Well its time to figure out which heating source I am going to go with. The shop is 48x76 with infloor heat layed out in 2 zones. The side walls were r25 spray foamed and ceiling was blown with r60. The floor has 2inch blue foam layed down plus side. Shop location is in iowa. I had radiantec help me design the layout and manifolds. They want me to use the Polaris water heater for the heating soruce. Pretty pricey but I understand gotta pay alittle more to get the right thing. So I am the type to try and do research and see what other people are using. I am pulling my hair out now trying to decide which way I should go. I really wanted to go geo but just cant spend that much right now with building a new house. Let me know if you need anymore info on helping decide on which one I should go with. Thanks
Which heating source for in floor heat?
- Thread starter Polaris88
- Start date
jlckmj
Well-known member
A couple threads that will get you informed somewhat, from here it is up to you to decide. I went with a used tank type water heater because I got one that was only one year old for nothing. So far it has been working well and the initial cost to set the system up was minimal. If I have to replace it in 5-7 years, so be it.
Good Luck, Jim
http://www.garagejournal.com/forum/showthread.php?t=171099
http://www.garagejournal.com/forum/showthread.php?t=49557
Good Luck, Jim
http://www.garagejournal.com/forum/showthread.php?t=171099
http://www.garagejournal.com/forum/showthread.php?t=49557
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tdkkart
Well-known member
What power sources do you have available, natural gas, LP, electric???
Where you at in Iowa??
Where you at in Iowa??
I would strongly suggest that you use a "real" boiler for this application, as opposed to a real water heater. The Polaris will work, but why would you want that amount of space and stored hot water.
Boiler selection will depend upon the heat loss calculation which you will start with. I'm going to guess that a Rinnai E110C Combi boiler will do it for you. The 110C comes with the low loss header to simplify the primary/Secondary layout. Lochinvar, Traingle Tube, Vieesmann, Buderus, etc all make good boilers. The 110 gives you 3.2gpm of hot water at a 75* rise and fully modulating het with outdoor reset built in. You do want the re-set program for your system. All of those listed are approx. 95% efficiency.
Boiler selection will depend upon the heat loss calculation which you will start with. I'm going to guess that a Rinnai E110C Combi boiler will do it for you. The 110C comes with the low loss header to simplify the primary/Secondary layout. Lochinvar, Traingle Tube, Vieesmann, Buderus, etc all make good boilers. The 110 gives you 3.2gpm of hot water at a 75* rise and fully modulating het with outdoor reset built in. You do want the re-set program for your system. All of those listed are approx. 95% efficiency.
hidollartoys
Well-known member
What did you calculate for heat loss?
theoldwizard1
Well-known member
Concur !
There was a thread here about a year ago from a guy who was having all sorts of issues using a water heater on a MUCH smaller floor. Experts then said, "Get a boiler !"
It will cost more but it will last longer.
theoldwizard1
Well-known member
If you are willing to put the money into it, the cheapest "cost of operation" would be a geothermal heat pump to water tank heat exchanger. This is an "atypical" installation, so you had better hire someone who has done it before !
You could add on A/C for very little cost !
You could add on A/C for very little cost !
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jvitez
Well-known member
OK, so the heating choices are LP or electric. What is your electric cost per kWh? It seems a few folks from the US midwest have some fabulous off peak rates available, which would make electric a viable choice. Will propane prices stay as high as they are now? If so, an electric boiler may in fact be cheaper as far as operating costs, but geothermal will always be cheaper than regular electric resistance heat. The question becomes one of capital cost vs operating cost. Get your prices, run some numbers and take it from there.
Great thread you attached. In having the same dilemma, I have NG on site and building a 1300 sq foot garage/shop and can't decide between a tankless condensing demand boiler or a tank style water heater ? I have yet to figure my loads. Help me Badger !
GYPSY400
Well-known member
After getting ridiculous quotes for a boiler system ( pex is already installed) im thinking of going solar!! Check out www.solartubs.com for ideas.
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Sent from my SGH-I747M using Tapatalk
98ssuck
Well-known member
The trick to getting a efficient system is to size your boiler to your load. If the heat loss calculation you do only takes 5 minutes it wasn't detailed enough and thus not accurate. You want to size your boiler to your load because the most boilers on the market are modulating condensing boilers. They require a few(10-20) minutes of running before they will reach there rated efficientcy. If you go to big the boiler will never run long enough, have a low efficientcy and short cycle. To small and you won't be warm.
Solar is great in radiant applications, but if you think the boiler was a lot, well hang on to your hat with the solar. I used to figure about 1.68 gallons of storage per sq ft of collector. Radiant being a very low temp application is terrific performance wise. At those low temps the collectors have screaming' efficiency. In my view, solar thermal is about dead. Very pricey for what you get. Solar PV is more the way to go, again, imho
anthony666
Well-known member
agreed .. do the math for load .. do the math for harvest, multiply that by three (24 hours in a day, only 8 provide sun) .. figure out a method of thermal storage for the 16 hours of 'darkness' .. then price out as many evacuated tubes as you can physically pile on your roof .. price out new roof extension and more tubes
make sure you have paramedics on standby
make sure you have paramedics on standby
GYPSY400
Well-known member
Yes I agree, the solar isn't going to be cheap.. Solartubs quoted me something like $8000 for a diy system. Thats two panels and 80 gallon storage tank ( with electric back up ) and all the fixins etc. Im still looking into it at the moment, and not planning on doing anything until spring.
For a garage it seems ideal as im only out here during the evenings.. so it has all day to get warm, and by the time it starts to cool down, im back in the house sleeping. For a house that inhabited 24 hours of the day - different story, some sort of back up heater would have to come into play.
I might do some sort of hybrid system of a gas fired storage tank to keep constant storage temperature, but like I said, im still in the planning stages.. so far im happy with the ceiling mounted 45kbtu Hot Dawg I had installed last week.
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Majordisorder
Well-known member
Polaris88, my Polaris water heater has been heating my residence for 13 or 14 years now with only an igniter replaced. I got ideas off Radiantec and bought my own materials. But my heat load is only 30,000 btu/hr on design day. The Polaris provides both domestic hot water and floor heat via an open system which is no longer acceptable and before I sell the house I plan to isolate the heat with a flat plate heat exchanger. That being said, it has been very economical and efficient.
My new shop has in slab heat and staple up under a second floor apartment. My main source of heat is with an outdoor wood boiler but after doing alot of research, I set it up so I can later add a modulating condensing boiler controlled by outdoor reset as Jackfre mentions.
My new shop has in slab heat and staple up under a second floor apartment. My main source of heat is with an outdoor wood boiler but after doing alot of research, I set it up so I can later add a modulating condensing boiler controlled by outdoor reset as Jackfre mentions.
ketas47
Well-known member
I have a 1000sq. ft. garage in centrel WI and use a Navien on demand water heater AND LOVE IT!(95 percent eff.) I use it for infloor heat and keep my garage around 55 degrees.F. I paid $450 for it used, 2yrs old. Cost around $50 dollars a month (Natural gas). to heat the garage !!!!, extremely cold winter,!!It is my second season without any issues! No mixing valves, very simple set up, Water heated to 115 and returns around 90 F. COULDNT BE MORE SATISFIED WITH SET UP. If I want instant , fast heat I swing 2 valves and turn heater up to 140 Degrees and run water through a heat exchanger., Paid $150 for used heat exchanger.
Cannonball
Well-known member
Hey Ketas.
Any picture of what you system looks like?
What size is the Navien?
Is it strictly being used for the in floor?
Thanks.
Any picture of what you system looks like?
What size is the Navien?
Is it strictly being used for the in floor?
Thanks.
If I had to choose between propane or electric I would consider a hybrid system that uses a tank style electric water heater with a solar loop option and then add a few racks of evacuated tube collectors on the roof, (unless you are shade covered). Basically its solar until it cant maintain (@ night or cloudy days) then the electric side kicks in.
I cannot understand how people think that stuff is in the thousands? Where are they shopping?
18 tubes $500 + freight.
http://www.ebay.com/itm/Evacuated-18-Tube-Solar-Hot-Water-Heater-Collector-SRCC-Spare-tubes-Stand-/230988529933?pt=LH_DefaultDomain_0&hash=item35c7fd410d
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Loop of few of them in a closed system with a tank heater designed for it (with an exchanger inside and electric elements) or get creative with a cheap DIY tank style heater.. Set the water heater to only run during off peak and then the thing can get what it can during the day. I am going to build one of these on my next garage shop.
I cannot understand how people think that stuff is in the thousands? Where are they shopping?
18 tubes $500 + freight.
http://www.ebay.com/itm/Evacuated-18-Tube-Solar-Hot-Water-Heater-Collector-SRCC-Spare-tubes-Stand-/230988529933?pt=LH_DefaultDomain_0&hash=item35c7fd410d
Loop of few of them in a closed system with a tank heater designed for it (with an exchanger inside and electric elements) or get creative with a cheap DIY tank style heater.. Set the water heater to only run during off peak and then the thing can get what it can during the day. I am going to build one of these on my next garage shop.
anthony666
Well-known member
check the rating diagram mr fast .. on a cloudy day in a cool climate one panel makes 3k btu PER DAY .. that's 125 btus per hour .. that's basically what you'd get out of a lit match .. if you had little to no heat loss it might work, otherwise you'd need hundreds of panels to make a difference .. also heat is not cumulative, meaning if you add the same volume of 90 degree water to 100 degree water you get 95 degree water .. so the panels output must be of greater temp than the water in your system or the effect would be negative
now, that said .. if you took ground source water, ran it through some solar panels to pick up a little heat and then put that into a heat pump .. you'd be onto something .. but replacing a boiler with a raft of solar panels just isn't effective, unless you live in arizona
GYPSY400
Well-known member
Solartubs. Com " claims" that their panels make 44000btu / day
http://www.solartubs.com/solar-Evacuated-Tube.html
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Well let's assume the tank is 180* & you can use it down to 80, so a 100* delta T. So, 80x 8.33#/ gal=666.4# of water x100* delta T= 66640 btu/ day. Given that a solar system would run and distribute heat thru the day you get some bump. Given that you will likely not get the 180* water every day, I'm going to call the two a push. Btw, the definition of a btu is the amount of heat needed to raise 1# of water 1* F.
The two collectors and 80 gal system is a good DHW system, but far short of what is required for reasonable space heat. The best return in the solar world today is PV.
The two collectors and 80 gal system is a good DHW system, but far short of what is required for reasonable space heat. The best return in the solar world today is PV.
Solar keeps my shop from going below 40 even this winter which is temp wise below the 30 yr average. I doubt I could build enough of an array to keep it in the upper 50s or low 60s though as in Maine late Nov thru the first week in Feb. are pretty cloudy. But yesterday it was in the low 20s, wind was howling but I had collector temps in the low 100s, and 70 degree water going into my floor. 22 yds of concrete is a pretty decent heat sink. I built the collector based on
www.builditsolar.com. It does what I wanted it to do, keep it warmer than it would be without heat. I use a woodstove if I need it.
My build is in my sig if interested
www.builditsolar.com. It does what I wanted it to do, keep it warmer than it would be without heat. I use a woodstove if I need it.
My build is in my sig if interested
Bingo, with only electric or LP you need to at least consider this option, LP is an arm and a leg to operate and geo will save about 70% over LP but will cost more up front. Geo also qualifies for a 30% of the cost tax credit!
I am doing a geo radiant floor in my garage with a ductless mini split for backup and cooling, but I also own the largest WaterFurnace geothermal dealership in the NW.
ketas47
Well-known member
Flexia
Well-known member
anyone use the Navien combi Boilers? They seem to be under the $3k mark.
anthony666
Well-known member
i've been using them religiously since the tsunami in japan caused a hiccup in delivery from rinnai (that's the story i got at the time)
now, i'm reconsidering my unwavering support .. this last one, an ncb 240 combi, ran for 6 weeks flawlessly and then the poop hit the air moving device .. it fires up, goes straight to overheat shutdown and shows no code .. water is not being moved inside the unit
first, after an hour on the phone, navien sent me a three way valve, which made sense .. i re & re'd that, not the problem .. next, three hours on the phone, videos sent of the problem, videos of the rest of the system, explanations on my part of my bleeding techniques and build theory etc etc, testing input voltages and water flow levels and they send me an internal system pump .. again .. not the problem .. repeat the phone process with three different techs who give three different answers ranging from star alignment to global warming and they finally decided to send a control board .. that is coming today .. at this point my customer has had no heat or dhw for 10 days .. 10 days in rural ontario in minus 20 c weather !!! there's a navien rep an hour away, he's too busy to come
between travel time, fuel, phone charges etc i would have been better to have stayed at home and give the entire job to someone else .. not to mention the stress and shame because a product i swore was awesome turned out to be short of the mark
sorry navien, you **** the bed on this one .. you should have sent your rep guy immediately and the fact that he hasn't as much as called these poor folk in the better part of two weeks makes me sick to my stomach and tells me they are not the only ones with problems
Flexia
Well-known member
Well how do the other ones preform? Would It be good in a garage with little use of DHW?
I only have 1000sq ft and wonding if the 210 may be to big.
anthony666
Well-known member
perfect, no complaints, but this experience has completely soured me .. one thing to think about, if you have dhw hooked up you will be warming that space all winter, you can't let the dhw freeze .. alternatively, if you have just the floor heat, a little glycol in the mix and you have no worries if the power goes out/propane runs out etc etc
210 is way over size
sands35
Well-known member
I have a 832 sq ft garage and a 140k BTU Hyrdosmart 115 is perfect for in a floor hydronic system.
DHW - Little use or none?
You could install a small boiler (electric or gas) just for the water and keep it separate from the floor heat. Have electric pipe heaters as backup if the floor heat dies.
DHW - Little use or none?
You could install a small boiler (electric or gas) just for the water and keep it separate from the floor heat. Have electric pipe heaters as backup if the floor heat dies.
Flexia
Well-known member
that was my other option but with a takagi and they make the hydrosmarts. I washing cars a lot in the winter and I know a little under sink water heater wont keep up. I may look into adding a heat exchanger for the hose hookup in the winter for the car washes. And then do a little electric under sink for hot sink water
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sands35
Well-known member
The only challenge with a heat exchanger for car washing is that the floor water also needs to be circulating. Probably not a problem for the ~30 minutes you are washing the car. Heat exchangers aren't that expensive.
You could put in a bypass loop to switch the hydronic system from floor heat to car wash heat.
You could put in a bypass loop to switch the hydronic system from floor heat to car wash heat.
Flexia
Well-known member
Yeah I was thinking a 2nd zone pump for the heat exchanger
I have seen "This old house" use panels like them used to make hot water to was dishes in a commercial kitchen. That was in the north east and it was in November IIRC, and it hit 160º before the install was even finished.
Now, the link I posted may not be the best parts you can get, I just picked that one to demonstrate what it looks like and what it was, but I will stand by my statement, evacuated tube solar can be a heat source.
anthony666
Well-known member
i honestly would like nothing more than to be proven wrong, i would heat my home for free in a heart beat
michael1968
New member
As a general rule, all things considered, the best bang for the buck is the modulating high efficiency boiler. Combining that with "outdoor reset" to automatically adjust the infloor water temperature will give maximum performance with greatest comfort, control and efficiency.
Remember, the radiant in-floor system will have anti-freeze in the swater so you will need a heat exchanger in line to transfer the boilers energy to the infloor system.
Reason for outdoor reset is obviously because the heat loss when it is 40 degrees is much less than when it is 20 degrees below zero! The warmer the outside temp the less heat/energy you need to use from the boiler.
Remember, the radiant in-floor system will have anti-freeze in the swater so you will need a heat exchanger in line to transfer the boilers energy to the infloor system.
Reason for outdoor reset is obviously because the heat loss when it is 40 degrees is much less than when it is 20 degrees below zero! The warmer the outside temp the less heat/energy you need to use from the boiler.
Legwound
Member
New member here just started reading multiple threads, so i haven't completely read this one. I am interested in radiant heat for a new shop to be built within 2 years.
Has anyone looked into wood fired boilers on this forum. I found some interesting info here
woodheating.ca
Aside from several robust wood only boilers there is a solar/wood combo unit.
I'm thinking wood fired with a 1-2 hour daily burn would be a good option for me. My wife is a talented woodworker so scrap and dust would become fuel.
cheers
Has anyone looked into wood fired boilers on this forum. I found some interesting info here
woodheating.ca
Aside from several robust wood only boilers there is a solar/wood combo unit.
I'm thinking wood fired with a 1-2 hour daily burn would be a good option for me. My wife is a talented woodworker so scrap and dust would become fuel.
cheers
anthony666
Well-known member
the solar aspect of that unit is for supplying domestic hot water during the summer/warm weather months
i honestly would like nothing more than to be proven wrong, i would heat my home for free in a heart beat
If you take the time to read my post, it is clear that I was talking about a hybrid system. My electric heat source runs very little to maintain 52º-56º in my shop here in Indy and it has been a very cold winter.
Would this type of system heat my shop for "Free", no. But if you factor in the days with sun it would really bring down the overall expense of running the system.
Your "Heat my home for free" comment is just more internet trolling BS. Stop discounting things just because you are unwilling to try them, or at least READ the post before you apply off handed logic.
Maybe if you move to Arizona you can heat your home for free ehh?
You really dont know anything about that new fangled "Solar" stuff do ya?