What heat are you transferring? Heat from a fire? Any less and you'll likely be disappointed, I'm told heat loss through a ceiling cavity is high. Heat from a fire starts at 80 degrees or more so there's plenty to lose, whereas 26 degree air from a heat pump you don't have much to lose if you still want it useful.

timmmay:

 

What heat are you transferring? Heat from a fire? Any less and you'll likely be disappointed, I'm told heat loss through a ceiling cavity is high. Heat from a fire starts at 80 degrees or more so there's plenty to lose, whereas 26 degree air from a heat pump you don't have much to lose if you still want it useful.

 

I have a wood burner in the lounge that puts out plenty of excess heat. Need to move it to the 3 bedrooms.

Slightly off topic, but when I looked at bathroom extractors in bunnings and mitre ten they only had small, low powered units. Most were the light in a fan style, but you could get small standalone extractors as well. When I went to a bathroom firm they put in a much larger, higher powered extractor, that does a much better job than the two bunnings units I had before.

My point is hardware stores may not be the best option. If you can say where you are someone may be able to suggest a suitable store. I know one in Petone, for example.

Some years ago I installed an inline Vortice ( pronounced vorta shay ) fan into my bathroom, this this was great at moving steam 4 - 5 to the outside world.

The trick was to mount the fan half way up the truss and you dont feel the vibration.

When our bathroom was re-moddeled a few years later they pulled that out and put in a manrose ceiling fan that is useless.

If you are using as a heat transfer you should use insulated ducting.

Also the bigger the fan, the slower it has to go to move the needed volume of air to work. It is also quieter. I had a DIY positive air system that supplied nylon rope to suspend from the roof to cut down vibration and noise.

I see there are some quite good looking DIY heat transfer systems on trademe for $750 which I doubt your could make any cheaper yourself to be honest.

My inlaws have a ceiling fan in the lounge that my MIL always hated until on winter day it got stuck on for some reason and moved a lot of warm air around the house and up to the bedrooms. It was so good she insisted that it be fixed. They have a 10" stud in their lounge so it is not a head hazard for tall people.

John

Insulated ducting is often very low R value. I'd probably wrap it up in some extra insulation - maybe lay a bale of pink bats over it? Check if that's safe first of course.

You know what would do a good job of this? A Cleanaire heat recovery ventilation system. $3K I guess, but it will improve ventilation while keeping the place warm. They could probably do a good quality heat transfer system if you asked.

here is a thought, why not move the cold air into the lounge and use the natural drafts to draw the heat up to the bedrooms? that way your not really loosing the heat into the roof space but its being use to heat the house.

I bought a three bedroom system from an earthquake munted house and installed it in our house. You can guess where we live.

System is a made up one from local components. Uses 150mm fan and insulated ducting. Inlet-3m duct-fan-3m duct-3way splitter-3m duct-outlets. 9m from inlet to each of the three bedroom outlets.

Inlet is 1m from log burner chimney. House has 2.4m stud.

Fan is the 150mm one here   http://www.pacificfans.co.nz/inline-centrifugal-fans 

Testing fan on the ground with 3m of ducting on either side the airflow was good. I was expecting good results.

Fully installed in the house and performance was not good: most unimpressed! I have a piece of cotton hanging from each outlet so that I can see if there is actually any air flow. I have made sure that all ducts are as straight as possible. Only seems to raise temperature of bedrooms by about 1degree.

Workmate is most impressed with the one he made up using 200mm components. I guess that 150mm is not really big enough for 3 outlets? 

I assume that the uneven internal surface of the ducting is the reason for the low air flow. Toying with the idea to replace it with 150mm smooth wall plastic pipe with insulation around it.

Might turn it on tonight and measure the temperature difference between the inlet and output.

We also have a ceiling fan that moves the warm air around. Shifts more heat down the hall to the bedrooms than the heat transfer system.

k1w1k1d:

I bought a three bedroom system from an earthquake munted house and installed it in our house. You can guess where we live.

System is a made up one from local components. Uses 150mm fan and insulated ducting. Inlet-3m duct-fan-3m duct-3way splitter-3m duct-outlets. 9m from inlet to each of the three bedroom outlets.

Inlet is 1m from log burner chimney. House has 2.4m stud.

Fan is the 150mm one here   http://www.pacificfans.co.nz/inline-centrifugal-fans 

Testing fan on the ground with 3m of ducting on either side the airflow was good. I was expecting good results.

Fully installed in the house and performance was not good: most unimpressed! I have a piece of cotton hanging from each outlet so that I can see if there is actually any air flow. I have made sure that all ducts are as straight as possible. Only seems to raise temperature of bedrooms by about 1degree.

Workmate is most impressed with the one he made up using 200mm components. I guess that 150mm is not really big enough for 3 outlets? 

I assume that the uneven internal surface of the ducting is the reason for the low air flow. Toying with the idea to replace it with 150mm smooth wall plastic pipe with insulation around it.

Might turn it on tonight and measure the temperature difference between the inlet and output.

We also have a ceiling fan that moves the warm air around. Shifts more heat down the hall to the bedrooms than the heat transfer system.

KennyM: I installed a 3 room transfer kit that I got from bunnings last year,



I could find the model of you wanted, it has insulated ducting, but agree that more insulation is probably required. (Which I've not done) one bedroom is not in use so I have the duct in that room screwed closed, there is a definite difference in temperature between the two rooms.

However, the temperature does drop not long after going to bed as the fire dies down.

This isn't helped by the fact our lounge is large, has a lot of single glazed windows, and no under floor insulation



For the price and running costs, I'm happy with it (cost was $599 I think)

I had a Heat Trans one installed in my last place - cost about $1000 fully installed. Pretty sure

Had a thermostat on a control panel in the lounge with the fire - when the room (at about lightswitch level) reached 20 odd degrees it kicked in. You could feel a rush of air back down the hallway if you were standing in the doorway.

Would recommend this brand http://www.heattrans.co.nz/