Heat Transfer Kit

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floydie

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#1796137 7-Jun-2017 19:33

having a ducted heatpump system i can HIGHLY recommend putting the outlets IN the bedrooms. that way you can close the doors and the room still gets heated. if airflow is an issue with doors closed then trim 10mm off the bottom edge of the door. that way cold air will be drawn out under the door and the bedroom will "fill" with warm air.

Willuknight

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#1796478 8-Jun-2017 10:20

Can you tell us more about your ducted heatpump? how do they work?

floydie

474 posts

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#1796554 8-Jun-2017 12:06

It's a 14kw fujitsu ducted system it has a double stacked unit outdoors and the inside unit is up in the roof space. We have 7 outlets in the ceiling one in each bedroom and three in the living area. It has two intakes with filters in the hallway ceiling . I was a bit hesitant at putting the indoor unit right above the kids bedrooms but it's fine noise wise. We can barely hear it running if at all. It keeps the whole house at a nice even temp. Best thing we put in our new house.
The only downside to the fujitsu is the dinosaur control system which came straight from 1986. No way of linking it into a home automation system etc. Thats one area they need to improve on big time.

Willuknight

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#1796610 8-Jun-2017 13:11

Damm, sounds like what I need in my house.

Can you turn individual rooms on and off or is it all together?

jonathan18

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#1796624 8-Jun-2017 13:40

Willuknight:

Damm, sounds like what I need in my house.

Can you turn individual rooms on and off or is it all together?

@Willuknight: totally depends on the set-up; many will install them as one single zone, but the option is available to control each room separately but the cost and complexity goes up as you'll be adding (a significant number of) automated dampers into manage airflow. Some units have built-in zone control (for example, the Daikin we have can control a number of zones), while others require additional controllers to manage the dampers/zones. We elected to have ours set up as two zones - 'bedroom' and 'living' zones (with the bedroom zone including the hall). We had intended on using it through the night, so planned to only warm the bedroom side being the only occupied one. In practice we've hardly used it that way, electing rather to turn on both zones in the morning and cope without heating through the night.

Just a word of caution - ducted heatpumps are a very complex beast, as I discovered, especially to retrofit to existing houses. so do your research! You can learn from others' mistakes (including my own) in other threads on GZ, eg:

https://www.geekzone.co.nz/forums.asp?forumid=141&topicid=175823

https://www.geekzone.co.nz/forums.asp?forumid=141&topicid=173759

https://www.geekzone.co.nz/forums.asp?forumid=141&topicid=193422

floydie

474 posts

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#1796699 8-Jun-2017 15:07

Ours is just one big zone . The bedrooms are very slightly cooler(maybe 1 degree?) than the main area which is perfect for us. We can adjust it by altering the airflow with the adjustable vents in each room

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andrew75

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#2576133 29-Sep-2020 20:39

I found this thread helpful when putting together my just installed system, so thought I'd update it with my experience.

We have 'long' house with a living room with a fire at one end, and another living area down the other, with bedrooms in between. The fire made one end toasty, and the other end got quite the chill in winter.

I decided to go a DYI for heat transfer. Purchased from MingFans a 200mm 'silent' mixed flow fan, a manual wireless stop / start/ speed control, and had 26m total acoustic insulated duct - R1.0. The run from one end of the house to the other is just under 20m. I kept everything 200mm because thought there would be too much resistance with 150mm ducting.

The inlet diffuser is a 'round' diffuser rather than the usual 'egg crate' style. I said i wanted to minimize the intake noise and was told by MingFans this is the best of the diffuser styles for this. 3 outlet diffuses were the down-jet variety, installed in the 2nd living area and 2 far bedrooms.

I wanted to minimize heat loss in the roof space so for over-kill i wrapped all the ducting in an additional R1.8 PET insulation blanket - Mammoth 870mm, purchased from Bunnings. Very conveniently 870mm is just enough to wrap the 200mm insulated duct, held together with cable ties and the seam down on the existing roof space insulation, and even better 1 pack did exactly my duct run.

Am very happy with the performance. It is a relatively cold night tonight, have just measured 44.5deg c just inside the intake diffuser and amazingly 44.3deg just inside at the most distant outlet diffuser. Before the extra insulation wrap was added i measured 2.5-3 degree heat loss which I thought was still pretty good (admittedly this wasn't on such a cold night).

There is a decent airflow at all the outlets. There is some airflow noise at the inlet diffuser still but not particularly intrusive. If I take out the central part of the diffuser this disappears so it is all flow noise from the diffuser and no motor noise. At the outlets if the dampers are closed slightly (which I do to balance the airflow) there is a subtle noise, but no noise if the dampers are fully open.

The system has made a huge difference to the temps at end of the house, normally i'd be running a heater in the computer room tonight, but not needed now.

One thing I would do 'next time' is make the lengths of ducting running to each of the outlets be proportional to the airflow i wanted out of each. The 'closer' bedroom has a higher airflow that I want. I'm managing by closing the damper slightly and also closing the bedroom door makes a big difference (you can feel a blast of cold air coming out from the bottom of the door) - but this generates some noise where otherwise there wouldn't be any. I think 200mm was well worth going for, at least with the long run I have, and the extra insulation wrap was also well worth it.

Hope the above is useful for someone else contemplating the same thing.

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