# Forum Home Renovation Heating & Cooling  Advice on heat transfer system

## barnes

Im thinking of putting a heat transfer system from my combustion heater in my new house. I have some questions. The distance from the spot of the ventilation grill is somewhere from 7 to 11 meters.
How big should the ceiling ventilation grill be (the one that air comes IN through before the motor)?   1.      How far should I put the ventilation grill (on the ceiling) from the combustion heater (from the flute kit)? 2.      Im thinking of putting a ceiling fan between my heat transfer ventilation grill and the combustion heater. Is it correct, or should I put a ceiling fan farther away from the heater, after the heat transfer ventilation grill? 3.      Do I need to order a fan (an option) to my combustion heater if Im interested that more heat should go into my heat transfer system, or I would be better without a fan in a combustion heater, so the hot air will go straight up? 4.      How far should the motor of my heat transfer system be from the ventilation grill, so I should hear it less, but it will still be efficient? 5.      Can I install part of my heat transfer (after the motor fan) into an existing A/C ducted system for the bedrooms, so I would not have to duplicate ducts into bedrooms?  6.      Is it better to use the company that will do my A/C ducted installation, or it is better to find someone who specialises in heat transfer systems only (if these guys do exist)?
  Thank you all for your help.

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## Smurf

Mine has the intake almost directly above the heater. Since the heater itself has no fan, the air up there is properly hot so that's what comes out the vents in other rooms - air that's quite warm not just a bit warm. Works well. 
Intake duct and fan is 250mm branching off to 3 x 150mm ducts to the bedrooms. 
Location of fan - put it in the middle to minimise noise. 
I did the installation myself, only took an afternoon to do the lot, but then I'm a sparky. There's a couple of businesses here in Tas that do install these systems and they don't do A/C as well (one of them does other heating, eg wood and gas, the other sells chains and hoses etc with heat transfer systems as a sideline). 
It works well and I'd say it's one of the best things I've added to the house. Got rid of the problem of having one room at 30 degrees just to get the bedrooms over 15 and now it's about the same temperature throughout the house. It's not a big house though but the system certainly works.

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## barnes

Than you Smurf. What do you think about using the existing ducted system for heat transfer, is it possible?

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## Moondog55

Ducting isn't all that expensive so it may be better to install the system as separate.

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## barnes

> Ducting isn't all that expensive so it may be better to install the system as separate.

  I'll look into it. If I will decide not to mix it with A/C, th*e*n I can try to install it myself and get a sparky to do connections.

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## Moondog55

Our roof is a bit cramped but it only took me a day and a lot of that time was struggling to get the big plenum box thought the manhole.
Not working at the moment as I need to reroute it now that we have no Coonara
Suspended the inline fan with strapping, sparky wired a switch to a line socket, just plug in the fan, hit the switch and away it goes
150mm is far too small tho
I scavenged a lot of the ducting tho as we only needed short runs

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## barnes

> Our roof is a bit cramped but it only took me a day and a lot of that time was struggling to get the big plenum box thought the manhole.
> Not working at the moment as I need to reroute it now that we have no Coonara
> Suspended the inline fan with strapping, sparky wired a switch to a line socket, just plug in the fan, hit the switch and away it goes
> 150mm is far too small tho
> I scavenged a lot of the ducting tho as we only needed short runs

  Did you buy a DIY kit or did you put it all together yourself?

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## Moondog55

150mm toilet exhaust fan kit via eBay for $50- then some work on making the plenum box; termite sheilds are exactly the right size to fit 150mm duct
A cheap experiment o see if it would work
It does but the volume of air moved is small
Been thinking of routing one duct down through a cupboard and putting a vent at floor level to destratify the air tho

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## Smurf

> Than you Smurf. What do you think about using the existing ducted system for heat transfer, is it possible?

  I don't know enough about ducted A/C systems to know if there would be a problem or not. No doubt it could be done but with what downsides I'm not sure.

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## Brian7886

> 150mm toilet exhaust fan kit via eBay for $50- then some work on making the plenum box; termite sheilds are exactly the right size to fit 150mm duct
> A cheap experiment o see if it would work
> It does but the volume of air moved is small
> Been thinking of routing one duct down through a cupboard and putting a vent at floor level to destratify the air tho

  Probably wanna insulate the duct mate

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## barnes

> Probably wanna insulate the duct mate

  What would you recommend for insulating the duct?

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## Moondog55

Brian I wrapped the 150 plain in 200 insulated then stuffed that inside 300mm insulated
I should have mentioned using heavily insulated ducting, R1.5 or better
Plenum box was a foam fruit box inside a plywood box then R3.5 all over it
There's a thread somewhere with pix

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## barnes

> Brian I wrapped the 150 plain in 200 insulated then stuffed that inside 300mm insulated
> I should have mentioned using heavily insulated ducting, R1.5 or better
> Plenum box was a foam fruit box inside a plywood box then R3.5 all over it
> There's a thread somewhere with pix

  But you still say that 150 mm is to small. What size would you recommend?

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## Moondog55

150mm into the rooms is probably OK but the initial intake I'd make minimum 250mm or even a 300mm fan much better depending on the number of take-offs and how much heat the wood-stove is making, this would be an argument in favour of a bigger Lopi heater
The more rooms with 150mm ducting into them the bigger I would make the fan and intake plenum
There is a thread somewhere
If you put in the transfer system I don't think you would need the ceiling fans, if fact I think they might work against each other

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## barnes

> 150mm into the rooms is probably OK but the initial intake I'd make minimum 250mm or even a 300mm fan much better depending on the number of take-offs and how much heat the wood-stove is making, this would be an argument in favour of a bigger Lopi heater
> The more rooms with 150mm ducting into them the bigger I would make the fan and intake plenum
> There is a thread somewhere
> If you put in the transfer system I don't think you would need the ceiling fans, if fact I think they might work against each other

  
So there is a whole thread on how to make the right heat transfer system?

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## barnes

*to Moondog55*
I think I have found the thread. It is called: Air transfer system progress. Is that it? (page 7)

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## Moondog55

http://www.renovateforum.com/f193/ai...ogress-109689/ 
That was it

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## chalkyt

I put in a similar system to Moondog's and Smurf's a couple of years ago. I bought all of the stuff (insulated ducting and fan) from the local TLE (electrical wholesaler). I spent some time wandering around the living room with a thermometer on a stick to find the warmest spot for the intake. It was just above the woodheater which is under a part of the 2400 ceiling where the hot air seems to pool. From there  the ceiling goes up to a cathederal ceiling. I expected that max temp would be at the peak of this, but not so. Maybe too much loss through the roof (it probably only has 50mm anti-con batts and sarking between the roof cladding and ceiling up there). 
Anyhow, I used 200mm insulated flexible ducting to an in-line fan suspended on webbing in the roof void. The ducting splits at that point and goes about 12 metres in each direction to opposite ends of the house, venting in the hallway outside the bedrooms. Leaving the bedroom doors open seems to let plenty of warm air in. 
Nothing was done in a super scientific fashion, just what seemed to be a good idea, and it all works well with the house temperature fairly constant when the system is on. And, it only took less than a day to do. A few pics are attached. 
I did find that the fan air volume was higher than I needed and that the resulting background noise was a bit obvious. This was fixed by fitting a fan dimmer to slow the fan down since the warm air only needs to transfer slowly. Low air volume (very quiet) seems to work just as well as high volume. 
Have fun!

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## barnes

*Thanks chalkyt. * Looking at what you have achieved it seems to me is not rocket science. A few questions though.
1. What is the size of your intake vent grill?
2. How far is your fan from the intake?
3. How far is the duct before it splits from the intake?
4. What is the size of your outtake vent grill?
5. What is the power of your fan?
6. How did you connect your fan to the power supply, did you call a sparky?
Your advice on measuring the temp on the ceiling is worth in gold. Thanks it's very clever.  :Smilie:

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## Moondog55

1 Same size as the fan chose
2 Inline fan so it goes where it fits easily 
3 where it's convenient
4 150mm
5 Ours is 150mm and about 250 watts
6 Sparky and run via the power circuit and a simple on/off switch in the hallway, Sparky also put a double GPO in the roof space and a light at the same time and while we had walls unclad
Light and GPO in the roof space makes working in there much easier 
Because heat rises I am seriously thinking about rerouting one of our ducts down thru a cupboard [ very heavily insulated naturally] and bringing in that outlet at floor level 
It isn't rocket science bit it is worth doing properly first up and the biggest cost is the inline fan and the electrician to do the wiring

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## chalkyt

My answers are pretty much the same as Moondog's... 
1. Intake vent is 200mm to suit the fan and ducting - nothing cleverer than that is what was available 
2. The fan is about 5 metres from the intake - position was more or less dictated by the geography of the ceiling space and availability of power (as you can see it is already surrounded by "stuff"... roof space is great for making unwanted stuff disappear!) 
3. The duct splits just after the fan - again dictated by geography. I had thought that the runs after the split should be the same length in order to have a balanced air flow, but mine are unequal and it doesn't seem to make any difference. I guess that if the duct diameter is big enough, the pressure difference over the short runs we are dealing with, doesn't matter. The temperature at each end of the house is the same after the system has been running for a while. 
4. The outets are also 200mm but because of their design/aesthetics the actual outlet vent area is probably less than that (pic attached) 
5. The fan is 75W/150mm on its rating plate. This makes sense as the inlet and outlet to the fan are sized to take the 200mm ducting. 
6. The fan can just be plugged into a GPO. But, as I am a sparky my setup is a little more complex than that...  
Firstly the fan is direct wired from a fan dimmer mounted near it which we used to set the airflow and noise level that suits us, then it is controlled from a Clipsal VETR3 push button timer, all connected so that it is wired as an "appliance", i.e. it all plugs into a GPO in the roof so that I can disconnect/isolate it if I need to.  
Originally we just had a switch and pilot light mounted on the wall near the fireplace (but a bit out of sight so that it wasn't "in your face") but we kept forgetting to turn it off when we went to bed. I have replaced the switch with the VETR3 push button timer set to 6 hours. So, in the afternoon/evening when we light the fire, we just press the button and the heat transfer runs for 6 hours. Once again, nothing special about the time, it just suits us as we let the fire die down when we go to bed and by midnight or so there is no more heat being generated to transfer.  
FYI CABAC now make a small push button timer that is cheaper and less obtrusive than the Clipsal/HPM units. The CABAC unit takes up the same space as a switch mechanism (but a bit longer) so if you used something like this, it could be mounted where you have an existing switch. It would be quite easy for your sparky to drop the wiring down with the existing wiring and just add a switch plate with another gang position. I agree with Moondog... a light and GPO in the ceiling void is one of life's little luxuries.  outlet vent

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## barnes

Thanks *chalkyt* for your help. You have started a thought process in my ex-builders mind.  :Smilie: 
But I still have a few questions.
1. What kind of a dimmer did you use for your fan (power capacity, brand and model if possible)?
2. What is the brand name and model of your fan?
3. How did calculate your fans power output? What figures did you use?
I'm trying to figure out how to make this DIY project work.

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## chalkyt

The simple answer to your questions is that I just bought the heat transfer kit that my local electrical wholesaler (TLE) had in stock and I used a Clipsal or HPM fan controller. The particular brand on the fan rating plate is Securi-fan. I imagine that Lawrence &Hanson or Rexel in Adelaide will have something suitable.   
The type of fan controller is important. It must be specifically designed for fans, not lights. Both Clipsal and HPM make them with a  75VA rating. Some fan controllers can cause a bit of humming of the motor at very low speeds. The ordinary light dimmers can cause motor heating problems (the technical reasons are to do with the effect on the motor's magnetic field due to the chopped waveform and is a bit too complex to go into here as essentially a motor's speed is determined by the supply frequency) but the fan controllers are designed to minimise this problem and make sure that the motor receives sufficient starting current to run properly. Your chosen supplier can advise you on this. 
A quick Google of heat transfer kits will show quite a few available from ventilation equipment suppliers (as well as eBay) and they all seem to be pretty much the same. i.e. in-line 150mm 75W (also known as 75VA) fans, 200mm ducting and 200mm vents... take your pick. Some do come with fan speed controllers or variable speed motors.  
Yet another case of "what you pays for is what you gets". Have fun... the installation was quite easy.

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## barnes

*To chalkyt*
Some Googling done. There are three common types of Inline fans - axial, mixed flow and centrefugal. In your opinion which is better (by the look of it on your photos you have put a centrefugal type in, but maybe I'm wrong).
Also there are other things to consider - like m3/hr figure, what would you recommend considering your experience and a pretty harsh climate you live in.
Do Clipsal and HPM products have the same quality (fan controkkers), or one brand is better than the other?
What insulating rating did your ducts have? 
I see that it's problematic to find ducts more than 1,5R.
I don't think that buying a standard kit will do a job in my case. I will first try to make a few drawings and than calculate everything to see where I'm at.
Thank you very much for your help and time.

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## Moondog55

Heat Transfer KIT 1 TO 2 Rooms AIR Transfer System Free Shipping | eBay  TWO Room Heat Transfer KIT 1 TO 2 Rooms 200mm AIR Transfer System | eBay  http://www.ebay.com.au/itm/HEAT-TRANSFER-KIT-1-to-2-rooms-Air-Transfer-System-200mm-Airefco-Fan/331823783763?_trksid=p2047675.c100005.m1851&_trkpa  rms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3  D20140106155344%26meid%3D49e0a9d542f0497a98571dd4c  7059f72%26pid%3D100005%26rk%3D2%26rkt%3D2%26sd%3D2  31904131498 
Note tho that this duct isn't insulated enough to be most effective R1.0 in a bigger size slipped over the top would be tho 
You could do more, like adding a thermostat switch etc but I don't think that is needed, 200mm is probably enough diametre for decent airflow

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## Moondog55

Heat Transfer KIT 1 TO 2 Rooms AIR Transfer System Free Shipping | eBay  TWO Room Heat Transfer KIT 1 TO 2 Rooms 200mm AIR Transfer System | eBay 
Note tho that this duct isn't insulated enough to be most effective R1.0 in a bigger size slipped over the top would be tho 
You could do more, like adding a thermostat switch etc but I don't think that is needed, 200mm is probably enough diametre for decent airflow

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## Moondog55

Heat Transfer KIT 1 TO 2 Rooms AIR Transfer System 200mm Airefco FAN | eBay

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## chalkyt

My installation isn't based on anything too scientific... just "moving the warm air to the ends of the house seems like a good idea". The reasons for reducing the fan speed were firstly noise (there wasn't much to start with but you could hear it), and secondly to avoid any drafts from the air flow. The speed controller had been very effective in both cases. As we aren't moving air for ventilation purposes the slow exchange of air is fine for evening out the temperature throughout the house. 
Both Clipsal and HPM are reputable suppliers of electrical components. Both were originally Australian owned but are now part of multinational groups. I think that my controller is HPM but either would do the job. Check with your fan supplier or electrical wholesaler. 
Don't remember what type of fan or R rating of the ducting is. The fan is probably axial, driven by a shaded pole motor (this type of motor works O.K. with "dimmer" type controllers). The ducting is probably something like R1.0 or R1.5. With insulation it is about 300dia suggesting about 50mm of insulation around it. As the roof sheeting has 50mm anti-con sarking under it and the ceiling has bats, the heat losses from the roof aren't too bad and with the relatively short duct runs the opportunity for heat loss from the ducting isn't great. Typically if the temperature outside is zero, in the roof it feels like 10 degrees while in the house is typically 20+ degrees. If I stand under the outlet vents I can just sense a gentle flow of warm air so any losses don't seem to influence the relative effectiveness of the system.

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## barnes

> Heat Transfer KIT 1 TO 2 Rooms AIR Transfer System Free Shipping | eBay  TWO Room Heat Transfer KIT 1 TO 2 Rooms 200mm AIR Transfer System | eBay 
> Note tho that this duct isn't insulated enough to be most effective R1.0 in a bigger size slipped over the top would be tho 
> You could do more, like adding a thermostat switch etc but I don't think that is needed, 200mm is probably enough diametre for decent airflow

  Thank you Moondog. I went through these kits, they do look nice, but I think I will go on higher R rating and bigger duct sizes. This I have to look into. I have made my first sketch yesterday. I'm planning a 300mm R2 main duct from the intake to the motor, 250mm R2 from the motor to the first split BTO on each side, 200mm R2 to the outlets (8 in all). So the first sketch lives me with 2,5 meters of 300mm duct, 19,5 meters of 250mm, 21 meters of 200mm. I will use insulated BTOs as well and will try to use the clever operating system, using your and chalkyt ideas. The only thing that worries me now is that my ducts are 11-12 meters in length and one is even 13,5 meters in all. I'm a bit uneasy on heat loss through these lengths. I'll study a bit more on that subject.

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## barnes

> My installation isn't based on anything too scientific... just "moving the warm air to the ends of the house seems like a good idea". The reasons for reducing the fan speed were firstly noise (there wasn't much to start with but you could hear it), and secondly to avoid any drafts from the air flow. The speed controller had been very effective in both cases. As we aren't moving air for ventilation purposes the slow exchange of air is fine for evening out the temperature throughout the house. 
> Both Clipsal and HPM are reputable suppliers of electrical components. Both were originally Australian owned but are now part of multinational groups. I think that my controller is HPM but either would do the job. Check with your fan supplier or electrical wholesaler. 
> Don't remember what type of fan or R rating of the ducting is. The fan is probably axial, driven by a shaded pole motor (this type of motor works O.K. with "dimmer" type controllers). The ducting is probably something like R1.0 or R1.5. With insulation it is about 300dia suggesting about 50mm of insulation around it. As the roof sheeting has 50mm anti-con sarking under it and the ceiling has bats, the heat losses from the roof aren't too bad and with the relatively short duct runs the opportunity for heat loss from the ducting isn't great. Typically if the temperature outside is zero, in the roof it feels like 10 degrees while in the house is typically 20+ degrees. If I stand under the outlet vents I can just sense a gentle flow of warm air so any losses don't seem to influence the relative effectiveness of the system.

  Thank you again. One more question, what is the longest combined duct you have? Since there is a split BTO on your photos that means you have at least 2 ducts at the end (on the output side) are they the same length? 
If they are of a different size, do you experience any difference in the temperature of the air coming through them?

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## chalkyt

When I got up in the roof to have a look, although the inlet near the fireplace is more or less in the middle of the house, one outlet is 7 metres and the other outlet is 10 metres from this as the crow flies, the actual duct routes are a bit different to this because of the roof geography and the need to dodge a few obstacles (i.e the cathederal ceiling means that you can't go as the crow flies).  
The run from the inlet vent to the fan is about 5 metres. It has a right angle turn in the middle of it. A metre or so from the fan outlet the duct splits and one branch then goes a couple of metres to one outlet (i.e the outlet is about 5 metres West and 5 metres South of the inlet vent, being 7 metres as the crow flies). The other branch of the duct heads East from the split for 12 metres. (i.e. it is about 9 metres East and 5 metres South of the inlet vent, being 10 metres as the crow flies). 
So , although the outlet vents are similar distances from the inlet vent, from the split near the fan outlet there is a run of 2 metres to one outlet and a run of 12 metres to the other. I don't feel any significant difference in the room temperature or air flown near each of the outlets which makes me think that over the short duct runs we are dealing with there isn't enough difference in air flow resistance or heat loss to make any practical difference.

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## barnes

It means that one duct is about 8 meters long from the intake and the other is almost 18 meters long and there is no big difference in temperature of the air that goes out. That is great. It makes my plan achievable.
Thank you again chalkyt. Your advice, help and support is great.

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## Moondog55

Our house only has 2 internal doors; on the bedrooms, so you also need to think a little about how the cooled air will circulate back to the room that has the inlet duct in it. Given the small total volume of air being moved a gap under the doors of 4 or 5 mm may be enough. Also? Do you really need to direct the air to all rooms? When I reconnect I certainly won't be, I'll be using it simply to break up the stratification problem and one outlet will go into the small hallway in front of the bathroom.
I'd go with a 300mm duct and intake fan if you can afford it but use 150mm duct into the rooms

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## barnes

> Our house only has 2 internal doors; on the bedrooms, so you also need to think a little about how the cooled air will circulate back to the room that has the inlet duct in it. Given the small total volume of air being moved a gap under the doors of 4 or 5 mm may be enough. Also? Do you really need to direct the air to all rooms? When I reconnect I certainly won't be, I'll be using it simply to break up the stratification problem and one outlet will go into the small hallway in front of the bathroom.
> I'd go with a 300mm duct and intake fan if you can afford it but use 150mm duct into the rooms

  Since i will put laminate flooring in every bedroom I will have gaps of up to 10 mil under the doors.
My thoughts were to deliver to all rooms (5 of them + 2 outlets in bathroom, 1 in the other bathroom). You are probably right, I will not need 200mm in toilet and bathrooms - 150mm is enough.
When you put an outlet in front of a bedroom and not in it - it means that hot air will stay in the hallway, it will not enter the bedroom, at least not all of it. Maybe I'm wrong, but A/C vent outtakes are always in every room, and they do accomplish the same thing as a heat transfer does - warm up the place.

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## chalkyt

I guess that heating in bedroom is a bit of "horses for courses". In a previous existence we ran a B&B in this region and had heaters in each room for the "frogs". We found that in practice, the temperature in living areas (20+ degrees) is too hot for bedrooms. Generally we found that air temperature around 15+ degrees is more than enough in a bedroom (although some people do like to crank the heat right up). 
That is why we decided in this house to have the heat transfer outlets in the hall outside the bedrooms thus allowing free circulation of the transferred air. The main bedroom is at one end of the house, and the other bedrooms are at the other end. We find that leaving the bedroom doors open allows the bedrooms to heat up quite adequately. Most nights we sleep quite comfortably with the window open a bit and no heater on. We do have under tile heating in the bathrooms. 
This isn't to say that outlets in each room isn't a good idea, you just might find that your outlets need some form of damper to tailor the temperature to suit the occupant of each room. After all, our system was set up to even out the temperature throughout the house rather than be an individual room heating system.

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## barnes

> I guess that heating in bedroom is a bit of "horses for courses". In a previous existence we ran a B&B in this region and had heaters in each room for the "frogs". We found that in practice, the temperature in living areas (20+ degrees) is too hot for bedrooms. Generally we found that air temperature around 15+ degrees is more than enough in a bedroom (although some people do like to crank the heat right up). 
> That is why we decided in this house to have the heat transfer outlets in the hall outside the bedrooms thus allowing free circulation of the transferred air. The main bedroom is at one end of the house, and the other bedrooms are at the other end. We find that leaving the bedroom doors open allows the bedrooms to heat up quite adequately. Most nights we sleep quite comfortably with the window open a bit and no heater on. We do have under tile heating in the bathrooms. 
> This isn't to say that outlets in each room isn't a good idea, you just might find that your outlets need some form of damper to tailor the temperature to suit the occupant of each room. After all, our system was set up to even out the temperature throughout the house rather than be an individual room heating system.

  Overseas I had at least 22 degrees in each room all year long. When it's 15 in the bedroom - I'm pretty cold and misses is even colder and she eats me alive about it. That is why I'm building a new house. In my 2 story existing house I cannot get my comfort level to the same extent that I have had overseas.  
 You are probably right about every room, but during Adelaide winter I would give a lot to say "it's finally warm everywhere in my house".
If I'll get too hot - I can always open the window, or close manually the outtake outlet, or put a thinner blanket on my bed. I will put the ones that can easily be blocked. I prefer 26c in a bedroom a lot more than 16c. 
What kind of heating do you have in your bathrooms hydronic or electric? In my case I will only have  an electric towel heater in my bathroom. I have one now and it doesn't heat up much.

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## chalkyt

Like I said. Heating in bedrooms (and anywhere else) is horses for courses. As a general rule, in this region we allow about 100-120W of space heating per sq metre of floor space, but of course this has to be modified in the light of room volume, insulation etc, etc. So typically a 1000W heater will be O.K. for a 3Mx3M well insulated bedroom with a low (2400) ceiling. 
Our main heating is the wood combustion fireplace. This is supplemented by undercarpet heating which is driven by a programmable thermostat. The undercarpet heating thermostat cuts out at 20 degrees and is on from 4pm until 10pm and from 7am until 9am. This warms the place up  from late afternoon until we light the fire which then takes over. The undercarpet heating turns off once the room temperature reaches 20 degrees. 
The bathrooms have electric undertile heating supplemented by IXL type heatlamps which are turned on manually if required (not very often). Under tile heating is usually supplied as thin mats (thin zig-zag heating elements attached to a fibreglass mat) that are laid under the tiles with a thermostat to control the floor temperature (alternatively the thermostat can also be used to control the room air temperature). Most of the mats are rated at something like 150-200W per sq metre, although depending on what effect you are after you can go quite a bit lower than this. For example I have 100W per sq metre in the bathrooms where we want to have the floor tiles warm for walking on rather than heat up the whole bathroom. Similarly I have only 75W per sq metre under the tiles in front of the fireplace so that they are comfortable to stand on in socks or bare feet. 
The "trick" with under tile heating is to run it through a programmable thermostat which turns the heating on only when you are likely to want it. For example our bathrooms winter floor heat is at 20 degrees from 5pm to midnight, back to 16 degrees from midnight to 6am, up to 20 degrees again until 9am, then 9 degrees until 5 pm. This minimises power consumption when the heat isn't needed but keeps the room (and floor) warm when you do. We turn the underfloor heat off in summer. Of course, depending on your electricity supply authority you can possibly run this heating on low rate off-peak) 
For undertile heating I generally use Coldbuster brand mats (there are other brands that are similar). Coldbuster also sell the OJ MCD4 thermostat (under their own brand name) which I have found to be easy to program and very flexible in programming to suit particular needs. The other approach is to use a similar product from Warmtech. The Warmtech system supplies a roll of heating element which has to be installed in a thermal screed before the tiles are laid. While laying the roll is more time consuming than the mats, its advantage is that the laying pattern can be varied to accommodate odd floor shapes and obstacles (WC, shower recess, corners etc) and can be spread out to vary the heat density per sq metre (such as I did for the fireplace tiles). 
Thus endeth the underfloor tile heating lesson. Have fun!

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## barnes

Wow, that is brilliant, this is the closest anyone came to hydronic heating without the actual radiators or underfloor pipes. You had really thought about everything. I'll study closely what you have suggested. Having all that under carpet and tiles power heat supply, no wonder you keep your heat transfer on to a minimum.
The only problem I will face is - no carpets in my new house. I hate them and try to avoid them. And another problem is the electricity bill, which in your case should be pretty big. I will try to find out how your idea works under laminate or bamboo. 
Thanks for the lesson.

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## woodbe

Yep. It costs. In 2000 we had a bathroom reno done by a fancy architect. Included was electrical under tile heater with a timer/thermostat. The floor was nice and warm in those cold winter mornings. Until. The. Power. Bill. Arrived. lol. Never been switched on since. 
In a new home being built, it would be worth considering an underfloor heating system using heated water. That gives options of an A/C water heater or a combustion stove, pellet heater, solar, or even gas. 
I agree re carpets. We're slowly replacing them with timber or bamboo. Will probably keep carpet (or a large rug) in the Lounge room but the rest will go. I can't believe the amount of stuff under the carpets when we finally pull them up.

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## chalkyt

We went with undercarpet heating because when we bought the old house it had carpet on concrete slab, a bit before DIY laminate "wooden" floors were readily available. The kitchen had tiles on slab so we couldn't easily do anything about that except lay synthetic "mess proof" outdoor/marine type carpet so that the "cook" wasn't constantly complaining about cold feet. It works O.K. as the kitchen is open to the lounge/dining area so the air temperature is the same. 
Most of the underfloor heating suppliers have 100W/sq metre mats that they recommend for under wooden floors or laminates. I have three mats under the carpet in the living/dining area which can be separately switched on or off, all controlled by the same thermostat. The idea is to have them under the exposed part of the floor and not under furniture. For example, the mat under the dining table is only switched on if we are going to use that area (we have a breakfast alcove off the kitchen which gets used most of the time). Another mat is under carpet between the lounge and TV and another behind the lounge which is more or less in the middle of the room. These two are ON most of the time with the one behind the lounge turned OFF if the early and late winter weather is mild. It is all great to walk on in bare feet or socks. 
Yes, power cost was a potential concern so we just had to suck it and see. Generally our "summer quarters" are around $300 (pretty much standard for fridge, freezer, TV, computer and lights) and the "winter quarters" are around $900. We think this compares O.K. with the cost of wood or bottled gas for the same result. 
Very roughly the extra $600 over three months equates to about 2-3 Kw of heating consumption consumption for each hour the living area and bathrooms floor heat is on ($600/$0.3/90 days/8 hours = 2.8Kw). Since we have about 5Kw of undercarpet heating over the area (about 40 sq metres) plus almost another Kw in the bathrooms, this represents a duty cycle of around 50%, which is more or less what I was hoping for when we installed the system. Of course this will be higher if the thermostat temperature is set higher or the ON duration is longer but it is worth having the extra heating capacity if (very occasionally) you need to crank it up. Quite often the floor heat will go off "early" once the fireplace does its job. Anyhow it works for us. 
Cheers.

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## Moondog55

We have under tile floor heating in our bathroom too; those comments are making me think I should direct one of the warm air outlets into the bathroom

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## chalkyt

Interesting to see Woodbe's comments. Yep, what you pays for is what you gets. If you want to use underfloor heating to warm the whole bathroom, it will cost... and there is always that temptation. Our approach was "warm the floor". To avoid the temptation of cranking up the bathroom heat, I deliberately spaced the underfloor heating so that it was about 80-100W per square metre, which limited the amount of power that could be used while still giving a nice warmish touch to the floor. Using the "off the shelf" products you will end up with up to 300W per square metre which can certainly chew up the power if turned on flat chat.

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## woodbe

The shot would be to have a thermostat on the tiles rather than half way up the wall like ours. Where are your thermostats chalkyt?

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## chalkyt

Hi Woodbe 
Our thermostats are about head height on the wall. However, the bathroom thermostats measure floor heat via a sensor embedded under the tiles, whereas the living area thermostat measures air temperature. 
Following the conversations of the last couple of days I looked at the thermostat readings in our en-suite this morning. Interesting... the floor temperature is set to 16 degrees and was comfortably warm to walk on in bare feet (it drops back to a "maintenance" setting of 9 degrees after 9am). The air temperature in the bathroom was 13 degrees yet the bathroom felt quite comfortable. At the time it was quite windy and the outside temperature was 8 degrees where we are, with zero and snowing in the mountains so it is a cold day. 
These settings are simply what we ran with on a "suck it and see" basis and as they work O.K. for us we haven't bothered to change them to anything else. I suppose we could finesse it a bit but haven't really bothered. None of it is terribly scientific, just what seems to work. 
If your bathroom underfloor heating is a bit expensive to run, and your thermostat is only sensing air temperature you might try setting the cutoff temperature to something between 15 and 20 degrees for the "use the bathroom" periods and cutting back the temperature for the "not so busy" times such as something like 10pm to 6am. Similarly, if the thermostat is measuring tile temperature, try lowering the temperature to something that is comfortable underfoot rather than "warm".  
If your thermostat doesn't allow you to set different temperatures for different times, there are some programmable thermostats out there that aren't too expensive. Installation also should be quite cheap as most of these fit in or on a normal electrical wall box (where your current thermostat probably is) and just need connecting up. 
I have used the Hanlin HA308 and the OJ MC series of thermostat from PAP Heating in Mitchell ACT. Their web site is quite good and I sourced mine through the local electrical wholesaler TLE. The HA308 from memory is a bit over $100 and will switch 16A (i.e. about a 4Kw load). The OJ units will switch more than this and have a few other sophisticated tricks such as holiday mode, child lock etc, which really aren't needed for a simple domestic application and so cost about twice as much as the Hanlin. 
As I said in a previous post "warm tiles are one of life's little luxuries". 
Cheers

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## phild01

Nice to keep the floor at foot comfort level only but I just don't  understand the craze for underfloor element heating $$$$$.
May as well run the old Conray heaters instead of A/C!

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## woodbe

I guess we'd still be running it if it was economical. Not turning it back on  :Smilie:  
We have slippers lol.

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## barnes

Here is my first drawing of the future system. Please have a look and criticize. I'm not a good drafter, but I hope you'll get the picture.

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## barnes

*To chalkyt.*
You are lucky if you are comfortable when it's 13 degrees and you are barefoot.  :Smilie:  Anything less than 20 wood make my misses cold, or very cold and me miserable. I got to work on it.
What does your bathroom feel like when temperature at night goes into negative - minus territory?

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## chalkyt

My earlier reply seems to have gone to the big mailbox in the sky...??? So here is another one. 
Anyhow I must admit that when I looked at the thermostat in the bathroom this morning I was surprised to see that the air temperature was again 13 degrees, yet the floor was warm and the bathroom was comfortable enough for brushing teeth, shower etc. This morning we had snow on the foothills and a very chilly wind (please take your Adelaide weather back!). I guess the bathroom felt more like 18 degrees (which is the point at which we sometimes manually put the floor heat on in the living room) 
I had read somewhere (probably in an advert for underfloor heating) that there is a psychological effect whereby if your feet and legs are warm, you will feel warm. With good insulation and the heating that we have, the bathroom rarely gets uncomfortably cold and if it does, the IXL heatlamps get pressed into service. 
The other trick that we have is for the heated towel rails to be on when the floor heat is on. This ensures warm, dry, fluffy towels.

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## chalkyt

Just saw your plan. Looks o.k. to me. Might be a bit of overkill but if you are doing it yourself does that matter? Better to be overdone than underdone. Other thoughts are...Will the fireplace be big enough, and is there merit in having a vent near the front door in order to get complete circulation around the lounge room since the recirculated air is all coming from the other side?

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## Moondog55

It is a large open space so Chalkyt has a valid point

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## barnes

> Just saw your plan. Looks o.k. to me. Might be a bit of overkill but if you are doing it yourself does that matter? Better to be overdone than underdone. Other thoughts are...Will the fireplace be big enough, and is there merit in having a vent near the front door in order to get complete circulation around the lounge room since the recirculated air is all coming from the other side?

  I will put a Lopi Cape Cod which is the biggest in the freestanding range. The front door is not there, it's at the bottom of the chart, I will put the heater between 2 big glass doors to my side yard to cut off the cold from them. 
The last thing I will look at now is radiators and hydronic heating, but that is for another thread.

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## chalkyt

Without looking too closely, I read the plan as having the front door at the bottom RHS (near what I think is the garage). Sounds like putting a vent down the bottom RHS is what you are considering anyway.

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