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New Home In-Floor Heat

Started by mitchstockdale, December 31, 2017, 11:53:00 PM

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John Mc

Quote from: Randy88 on March 16, 2018, 03:01:34 PM
Here the norm is pretty much central air for the whole house and to cool it to at least the mid 70's or lower, we try to keep the house in the low 70's year round.      Forced air is the only way to achieve it, guess there is a huge difference in area's and their needs.      

 
There sure is. We keep our house about 70+ in the winter (not by my choice, my wife likes it warm. I'd keep it mid 60s if it were up to me), and it stays below 75 most of the summer by itself, if we do things like manage the curtains and awnings on hotter days.
If the only tool you have is a hammer, you tend to see every problem as a nail.   - Abraham Maslow

Holmes

Randy88 I remember your problems from back a few years ago. What I did not know back then was when you go below zero all standard heat loss calculations become totally inaccurate to the tune of 2 to 4 times more heat loss than what the original calculator came up with.
Think like a farmer.

John Mc

Quote from: Holmes on March 16, 2018, 04:46:22 PM
Randy88 I remember your problems from back a few years ago. What I did not know back then was when you go below zero all standard heat loss calculations become totally inaccurate to the tune of 2 to 4 times more heat loss than what the original calculator came up with.
Sounds like a pretty flawed calculator. Heat loss should be a linear relationship between the inside temp and outside temp, though wind chill will have an effect as well.
If the only tool you have is a hammer, you tend to see every problem as a nail.   - Abraham Maslow

Randy88

Yes to an extent, heat loss is linear, and yes wind chills are a variable not really anyone can give an answer for in terms of heating needs, wind chills affect buildings differently depending on how they are built, where they are located, how protected they are and the list is endless.          

All the heating experts told me and everyone else in my area, a certain sized furnace was needed to heat the space to conformable temps, running say for example 50 percent capacity, well when you double the heating needs and run it constantly, it'll keep up, when you triple the heating needs, there's no way it can keep up and its a slow and steady decline in temps inside the structure.      

The only choice I had then was to increase the size and capacity of the outdoor boiler, add on a waste oil burner in the shop to help with recovery when I opened the door to bring in equipment and when we needed fast warmup in the shop, we fired up a salamander heater as well.      

The other issue I had was, the more stuff we put in the shop, the more floor space was covered with low belly clearance machines and that cuts heating capacity of the building, which also lowered inside temps to the point of being critical and near freezing in the building as a whole.    We're planning on installing forced air radiators off the wood boiler as well, to help solve this issue, just haven't had time yet to do so.


John Mc

Quote from: Randy88 on March 16, 2018, 10:22:52 PMThe other issue I had was, the more stuff we put in the shop, the more floor space was covered with low belly clearance machines and that cuts heating capacity of the building
I had not thought of that one. I've often wished I had in-floor heat in my workshop. It's currently unheated. I just use an electric space heater when it's not frigid out, and a portable propane heater when the mercury really plummets. Eventually I'll put in a permanently installed heater - either a propane heater, or perhaps a split off of a cold climate heat pump, if my wife ever decides to put one of those in for her workshop upstairs.
If the only tool you have is a hammer, you tend to see every problem as a nail.   - Abraham Maslow

Randy88

John, not sure what you have for a shop or what you do in it.     But the more floor space you cover with machines that sit on the floor, like cabinet saws, or stack wood on the floor or even have work benches that sit on the floor, all take away from the square footage of heating space for the room or building.     In floor heat is great, especially if your sitting or laying on the floor to work on things, keeps your feet warm and gives a much more even heat from the floor to the ceiling, with forced air heat, its far warmer at the ceiling that on the floor, whereas with floor heat, there's only about five degree's difference from the floor to the ceiling.

The downside is that you really need to heat the space all winter long, from cold to warm in the dead of winter, it'll take days or even longer to get the building warm, in frigid temps if the floor is cold, it could take a week to warm it up and get the building warm.    There are a lot of variables in this equation, how thick the floor is, what the outside temps are, how much heating space there is left in the building that doesn't have the floor covered with something and the list keeps going to factor everything in.    

My shop is for heavy equipment and tooling, lathes, mills, welders and the like, our wood shop is in the house basement.     What issues I have is when I bring too many low to the ground things in at once, like trailers, vehicles and things like that where the heat can't get out from under, skid steer loaders with buckets sitting on the floor are another issue, all those cover the floor and limit the overall heat output to the building itself and if there are too many of these things in at once, my floor heat will never shut off and the building will be below freezing in the morning, but the underside of those things will be over a 100 degrees to the touch or whatever temp you have the floor heat set at, in my case its 120.    

The same is true with warming up a house, most kick the heat when it gets chilly inside, about 50 or so in the fall, only needing to warm it up about 20 degrees with the outside temps about the same, or the difference between inside and outside of only 20 degrees, then form then on, its just got to maintain the temp, when you have to do that in the dead of winter, you might have 70 degree's difference from outside to inside.     When its frigid out, and something has happened to knock out the heating system and the outside temps are 50-80 below and inside its cooled to zero and your trying then to heat up the house with a partial system working is when things take a lot longer and gets a lot tougher.    You then need to warm up the system with 150 degree temp difference and no heating system is designed to do that, most are not even capable of that at all.

What got many in my area is when backup systems could not work, electric lines sheared off with frost heave, along with gas lines, leaving the house without any options to keep it warm, by the time something was done to get any option working, the house was too cold to get warmed up with a system designed to supplement heat, not a stand alone heating system, so in the mean time, things froze up many forgot about, washing machines froze and were not discovered till later, toilets froze and cracked, in floor heat lines froze and many burst or were cracked, water pumps froze with water in them due to no electricity to pump the water out and the list was endless, so once back warmed up, the main heating systems still didn't work properly and couldn't maintain the house temps or causing more issues once warmed up again, water lines leaking, walls, wood floors, carpets, insulation soaked and the list went on and on.

We initially wanted to heat my shop with in floor heat exclusively, after some years of issues and learning, we now use it to do a portion of the heating, in mild weather it does it all, in frigid weather maybe 50 percent, with too many of the wrong machines inside, it'll do maybe 20 percent of the heating and that changes daily depending on variables.   

mitchstockdale

Finally started on the install yesterday.  This is a 300' loop used "j-straps" plastic clip with a ring nail to attach the tubing to the underside of the sub-floor.... surprisingly not as difficult as i thought it would be. Will try and keep posting pics as I progress through installing all the pipe and insulation.


E Yoder

HeatMaster dealer in VA.
G7000

Hilltop366

Quote from: John Mc on March 16, 2018, 05:42:29 PM
Quote from: Holmes on March 16, 2018, 04:46:22 PM
Randy88 I remember your problems from back a few years ago. What I did not know back then was when you go below zero all standard heat loss calculations become totally inaccurate to the tune of 2 to 4 times more heat loss than what the original calculator came up with.
Sounds like a pretty flawed calculator. Heat loss should be a linear relationship between the inside temp and outside temp, though wind chill will have an effect as well.
Read a article a few years ago about how fibreglass insulation losses its insulating effectiveness as temperatures drop, apparently due to it's lack of density it will allow air to move inside the wall cavity (even if completely sealed)

As the temperature difference increases when outside air cools the outside of the wall then the cold side of the wall cavity will have air next to it that wants to drop and the warm side of the wall cavity has air in it that wants to rise causing air movement in the wall cavity that is now colder than the inside of your house causing the same effect inside your house = heat less.

So the colder the outside temperature the more of this effect takes place = a non-linear relationship.

Apparently foam board, cellulose and other more dense insulation significantly reduces this effect.

Rebarb

We recently built a home, a daunting task for old folks like us.
We live in the mountains with lot's of access to firewood so i already knew a wood furnace would be a viable option plus we've burned wood our entire lives including childhood. 

Well my wife kept pushing hydronic / radiant heating, glad i listened. 

It's been the best and most efficient heat we've ever had.
We have it in the finished basement and garage and it effectively heats the entire house.
The downstairs is set at 73 and upstairs stays 69......4800 sq ft.
This is VA with typical 30's in winter. 

mitchstockdale

All six loops are installed and insulated.  Ended up using 4 loops of 300' and 2 loops of 250' worked out perfect.

Used 1" Silverboard insulation with a reflective facer on each side and cut to fit tight between the floor joist diagonal webs and pushed it up tight against the top chord of the joist to give me 1-1/2" airspace. Secured the insulation with a shot of spray foam in the crotches of the webs seems to have worked well.






E Yoder

HeatMaster dealer in VA.
G7000

Hilltop366

Well done, looks like a lot of work!

mitchstockdale

Ya it turned out really well and went much smoother than anticipated.  I did however leave a couple joist bays un insulated since this was in a location where there was a wall upstairs and had several wires and pipes coming through the floor.  It was easy enough to run the pex but not the insulation. 

I hope it makes the system perform better than not having it, and reduces the operating temperature.

Thank you all for your comments and input. Will keep posting pictures as the system progresses.

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