Hydronic in outside walkway.

Phantom · 04-30-19, 02:02 PM

I have been working on building a front porch using allen block and dense pack gravel to be capped with pavers. The porch in about 25ft wide by 11ft and will have a walkway on one side that leads to the driveway, the walkway will be about 35-40ft long.

My thought is to set pex (1/2in) on the base and cover with polymetric sand for the sidewalk. The purpose will be to help buffer the brick temp in the winter allowing for snow to melt as the first 10ft is shaded all day in the winter. In the summer I will use it to preheat the water heater.

I will be using a propylene glycol mix to prevent freezing since the line will be about 4in below the top of the brick. I will figure out the heat exchanger and pump for it later.

What are your thoughts on this idea? Located in Northern KY.

What should I use to protect and seal the pex entering the house via basement cement wall?
Do you see issues if I install a short loop where the walkway will be and just cut the pex and splice in a longer run when I build it? Alternitively I would run a single loop of 100ft.

I plan on adding hydronic under the floor in the house in the future and possibly adding solar HW.

u3b3rg33k · 05-01-19, 05:25 PM

I'd be using HPDE instead of PEX for outdoor applications. seems to work for the geo guys.

SDMCF · 05-24-19, 04:31 AM

I had a similar idea for keeping our front steps free from ice. This is a much smaller area than you are planning but even so I could not make it work. My idea was to pump water heated by our solar panels through pipes underneath the (wooden) steps. I had hoped that I could use relatively cool water available when the panels were not producing enough to contribute to hot water or space heating. In reality even if I use hot water at peak panel output it doesn't keep the steps clear of ice. It does help a little but not enough to be worth bothering with and I have given up on the idea. I haven't even tried it for the last few winters.

Of course you may be better at this than I am but I would not be optimistic that you can heat a large walkway using this approach unless you put an awful lot of energy into the system.

04-30-19, 02:02 PM	#1
Phantom Apprentice EcoRenovator Join Date: Sep 2010 Location: Louisville, KY Posts: 101 Thanks: 13 Thanked 8 Times in 7 Posts	Hydronic in outside walkway. I have been working on building a front porch using allen block and dense pack gravel to be capped with pavers. The porch in about 25ft wide by 11ft and will have a walkway on one side that leads to the driveway, the walkway will be about 35-40ft long. My thought is to set pex (1/2in) on the base and cover with polymetric sand for the sidewalk. The purpose will be to help buffer the brick temp in the winter allowing for snow to melt as the first 10ft is shaded all day in the winter. In the summer I will use it to preheat the water heater. I will be using a propylene glycol mix to prevent freezing since the line will be about 4in below the top of the brick. I will figure out the heat exchanger and pump for it later. What are your thoughts on this idea? Located in Northern KY. What should I use to protect and seal the pex entering the house via basement cement wall? Do you see issues if I install a short loop where the walkway will be and just cut the pex and splice in a longer run when I build it? Alternitively I would run a single loop of 100ft. I plan on adding hydronic under the floor in the house in the future and possibly adding solar HW. __________________ To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

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05-01-19, 05:25 PM	#2
u3b3rg33k Apprentice EcoRenovator Join Date: Mar 2018 Location: Rustbelt, USA Posts: 114 Thanks: 5 Thanked 10 Times in 9 Posts	I'd be using HPDE instead of PEX for outdoor applications. seems to work for the geo guys.

05-24-19, 04:31 AM	#3
SDMCF Apprentice EcoRenovator Join Date: Jul 2014 Location: Finland Posts: 125 Thanks: 5 Thanked 35 Times in 34 Posts	I had a similar idea for keeping our front steps free from ice. This is a much smaller area than you are planning but even so I could not make it work. My idea was to pump water heated by our solar panels through pipes underneath the (wooden) steps. I had hoped that I could use relatively cool water available when the panels were not producing enough to contribute to hot water or space heating. In reality even if I use hot water at peak panel output it doesn't keep the steps clear of ice. It does help a little but not enough to be worth bothering with and I have given up on the idea. I haven't even tried it for the last few winters. Of course you may be better at this than I am but I would not be optimistic that you can heat a large walkway using this approach unless you put an awful lot of energy into the system.