How to add a ceiling air vent?

[Michelle64]

I am building a simple hot/cold air transfer system in order to pass both cold or hot air from living area to 2 bedrooms. I will have a wood heater and also a reverse cycle air con that i want to pipe to closed door rooms if needed. I expect i will need a ceiling vent sucking air from the living room ceiling, either flexible or solid ducting to take that air in a 3m straight line from living room to the first bedroom, then a 90 degree turn, then a 9m  straight line to to the second bedroom. I want to have the fan on a switch in living room, and have the ability to easily open or close each bedroom vent as needed to cater to temp preferences. I see that these vents have an open/close feature, but i can see how that actually works. https://www.bunnings.com.au/haron-international-150mm-round-jet-diffuser-ceiling-vent_p0811074

 I want to work out a way to open and close the vents without leaving the floor. 

I don't expect the system to operate like a ducted air con system, just to help with moving the heat/cool to the rooms.

I would appreciate any advice on whether the cheaper flexible ducting would suffice, and whether i would then need to have some sort of right angle piece or just curve the flexible ducting around the corner. Is it the sort of material i can cut into, in order to vent to the first room from the one duct. 

Thanks for any help with this. 

Michelle 

[EricL]

Hello @Michelle64 

You can technically use ordinary foil ducting to transfer cold air from one room to another, but it’s not the most effective option. Foil ducting is typically designed for ventilation rather than efficient air transfer, so it may not insulate well enough to keep the air cool over a distance. If the ducting runs through a warm area, you’ll likely lose a lot of the cool air before it reaches the other room. Please keep in mind that the further the room is the more powerful fan you'll need to push the air to the other side.

In this particular instance, I suggest engaging the services of an air-con specialist who offers ducting services or is familiar with aircon ducting. It would be a shame to put all that effort in only to realize that over 50 percent of the cold air is being lost during transit. Whereas a properly built ducting will give you efficient transfer of cold air with none of it being wasted.

Let me call on our experienced members @Dave-1 and @Nailbag for their recommendations.

If you have any other questions we can help with, please let us know.    

Eric

[Dave-1]

Evening @Michelle64 

I like your thinking and have been down that thought path myself.

The ability to transfer the heated or cooler air over the distances you have mentioned would be problematic and I mean the distance and the ability to retain the temperture. I would also suggest a properly designed air con system. Depending on where you live In Aus or NZ the types of humidy will also play a large part in what type of air conditioning/heating you may have.

The amount of money that you potentially spend in putting in some kind of transfer system may work out to take you 2/3rds of the way to a seperate air con/heating unit. I wanted to use the earths stable temperture 1200mm below the ground surface (stable at around 19-21degees) I think and once I really started costing it the expense was not so appealing, same as heating the pool water using piping running through a concrete slab and transfering it to the pool. Once I started costing it the price really added up. 

I like the idea, but trying to figure out how to insulate that duct plus transfer the heat via it without disapation. Answer that one and then it becomes possible.

Dave

[Nailbag · Accepted solution]

Hi @Michelle64 

I believe there is already systems in place that you could install or have install for just this type of system. I only know of this as a friend of mine had one installed in his home quite some years ago. His only form of heating is a large free-standing wood heater, which now heats several other rooms. He figured the system out from much research and works on natural convection techniques (way of my level of understanding). but on asking him he sent me this link to give you an idea. Hope it helps.

Nailbag

[Michelle64]

Thanks heaps for the info Dave. I have talked more to my son in law who has something similar but he suggested i do separate ducting for each room with insulated ducting and an inline fan for each near to but outside each room (for noise minimising). That way i can cut the longest length to about 6m. I can then put a switch near the door of each room to turn the inline fan on for that room. I can have a vent in the living room  ceiling to catch as much hot or cold air as i can. He suggested that i might need to go to a specialty place to get the insulated ducting, but it's not likely too expensive. i think the rest i can get at Bunnings, and hoping that it might work out a bit cheaper because power point and switches for the fans will be done as part of the build. Will post once i do some more research on costs. Thanks again.

[Michelle64]

Thanks heaps for the info Nailbag. Really like the link you sent me to, which has helped visualise. I have talked more to my son in law who has something similar but he suggested i do separate ducting for each room, and with insulated ducting and an inline fan for each near to but outside each room (for noise minimising). That way i can cut the longest length to about 6m. I can then put a switch near the door of each room to turn the inline fan on for that room. I can have a vent in the living room  ceiling to catch as much hot or cold air as i can. He suggested that i might need to go to a specialty place to get the insulated ducting, but it's not likely too expensive. i think the rest i can get at Bunnings, and hoping that it might work out a bit cheaper because power point and switches for the fans will be done as part of the build. Will post once i do some more research on costs. Thanks again.