Basement Infloor heat question.

[leeelmer]

Hi Guys,
Back story, this spring we are planning on digging a basement, and putting our log cabin on it, also with a addition on the side(basement under addition as well) My grandfather, and father built the cabin about 20 years ago, on our property, and I will move it into place and have it set on the basement by a crane. Then start the building of the log and stone addition(this I can do and helped build log buildings with my father and grandfather in the past)
Now we are not building a huge place, the cabin is 24'x20'
Addition is 14'x22'
So our total square footage of basement is only going to be around 750 square feet.
I plan on running infloor heat before the basement floor is poured.
My question is what type of boiler,on demand, or hot water tank should a guy be looking at?
The local plumbing shops around here, all want a $10,000.00 boiler(that by my research is designed to be used for much much larger heating uses than mine)
I have seen systems, with both on demand, and standard hot water tanks, and am seeing what you guys have used, and the pros and cons?
Any help is greatly appreciated.

[DiabeticKripple]

Cabertosser will know what you need.

For that size of basement I would think a separate hot water tank would do fine

[FCLightning]

Here is some reading for you
https://www.radiantec.com/wp-content...ion_Manual.pdf

[liar]

my last garage was 960 ft2 and i used a hot water tank and it worked great . other than you cannot use a hot water tank just for hot water heating . if the tanks primary function is to heat potable water i am told you can set up a pump and small heat exchanger to heat the floor . check with your local municipality , the rules are not always the same everywhere .

[LKILR]

My basement is 750 sq ft and I heat it with a 40 gal hot water tank. Three runs of pipe and one pump. The basement is spray foamed insulation.

[^v^Tinda wolf^v^]

I have a Bradford White water heater running my home and it works great!
The heater has some great features on it that help reduce sediment build up with the hydro jet feature. I’m not sure how many gallons she is but it stands about five feet or better.
I recall paying about $1800 to have the in floor completed when we bought the house. My basement is 1000+ square and my garage is 24x24. The water heater has no problem keeping up with all three of its duties.

The price you were quoted seems a little out to lunch if you ask me.

[canuck]

I wouldn't **** around with hot water tanks.
If you are dead set on HW heat, get a decent modulating boiler and an indirect tank for your domestic
Simple system - 3 pumps (4 if you are going to infloor the main floor) controlled by a basic pump controller
Yes, its more expensive

[NCC]

I built a 1200ft2 shop about 20 years ago with under floor heat. It consists of a used nat gas hot water tank that was given to me, a Grundfos pump, and a thermostat that tells the pump when to run. My brother owns the place now and it has given zero problems in 20 years. There is a separate hot water tank for water.

Since then, in one house I had a hot water tank with a glycol loop that lasted less than 8 years and cost $2500 to replace.

I built a new shop in 2013 and spent $10 000 on an on demand heater that has crapped out a couple of times and cost more to fix each time than a regular hot water tank would cost to replace.

I built a new house with an on demand heater that has crapped out once already (7 years old).

It may not be up to code, but the $200 system I installed myself has out performed all three of the $10 000 systems I had installed. Maybe I’ve just been very lucky with the hot water tank and very unlucky with the other 3.

[leeelmer]

My biggest question is why not a hot water heater?
No one can explain except to say it won't last?
Well I could replace it every 5 years for the next 50 years for the cost of a boiler system(and the boiler system would need a expensive water softener to work as I am on well water)
Or it wont heat effectively? The water temp that the floor heats at is much less than what a water heater puts out.

[CaberTosser]

You can't use a water heater that is also supplying the domestic hot water to supply the floor heat, unless you separate the systems through use of a heat exchanger. The reason being they don't want the stale water in the floor system (say when its been left off all summer and has had time to get funky) getting into the domestic water that will be consumed. After the heat exchanger, the temperature can be mixed down through the use of a thermostatic mixing valve to be suitable for running through the floor. There are many ways to accomplish it, I personally just use boilers that can modulate down to such low output temps (its where they function the most efficiently). Seems to be lots of stories of equipment going kaput, which I do see with certain models prone to failure or just bad installations. You don't hear complaints from those who have had good experience and quality equipment though. My own system at home for instance has been running problem-free for a decade now, probably something to do with following the installation instructions.....

Be sure when setting your grade that you leave enough space for a couple of inches of foam insulation under the slab, you don't want to be paying the fuel bill for reverse geothermal!

[leeelmer]

Hi Caber
Yes I know it needs to be a closed loop system with a heat exchanger. So the domestic water does not run threw the infloor system.
But I would be way cheaper even to run, one tank for infloor and another for domestic water, than the cost of the boilers, as well as a lot less electronics.
I have the insulation stuff figured out for under the slab, and the concrete contractor that is building the basement, knows that infloor heat is going to be run before the pore,after the cabin is set on the walls.

[CaberTosser]

Originally Posted by leeelmer

Hi Caber
Yes I know it needs to be a closed loop system with a heat exchanger. So the domestic water does not run threw the infloor system.
But I would be way cheaper even to run, one tank for infloor and another for domestic water, than the cost of the boilers, as well as a lot less electronics.
I have the insulation stuff figured out for under the slab, and the concrete contractor that is building the basement, knows that infloor heat is going to be run before the pore,after the cabin is set on the walls.

The equipment cost is a factor for certain, the boilers I use don’t require any external electronics so it simplifies the wiring. If a person is to be running glycol for freeze protection though, then the physical volume of a water heater adds a significant cost there. I only use glycol if there is a reason, such as a garage slab with overhead doors (we’ve all seen doors inadvertently left open) or if there is a hydronic fan-coil that has an outside fresh-air duct piped into its return-air.

For my own basement I ran 2” styrofoam against the outside wall as a thermal break between the slab and the foundation wall prior to pouring.

[Twin Valleys]

Originally Posted by leeelmer

My biggest question is why not a hot water heater?
No one can explain except to say it won't last?
Well I could replace it every 5 years for the next 50 years for the cost of a boiler system(and the boiler system would need a expensive water softener to work as I am on well water)
Or it wont heat effectively? The water temp that the floor heats at is much less than what a water heater puts out.

that also has been my experience, probably jinx myself by saying this, but our designated hot water tank for in-line basement and garage heat is on it's 25th year, mind you we have soft well water and have only replaced the household tank once in that time