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[coolidge]

 24 x 46 first floor, three runs of .75 Onix in each bay under subfloor and wood flooring. Joist are logs so have to go around with the onix.  Joist width vary from 18" to 23".  Insulation for radiant is 2" r14 foil faced foam board, edges from foam board to joist is sprayed with closed cell foam to seal up.

 Now I have to run 160 degree water through the radiant to maintain 68 degrees overnight on the colder night.
There are no transfer plates, but am planning on stopping by a metal fab shop in the morning to see what it would cost to make some.$$$$$$$$

ANY ideas.

Forgot to add, runs are 200 ft or less

[yoderheating]

 It sounds like you simply need to add some more pipe. I normally use the one foot of pipe for every square foot of space rule.

[coolidge]

I do have another 600 ft of pipe, but to cut all that insulation out is what I am not looking forward to. I am going to check into having some plates made also, if I am going to dig into it then that tubing is getting everything they make for it.

[yoderheating]

 Are you sure several of your loops are not air locked? Do you have valves on each one where you can force all water flow through one at a time to make sure there is no air pockets?

[coolidge]

Yonder,

    yes I have valves, no its not airlocked, tried that twice. Ordering some plates in just a few, chanves of me getting all this done before next year is slim and none, work is CRAZY

[Woodboiler]

I have the same deal.  Under sub-floor radiant floor heat.  I was told that I need to create an airspace between the insulation and the pex tubing, otherwise the heat cannot escape or transfer to the surrounding structure.  I haven't done this yet as I will need to remove my insulation and not looking forward to that work.

[coolidge]

I have the airspace just not enough heat transfer through the wood.

[skid]

did you do a heat loss calculation? if so whats the heat loss? You only get so many btu's out of each foot of pipe. Sounds to me like you didnt install enough pipe maybe.

[coolidge]

No I didn't do a heat loss, it was around this time of year when I HAD to get some pipe in the floor, like I said I do have another 600 ft I can install and will when I get my transfer plates.

[slimjim]

COOLIDGE check out Ultra-Fin

[macmgfd]

Slimjim, What is your thoughts on Ultra Fin because i have been researching them some and have found very little positive posts about them from installers. Mostly about their efficiency claims and capabilities.

[coolidge]

Thanks for the info Slim, I have talked with a guy who had some of those installed in his garage ceiling to heat the apartment upstairs, he suggested I don't use them, he is not happy.

[willieG]

most radiant  floors are designed to deliver about 25 btu per square foot...that would be a ver well insualted house on todays market. ifyou have an older house without really good insulation and new windows floor heat may not do well for you..a bedroom of say 12x12 (144 square feet  x 25 btu 3600 btu per hour) an older house with minimal insulation may require 35 to 50 btu per square foot (?)

[willieG]

you might actually do better adding yoru extra pipe in the form of a baseboard heater or wall heater than more radiant floor. a baseboard could give you roughly 500 btu per hour per  foot of basebaord. your existing radiant would give you warm floors and the other heat appliance would give the room the needed btu it needed?

just a thought

[coolidge]

Not this old shack, built in 1889. I have it tight enough I had to put in a HRV. R 50 closed cell foam in the roof, R 28 in three exterior walls and r 35 in all north walls, basement rock walls all R 21. Wife ordered some insulated curtains for the 13 ft wide patio door. What I difference just that made.