The tube, with an air gap, and then a good insulation will transfer more heat to the floor, than the uninsulated plate.  The insulated plate will transfer more heat to the floor than the tube with an air gap and then insualtion.

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A thermostatic mixing valve (TMV) is a device that automatically controls the temperature and flow of water in your shower and sink. A TMV works by maintaining a set temperature, so you can enjoy comfortable showers without worrying about scalding or freezing. This means there’s no need to turn it off when someone else wants to use the hot water because the TMV will keep it at a comfortable level for all users. With a TMV, you also don’t have to worry about adjusting the tap every time you want more hot water because it will do this automatically.

This 2 1/2 inch stainless steel double check valve backflow preventer assembly is designed to prevent the reverse flow of objectionable but not toxic water.

when you insulate, don't bother with reflective foil.  I like friction fit rigid foam, with good air sealing at the ends of the joists and, if it's cold below, around the cracks.

Thermostatic mixing valves are an important part of any hot water system. These valves allow for the mixing of cold water with hot water, which results in a comfortable temperature. This is helpful because it reduces the amount of time that you need to spend adjusting the temperature on your shower or sink. Other benefits of these valves include:

For the ground floor, the heat coming through the floor warms it perfectly adequate.  The floor, walls, and ceiling of the ground floor seem to be generally identical temperature, and the floor is a little warmer in the vicinity of the fin tube underneath it.

And you are right to say that, as a living space, the basement slab may be too cool, although I am not sure if it is.  I am down there all the time in my bare feet, and sense no issue about the slab temperature.  I can definitely feel the radiant heat from above, and sense that it also heats all the objects in the space.

insulation doesn't help the heat move upward... it prevents it from moving downward.  it's a perhaps subtle distinction but it's important.

this is because the plate contacts a LOT more of the pipe than naked staple up does, and conducts that heat to a much wider area of floor.  but, this depends on your plate having good contact to the pipe as well, which is why lightweight plates are not nearly as good as the heavy gauge firm grip plates are.

As I mentioned, I have really high insulation values with minimum R-40 in all walls, including the basement walls.  With that much insulation, the heat loss is slowed down to the point where the heat has time to diffuse through the house and distribute evenly.  So it reduces the need to focus and concentrate the heat distribution to exactly where it is most needed inside the building envelope.

I know what you meant, as well as many others do. But I've observed these terms being misused over and over again in these sorts of discussion topics. I think it best to keep terminology accurate so as to not perpetuate misuse and misunderstanding.

Any recommendations on sources, wbsites, and/or minimum aluminum thickness? If I'm going to do this, I want to get it right.

Thermostatic mixing valvehow it works

360 TEKMAR Mixing Valve Floating Control with Reset · Tekmar ...

Water pressure reducing valves are typically installed on the building supply main in homes and businesses. They automatically reduce the pressure to a more ...

Thermostatic Mixing Valve15mm

Thermostatic mixing valves function by using the water pressure from the hot water supply line to open a pathway inside the mixing valve which allows cold water flow to enter the mixing chamber. The cold water is then heated up by passing through coils that are immersed in hot water. When it reaches the desired temperature, an actuator closes off the valve so that there is no more cold water entering into the mixing chamber. The valves are designed with an anti-scald device that prevents sudden temperature changes and avoids burns caused by hot tap water coming out of a faucet when the hot water is turned on.

Thermostatic Mixing ValveBath

But there is heat loss through the slab, and its mass makes it slow to gain heat and slow to lose it.  I shut the temperature down at night, so the slab ceases to gain heat.  If I maintained full heat all day and night, it would be easier to see where the balance is between the loss through the slab and the gain from the hot ceiling.

Thanks--my mistake is in thinking that the reason for plates was to reflect radiant heat, but their real function is to unload the heat from the pipes and help tranfter that heat--right? So you want the plates to be in tight contact with the pipe, if that's the case.

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it depends, but typically I'd say either your load is so low you don't need plates, or it's not and you should use the heavy gauge "C" fins out there.  We deal in Thermofin, but there are other brands as well.  the lightweight plates out there are suitable for some applications but typically I would use them only in otherwise lower-R assembly situations like radiant ceilings or over the subfloor sandwiches... in a joist you just need more oomph to make a big difference.

Thermostatic Mixing Valve22mm

it's dramatically oversold for radiant applications and in an upward facing application it gets dirty and loses efficacy over time.

Water Regulation Compliant pressure reducing valves (PRV) for pressure relief and management. Valves available with gauges for accurate adjustments.

Thanks a lot for the thoughtful responses. Great information, served in bite-sized pieces. I'm convinced now to spend the extra money and install the transfer plates. This project happens to be my own house, and as always, we're constrained by limits on our available cash, but we are also trying to think about long-term benefits and efficiency in everything we do.

previous posters are not quite correct.  INSULATION provides the direction for heat.  Plates provide increased output to the wood, but if you are not insulated below you'll increase downward output even with plates as well.

Thermostatic mixing valves are an important part of all hot water systems because they can easily and consistently achieve the desired water temperature. To prevent scalding, inspect your current hot water system to see if thermostatic mixing valves are needed. Newer homes were likely built with TMV’s as part of the building code.

plateless pipe is just a very weak output method.  practically speaking you shouldn't plan on much more than 15 BTU/sq ft unless you are using very high water temps and I would never consider plateless installs without a serious room by room analysis to ensure it will keep up unless you are just adding some "floor conditioning" to an already full capacity emitter like an existing baseboard or radiator.

Thermostatic mixing valveoutside tap

But w/o the water flowing through the slab, it is cool, uncomfortably cool.  That's certainly not as pleasing a feeling as walking w/o shoes on a radiant slab .

Unless terminology has changed since I took that course in Heat Transfer way back in engineering school, heat transfer does not occur solely via conductivity from the hot water to the floor surface. Rather, it is a combination of convection and conduction. (heat is convected from the hot water to the side of the pex, then conduction through the pex to its outside surface, then convection again to whatever surface is touching the pex or to air, etc. There is also a radiation component in the whole mess but that would be very negligible.

insulation doesn't help the heat move upward... it prevents it from moving downward.  it's a perhaps subtle distinction but it's important.

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you're on the wrong track.  conduction to the surface dwarfs most other concerns once you are appropriately insulated.  you can't compensate for lack of plates with insulation at all.  lack of insulation can cause ANY radiant method to underperform, including a plated system, as whatever you have for downward loss reduces your upward heat transfer.  that doesn't matter if you're plated or not, that's a simple heat loss equation.  it's worse with a plateless system because its output is already low, that's all.

Now, salvage and $ limited the 2nd floor to 2x6 @24" oc.  Exterior still flush.  R in high 20's, when I figured it, I'm remember near 30.

Convection occurs in a fluid (and air is a fluid).  You don't get convection to "whatever surface is touching the pex" -- that's conduction, by definition.

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Thermostatic Mixing Valvetap

and since it's our real whole house heat source, it's location in the lower level is a necessity.  But this discussion isn't about forced air comparison, if that's your system.

Foam, or other insulation provides resistance to all types of heat transfer (radiant, convective, conductive). but its effectiveness is mostly dependent on its thickness, usually expressed in R-values.

It seems to me that, in order to compare the effectiveness of plates alone vs. insulation alone, one needs to know how thick (or, R-value) the foam needs to be in order to acheive better resistance to heat transfer than plates alone.

Plates, with air gap, provide resistance to radiated heat--I suppose they could also reduce somewhat the effect of convection transfer.

heat emission varies with conductivity from water to room floor surface.  plates lower this average number significantly compared to staple up naked pipe, so you actually emit more heat.  You can put R-10,000 under a staple up system and never ever get any closer to an R-20 under a plated system in output... the heat simply will not be removed from the pipe and it will return to the heat source.

No problem Calvin, but if you disagree with what I said about radiant floor heat, I would be happy to discuss it and listen to all views on the subject.  As far as I can tell, I never said anything that disagrees with what NRTRob has said in this thread about the subject.

As we previously mentioned, a thermostatic mixing valve is a device that regulates the flow of hot and cold water to ensure that the water temperature stays within a specific range. These valves are installed in showers, sinks, faucets, spigots, and other plumbing fixtures. There are two types of TMV's: single-control (SC) and double-control (DC). Single control TMV's have one handle or knob for controlling both hot and cold water together. Double-control TMV's have two handles that separately control hot and cold water. SC valves are often used in residential applications because they can be installed on an existing fixture with existing piping connections. DC valves are typically used in commercial applications.

Thermostatic mixing valvetemperature setting

I live in MN too, and we have a "split entry", with the bottom floor (where our bedroom is) 3-4 feet below grade.  Concrete slab.  We have carpets down there, and we don't (with dual zone heating) notice any significant difference between the temps down vs up, except that the downstairs bath tile floor does get a bit colder than upstairs.  But that's what bath rugs are for.

Have 22 yrs in this house and unless there's some differences, I'm thinking that your slab will not be warm (to comfort) while not being the cold of ambient ground temperature-low 50's, like not too cold beer.

Thermostatic Mixing Valve28mm

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The warm air layer under the basement ceiling conducts heat to the ground floor, including joists, subfloor, and finish wood floor.  The warmed ground floor/basement ceiling radiates heat upward into the ground floor space and downward into the basement.  It also heats the air film contacting the ground floor by conduction, and that heated air then rises and circulates in a convective flow in the ground floor space.

What I was talking about in that other thread was heating both the ground floor space and the basement as one zone by placing fin tube in a distribution loop about a foot below the open-joist basement ceiling.  This a compact 24’ X 28’ basement and first floor, and there is an open stairway connecting the two spaces.  The fin tube warms the air and the warm air stratifies at the highest temperature near the basement ceiling.  Some of the warm air rises up the stairwell to enter the ground floor space.

EDIT:  My apologies, I confused you rd with another poster that really doesn't listen when radiant and how it works (at least from a few) discussions take place.   If I could, I'd insert one of those smiley things up there now .  Really................., sorry.

But, with the open living area and well opened to the second floor and a circular movement of air from down to up and back again, works like a charm.

The beauty of the radiant slab and the contra flow heater with it's slow releasing mass-warm down and cooler yet not uncomfortable in the sleeping rooms.  Have tube under plywood/tile in the upstairs baths and installed 2-4' water basebds in the two remote bedrooms - for the ability to close the doors and still have comfort.

Plates are required in most full heat situations unless you use very high water temps or have very low heating loads.  You can crank up to 30/BTUs/sq ft with the heavy guage plates.

If you do multiple houses and are looking for cost effective radiant... consider radiant ceiling as a go-to option.  it has some big benefits and it's only slightly a step down from floor for heating comfort.  does require a flat ceiling though.  it's cheaper, high output, invisible, no flooring risk, and if done properly... it can do cooling (there are other considerations of course...)

the reason we harp on conduction is because without it, you have a low strength emitter.  Better conduction and conductivity is what translates into high performance in the case of a radiant emitter.

I understand what you are saying about the basement slab.  While it does receive some heat by radiant transfer from the ceiling, it will never heat up like it would if it had hot water running through it.  Even the ground floor will not heat up to that extent, but it heats up more than the basement slab.

Sorry to give that impression--the fact is, I "listen" to your posts with interest and nearly always learn something from them.

A thermostatic mixing valve is a type of valve that is used in mixing hot and cold water to get the desired temperature. They are often found in showers, sinks, and other household plumbing fixtures. Different types of thermostatic mixing valves can be purchased for homes or offices. Some are more common than others, but all have their own benefits. The most popular type of thermostatic mixing valve is the 2-handle model which has one handle for hot water and another for cold water. This type of valve tends to be easier to install because there is only one hole needed in the wall instead of two like you would need with a 3-handle model.

But, and we did discus this, the idea that the ceiling heat is going to radiate down and warm the non heated but insulated concrete mass I don't think will work.  Reason being, I have a perimeter isolated and insulated radiant slab, but use a contraflow heater to do the job in the spring, fall, and as added heat source in the winter.

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EDIT:  My apologies, I confused you rd with another poster that really doesn't listen when radiant and how it works (at least from a few) discussions take place.   If I could, I'd insert one of those smiley things up there now .  Really................., sorry.

202215 — There are two types of TMV's: single-control (SC) and double-control (DC). Single control TMV's have one handle or knob for controlling both hot ...

It was indeed a nice weekend here.  Minnesota has been exceptionally warm this winter with hardly any snow.  This last week has gotten down to more like normal temperature with highs in the +10 to +25 range.  But it has been in the 35-50 degree range much of the winter so far.

conduction is by far the strongest method of heat transfer.  convection and radiation work... in fact, in suspended tube systems in joists those are the only two methods working for you.  but they are weak.

Ball check valves are one of the most important components when controlling water flow from the feed pump to the boiler. As boiler pressure increases beyond the ...

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