picts of your in-floor heat set ups.

[kj_mustang]

If you aren't worried about the ROI of the spray foam cost over other insulation choices, then why worry about the ROI of radiant versus other heat. Radiant has other factors that should also be considered as to if you want that style heat not just cost.

 

[Rc_Guy]

This thread is now nine years old and I notice one thing in common: people seem to be unwilling or afraid to report back with what their actual heating costs were, in dollars and cents. I’m wondering if maybe it cost way more than anticipated, and people don’t want to admit their disappointment.

Or they are like me and don’t care what it cost per month.

It's just like gas milage, some guys will ask what kind of gas milage I get with our 3/4 ton 6.0 Silverado, when I tell them I've never checked the milage they look at me like I'm nuts, I don't care what the milage is.

 

[forAK]

If you aren't worried about the ROI of the spray foam cost over other insulation choices, then why worry about the ROI of radiant versus other heat. Radiant has other factors that should also be considered as to if you want that style heat not just cost.

Very valid point. A shop/garage isn't the tightest of envelopes to worry about ROI in regards to heating. Just look at the heat loss alone with huge garage doors and if you have windows. It's about comfort. Comfort at noise/dust/space saving/rolling on floors. I simply love it compared to my forced air in the other shop. It works for me.

 

[2011laramie]

Went through all the pages on this thread, really thought id see more mid efficient cast iron boilers.

Im insulating a 2800sq ft shop and the local dealer has a good deal on a 85% efficient cast iron boiler thats been sitting in the crate for a while.

 

[cs26k]

I also went through this whole thread (and forum, really) looking at pictures of guy's setups. Got mine in so I figured I'd share while I'm waiting on flatwork.

Critiques welcome!

 

[bams50]

If you aren't worried about the ROI of the spray foam cost over other insulation choices, then why worry about the ROI of radiant versus other heat. Radiant has other factors that should also be considered as to if you want that style heat not just cost.

I’ll be glad to explain it to you. The reason is, because in my case monthly operating costs are going to be more important than initial purchase cost. Spray foam is one example – the difference in cost between fiberglass and spray is substantial, but over the course of a loan it’s not that much more per month. It’s the same with any aspect of the project: building size, interior height, construction type, heating type, etc. They all add to the final cost.

In my case, I will have to borrow a large portion of what it will cost. I can’t afford to just have everything my heart desires. So, I have to make a decision on every aspect, and a big part of that is ROI. I know the advantages of radiant heat versus my current hanging gas forced air. Both ways have their advantages and disadvantages aside from operating costs, and of course, they factor into the ROI. But, a big part of that will be some idea of Real world operating costs. In other words, do I spend say another 30 grand for a heating system that is going to save me X amount per year over the other way? Unfortunately, my lack of wealth forces me to consider such things. Your mileage may differ.

THAT is why I had interest in real-world operating costs. See?

 

[bruincounselor]

I’ll be glad to explain it to you. The reason is, because in my case monthly operating costs are going to be more important than initial purchase cost. Spray foam is one example – the difference in cost between fiberglass and spray is substantial, but over the course of a loan it’s not that much more per month. It’s the same with any aspect of the project: building size, interior height, construction type, heating type, etc. They all add to the final cost.

In my case, I will have to borrow a large portion of what it will cost. I can’t afford to just have everything my heart desires. So, I have to make a decision on every aspect, and a big part of that is ROI.

Installing the tubing is relatively cheap up front; especially if you DIY. The rest of it can be done later when funds allow.

If you don't DIY some jurisdictions require a licensed plumber to lay tubing - significantly adding to the expense.

My $.02

 

[koditten]

Went through all the pages on this thread, really thought id see more mid efficient cast iron boilers.

Im insulating a 2800sq ft shop and the local dealer has a good deal on a 85% efficient cast iron boiler thats been sitting in the crate for a while.

That's what I'm using. After doing the math, it would be 35 years before I broke even. 85% vs. 96% is not that much in lost efficiency.

 

[bruincounselor]

That's what I'm using. After doing the math, it would be 35 years before I broke even. 85% vs. 96% is not that much in lost efficiency.

And, if you don't have a true floor drain you don't have to deal with condensate either. (Win/Win). DAMHIK

 

[rclassic]

1000 sq.ft @ 57 degrees cost me $30 a month for natural gas . I could not be happier with this set up. I'm in western pa.

 

[homebuilt burner]

I built a small wood working shop 3 years ago. 14 x 26 2x6 walls with 1 1/2” closed cell spray foam and 3 1/2” of fiberglass, 1” of foam under and around a grade beam slab, 16” of blown in cellulose in the attic, in floor heat, natural gas water heater running the system, one walk in door and one garage door 7’x8’ . The building is kept at 60 degrees 24/7 from October to April. Cost $5 - $15 per month, never more, usually $5. Total cost to build under 12k. I hired the digging and concrete only. 30 miles north of Madison, Wisconsin. I wouldn’t change a thing.

Keep in mind it is a wood working shop so the big door rarely gets opened when it is cold.

 

[jlckmj]

Thanks for the responses. I understand that there are too many variables to make any substantive comparison. I was just hoping to get some ballpark ideas. I asked this question maybe a couple years ago and nobody wanted to answer.

I want to build a 50 x 100 x 16‘ interior height building. It will probably be pole construction, metal interior and exterior, with spray foam insulation. I talked to a few radiant heat dealers, and nobody had any answers as regards ROI. It made me a little skeptical as to whether the cost of a system made enough savings to justify over my current hanging gas forced air heater.

My system has been up and running for 6 years now. I have no idea what the costs are as I did the shop with the house when we did a complete gut of the house, therefore, we have no idea what part of the bill is house and what part is shop.

I would guess that my bills are $40 to $50 per month for the shop in the coldest months, I really do not care what the cost is though, it is the best heat system you can put in for a garage.

[/url][/IMG]
Jim

 

[NitroGarage]

My system has been up and running for 6 years now. I have no idea what the costs are as I did the shop with the house when we did a complete gut of the house, therefore, we have no idea what part of the bill is house and what part is shop.

I would guess that my bills are $40 to $50 per month for the shop in the coldest months, I really do not care what the cost is though, it is the best heat system you can put in for a garage.

[/url][/IMG]
Jim

Hi Jim,

What size tank is that WH? BTU output and floor sq ft?

Been thinking of doing the same thing.

Sent from my SM-N960U using The Garage Journal mobile app

 

[jlckmj]

Nitro,
I think it is a 40 gallon heater, no idea of btu's never looked.
Heated part of garage is 24 by 36

Jim

 

[Nivekdodge]

I built a small wood working shop 3 years ago. 14 x 26 2x6 walls with 1 1/2” closed cell spray foam and 3 1/2” of fiberglass, 1” of foam under and around a grade beam slab, 16” of blown in cellulose in the attic, in floor heat, natural gas water heater running the system, one walk in door and one garage door 7’x8’ . The building is kept at 60 degrees 24/7 from October to April. Cost $5 - $15 per month, never more, usually $5. Total cost to build under 12k. I hired the digging and concrete only. 30 miles north of Madison, Wisconsin. I wouldn’t change a thing.

Keep in mind it is a wood working shop so the big door rarely gets opened when it is cold.

How big is your water heater? I'm doing something similar and would like to be in your monthly range

 

[Firebrick43]

Using a standard gas water heater is not recommended without a thermostatic mixing valve. The low return temps put the heater into condensing temps creating acid condensate which corrodes out the bottom of the center tube. A mixing valve is 100-125$ and 15$ more pipe.

For higher efficiency you can use a condensing water heater such as a Polaris or a htp phoenix LD as I have. Yes they cost more but have a longer life and are 96% vs 78~% efficientcy

Here is pics of my system under construction currently.


View media item 88766

 

[rustyjames]

^^^^That's a nice plumbing job.

 

[stingry]

Using a standard gas water heater is not recommended without a thermostatic mixing valve. The low return temps put the heater into condensing temps creating acid condensate which corrodes out the bottom of the center tube.

Please explain. I keep hearing this argument against conventional water heaters used in radiant heat applications. It seems to me that returning loop temps are generally warmer than incoming water temps in a water heater used for domestic water heating. Not sure about city water, but my well water is about 50 degrees year round and I see no evidence of condensing in the two tank water heaters in my house.

 

[Firebrick43]

Please explain. I keep hearing this argument against conventional water heaters used in radiant heat applications. It seems to me that returning loop temps are generally warmer than incoming water temps in a water heater used for domestic water heating. Not sure about city water, but my well water is about 50 degrees year round and I see no evidence of condensing in the two tank water heaters in my house.

It does happen when you draw in cold water to a degree, but in an average house it happens for minutes a day not hours that a system heating a space puts stress on the equipment.

It obviously works. I am suprised that someone got 6 years out of one without a mixing valve. But there were people who had good service out of a Yugo
It's up to the individual to decide if short life span and the possible damage caused by equipment failure is worth it or not. Some might still choose to do so and that's alright. But at least they have been informed and hopefully understand when things fail.

 

[Burl]

I have a pic of my old system in the first few pages of this topic, and the thing about condensation, which causes rust, is quite true. My Lowes generic HWH lasted about 5 years, I used to pull out the burner about every 3 weeks and empty a considerable amount of rust from the top of the burner. I have since switched to a Hydrosmart system. Also, the BTUs put out by the HWH is important to keep the water temps up as the slab heats.

 

[KST1]

I intended to use a conventional HWH for my system, but the price of the glycol for the extra volume of water stopped me (I had a free to me 80 gal HWH). Instead I went with an electric on demand. No stored water meant less glycol.

My system is just like Bloomington Mike's (Menard's copy) and he has documented it so well, I don't have too! This will be my first full winter with it in use. 2 months last year and so far this year, no problems.

 

[Nivekdodge]

I have been running over the picture of Firebrick's plumbing in my mind. Considering your trying to get water to circulate in the lines..., how much better would the softer bends be?

 

[Firebrick43]

I have been running over the picture of Firebrick's plumbing in my mind. Considering your trying to get water to circulate in the lines..., how much better would the softer bends be?

That's another good reason to bend pipe.

I don't have the physics to say how much a bent tube has but as an example.

A 3/4" 90 degree copper elbow that you find in your local hardware store has the friction equivalent of 2.0 feet of straight pipe. A long radius 90 copper fitting (available from supplyhouse.com but more money) have the friction equivalent of half the sharp elbow or 1 feet. An even longer radius such as I made have even less, create less turbulence as well because of the lack of joints.

Also notice I like to use 45's were possible as the flow even better and use less tubing. I am always amazed how many pipe
Fitters only use 90's and never 45's like only their brain can work in one plane or direction at a time.

 

[Nivekdodge]

soft copper with a spring inside?

 

[Firebrick43]

soft copper with a spring inside?

I assume your asking if I used soft copper?

I used hard copper pipe in L thickness. Used rigid ratchet benders to bend.

 

[crankshaftdan II]

I assume your asking if I used soft copper?

I used hard copper pipe in L thickness. Used rigid ratchet benders to bend.

Was it bent at room temp or did you use heat?

 

[Firebrick43]

Was it bent at room temp or did you use heat?

Room temp. If you use har drawn L or K its no issue. If you use M it will kink.

Some times a bend is slightly off, especially in relation of one bend to another. I will anneal with a MAPP torch a small area (not always in the bend) to tweak it slightly by hand, normally a twist, but small or bad things happen.

 

[xyster101]

It does happen when you draw in cold water to a degree, but in an average house it happens for minutes a day not hours that a system heating a space puts stress on the equipment.

Everyone here talks about short life of a water heater due to cold temps, but my well water is also 50 degrees. If I take a shower and my wife takes a shower plus other people in the house that is 40 min of cold water entering the heater. Also we have a large tub with jets that takes 20 min to fill and empties the heater of hot water.
If a water heater is used as an in floor heat source the water leaving the floor is going to be well above 50 degrees and entering a tank full of hot water. So it would seem that it would be less condensation with an in floor set up.

Are there people here that have not gotten 10 years out of a water heater set up?

 

[seanc_mt]

^^^ My exact thoughts on the boiler vs hot water heater debate. My on demand at my house does 4 bathrooms and a huge jacuzzi tub. Incoming water is 42 degrees F. The return on an in floor heat set up will be atleast 100 degrees so it will have to heat less and work less...

For one boiler I can buy 4 or 5 on demand hot water heaters. If each one lasts 10 years thats a 40 year service life. And dont tell me a boiler will last 40 years without needing some replacement parts or even a whole unit replacement...

 

[Firebrick43]

^^^ My exact thoughts on the boiler vs hot water heater debate. My on demand at my house does 4 bathrooms and a huge jacuzzi tub. Incoming water is 42 degrees F. The return on an in floor heat set up will be atleast 100 degrees so it will have to heat less and work less...

For one boiler I can buy 4 or 5 on demand hot water heaters. If each one lasts 10 years thats a 40 year service life. And dont tell me a boiler will last 40 years without needing some replacement parts or even a whole unit replacement...

I am not sure why your trying to support your ideas against established science?? No one is stopping you from using a dhw appliance as a heating appliance.

Again, a duty cycle thing. Both of you list unusual hot water usage and it still only an hour a day compared to 12 plus hours a day for a heating application when cold. It matters not if return temps or incoming temp are 50 or 100. Physics dictates if the temp are below 120ish the heater is condensing. It's the total time operating below this temp that matters.

An on demand heater is not 4 or 5 times cheaper unless your comparing the cheapest on demand to the most expensive boilers. It more on the 2 to 2.5 time ratio for comparable tech. And more power to you. But your not considering most have to hire it done and the installation cost is typically close to the equipment coat and changes in piping as models change over the years.

And actually cast iron boilers are noted for their long lifespans, and are common to last 40-50 years with minimal cleanings. On demand heaters need cleaning yearly. Read post 860 to see a personal account of failure. As for 10 year life, average dhw last 8 years if I remember correctly.

 

[xyster101]

Again, a duty cycle thing. Both of you list unusual hot water usage and it still only an hour a day compared to 12 plus hours a day for a heating application when cold. It matters not if return temps or incoming temp are 50 or 100. Physics dictates if the temp are below 120ish the heater is condensing. It's the total time operating below this temp that matters.

I am not fighting this, just curiosity of it all because I am no expert at this. Basically it comes down to it will condense not matter what the usage, domestic HW or heating. The difference is domestic runs 1/10th the time so it last longer. So if you a DIY person, then switching out a water heater is no big deal, but if you are not then spending $500 plus a water heater is not worth it every 5-10 years in which case spend the money on a boiler.

 

[Jon_E]

Finally after a long, slow process that has taken almost two years, I finally got my heating system up and running in my garage. A lot of the delay was actually procrastination owing to the fact that I had very little experience with plumbing and I was afraid that I was going to mess it up big-time. I did make a few minor mistakes but not enough to be a problem, and learned an awful lot in the process.

The system is fed on the left side from my outdoor wood furnace, which supplies water that ranges from as low as 100° (if I am negligent in keeping it fed) to a high of 180°. Mostly its in the 160° to 180° range. This is too high to directly feed the embedded PEX in the floor, and it is an open system, so I ran it through a 20-plate, 3x8 HX. Mistake #1 was not uncapping the roll of PEX before putting everything together, and realizing that the lines had to cross in order to match C with C and H with H. That's why there is silicone heater hose in the feed lines. Also, the PEX, when heated, got almost 8" longer with the temperature rise. I would have broken something if the silicone hose wasn't there. Since the system will be back at ground temperature in the summertime, it will shrink again. The hose will likely remain permanent.

All of the manifold is soldered 1" Type L copper. I was a LOT nervous about soldering that much copper, due to nearly zero experience, but meticulous preparation means everything, as well as proper materials and tools, and the system is 100% leak free. The pump will eventually be wired through a line-voltage thermostat and then plugged into a regular wall receptacle nearby.

At the time I am writing this, the system has been in operation for about 20 hours, and the garage is warmed up to about 50°. Not huge but the slab temp was right about 34° yesterday morning and there is a huge thermal mass in the garage - 6" of reinforced concrete and about 8,000 board feet of lumber sitting directly on the floor slab. It will take a while to get everything up to temp. I am shooting for 65° because I still need to spray foam parts of the walls, and then I will stabilize it at 55° or thereabouts until spring.

I want to extend a big THANK YOU to a lot of you guys on this forum who posted photos of their systems, explained what they did and helped me to learn how these systems work so that I could build my own.

 

[JermB]

Hey guys, this is my first post. This is my heat setup.
3 loops of 250' 1/2" oxypex
22'x40' pole barn (back 8'x22' is separate room, not heated, 22'x32' is heated)
Heat kit came from radiantcompany.com I had them prepare it as a vertical setup. So far works great! I'm running premixed glycol, I did add a bit of water to it to thin it out. Still learning how to set the temps etc. I just added a nest thermostat to it so I can set temps and start the heat process from my cell phone if needed. (nest thermostat is not shown in pics)

 

[31vicky with a hemi]

great thread

 

[Burl]

People can state their opinions on the boiler/HWH debate, I have real world experience. I went through 2 HWHs in 11 years in my 30X32 garage with 900' of pex, both with the center steel draft tubes rotting out. I would pull the burner assembly out about every 2 weeks and clean the rust chips off of the top of the burner. I have since went to the HydroSmart system, no problems thus far. Just another argument for using appliances for their intended use.

 

[Latitude42]

People can state their opinions on the boiler/HWH debate, I have real world experience. I went through 2 HWHs in 11 years in my 30X32 garage with 900' of pex, both with the center steel draft tubes rotting out. I would pull the burner assembly out about every 2 weeks and clean the rust chips off of the top of the burner. I have since went to the HydroSmart system, no problems thus far. Just another argument for using appliances for their intended use.

Could you please post a pic of your system??
Thanks

 

[JeepTree]

Hey, my first post on the forum.

My setup uses an Electric Hydro Shark 19 KW boiler made by Stiebel Eltron and a Hydr Smart low temp pump panel both purchased from a local big box store. I have 6 - 300' pex loops with 2" foam insulation below the concrete and 2" around the perimeter.

This setup is installed in 30' x 56' pole building with a 12' ceiling and has been extremely efficient considering I am located in North Dakota and we haven't had many days above zero the last couple months, actually reached 30 deg F below zero for a couple days last week.

I currently don't have a secondary heat source in the building so I signed up for the off-peak reduced rate program with my utility company. Because of the reduced rate the boiler can only run from 10 pm to 6 am. I have the thermostat set to 48 and on the coldest day it dropped to 44 deg F without getting any power during the day, not to bad considering 30 below zero. For the most part the temperature maintains right around 48 deg F during the day.

I am amazed how well the heat radiates from the slab throughout the day and how warm 48 deg F feels when working in the shop!

I volunteer on my local Fire Department so I borrowed our thermal imaging camera and attached a couple pics of the pex in the concrete the day I started the boiler. Neat to see the temp of the supply lines vs. the return lines. Also scanned all of my insulation and doors for drafts while I had the camera and marked the areas that needed some attention.

I appreciate all of the threads and posts on this forum, I have learned so much about all aspects and stages of my build and my building is much better because everyone's willingness to share their experiences and wisdom.

 

[Vicious_Cycle]

Great first post, and welcome! I don't come around very often, but I'm subscribed to this thread because I'm throwing together a system for my shop addition and I like to see how others do it. Yours looks like a nice, compact system. Can't say I've seen too many expansion tanks mounted sideways like that, though!

 

[Nivekdodge]

this was an awesome read. i am working on a DIY hydronic floor heat in my 24x30 garage with 18x30 upstairs room/bathroom. slab has 3 250' runs of 1/2 ex and i have aluminum fin under the subfloor between the floor joists for the upstairs, as well as in the bottom 4' of the walls. to add to the fun i have solar evacuated (156 total) tubes heating a 600 gallon tank that preheats the water before it gets to my heat source. it is a work in progress over the winter and will post up pics once more progress has been made.



I'd really like to see pics of how the tubes tie in to the system. How do you keep them cool in the summer?

 

[Nivekdodge]

this was an awesome read. i am working on a DIY hydronic floor heat in my 24x30 garage with 18x30 upstairs room/bathroom. slab has 3 250' runs of 1/2 ex and i have aluminum fin under the subfloor between the floor joists for the upstairs, as well as in the bottom 4' of the walls. to add to the fun i have solar evacuated (156 total) tubes heating a 600 gallon tank that preheats the water before it gets to my heat source. it is a work in progress over the winter and will post up pics once more progress has been made.



I'd really like to see pics of how the tubes tie in to the system. How do you keep them cool in the summer?

Above was a 2016 post from MNMKIV but he's never posted again