# Forum Home Renovation Heating & Cooling  Hydronic Heating

## Nifty1

I'm inclined to allow for radiant panel hydronic heating in a renovation I'm doing, although I probably can't afford to install it just yet. I could easily install the pipework though (rough-in) since the floors are up. This sort of implies that I need to get the design basics right, even if the details are left til later. Hydronics companies indicate that there is real black magic involved, but it seems pretty straight-forward to me. Am I right in thinking that I require a ring-main system, either run from room to room or via a manifold, as a starting point, and using a pex-al-pex type of pipe? Or is it really as complicated as they are telling me?

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## Bloss

It requires good design and to do that needs knowledge of the issues involved with the water flow as well as the thermal characteristics of the system. But there is plenty of information on the web for DIYers (some in Oz, but most in the US and Europe where this has been a common space heating system for a long time). So google is your friend and a search on this site will also bring up plenty of threads that will get you started. 
As with lots of DIY what seems simple in principle is actually complex in practice - and ends up being more costly than a commercial solution. Not always, but often commercial solutions are better value because they have already built upon mistakes and experience over many installations. 
In this case the consequences if you get it wrong are potentially very high - in cost and inconvenience., but if you do your research you will see that many have already trodden the path with some success. Remember that this is work that must be performed by a licensed plumber - or least signed off by one. There are also DIY kit-form systems that allow self-installation up to a point with final commissioning done by an authorised person. 
A good option when teamed with solar heated HWS or ground or water geothermal loop systems. There are other options too such as http://www.solarfloorheating.com/how.html. See  www.hurlcon.com.au too for some info as well as the attached.

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## GraemeCook

Nifty,  I liked Oldboss's response, although I am always suspicious of sites like solarfloorheating that are strong on advertising hype but which give no hard data.  How much heat will it produce?  Will it heat through a Victorian winter, or night, etc. 
We had radiant panels when we lived in Boston, USA.   Took about 15 minutes to heat the house when it was "twenty below" outside -  about -10*C.     
Now lets get technical.   Radiant heat is much more comfortable than convective heat.  (To understand the difference think about sitting outside in the shade on a cool day;  you are largely being warmed by convective heat, move into the sun and the radiant heat will make you feel much warmer but the temperature has not changed significantly.)    The difference in a hydronic unit is in the size of the panels - radiant heat panels are much larger and more visible than convective panels, and fan convectors are even smaller.   But radiant heat is so much nicer that will can turn down the thermostat by 2-3*C for the same comfort level.  Some sources say that one degree celsius cuts the fuel bill by 10%.   This decision must be made early as radiant heaters operate at lower temperatures than convective and thus require larger pipes to move larger volumes of warm rather than hot water. 
If your floors are suitable, also consider underfloor hydronic.  See radiantec.com. 
Keep us posted 
Good Luck 
Graeme

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## Bloss

Many many ways of doing this. I threw in the link with the pool heating system adapted for home space heating as he was an ABC New Inventors winner and it is very simple, cheap and known technology. He is new in the business and a sole trader with all the risks that entails, but he is using bog standard fittings and a proven technology so in my view a reasonable solution - especially for someone pondering DIY as one of that guy's problems is that he has no access to patent or copy protection so far as I can tell. His is an underfloor hydronic system that uses low flow and low temperatures (and very low costs). 
All he has done is to add a storage tank (or two) and instead of the thermal exchange unit being the swimming pool he is storing the heated water during the energy input daylight hours then sending the heated water through underfloor loops (but he could use radiators at increased cost) as needed. This has a number of advantages when DIYing including low cost and low incremental cost for any expansion; ease of expansion in different climate areas by increasing the surface area of the collector on the roof (it is modular), increasing the storage volume by using a larger tank or adding tanks; increasing the output heat by using more loops under the floor and so on - most of which can be retrofitted if the original design were found to not perform as expected. And like all solar systems can have gas or other backup fitted for longer low solar insolation periods. 
What that guy is doing anyone could do - although again why re-invent the wheel if you can buy one reasonably (of course you might enjoy building the better mousetrap and have the time to do it too). 
So you have much to ponder on and research.

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## Nifty1

Thanks for your comments and suggestions, gents. I've found a helpful man in the industry and we are working on step 1, the heat loading per room. Indications are that a lot of the mystery comes down to a plain lack of understanding, even within the heating industry, about how these systems work. I'm heartened by the availability of a boiler package that includes the pump and expansion tank etc, meaning that pipes and panels are about all else that is needed. 
I had already examined the Radiantec option but I didn't think that heating from under 130mm wide floorboards was a good idea, both because wood is a fairly good insulator, and because I don't want the floor opening up as it dries out. But that underfloor heating is the best I've ever experienced, all the same. 
At this stage of the project I just need to heat a very small house, but I plan to extend in a few years and this would be an easy task using hydronic. Hydronic seems to be ideally suited to coping with a broad range of loadings like this, too.  
Yes Graeme, I like that radiant heat. Daughter has ducted gas with ceiling vents, and the blast of air when it fires up is enough to knock a frail old man over. Also pleased to hear about the responsiveness of the system you had. Even my local plumber tells me that hydronic isn't suitable for the area because it takes too long to heat up and cool down (and he is talking about radiant). The volume of water in the radiators, and the circulation rate, make it obvious that responsiveness will be comparable with electric wall panels, once the boiler is fired up. 
I'm considering single layer panels, based on wanting more radiation than convection. Also, double layer panels would appear to do a good job of heating the wall behind the panel and I can't see the point of that. Looking at panel prices, they seem a lot less expensive than people reckon. One problem that is looming is finding suitable panel locations when wife has firm ideas about where furniture is to go. How effective are those very tall (1800h) panels? 
Oldbloss, that solar system would be very interesting if I was doing slab heating, but I suspect that it would be less effective with radiant panels that need a higher water temperature. I am installing a Rayburn wood stove, with wetback option, but I'm leaving that right out of the planning at this stage in an effort to simplify the project.

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## Bloss

> Oldbloss, that solar system would be very interesting if I was doing slab heating, but I suspect that it would be less effective with radiant panels that need a higher water temperature. I am installing a Rayburn wood stove, with wetback option, but I'm leaving that right out of the planning at this stage in an effort to simplify the project.

  Solar for hydronic heating a no-brainer. The el cheapo system I mentioned is just that - a low cost complete option. If you are using radiator panels and tanks then solar is still the go - but using evacuated tube technology and larger or multiple storage tanks with the Rayburn becoming the winter backup system. Evacuated tubes output can heat well above boiling - a major design issue is managing that to keep the water you need at 70 degrees or less. 
I know a couple of people who have used the system from this guy and they are rapt: http://cgi.ebay.com.au/SOLAR-HOT-WAT...QQcmdZViewItem. I am looking to buy the colder climate system myself - this is about 1/3 the price of Hills & others, but needs a person who is handy and/ or a very friendly tradie to help set up. 
This too has the advantage of being expansible - in fact with the wide summer & winter temperature variations and insolation differences in and around the ACT many owners remove a number of tubes for the summer and replace them for the winter (they are a plug-in type fitting) to make it easier for the auto controllers to manage the heat output.

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## GraemeCook

> Many many ways of doing this. I threw in the link with the pool heating system adapted for home space heating as he was an ABC New Inventors winner and it is very simple, cheap and known technology. He is new in the business and a sole trader with all the risks that entails, but he is using bog standard fittings and a proven technology so in my view a reasonable solution - especially for someone pondering DIY as one of that guy's problems is that he has no access to patent or copy protection so far as I can tell. His is an underfloor hydronic system that uses low flow and low temperatures (and very low costs).
> .

  Thanks OldBoss.  This guy sure has picked a difficult business, exacerbated by the professional manpower needed to produce and dessiminate the detailed science.   Lets hope he does not get lost among the snake oil salesmen. 
The hydronic system that we had, Nifty, was run from an oil fired water heater (apparently thats different from a boiler) in the basement.  The radiators were on the exterior walls and were about 3,000x300mm - they operated at very warm temperature, not boiling hot.   They would not burn if you touched them - if you put your hand on them then they were uncomfortably hot but you could keep your hand there for a minute or so...   Totally silent in the house.   In the basement there was a low rumble from the water heater and the pumps. 
Several friends there had underfloor hydronic heating - totally invisible and silent - and movement of the floor boards did not seem to be an issue.  It was never mentioned and all had polished floor boards approximately 100mm wide.   Contrary to popular belief, wood is not a very good insulator;  19mm of TasOak (aka Vic ash) has a insulation value of R=0.18, as compared to 3mm window glass where R=0.19. 
Big Mal was right when he said "life was not meant to be easy". 
Graeme

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## Knotaclue

Sorry if I am a bit late with this response but I hope it helps. A bit long winded too. 
I installed hydronic heating about 20 years ago in our solid brick victorian era house.
It works on a gas boiler ( Italian Sime brand ) with copper pipes to pressed  steel ( Italian Ferroli/Biasi brand) wall mounted panel radiators. 
Bought all the bits from Hunt Heating ( Melb southern suburbs) and did the calcs on pipe sizing and room volume/window heat loss etc before choosing radiator sizes.
This is effectively a sealed system with anti corrosion chemicals in the water.
Water is heated and stored at temperature in a cast iron boiler then circulated to radiators by pump when thermostat triggers it. 
Works an absolute treat...even with our very high ceilings and heat stratification.
Panels are the absolute bees knees as clothes driers in winter!! 
But wait ....I have found a better system which I am about to install for my daughter.
Go to   www.*greenheat*.com.au/   and talk to Zac   (He will calculate the radiator sizes for you if you send him a plan?) 
This system  uses a plastic  ring main and an intantaneous/constant flow ( eg Rinnai) heater.
The difference with this system is that it is also part of the potable house water supply...therefore you cannot use anti rust chemicals..which means that you must also use only copper radiators ( not steel/cast iron). Greeenheat make copper radiators ( powder coated) which look like the tubular towel rails with which you are probably familiar. 
You can also use the copper -finned skirting board modules which were made by Hendy of Blackburn Vic....now taken over by Hurlco ( see previous thread/link) if they are still available. 
How does it work?
Commercial model of Rinnai heater..high output
Close-coupled housing by Greenheat containing circulating pump valves etc..mounted directly under heating unit.
Rehau ( German ) plastic pipe ring main( insulated with that black foam tube) with flow and return pipes and a narrow-bore restrictor loop at the far end to create back pressure on the flow.
ALL hot water for house is tapped off the flow pipe of the ring ..ie bath/laundry /kitchen and tappings for room heating radiator as the ring passes by.
Kitchen /bath water etc is taken via heated mains pressure and sent to waste /sewer  as normal total loss.
Central heating water is taken from ring main flow pipe and returned as cool.. back to the heater. This is controlled by a pump and thermostat. 
So in summer or when heating is off it is a normal house hot water system. 
Turn on the heating thermostat and the pump kicks in and hot water is circulated past the radiators ( each has its own control tap or whatever.. as usual and can be isolated ) back to the heater via the return loop for reheating. 
The ring main is 3/4 flow and return and the tappings are 1/2 inch  so you are only ever keeping the insulated 3/4 pipe contents hot when not in use. Much better than storage tanks and the central heating is available immediately. 
My old system requires me to commission and crank up the heater and heat the storage boiler. This is OK  when left on in Winter but you would not bother on those one-off  cold unseasonal days. 
Worth a look...I reckon 
Good thing is that you could have your plumber install the ring main and domestic hot water now...then later, simply cut and tap the plastic main for heating flow/return.
The big outlay is for the new Rinnai heater and the pump box assembly..and the cost of copper radiators ( we know about the increasing cost of copper!!!) 
The other good thing is that ( I assume/hope ) the Radiators are still  made locally (Melb northern suburbs)  ...nice to see some local manufacuring. 
As I said ..hope it helps 
Cheers 
 Bob

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## Nifty1

Well Knotaclue, that's very interesting! I had just today pretty much dismissed hydronic as an option, for a surprising reason. The amount of heat I need will be too small for a standard boiler package to supply (although I know smaller units are available overseas). My small house will require only about 7kw, and this may reduce further as I add insulation, admit more sun, and stoke up a Rayburn stove. Most boilers seem to run happily down to about 50% of their full heat output, otherwise they need to short-cycle. I also started to consider the possibility of heading north for a few months of winter like these grey nomads do, and suddenly I'm seeing hydronic as overkill. However I have been very pleasantly surprised at the costings, based on a self-install but with a plumber to connect and commission. Greenheat may solve the heat load problems, although I suspect the radiator cost will be prohibitive.

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## GraemeCook

Lets see, Nifty.  You are too efficient to install an efficient heater....   Crazy. 
Have you looked at firing it from a larger heat pump hot water system?  Heat pump efficiency probably makes it a little cheaper to run than gas, and there are some lovely subsidies and rebates available if you satisfy the bureaucratic minutae.   There is another thred on this site. 
Cheers 
Graeme

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## Nifty1

This has been an interesting and worth-while exercise. If my house was a bit bigger I'd be putting in a gas-fired hydronic system at a very moderate cost, in spite of originally believing it was going to be outrageously expensive. I checked the Greenheat option, but those copper radiators are just too expensive at about four times the cost of steel, so had to drop this option on cost grounds. And the standard self-install option with steel panels is just too powerful to make sense in my little cottage. Even my original plan, to run the pipework now against a later installation when I extend, is not looking to make so much sense. I expect to stay with radiant heating, and use electric wall panels instead. This will defer the costs for another 9 months, and be less than half the capital cost of hydronic. Running costs will be a bit higher though. 
If you are like me, hate the miserable heat given by the blown hot air systems, and are concerned by the high initial cost of hydronic, take heart. With some DIY skills and the right contacts, you can probably have a fine system for the same cost as a commercially-installed ducted gas system. Many thanks for the ideas and interest from forum members.

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