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Topic: Heat transfer systems

by Jessica 14 Dec 06, 142 replies : Last Post Sort by:
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6 posts
Heat transfer systems 
Posted 14 Dec 06 3:16 PM
Does anyone have any positive or negative experience of these? There are different systems out there and hard to know which one to choose.

6 posts
Re: Heat transfer systems 
Posted 22 Dec 06 8:53 AM
Heat transfer systems simply move warm air in a tube from room to room. All systems are very simliar. They can be useful in some circumstances but don't expect too much. Probably shifting heat from a log burner room to others is the best application, the other rooms will certainly get warmer - but never hot. And if the tubing is long it won't really work at all.

35 posts
Re: Heat transfer systems 
Posted 28 Dec 06 12:04 PM
Pushing heat through a barely insulated duct in an uninsulated roof space will only work as jaykay says with short runs, the heat lost will be too great on long runs.
A solution is to reverse fan and suck cold air from cold room to heated room which allows heat to drawn to cold room through the insulated house, I have heard this has worked well for some people.

6 posts
Re: Heat transfer systems 
Posted 31 Jan 07 3:36 PM
Hi Jeff,

I have found HTS to be almost as big a can-of-worms as solar water heating!

It seems to me that the type of system that takes warm air from the roof void and ducts it into the house is a sensible use of otherwise wasted heat. The manufacturers of these systems say they don't claim to be a heating system; rather, that by adding dry roof air into a home and forcing damp air out, the air becomes easier to heat because it is dry. However, I have spoken to people in the UK who say you should never use loft air to ventilate a home because of the contaminents it may contain. Systems with a heat exchanger will get round this problem and will also recover heat from air extracted from bathroom/kitchen. However these are very expensive.

We have just installed a couple of systems of the most simple type that simply duct air from a warm room to a cold room (only about $400 for a 1 room to 2 room system) so we will see how well they perform...

3840 posts
Re: Heat transfer systems 
Posted 9 Feb 07 8:37 AM
We use a heat transfer system to take hot air from the top of our lounge, where we have a log burner, and duct it into other rooms in the house. It really is excellent and works VERY well. The other rooms get nice and warm, and the movement gets air continuously circulating through all the rooms. Very impressed with it. Not sure exactly what system we have, but I think many are very similar - not very high tech, just an intake vent, ducting and outlets.

3840 posts
Re: Heat transfer systems 
Posted 29 May 07 9:17 PM
I fitted a ducted system with the inlet a couple of metres from the log burner and the outlets 6-10 metres away in adjacent rooms. It works well and we get heat all over whereas before it was too hot by the fire and cold everywhere else. I put a thermostat high up near the intake and set to 25 degrees so the fan only runs when there is warm air to distribute otherwise you get a cold blow feel. it also provides some airflow when it is really hot in summer. it is the system you see in the trade stores. I also fitted a speed control as the fan inlet noise is a bit intrusive on full bore

1 posts
Re: Heat transfer systems 
Posted 13 Jun 07 10:14 PM
I am just about to retro fit a house. Can you tell me what system or products you used in your example.
It sounds like the same length of duct runs etc.

3840 posts
Re: Heat transfer systems 
Posted 24 Jun 07 10:20 AM
Hi david,
I am just in the process of installinga kit into my house in Northland. it is a 2 room kit from Securimax Ltd purchased through Mico Plumbing in Whangarei.
Probably have it finished next weekend or the one after so will let you know how it performs. Certainly the installation is simple enough.

1 posts
Re: Heat transfer systems 
Posted 30 Jun 07 12:33 PM
can you tell me what kind of kit you used, and what size was the ducting? Thanks.

2 posts
Re: Heat transfer systems 
Posted 5 May 08 9:30 PM
For anyone interested. I have done extensive research on Heat Transfer Systems prior to purchasing one for our 4 bedroom home.

We have a rather unique chapel ceiling 4 bebroom house with an open living room, dinning, and kitchen and a second living area as well.

In our main living area we have a free standing wood burner which generates a lot of excess heat. after the room is heated at standing level the temperture is 22 - 24 degrees and at ceiling level the tempeture is 32 - 34 degrees.

We looked at 3 models:

Heat-Trans (Securi-Max)
Pioneer (Metrofires)

We decided that pioneer was the best (and the most expensive) followed by Heat-Trans, then Weises.

Although most of the products are the same the Heat-Trans and Pioneer have a much more powerfull fan, therefore able to push through more litres of air per second. This becomes important in larger homes where there are 4 bedrooms or longer ducting required.

Important notes:

get a thermostate and check how much excessive heat your fire does generate. To be effective the heat at the ceiling level should be at least 30 degrees or more.

Remember the the longer your ducting the more heat that will be lost during the transfer. Approx 1/3 a degree per metre. That's 3 degrees lost over 9 metres of ducting.

Installation Notes:

1. Keep your ducting tight and try to minimise bends. This aids with air flow.

2. Hang you fan unit from the roof beams by using a 4mm - 6mm rope, this helps eliminate noise from Fan vibration.

anyway for those of you looking to buy a Heat Transfer System. I hope this helps.

1 posts
Re: Heat transfer systems 
Posted 10 Jun 08 11:02 PM
Thanks for all of that info, very helpful.
Can anyone tell me what difference there is from a heat transfer system and a DVS or HRV. I know that they get the air from the roof blah blah but whats the difference from getting warm dry air from another room in the house (sunny warm room) and transfering it to a colder damp room?
You are still creating a positive air flow to push out the damp air are you not?
I have a downstairs room that suffers but the rest of the house upstairs is warm and dry. Should I just transfer the warm dry air from upstairs to the downstairs room for about $250 at Bunnings or can someone convince me I need to spend $2500 on a HRV or DVS?

2 posts
Re: Heat transfer systems 
Posted 11 Jun 08 9:52 PM
DVS is a heat transfer, with a basic filter and a de-humidifier. If you want heating it costs extra.

HRV does all of the above but has a few features more than the DVS like re-cycle the air in your house every 20-30 mins so gets rid of cooking smells, condensation, mould and mildew etc.

3 posts
Re: Heat transfer systems - Try Heat Exchange Recovery 
Posted 26 Jun 08 3:25 PM
We have done a lot of investigation on True HRV and Air to Air Heat Exchangers... also heat transfer as above and ventilation solutions... we finally selected Intelivent

We had no condensation from the day it was installed and 6-7 degree temperature gains in the coldest part of the house - so pretty wrapped with the results

Problem is with the HRV/DVS and other systems they just pressurize the house, and that means air is escaping with out any control of it, if its escaping then so is heat - not very smart really.

With heat transfer you get heat to the other side of the house but your also transferring the old stale air, very bad health issues as its usually damp from breathing and cooking and cleaning etc...

Heat Exchangers like Intelivent takes the old stale air and exhausts it out side, because it does this in a controlled way it is able to take the heat energy out of it and transfer it to fresh dry filtered air... at the same time its doing this its recovering lost heat so its saving money on the power bill.

We have had ours for a month now and its great, have not seen out power bill yet, but I had seen a testimonial where someone had saved 50% so will be keen to see how we go.

google them or might be or check out for ventilation information.

96 posts
Re: Heat transfer systems - Try Heat Exchange Recovery 
Posted 26 Jun 08 4:42 PM
Warning bells ring when I read statements on the website like this - "1kW of input can deliver up to 20kW of benefit"

12 posts
Re: Heat transfer systems - Try Heat Exchange Recovery 
Posted 1 Jul 08 11:42 AM
A true HRV such as the Mitsubishi Lossnay,Smartvent synergy,Cleanaire HRV and perhaps the intellivent (but they dont publish how there system works or its efficiency so im dubious) ,needs to maintain a speed that does not run air too fast through its heat exchanger this is so that the air stays within the heat exchanger long enough to transpose its heat into the returning fresh air stream.To effect proper heat transfer at a rate to make a significant difference to personal comfort reduces the efficiency of the heat exchanger.The Weiss-securimax kits etc are fine for heat transfer but are best suited for use with a woodburner or similar device that creates stratified heating layers within the room enabling the exhaust outlet to transfer air that is significantly warmed and then will have some greater benefit to the room it is sent to.
Use of a heat transfer system with a heatpump is of a lower benefit as the heatpump by its nature creates a room that is typically evenly heated from floor to ceiling therefore the hot layer of air at the roof does not exist to the same extent.Trying to increase a heatpumps temperature to make it warmer also warms the rest of the room making it uncomfortable and inefficient.
True HRV heat exchanger units will transfer"some" heat depending on outlet placements and ducting runs but the ideal fan speeds are designed for effciency so putting them on boost power to operate as a heat transfer is reducing there heat recovery and therfore their heat to the outlet so it defeats the purpose.
The 1kw to 20kw statement is a little misleading but the "recovered heat" of a heat exchanger unit can be over 800% more than the cost to run the fans.However it is recovered heat not generated heat

1 posts
Re: Heat transfer systems - Try Heat Exchange Recovery 
Posted 23 Aug 08 11:08 AM
This thread is very informative, in fact there is so much information here and all over the internet that I'm a bit overwhelmed. I live in a 100+ year old villa. The front part of the house (3 average sized rooms and one large 6/7 metre room) are being rennovated and are going to be used as offices/meeting rooms. These all have very high ceilings. There is a pot belly in the large room which is useable. The rest of the house which is our living area has two bedrooms and a kitchen/dining/lounge area, because this was an extention in the 30s or 40s (we think), the ceilings are lower. I am trying to figure out the best way to heat the whole house cheaply. Mitre 10 sells heat transfer systems that are quite reasonable but only heat up to 3 rooms, we have seven spaces that need to be heated. We could use the pot belly in the big room and transfer the heat to the other six by using extra ducting and duct fittings or we could install two seperate systems, one for the front and one for the back of the house. There are also heating systems that can be installed in the ceiling to keep the air hot as it travels, I'm not sure if these are worthwhile. Does anyone have any experience or relevant information on heating a house like this? Any ideas?

3840 posts
Re: Heat transfer systems - Try Heat Exchange Recovery 
Posted 23 Aug 08 2:20 PM
Heat transfer kits don't work. Had two of them and it is a rather silly concept if you have to over heat one room to heat the others a bit.
The way to go in your case is central heating with a boiler and radiators it works well, you can control the heat plus it is energy efficient and therefore cheap to run.
Of course it works even better with insulation and double glazed windows (timber or PVCu) if your budget allows??

57 posts
Re: Heat transfer systems - Try Heat Exchange Recovery 
Posted 24 Aug 08 10:40 AM
Heat transfer kits do work, and they can be a useful way of moving energy around if you have access to free wood for a log burner. However there are severe limitations with such kits.

As for Savona - their system is NOT energy efficient and will NOT be cheap to run. They should pay more attention to heat pumps.

57 posts
Re: Heat transfer systems - Try Heat Exchange Recovery 
Posted 24 Aug 08 10:52 AM
Just had another look at the Savona site, it has a number of basic errors and incorrect statements. Even the most innefficient hot water heat pump will use much less energy and cost far less to run than one of their gas boilers.

3840 posts
Re: Heat transfer systems - Try Heat Exchange Recovery 
Posted 24 Aug 08 1:52 PM
I had alook too, marketing hype, dont believe everything you read. NZ houses typically are not insulated to the same standard as the europeans, thus heating a whole house is very energy hungry. Unless the whole house is insulated to at least double the NZ standard its better to heat the rooms in zones or depending on occupancy rather than heat the whole house. OK for new houses as you can install the required insulation to make this cost effective. Retro-fits to existing older houses is more problematic and heating a whole house with a gas heated hydronic system is stupid and wastefull. Also the gas line charges ensure you are paying dearly for this option when during the summer virtually no heating is required.
I agree with JK, heatpump heating either by air or hydronic is more cost effective than gas and if combined with passive solar makes an ideal solution on days when there is no solar input.


3840 posts
Re: Heat transfer systems - Try Heat Exchange Recovery 
Posted 25 Aug 08 8:31 AM
hydronic central heating can be run with a wood boiler, diesel boiler, gas boiler, pellet boiler, gas boiler, heat-pump, geothermal heat, or a combination of and supported by solar (activ and passive).
The savona website was just an example not saying that I
back 100% what are they saying.
If you look at a modern well insulated home I would say their gas boilers are totally over dimensioned.
The other beauty of hydro central heating is the fact that you can control the amount of heating in each room and it provides far more comfort than blowing warm air into a cold room.

3840 posts
Re: Heat transfer systems - Try Heat Exchange Recovery 
Posted 8 Oct 08 3:06 PM
Have a look at

They make true HRV and ERV systems and have better efficiency's than other avalible products.

They have a NZ distributor.

I never understood why people would use somthing like DVS that doesn't reclaim heta form the air you are exhausting and use it to pre heat the incoming air, real HRV units should preheat the incoming fresh air to about 70% of the temp of the stale air being exhausted, all this for the price of just running a fan. So it is possible to get about 15kw worth of heatin out of 1kw of fan power.

3840 posts
Re: Heat transfer systems - Try Heat Exchange Recovery 
Posted 8 Oct 08 7:38 PM
That looks like something worth considering rather than
HRV, DVS and other crap.
Kiwis like to buy crap rather than decent things, no wonder why 95% of the houses are not comfortable, energy intensive to run and of course those hidious ali windows........

11 posts
Re: Heat transfer systems - 
Posted 27 Mar 09 9:11 AM
Note to all forum users that it is normal ettiquette to declare your buisness association with the products that you are publicising in the above posts.
it is not hard to determine that a number of posts above are by people involved in the industry it is only FAIR to the general public to know if you hold a commercial interest in the products you"promote"particuly people like ECO ECO for instance who changed the topic is noted that other topics on this site were changed to Try Intellivent.and now this thread is Try heat echange recovery.Coincidence I think not.If your product is any good by all means discuss it and then give us YOUR details so we can contact you.If you believe in your product then you will do this.or what are you hiding.

149 posts
Re: Heat transfer systems - 
Posted 28 Mar 09 8:05 AM
Deans, the problem is largely a fault of this website. It allows anonymous postings and doesn't remember my login. I know I have asked the administrators to sort it out, to no avail.
I ask again...
No anonymous postings.
Sort out the login.
Then we will see who is posting what.

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