Hydronic Radiant Heat Q's. System layout and insulation

[HellaFab]

I am looking to do my second install of hydronic radiant heat and I have a few questions relating to some different thoughts for this configuration.

The garage I am heating this time is (interior wall sized) 13.5'x23.5' and I believe I can do the entire slab with one loop.

1. Am I able to put the heater, expansion and pump in the ceiling space to keep my (limited) floor and wall space free'd up?

2. If my building is 2x4 wall construction with R14 Roxul in the walls, would I be over-insulating the floor with R10 polystyrene (2") to the point that the walls would be my weakest link? I am trying to determine if there would be any ROI of 2" poly insulation vs 1" or 1.5".

Thanks!

Matt

 

[BadgerBoilerMN]

2" XPS is the practical standard as you can staple tube to it and it will stand up to foot traffic. Otherwise you seem to have it right.

Some codes restrict appliances above the ceiling, but it should be accessible. We are talking about a couple square feet. I would find a wall for it.

 

[theoldwizard1]

Ontario ?

Seriously consider 4" below the floor and don't forget to insulate the foundation wall all the way down to the frost line. You need the best "thermal break" you can afford between the concrete floor and the ground, especially when that ground is directly connect to the outside where temps will be well below freezing.

You pay for insulation once, you pay for energy to heat yout building the rest of the time you own it !

 

[Highbeam]

Ontario ?

Seriously consider 4" below the floor and don't forget to insulate the foundation wall all the way down to the frost line. You need the best "thermal break" you can afford between the concrete floor and the ground, especially when that ground is directly connect to the outside where temps will be well below freezing.

You pay for insulation once, you pay for energy to heat yout building the rest of the time you own it !

The return on overinsulating the slab is too long to be practical. 2" is the standard for a reason and less is even more common than more. Money would be better spent on the walls and ceiling should you desire additional insulation.

 

[BadgerBoilerMN]

My software confirms. Remembering that heating systems are properly sized using the differential temperature between outdoor and indoor air with heat loads from the floor typically in the single digits.

A heated slab edge is the only area of real concern.



http://nsidc.org/fgdc/maps/gtmap_can_us_browse.html

For further study see: http://ktisis.cut.ac.cy/bitstream/10488/870/1/C55-PRT020-SET3.pdf

 

[HellaFab]

My software confirms. Remembering that heating systems are properly sized using the differential temperature between outdoor and indoor air with heat loads from the floor typically in the single digits.

A heated slab edge is the only area of real concern.



http://nsidc.org/fgdc/maps/gtmap_can_us_browse.html

For further study see: http://ktisis.cut.ac.cy/bitstream/10488/870/1/C55-PRT020-SET3.pdf

In the case of floor heat and the slab edge, what is the fringe area that would be effective? my garage is pretty small (14x24) granted its relatively cheap compared to doing the entire slab of a 40x60 or something i would still like to reduce costs if there is a negligible difference.


Going to read those links now.

 

[BadgerBoilerMN]

You should insulate. The smaller the building the greater the heat loss, as a percent, is the perimeter loss.

Do as High says.