Hydronic radiant design questions
I posted a pretty naive question last week regarding selecting the proper heat source. I’m not an HVAC expert by any stretch but as an owner of multiple degrees and a home improvement nut, I don’t want to back away from this just because it is quite a bit more intricate than I realized.
I’m in the process of educating myself on hydronic systems. I’ve purchased one text book and downloaded a design manual from Uponor (light reading). I know phase one is just to get an understanding of how the various components come together to form the system. That said, I couldn’t help myself and I’ve also downloaded a number of software packages (all free via trial) to begin the design process. I realize this is putting the cart before the horse to some extent.
With that said, I have some general questions as I begin educating myself.
1) Is this the best forum to ask questions? I’ve received excellent advice thus far but I suspect there are websites dedicated to hydronic design. I post here because I subscribe to GBA and FHB.
2) Cost not being the primary concern (we’re a modest home surrounded by million dollar mansions), in a between joist retrofit is it correct to assume that heavy extruded aluminum plates will deliver the best results and lowest operating temperatures? I’ve seen a number of options including thinner (and cheaper) aluminum sheeting, new graphite plates, and fins (where the pex doesn’t touch the subfloor). No need for a lengthy explanation. It seems to make sense that a thick aluminum plate with solid contact to the tubing would transfer the most heat from the pex. Would just like validation.
3) I have tubing layout software (free for 30 days) that I plan to use to design the pex layout. When designing between joists, I’m curious if I can/should design the circuits by zone rather by room? In other words, do I need to concern myself with the walls above me? It seems like designing a single circuit for two small rooms would offer a more efficient layout than two separate circuits. If it is bad practice to heat directly beneath walls, couldn’t I just pull the tubing 2-3″ off the subfloor when I cross a wall?
4) Are there other best practices I should consider when designing the circuit layout (manifold location, entry location for rooms, perimeter banding, keeping water temp of circuits at/below certain temps, keeping all circuits at the same temp, ideal PEX type for between joist)? FYI, I have a steel I-joist running across the center of our basement. My thought is to run the manifold connections in a soffit I’ll build adjacent to this I-Joist. Hence all circuit access/egress will come along the center of the building’s floor plan.
5) Something tells me this is a bad idea but I have to ask as some DIY Radiant companies mention this (albeit for open systems which I don’t want). Going radiant means I will not have an air conditioning system for the summer months (we’re in Chicago so there is ~month every year when we really could use some cooling & conditioning). We’re also on a well (crazy since we’re only 10 miles from downtown) which means I do have access to (limitless?) ~50 degree water. I already have several dehumidifiers that we run in the summer to tackle humidity. So, the question is whether I could safely/efficiently run that well water through the circuits without burning out our well pump or creating a mold farm from condensation? If this is a terrible idea I don’t need a lengthy explanation. Just tell me its crazy and I’ll drop it. I already suspect I need to install a small minisplit system for summer cooling/conditioning.
6) Lastly, (maybe this should have been firstly) would any expert on this forum be willing to review my draft circuit layout, mechanicals selection (likely centered around the HTP Hydro), material list, and occasional installation advice? I would of course compensate for this activity. I’m not ready for this yet but I also know it would be asinine to spend $20K on a system without knowing it will work efficiently and effectively.
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