence save an enormous loss of energy?

The other weakness is that, under the existing system, in order for the air to get back to the one return vent, there has to be a space under the doors of the bedrooms and Home Theatre, which of course allows noise to pass through the house. If these rooms had a return vent then the doors could fit closer to the ground and help keep in any noise.

By the way, before someone mentions it, I am aware that the main return vent in the ceiling contains the filter and that if you had separate return vents for certain rooms you would have to devise a way of making sure the air from them also passed through the filter. Perhaps this could be done by having the main return vent in a cupboard with a louvered door, whereby the general air would return through the door and the separate return vents from the individual rooms would come into the cupboard through its roof to then allow their air to pass through the filter in the main return vent. By having the main return vent in a cupboard you could also have it lower down and also much easier to reach for cleaning the filter. The cupboard would just look like a large broom closet.

Also, of course, the air conditioning unit would have to have the ability to lower fan speeds etc when conditioning just one or two rooms.

Has anyone ever tackled this problem? Has any domestic air conditioning company ever thought of doing what I have suggested? Am I going to be told it’s just too difficult or too expensive?

what you say above is correct to some level. However just because you run r/a pipes to each of the bedroom you will have better access to the air however you will also introduce additional loses and then the air cond actually works harder trying to move air around. These pipes will need to be long an thus the air in them will heat up from being in the roof cavity for too long.

Basically in a domestic environment this is an over kill. Best to keep things simple and more reliable. You will also have trouble keeping the air outlet far away from the air in let.

You will find that the bedrooms heat and cool very easily any way.

Your points are well taken and make sense.

However, I still feel that there is a fault with the present system of air conditioning. For example, in our new home we plan to have the Home Theatre at the back of the house on the Ground Floor. When we are watching tv at night we could just have that zone on, but the conditioned air would still have to return via a large part of the ground floor, up the stair well and to the ceiling return vent in the First Floor ceiling, thereby losing a huge amount of its heat (winter) or cold (summer). Also this would necessitate a gap, small, but significant, under the Home Theatre door, to allow such an air return, thereby undoing a lot of the soundproofing qualities built into the Home Theatre.

You said that the air would heat up from being in the roof cavity for too long. However, I envisaged the return air ducting to be insulated in the same way the other air conditioning ducting is. You also said that the air conditioning unit would have to work harder to pump air back through return ducts. A valid point. However, my point would be that in the present designs, where the air conditioned air has to return under the doors of bedrooms and Home Theatres, that this greatly restricts air flow and places extra load on the unit. Some may reply that all the doors should be open. This is hardly a solution, because the whole idea of a Home Theatre should be that you can close the door so as not to disturb others inside or outside the house. Similarly, it is hardly practical to tell all residents and guests of a home that they must keep their bedroom doors open all night so that the air conditioner can work properly.

I still think intelligently designed return air vents may be worth considering.

First of all what heating/cooling system are you considering???
I have a basic brivis system where you cant control the output power of the compressor. So on a system like this it is use less designing a system to work with only one room.

Secondly the more duct work you have in the roof the less efficient the system the system is. Just because you insulated it doesn't mean it will not heat up.

I guess in a big house (very big house) this will be worth looking into, or even double storey houses. It should be possible to do with most system with current technology I have already thought about this previously. All you need to do is wire two zone motors on each relay. One for the air outlet one for the intake. But it still a little more complex than this.