Suspended ceilings

Neosdad · Jan 23, 2023 11:21 am

We are looking to fully renovate a full double brick, double storey home (with concrete flooring between the levels). It currently does not have downlights or ducted air and we wish to have these installed. Is my understanding correct that:
1) adding a suspended/dropped ceiling using gyprock is the most economical way to hide A/C ducts and electrical wiring?
2) If the above is true, what is the absolute minimum dropped height/void I can get away with? Would like to keep as much of the current ceiling height as possible.

ponzutwo · Jan 23, 2023 11:27 am

unsure, but AC ducts are traditionally pretty massive. There are smaller duct systems like AirSmart which solve that problem, but are very pricey. Something to be aware of.

alexp79 · Jan 23, 2023 11:58 am

Yes, ducts will be an issue. I would recommend to solve it in the below ways:

1) Integrate split A/C system by placing some of the units into bulkheads (e.g. in kitchen, living rooms), some into the ceiling and walls (where applicable).

2) Locate 2-3 spots where you could use you second story cabinets or columns to pull through your duct directly from the roof area to the ground floor grille without any bending.

3) Maximise the use of fans in order to maximise the movement of the chilled air throughout the bigger areas.

4) Negotiate your pricing with AirSmart. For double brick home you might be okay with a smaller system due to high density walls thermal mass effect. In reality, you might only need to run/use your A/C for an hour or two to cool your bedrooms before going to bed.

Pulse · Jan 23, 2023 8:45 pm

second that, bulkheads with downlights shining on wall art. Ducting and vents in bulkheads, you can use the whole bulkhead as a plenum space.

Locate a couple of bulkhead splits in areas you can have 2100mm ceilings, bathrooms, kitchens hallways, foyers etc, they only need about 200- 250mm last time I checked. It will look awesome. Get a few holes core drilled for air flow or knock out a few bricks.

Neosdad · Jan 23, 2023 9:38 pm

Thanks for all the replies. Some great ideas to think about. I wasn't even aware of AirSmart, but if it is indeed pricey, I could just go with "traditional" ducted and use grilles for the air diffusers in bulkheads above each rooms built in robes.

chippy · Jan 24, 2023 12:18 am

Depending on what the ceiling heights are down stairs sometimes you can get away with dropped ceilings or bulkheads in certain areas that are capable of taking the AC ducting and then just a very small drop for the areas that only need the electrical work.
Our previous house had the main AC duct run down from up stairs into a dropped ceiling in the laundry. It then branched to a bulkhead in the theatre room another outlet in the void and another through a dropped ceiling over the kitchen to the family room. The slab/ceiling was 2750 throughout the remainder but the laundry and kitchen had false ceilings at 2400 in order to run the ducting.
All those outlets were linear diffusers out the side of bulkheads.

Neosdad · Jan 24, 2023 8:38 am

Hi Chippy,

Is the main duct that ran from up stairs to downstairs larger? Then the ducts that branched out to linear diffusers are smaller? Is that how it works? Or are all the ducting circumference the same size throughout?

chippy

Depending on what the ceiling heights are down stairs sometimes you can get away with dropped ceilings or bulkheads in certain areas that are capable of taking the AC ducting and then just a very small drop for the areas that only need the electrical work.
Our previous house had the main AC duct run down from up stairs into a dropped ceiling in the laundry. It then branched to a bulkhead in the theatre room another outlet in the void and another through a dropped ceiling over the kitchen to the family room. The slab/ceiling was 2750 throughout the remainder but the laundry and kitchen had false ceilings at 2400 in order to run the ducting.
All those outlets were linear diffusers out the side of bulkheads.

chippy · Jan 24, 2023 11:00 am

Neosdad

Hi Chippy,

Is the main duct that ran from up stairs to downstairs larger? Then the ducts that branched out to linear diffusers are smaller? Is that how it works? Or are all the ducting circumference the same size throughout?

chippy

Depending on what the ceiling heights are down stairs sometimes you can get away with dropped ceilings or bulkheads in certain areas that are capable of taking the AC ducting and then just a very small drop for the areas that only need the electrical work.
Our previous house had the main AC duct run down from up stairs into a dropped ceiling in the laundry. It then branched to a bulkhead in the theatre room another outlet in the void and another through a dropped ceiling over the kitchen to the family room. The slab/ceiling was 2750 throughout the remainder but the laundry and kitchen had false ceilings at 2400 in order to run the ducting.
All those outlets were linear diffusers out the side of bulkheads.

That's correct. The fan coil unit that sits in the roof normally has 2 or 3 outlets. These are larger ducts that then get get split into smaller ducts for individual zones.
We had one large duct that ran down through a AC duct to the ground floor and then split into 3 smaller ducts that went to the 3 separate zones. Our ground floor was largely open plan except the theatre room, so essentially we had 1 zone for that and 2 for the downstairs. The outlet in the void/entry was a constant if I remember correctly whereas the theatre and living were on zones.

If you take your plans to an AC installer they can tell you what would be a good plan of attack. How big is the downstairs and is it open plan or separate rooms?