Whole Home Radiant (Hydronic) Heating?

We’ve replaced our basement slab and took the advice of those here to include PEX for hydronic at a later date. I’m debating whether to make the switch and heat the whole house with hydronic?
Our home is a 2023 sqft (outside dimensions) semi in Toronto. Basement and Main = 733 sqft each, Second Floor = 556 sqft.
I’ve got the whole house open to the joists and I’m doing mechanical, electrical, and plumbing new. All windows and walls will be sealed and insulated with spray foam including the basement.
What makes me consider doing all hydronic is the amount of space that the ducts will take from the basement!
So my questions:
If I combine Hydronic Heating with an HRV, is there a need for any duct work?
For A/C, could I simply do a ductless, multi zone solution that takes care of the first and second floor?
Can I integrate the Rinnai R75LSI tankless HW to do double duty? boiler and domestic hot water?
Cheers
Van G
Edited 12/14/2008 9:43 am ET by Van_G
Replies
Do you have access to Natural Gas or are you on LP?
In Ontario I would think that you need a better efficiency than you will get out of the Rinnai, probably a Quietside or similar condensing boiler.
How good is your building envelope? how brutal is your climate where you are?
m
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"You cannot work hard enough to make up for a sloppy estimate."
Natural GasBuilding is completely opened and will have all windows/doors sealed, exterior walls blown with 1.5" closed cell spray foam (R9), new basement slab has poly + 2" XPS underneath, basement walls will be blown with 4" of closed cell spray foam, attic will be topped up to R40.I wanted to integrate the Rinnai since it will be in place but if it's not the right equip for the job then we will look at something else.Toronto isn't that brutal but I suppose it's relative. 4 seasons and we'll see a handful of days that are -15 to -20 during the winter. In the city and fairly sheltered from east and west winds.Am I correct in assuming I can stay away from ductwork if I go down this road?Van G
VanG
Your ventilation system will still need ductwork, of course, but its demands are much less than the demand of a heating system. Four inch ducting, which can be squeezed into a stud wall will do almost all of it with a six inch trunk possibly needed as you approach the HRV.
That wall insulation spec seems a bit light. Is there a reason for that?
Ron
Can only get R9 on the above grade exterior's - R9 is a closed cell spray foam is as good as I could get because we are strapping the walls with 2x3 on it's side. Better than what was there before - nothing!What about the boiler units on the market that are branding themselves as dual purpose? Are these open systems as well?Not sure if you've seen this on youtube but it is where I first got the idea:http://www.youtube.com/watch?v=Ypylfuh39kU&feature=relatedVan G
That's not the most efficient system and I think you would want to do better for your cold climate. Something like that will work only if you have a really well insulated envelope which you are a little short on. I think it would really make sense to step up at least the $800 or so to a modulating condensing boiler. And I agree with Bill that you should isolate the radiant from the domestic hot either with a flat plate heat exchanger or else with a combo boiler like the Quiet side which is designed to heat both hot water and radiant. In the you tube video they are rinsing their floor by cycling the supply water for their domestic hot through the floor during the off season which is a time honored way to do it but most plumbers are going to heat indirect systems that isolate the potentially bacteria laden water in the floor from the water you shower in. The risk is that you could inhale legionnaires bacteria from your floor when you take a shower and it would give you pneumonia i.e. legionnaires disease. It's actually a small risk and you would need to be immune compromised but the heat exchanger and hardware to install it is maybe $400 and it seems good insurance as compared to the risk of killing someones grandmother. I also run my slabs at a much lower temp than my staple up zones and he doesn't seem to be recognizing the difference. But that is more a matter of how detailed you want to go and I may not be reading his pipe layout correctly. ------------------
"You cannot work hard enough to make up for a sloppy estimate."
Good advice.For planning purposes, what are the rough numbers for boiler? And distribution/management system?I've got 2 loops in the basement (250 + 250) and they're 1 zone. I'll have to do electric radiant for the back room which we didn't pour new slab.Main floor is open concept so I'm assuming 1 zone with 3 loops.Upstairs (3 bedroom, hallway, bathroom) I would guess 2 zones (hallway + bathroom on 1, bedroom's on the other) Would likely require 3 loops to hit the upstairs).Main floor is being stripped to the joists and new subfloor installed.
We had planned to leave the second floor in place (1/2" x 3" planks running at 45 to joists subfloor with 5/8" strip hardwood.I've started speaking with PEXsupply.com who will design system and supply with plans. I'll do pex install and work with plumber to build out system.Van G
I will be installing a mod/con boiler and indirect tank in my home soon. From my research, tankless units do not function as efficiently when used in a hydronic application. Short cycling is common and they make small amount of very hot water better than lower temp common in hydronics.Closed systems are best, numerous reasons but less contamination of the system and no need for stainless or bronze pumps if you go with a closed system. Your air and dirt separator systems must be installed in the perfect location in an open system as well.I used Uponor(Wirsbo) products for my tubing and manifolds and you can also download their ADS design software to help with the heat loss calcs and such. It is a great tool but you need to call the 800 number and speak with a service rep to get access to the dowload.Built-in individual room AC units are hard to beat - no need for ductwork at all. I'm not sure the high velocity systems are really any good either, I left out all ductwork in my home and plan on utilizing the windows and doors for cross ventilation to handle the AC and have provided a make up air vent in the rim joist of the basement.Sounds like you are on the right track, good luck!HeatingHelp.com is a great resource for hydronics
would you be opposed to any stored hot (warm at 120 degrees) water? like 40 gals in a tank? How often does the water get completely flushed from a DHW heater? Just as dangerous. The legionnaires disease fears don't pan out - no known cases from the many open systems out there (IBC approved). This is disinformation.
I think its a little strong to call it disinformation but I agree that it is very controversial. I still have an open system in my own house but I install closed systems for my customers and plan to eventually put a flat plate heat exchanger on my own house. My immune system is strong and I don't worry about legionnaires but many people I respect feel very strongly about the risks of open systems and the fact is that it really isn't that expensive to put a heat exchanger and an extra pump and controller on the systems. It's not the odds, it's the stakes.m------------------
"You cannot work hard enough to make up for a sloppy estimate."
sorry if I was a little strong.
you can use the hot water to heat without it being radiant... a small heat exchanger blower set up... ie... a fan blow'n through a coil that's heated with hot water.. i have a whole office building set up this way and it's pretty cheap to heat...
p
Combining hydronic heat & domestic hot water means "open system" I strongly recommend against that type of set up.
Too many things to contaminate the drinking water.
I'm also questioning the R-9. In Toronto (center of the Universe) that CANNOT meet code, and you are going to have a very expensive HVAC cost going forward. Maybe meet Mike Holmes?
2x3 walls above grade? Brutal.
I suggest (it's your house) you deepen the existing 2x3s with an extra 2x4 in front and screw them together. That will give you space for R-20, and if you can manage it, 5/8" XPS over top of the studs to give a thermal break. I did that upstairs here in La La land and it makes the area tolerable with very little added heat.
Natural gas is cheap right now, but if you are building for 30 moore years, or resale value ......
Quality repairs for your home.
AaronR Construction
Vancouver, Canada
Sorry I didn't clarify, the foam will add an R value of 9 to the existing wall. Total R value of 17 for above grade walls and 24 for basement.I'll check out heatinghelp.comAny thoughts on costs?Van G
Van-G
ADDING R9? Whole other story then. That's quite acceptable.
So you've torn up the basement slab, gutted the interior, removed subfloors - probably removed old wiring and plumbing. maybe siding and roofing too unless you're going to do that next year - must be a great location.
No, wait, you said Toronto, didn't you?
Ron
Everything on the inside is down to studs (sold 2x4 and 2x8 timber). Roof is 5 years old and attic has 9 inches of shredded pink which we'll top up with blown. Although smaller than most it's a solid home in a great area - good lifestyle choice. This is why I'm going through the process to research radiant heating to avoid chopping up the basement with duct runs. Not a lot of room to spare!Toronto it is indeed. When you come and visit bring a couple boxes of Oyster's and a dozen Lobster.Van G
VanG
When you top off the attic, you might think about using cellulose instead of glass because it will reduce heat loss through convection within the glass. You will gain more than way than you will lose due to the glass getting compressed a bit.
Lobsters? Prices are so low now that fishermen are apparently not covering their costs. A lot of them are staying ashore. Myself, I can go a long time between lobsters and not feel deprived. Good fresh scallops, on the other hand - right out of the shell, still cold from the water - heaven!
Ron
Blown cellulose for sure. HD rents the blower and everything. Pretty simple job.What approach for the PEX install should I be considering?Staple and insulate below sub?Track product with reflective material installed on top of sub (can only do this on main floor unless second floor sub is done as well.In my mind the easiest install is going under the floor but do you get a good product that way?Van G
Had a chat with Reliance (equip rental) and my contact cautioned me on the QuietSide QVM9 boilers - very high service call level so they pulled them from their program.I'm interested in either a dedicated boiler or a dual purpose unit (wall hung ideal) that does DHW on separate system.Suggestions?Does anyone know of any resources on the web that show different system designs?Van G
The most efficient system you can come up with to burn fossil fuels and produce hot water is with a modulating/condensing boiler that has an indirect water heater for domestic hot water. With a properly sized boiler, this system is parctically an instantaneous water heater and mod-con boilers operate at 90% efficiency or greater, whereas tankless water heaters are more about 65%. There are many manufacturers that provide this type of systems. The plumbers and heating experts that hang out over at the Wall at heatinghelp.com can provide their input on their favorite brands. I like the Weil-McLain Ultra products.
To ventilate and/or air condition I would advise against a ductless split unit. A variable speed hydronic/DX air air handler and the ERV would be a good combination, especially when combined with a good high quality mechanical media filter and a computer controlled powered humidifier. Duct work takes up space. Accept and deal with that.
VanG
I have opinions on the installation of heating tube, but they aren't backed up by knowledge.
Someone else will be along in a little while.
Ron
I sat down with a supplier in town to get the general walk through on a whole home system and the price is way out of scope for our project. Just roughing numbers I'm looking at $6000 for a boiler (Prestige or Viessmann) and $1500 per zone for modular system like Paw (3 zones).They had an engineer on staff who will do full plans for $600 including HRV plan which I thought was a good deal and money well spent (full CAD plans delivered).I do have access to rental program for Viessmann Vitodens 200 and Vitocell 300 which would cover my radiant and DHW supply, but I still think I'm looking at 10-15K for the hardware after the boiler and supply for runs and material to put it in place (I'll do labour for run install). And that leaves me still planning an A/C system.Is my ballpark estimate close?Van G
Lots of good advice so far.
I would beg to differ with Tim's opinion on duct work and ERV.
Whole home radiant with an HRV is wonderfully comfortable. The addition of A/C minisplit will probably work well if your 'new' envelope is properly detailed. Minimize the air changes and heat gain and thus reduce the load. The ductless works well with open concept mainfloor.
Not to offend or denigrate the skills of the many great plumbers out there but hydronic systems are not just a bunch of tubes connected to a hot water making device.
The youtube video you referenced fails to address numerous issues and is easy to dismiss as rubbish.
Good hydronic design is a specialty. Enlist someone knowledgeable and local who can be held responsible for their work. Get their references and check them.
Hydronic heat will not be comparable in price to scorched air so be prepared for a possible factor of 2 or 3 times FA.
If you fail to get good design and execution you will not be happy with the performance of your system. Too hot, too cold, unresponsive , expensive etc.
Ask what you want, heat or comfort. Low budget FA produces heat but does it produce comfort? Same applies to radiant. By all means DIY the tubing under instruction and mind the details but save yourself the despair and make sure whomever does the boiler is more than a plumber. Ask me how I know. :-(
Your mention Viessmann and I wholeheartedly endorse them but there are other excellent mod/con boilers available that are a little cheaper. More important than the boiler is design and installation.
Is this a place to stay in or a resting place along the way?
Cheers
In the middle of doing our whole house radiant heating system....Wow its fricken expensive compared to hot air. What shocked me the most was how much an indirect tank costs! Triangle Tubes 120gal model costs $3000! and its just a fancy insulated water holding device... If that $6000 number includes the prestige 110 solo and their smart indirect heater thats pretty good.
I reccomend you go online and buy all your supplies and do the lionshare of the work yourself.
Building up the 'control panel' is not something you should do yourself. We had our system designed-planned and the control panel done by NRTRob here on Breaktime. Once you see how complicated a control board is you'll be glad you got an expert to do it. Robs place is called NorthEast Radiant Technologies you should at least give him a call and chat about what you want to do. He won't sell you the boilers but every other widget you can get from them.
For us we only needed a prestige 60 boiler and I went with the rinnai 795LSi for the hot water both bought from ecomfort.com free shipping and no sales tax!
check out the blog in my sig all the recent entries have been about the heating system.
Daniel Neumansky
Restoring our second Victorian home this time in Alamdea CA. Check out the blog http://www.chezneumansky.blogspot.com/
Oakland CA
Crazy Homeowner-Victorian Restorer
Triangle Tubes 120gal model costs $3000!
Why in the world would you need a 120 gallon indirect tank with an efficient modulating boiler?
I installed a Prestige 110 with a TT 40g smart tank in a two-bath house, and they'll never run out of hot water.
By the way, I got the boiler, tank, circulators, all parts and accessories, manifolds and PEX for two floors of radiant heating for $6100.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Edited 12/18/2008 5:28 pm ET by Riversong
The 120 gal tank was because the tank being heated by the boiler was only the mid way solution. Eventually we were going to get solar hot water and then use this tank for storage with a small tankless backup.
We didn't need the larger 110 boiler in fact the 60 is still too big. Our calc heat load is only 28KBTU's ! Guess I coulda gone with a 30k electric unit.
Since the house is sorta big we are planning on going with 2 Rinnai tankless units. One for the bottom two floors and one for the top floor which will have 2 baths and the laundry.
Daniel Neumansky
Restoring our second Victorian home this time in Alamdea CA. Check out the blog http://www.chezneumansky.blogspot.com/
Oakland CA
Crazy Homeowner-Victorian Restorer