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panel radiator surface temperature

bingy30
bingy30 Member Posts: 1
edited February 2018 in Radiant Heating
Hi all,
Does anyone know what is the surface temperature of the panel radiator relative to the supply temperature? I am in the process of updating the system and want to replace the old convectors by panel radiator. I am worried that at 180F supply temperature, the panel will be too hot to touch. We have pets and will have infant in the house. I currently have oil boiler (new boiler will be installed with new rads) with no access to natural gas on the street. Any feedback, suggestions or comments are welcomed. Thanks!

Michael

Comments

  • Jamie Hall
    Jamie Hall Member Posts: 23,159
    The amount of heat you get out of a radiator is related to it's surface temperature. The more heat you need, the higher the temperature. At a 180 F supply temperature, the surface will be close to 180 F -- which is definitely too hot to touch.

    Can you design your system to run at a much lower surface temperature? It will require bigger radiators, but you may be able to use a condensing boiler if you do, which improves efficiency.

    Even so, it is unlikely that you can get the radiator cool enough for the infant to lie against. The pets? Chances are pretty good that they'll figure it out pretty quickly -- all the cats and dogs I've known have, anyway.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Ironman
    Ironman Member Posts: 7,366
    That's a mis-conception. If it's too hot, God-given common sense will tell them to stay off of it.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
    CanuckerMark EathertonGordy
  • hot_rod
    hot_rod Member Posts: 22,018
    upsize the panel rad to get the output you need at lower temperature. unless the rest of the emitters need 180 SWT?
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • BobC
    BobC Member Posts: 5,476
    I've lived with steam heat for 70 years and when I was young I'm sure I got burned by a radiator. If I got burnrd more than once or twice it's not the radiator's fault.

    Kids are better off learning about stuff like this when their very young, they are a lot more resilient then you think and it's good training. A boiling pot of water on a stove is infinitely more dangerous.

    Bob
    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
    IronmanCanuckerGordy
  • Gsmith
    Gsmith Member Posts: 431
    It's pretty hard to keep any part of your body in touch with a hot steam radiator, the natural reaction is to pull away even or especially for little kids. That said one has to guard against a situation where one could fall or otherwise be put in a position where you can not physically pull away. Elderly and infants are particularly vulnerable
  • Jamie Hall
    Jamie Hall Member Posts: 23,159
    hot rod said:

    upsize the panel rad to get the output you need at lower temperature. unless the rest of the emitters need 180 SWT?

    You'll never get it cool enough to be safe to lean on -- if you do, it's not a panel radiator, it's a radiant heat floor or wall, which is a very different beast.

    In some ways hotter is better -- the reflex withdrawal is quicker.

    That doesn't protect against someone somehow getting stuck touching a radiator...

    So if you are really truly concerned, you have two options: scorched air or in-floor or in-ceiling radiant.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Gsmith
    Gsmith Member Posts: 431
    A radiator cover would also help, but cuts down on the heat radiated.
  • rb_6
    rb_6 Member Posts: 222
    Google search, "the exposed surface temperature of a steam or hot water radiator shall not exceed" and read to your hearts content [:@)

    Also the child brain development includes reflexes...have to do some digging but some early responses by infants is to palm stimulation is to grip rather than release...again one would have to dig deeper maybe it's nothing to worry about but then again maybe it is...

    Also....consider the parent who brings a swaddled baby into a room in bassinet and sets it next to a very hot radiator or on an uncontrolled heated floor...maybe the child is awake and can express discomfort maybe it's sleeping and doesn't wake up...overheating of infants is a real possibility...

    Just a few things to consider...or not [;@)


  • Jamie Hall
    Jamie Hall Member Posts: 23,159
    OK. Let's make some assumptions here, which seem vaguely fair, see where they take us, and see what might be recommended.

    First, there will be an infant/toddler in the room. Second, there is a concern that the caretaker of the infant/toddler may have a brain fade and leave the kid too close to or touching a radiator.

    This is clearly not desirable. Somehow we survived this long without undue problems (my kids grew up in houses with exposed wood stoves), but still -- it's not desirable in today's world.

    So. The only realistic option for assuaging the concern is making sure that it simply can't happen. There are very few options, and I will leave it to @bingy30 to take their pick:
    1. Build enclosures around any radiator -- panel or otherwise -- with sufficient clearance and insulation that the surface temperature will not exceed a safe temperature -- probably around 90 F.
    2. Heat the space using radiant floors/ceilings/walls, all of which operate at surface temperatures which are safe.
    3. Transfer the heat to the space by a medium controlled at a safe temperature, which translates to hot air.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Ironman
    Ironman Member Posts: 7,366
    "An uncontrolled heated floor" that's so hot it kills an infant but the adult didn't sense it? Seriously?? What are you smoking?
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • Jamie Hall
    Jamie Hall Member Posts: 23,159
    Ironman said:

    "An uncontrolled heated floor" that's so hot it kills an infant but the adult didn't sense it? Seriously?? What are you smoking?

    I missed that line, Bob. Ouch.

    [begin rant].
    Would someone kindly tell me how I and my kids survived to adulthood? We grew up on a farm. For a good bit of the time we had open wood stoves (one of them a Glenwood -- that baby could really produce heat!). We played in the barnyard. We rode (and drove) farm machinery. We had big and little critters -- and played with them (horses, cows, barn cats, dogs...). We swam in the farm ponds and the brook. We used farm tools. But here we are, for better or worse...
    [end rant]

    Funny world.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    Ironman
  • Ironman
    Ironman Member Posts: 7,366
    edited February 2018
    Jamie, me too. We raised seven children with a hot wood stove and none of them ever got hurt on it. Of course, we told them repeatedly that it was hot before they could crawl. Did any of them have to learn by experience? Probably, but I don't recall it.

    To be honest, there's a real threat of CO poisoning from not maintaining a furnace or a boiler. It happens on regular basis. But most folks aren't concerned about real issues today, just perceived ones.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • Gordy
    Gordy Member Posts: 9,546
    Interesting topic. Maybe even a con to steam heating :)

    As @hot rod suggested the only real option is to size the radiator (s) for lower supply temps which would only increase contact time before burning. Enclosures could work, but depending on design could get just as hot, or decrease output.

    I don't mean to be rude, but this issues falls under about any other house hold danger to toddlers, or pets, and who is responsible for their protection.

    Some of my fondest childhood memories, and learning experiences were a finger in a lamp socket without a light bulb, hand on toaster after it was just used,stepping on a nail, pulling a coffe pot full of hot coffee off the table on to myself, the sharpness of a cutting instrument, skin friction burns on carpet, and scrapes on concrete.

    Not poor parenting, just a quick little child. Oh yeah the other uses of the wooden spoon...............
  • Sal Santamaura
    Sal Santamaura Member Posts: 529

    ...Would someone kindly tell me how I and my kids survived to adulthood?...

    A combination of child intelligence, good parenting and luck. :)
    Canucker
  • rb_6
    rb_6 Member Posts: 222
    "An uncontrolled heated floor" that's so hot it kills an infant but the adult didn't sense it? Seriously?? What are you smoking?
    ___

    Did you see what just happened there?

    The adult should have been able to sense what the child was sensing - but they didn't. That's why the child died. You could have asked, "why didn't the adult sense what the child sensed?" Right? I mean there are lots of questions in a death of a child. Questions that can lead us to learn. But you wanted to know what I was smoking? How does that contribute to the knowledge base of a professional and those following this thread?

    Heat stroke in well wrapped infants is not uncommon but in the 1988 case the child was wrapped in two blankets, a vest, a nappy and baby suit. Then it was placed on an unregulated floor of sufficient temperature to raise the temperature under the blankets to 42C (107F). In 2012 a three month old overheated and suffocated next to a radiator after getting wedged between it and a bed. Its inexperienced caregiver had fallen asleep. In April of 2016 a senior fell on a heated floor with unregulated temperatures and subsequently died. Then in May of 2016 a malfunctioning heater contributed to the death of a 17 month old girl. The caregivers were in their own bedroom asleep.

    What possible lesson could the deceased have learned in the past that would have prevented them from dying under the circumstances? How would a parent unable to sense the infants experience know any different? Is it reasonable to expect the average layperson ought to have known that the floor temperature was unregulated? Are we suggesting that a person in a cold climate sitting indoors next to a large inefficient window and wearing winter boots on a hot floor but exposed to a cold draft would have enough awareness of the floor temperature to get the child off the floor? The inexperienced caregiver was negligent but they didn't know that until the child died. The parents asleep in their bedroom had no control over the failed heater...what could they have done different? The senior was the recipient of unfortunate circumstances and an incompetent contractor but what experience would he have from his past to prevent his death?

    Your point about 'pain teaches' is valid...pain teaches us not to fall off our bikes, not to touch hot surfaces, to not step on weak branches...the common denominator is the capacity to 'do, survive and not do again'.

    But many in society - by no fault of their own - don't have the capacity to 'do, survive and not do again'

    These people put their faith in others to protect them...those 'others' are called 'professionals'.

    The statement and question, "Seriously?? What are you smoking?" Tell me how that progresses professionalism?

    Sincerely serious,

    Robert Bean


    Rich_49Sal Santamaura1MatthiasMark Eatherton
  • Gordy
    Gordy Member Posts: 9,546
    I think in all cases you mention, and some undocumented, or not shared for others to learn from is the issue. In other words professional education.

    In most of the incidents you mention it does fall under some neglect as a parent, equipment failure, In the case of the senior, bad luck coupled with a poor radiant panel design.

    We’ve always known infants/toddlers, and seniors are more susceptible to scalding from hot water thus tempering valves, or some sort of DHW temperature control was implemented.

    Like the bridge failure in Miami. The NTSB, and other investigative entities will be looking for the cause of its collapse that killed 6 people.

    Depending on the findings could rewrite protocol for many things. Sadly the construction industry will learn from others misfortune. Not uncommon in any industry.

    Design
    Materials
    Erection
    Tensioning
    Traffic control

    Just to name a few.

    The design aspect for radiant panel floors has always been the 85 max threshold number. That number is a base line for comfort, and 82 for certain flooring material safety. No one ever thinks about what breaching that number could do to human life.

    So unless the documented events are freely shared for others to learn from, how can the industry teach?
  • Sal Santamaura
    Sal Santamaura Member Posts: 529
    In my opinion, Robert Bean is not only infinitely more knowledgeable about comfort systems than I am (and likely more than many of the professionals who frequent this site are), he's a far more tolerant and diplomatic person to boot. Always ready to educate. Thank you, Mr. Bean.
    rb_6Rich_49Zman
  • jumper
    jumper Member Posts: 2,226
    Most practical radiant heat is ceiling height panels. Electric or hydronic. Nobody touches them. Nothing gets in the way. 100% radiant. And way less complicated and expensive than embedding pipes in ceilings,floors or walls. They have been available for decades but are rare in non-industrial locations.
    Mark Eatherton
  • rb_6
    rb_6 Member Posts: 222
    edited March 2018
    Gordy

    One aspect that many in industry fail to understand is that the range of floor limitations always corresponds to people wearing shoes and assumes a maximum 10% dissatisfaction. 10% dissatisfaction corresponds to a floor surface of ≈ 28C (82F) +/-.

    The ideal base temperature where there is the lowest dissatisfaction is ≈ 24C (75F) +/-.

    This aspect of radiant design is very important for people who stand on heated floors all day long such as working behind a counter at an airport or working in a welding shop.

    When people are barefooted or wearing socks the temperature is important but so is the flooring conductivity. Generally the more conductive the floor the higher the preferred temperature. The recommended values are discussed in the ASHRAE Handbooks but you can read a summary here:
    http://www.healthyheating.com/Thermal_Comfort_Working_Copy/Definitions/floor_temps.htm

    Where people are wet and mostly naked and not standing for long periods it is acceptable to push the surface temperatures. For example pool decks or showers or bathrooms.

    It’s also important that reader understand these temperatures are maximum which means for most of the year they should be operating at less than design conditions.

    In practice few designers and installers actually control surface temperature which exposes them to risks of various kinds.

    Sal

    Thank you for your kind words.

    Jumper

    At the surface temperatures normally associated with ceiling panels there is about 10% convection associated with their output.
  • SuperJ
    SuperJ Member Posts: 609
    They do make panel rads specifically for low surface temperatures. Looks like some sort of buffer or in cover. http://www.purmo.com/en/products/panels/lst.htm#tab-technical-data
  • Gordy
    Gordy Member Posts: 9,546
    Robert, I’m well aware of radiant panel design temperatures in contrast to human comfort levels in different situations as you noted. Not in situations that never cross our minds

    However, it seems the usual question, and thrust of radiant panel design can be by the novice to accommodate an owners dead set wishes to have radiant. Then it always embarks on the most output a radiant panel can achieve to service the load. Which in certain cases of high loads, pushes the envelope of exceptable design surface temps with out supplemental emitters either of same variety with an added surface, or a different type. Then it’s cost for the added supplemental emitters in the design.

    Most here realize that design temp limitation. Mostly about comfort to bare feet, materials used in the panel, and efficiency of the entire system through using as low water temps possible. Few including myself have come across through casual reading the tragic events that you have pointed out. Most would never have thought to research those types of events to change the way we think.


    We could also analyze the events you pointed out, and point lots of fingers, and add, or subtract scenarios. They all, except for the case of the senior point to negligence of the care giver. In the case of the senior what if that person fell into the fireplace, or on an active stove, or outside on to hot asphalt. I mean where does it end in the revolution of litigation, and protecting ourselves from ourselves, and others.


    Thanks for the lesson to an aspect of emitter temperature, one would never think of RB.



    rb_6
  • jumper
    jumper Member Posts: 2,226
    Going back to OP his concerns are addressed with ceiling height panel. Then he has choice of HHW temperature versus panel size. I recommend high HHW temperature for comfort but others may recommend opposite for same reason.
  • rb_6
    rb_6 Member Posts: 222
    Super J et al

    Most manufacturers publish correction factors for running radiant panels at lower temps...for general discussion there is about a 10%+/- reduction in output for every 10F drop where output at 180F =100%, 170F=90%, 160F=80%, 150F=70%, 140F=60%, 130F=50%, 120F=40%, 110F=30%

    We have a page that discusses this principle here:
    http://www.healthyheating.com/Windows/Infloor_Radiant_Design_Temperatures.htm



  • rb_6
    rb_6 Member Posts: 222
    Jumper et al,

    I've never had a client who wanted to invest in a high efficiency appliance only to run it as a mid efficiency device. So in our practice, the first strategy in design is to start with the boiler or heat pumps efficiency and work backwards. For example, if the boiler is rated at 97% efficiency at a 80F return temperature then our clients heating system are going to based around 80F return temperatures. That automatically drives choices in the system but it also forces our client and their architect to look at the enclosure to get the loads down; and it forces the client and their interior designer to look at floor finishes (if they decide on using radiant floors).

    It also requires our design team to work with a single low temp system which eliminates mixing devices; but also requires us to solve rogue zones with other low temp solutions. That's why you'll often see us use radiant walls and ceiling in conjunction with floors.

    We've started to publish our design case studies which are available online; and have a free webinar coming up courtesy of ASHRAE and Uponor on using online thermal comfort tools to assist in design solutions. https://tinyurl.com/yb8treo6




    ratioRich_49
  • Mark Eatherton
    Mark Eatherton Member Posts: 5,853

    In my opinion, Robert Bean is not only infinitely more knowledgeable about comfort systems than I am (and likely more than many of the professionals who frequent this site are), he's a far more tolerant and diplomatic person to boot. Always ready to educate. Thank you, Mr. Bean.

    That's a serious under statement Sal. Robert Bean is one of, no scratch that. He is THE smartest man I know when it comes to human comfort. And always willing to share.

    Bob Boan, I've read and re-read this string numerous times, and don't understand where you are coming from. Did I miss something? Stuff happens... Smart people learn from their mistakes.

    ME

    It's not so much a case of "You got what you paid for", as it is a matter of "You DIDN'T get what you DIDN'T pay for, and you're NOT going to get what you thought you were in the way of comfort". Borrowed from Heatboy.
    ZmanRich_49rb_6
  • jumper
    jumper Member Posts: 2,226
    rb said:

    Jumper et al,

    I've never had a client who wanted to invest in a high efficiency appliance only to run it as a mid efficiency device. So in our practice, the first strategy in design is to start with the boiler or heat pumps efficiency and work backwards. For example, if the boiler is rated at 97% efficiency at a 80F return temperature then our clients heating system are going to based around 80F return temperatures. That automatically drives choices in the system but it also forces our client and their architect to look at the enclosure to get the loads down; and it forces the client and their interior designer to look at floor finishes (if they decide on using radiant floors).

    It also requires our design team to work with a single low temp system which eliminates mixing devices; but also requires us to solve rogue zones with other low temp solutions. That's why you'll often see us use radiant walls and ceiling in conjunction with floors.

    We've started to publish our design case studies which are available online; and have a free webinar coming up courtesy of ASHRAE and Uponor on using online thermal comfort tools to assist in design solutions. https://tinyurl.com/yb8treo6

    Boiler & heat pump efficiency does not necessarily determine overall efficiency. When occupants are unhappy with low temperature result then there's demand to overheat the building. This website regularly has folks praising the "feel" from high temperature radiant.

    Also after your architect gets the load down the payback from super high efficiency grows longer.
  • Gordy
    Gordy Member Posts: 9,546
    I’ve always stood by the fact true comfort is something that you don’t realize an outside mechanism exists to make it so. Meaning I don’t feel hot, or cold, just right. It’s also silent....

    The mass of your surroundings are neutral. Which means the mass doesn’t add heat to your body, or take it away. Same for humidity.

    The only way to achieve this is through controlling the envelopes losses. Once that’s done true neutral emitter surfaces can be achieved.

    The warm feel of radiant was true when envelopes had huge losses, and fuel was cheap. Now days the huge losses still exist, and fuel is not cheap.
    Rich_49ratio
  • Rich_49
    Rich_49 Member Posts: 2,766
    jumper said:

    rb said:

    Jumper et al,

    I've never had a client who wanted to invest in a high efficiency appliance only to run it as a mid efficiency device. So in our practice, the first strategy in design is to start with the boiler or heat pumps efficiency and work backwards. For example, if the boiler is rated at 97% efficiency at a 80F return temperature then our clients heating system are going to based around 80F return temperatures. That automatically drives choices in the system but it also forces our client and their architect to look at the enclosure to get the loads down; and it forces the client and their interior designer to look at floor finishes (if they decide on using radiant floors).

    It also requires our design team to work with a single low temp system which eliminates mixing devices; but also requires us to solve rogue zones with other low temp solutions. That's why you'll often see us use radiant walls and ceiling in conjunction with floors.

    We've started to publish our design case studies which are available online; and have a free webinar coming up courtesy of ASHRAE and Uponor on using online thermal comfort tools to assist in design solutions. https://tinyurl.com/yb8treo6

    Boiler & heat pump efficiency does not necessarily determine overall efficiency. When occupants are unhappy with low temperature result then there's demand to overheat the building. This website regularly has folks praising the "feel" from high temperature radiant.

    Also after your architect gets the load down the payback from super high efficiency grows longer.
    Jumper , Please don't take this the wrong way .
    It is really not all about payback .

    Heating and indoor environmental systems are not an investment , they are necessities and there is no payback as such . Quality HVAC systems that are designed for human comfort whether hydronic or other are becoming more expensive at a rapid rate . Hell , a quality advanced , well designed forced air system is no longer cheap , a well designed , installed hydronic system is a rarity also and the difference between the 2 is narrowing as that technology advances .
    This game is far more about health and comfort than payback .

    This thread put a higher priority on SW and panel temps to protect folks than for efficiency .

    The world is rapidly changing and multi fuel systems and other various technologies are becoming mainstream . Not gonna get into Global climate change , fossil fuels versus everything else . Houses , fuels , construction and mostly attitudes are changing despite what WE say . I Know you missed RBs point . Read some of his stuff , it'll take years , then you'll know why he says the CRAZY things he says . " Remember , a heating system is a pig , it eats fuel and poops heat . We need to put that pig on a high fiber diet " , ( John Barba ) . Or as Robert stated , The 3 little pigs must die .

    You were right about one thing boiler / heat pump efficiency don't mean anything unless they are part of SYSTEM efficiency .

    After your architect gets the loads down your requirement for super high efficiency becomes less important from your equipment . But will it be combustion equipment in 20 years or even 10 years ?
    You didn't get what you didn't pay for and it will never be what you thought it would .
    Langans Plumbing & Heating LLC
    732-751-1560
    Serving most of New Jersey, Eastern Pa .
    Consultation, Design & Installation anywhere
    Rich McGrath 732-581-3833
    Mark EathertonGordyrb_6
  • rb_6
    rb_6 Member Posts: 222
    edited March 2018
    Thanks Mark and Rich,

    One of the strategies we use with builders and clients is plot the heating and cooling temperature profiles to illustrate what drives the system temps up in heating and down in cooling. By pointing that the system has to run unnecessarily warmer or cooler because of a rogue zone we can usually convince them to improve the enclosure and/or change the flooring - in that zone. What we want to see is a line as flat as possible. In heating it should be as low as possible and in cooling as high as possible. When we achieve this we have eliminated mixing devices thereby reducing costs and simplifying the system whilst extracting the highest efficiency possible from the heating and cooling plant.

    What Rich asked is very important...as we move away from fossil fuels to electricity - those system designed for higher temperatures will be more difficult to adapt to low temperatures systems.

    Sample plot...with descriptors as to why the rogue zone exists.

    Sidebar: what you are also seeing is how we manipulate delta t's to harmonize fluid temperatures, flows and pressure drops throughout the system. Depending on how aggressive or conservative we need to be, we'll play with spacing, diameters, tube patterns and depth and in some cases recommend a change in flooring to make sure we have good floor temperature efficacy.

    CanuckerRich_49Mark EathertonGordy
  • jumper
    jumper Member Posts: 2,226
    @rb,
    Aren't you talking about new construction? As Gordy says we don't need much heat in modern tight home. But OP sounds like he's going to replace convectors with panels. Not build a new house. He's concerned about safety so I suggested that he mount panels high on wall where he can safely enjoy high surface temperature. The real problem with my suggestion is that those work better on interior walls but existing pipes are probably for terminators under windows.

    Many people earn their livelihood installing hydronic floor radiant. But for new construction the practice is somewhat like owning a RollsRoyce to drive next door.
  • Gordy
    Gordy Member Posts: 9,546
    @jumper neutral mass is neutral whether it be new, or old construction. Getting the envelope to where neutral mass can be achieved is the key, and not always possible, or cost effective for the owner. However the rewards are in the down sizing of the system, and increasing its efficiency to maintain neutral surfaces.

    I have never met anyone who didn’t like radiant heat other than the cost to have it. It becomes how much do you really love being comfortable, even if it's new construction. I would liken it to driving a life time in a rolls royce, or a pick up truck. Both will get you where you’re going however one gets you there with more comfort. Again the comfort part drives more people than others. I knew a few people who owned crouch rockets. They look to be the most uncomfortable thing to ride on I said to a guy. His reply was “yeah, but when I get there I look cool” some people sacrifice comfort for a need, and it never makes sense sometimes.......it's not always cost.


    I think with new construction coupled with radiant it just takes less emitter to give the same comfort. Maybe someday just radiant windows will be all you need. Negate high loss areas.



    Mark Eatherton
  • Rich_49
    Rich_49 Member Posts: 2,766
    jumper said:

    @rb,
    Aren't you talking about new construction? As Gordy says we don't need much heat in modern tight home. But OP sounds like he's going to replace convectors with panels. Not build a new house. He's concerned about safety so I suggested that he mount panels high on wall where he can safely enjoy high surface temperature. The real problem with my suggestion is that those work better on interior walls but existing pipes are probably for terminators under windows.

    Many people earn their livelihood installing hydronic floor radiant. But for new construction the practice is somewhat like owning a RollsRoyce to drive next door.

    Older home or new , regardless of what the OP is doing he does not necessarily require high surface temps . He needs to size whatever emitter he puts in so lower temps can deliver the needed heat .
    You didn't get what you didn't pay for and it will never be what you thought it would .
    Langans Plumbing & Heating LLC
    732-751-1560
    Serving most of New Jersey, Eastern Pa .
    Consultation, Design & Installation anywhere
    Rich McGrath 732-581-3833
    rb_6
  • Mark Eatherton
    Mark Eatherton Member Posts: 5,853
    Gordy, We're already there. Super insulated passive homes don't need a heating system, just window that aren't cold.

    ME
    It's not so much a case of "You got what you paid for", as it is a matter of "You DIDN'T get what you DIDN'T pay for, and you're NOT going to get what you thought you were in the way of comfort". Borrowed from Heatboy.
    Gordyrb_6
  • Gordy
    Gordy Member Posts: 9,546
    I know Mark, we need to see it mainstream, and a common place option. Both residentially, and commercially.
    Mark EathertonCanuckerRich_49
  • Rich_49
    Rich_49 Member Posts: 2,766

    Gordy, We're already there. Super insulated passive homes don't need a heating system, just window that aren't cold.

    ME

    I'm tellin Dale on you ME .
    You didn't get what you didn't pay for and it will never be what you thought it would .
    Langans Plumbing & Heating LLC
    732-751-1560
    Serving most of New Jersey, Eastern Pa .
    Consultation, Design & Installation anywhere
    Rich McGrath 732-581-3833
    rb_6Mark Eatherton
  • rb_6
    rb_6 Member Posts: 222
    edited April 2018
    Gordy,

    Re: Which means the mass doesn’t add heat to your body, or take it away.

    I understand what you are saying - just for clarity for others following....

    I suppose it's possible, but probably more unlikely that the mass would ever, "add heat to your body." In order for that to happen it would have to emit at a wavelength much greater than the skin (which is around 9 micron (um) to 10 um at room temp). Shortwave radiation (at appx 0.5 um) can do this but shortwave is usually isolated to windows or high intensity sources such as fireplaces (or a really crappy building in a hot climate at peak solar seasons). But what more typically happens is the mass temperature (tied to the mean radiant temp or MRT) becomes sufficiently high enough to emit longwave radiation that is close to that of the body. This effect prevents the person from shedding heat at a rate fast enough to keep themselves cool (between 350 and 450 Btu/hr at lower met rates) ...in most cases this is the cause of the overheating sensation. Again I do get what you were saying...just wanted to clarify.

    For general knowledge, radiant floor heating and humans radiate at about the same wavelength, appx. 9.5 um. This means the body doesn't necessarily feel the heat from the floor as often cited in literature (sans discussion about feet and conduction) rather it feels its own heat...in other words its the retention of body heat that people sense and why they perceive the space to be warm. If radiant floors actually provided the same heat as the sun or a fireplace ones house would be on fire [;@).

    On the cooling side because the flow will always be from the occupant to the enclosure it is true the occupants won't want the cooled surfaces to take heat away any faster than the rate of production so met rate is important as is clothing.

    But there is another aspect to all of this and that falls under the heading of Alliesthesia. There is a body of research work that is suggesting that humans benefit from exercising their sensory systems including sensations and perceptions of thermal comfort. It's the slipping out of homeostasis (experienced as degrees of discomfort) and seeking to regain balance that is pleasurable for some. This is much like the athlete who's sense of balance is developed by being repeatedly knocked out of balance. This study is populated by researchers from the adaptive comfort camp. There is good argument for it in moderate climates.

    SuperJGordy
  • Gordy
    Gordy Member Posts: 9,546
    I always liked the fireplace for homeostasis benefits. Especially after being outside in the winter. Same for summer getting into the ac after a hot day outside.

    My reference to neutral mass was both heating, and cooling seasons.
  • jumper
    jumper Member Posts: 2,226
    What rb says regarding radiant heat transmission is scientific but I wonder about sensation and comfort? When we feel a high temperature source then can we be comfortable at a lower air temperature? Sometimes anyhow? For example ceiling radiant heated homes from the fifties are comfortable except that women sometimes complain that their legs are cold when their legs are under a table. Seems to me that the air must be pretty cool for women to notice.

    When tepid air heat pumps came in in the seventies people complained that registers blew "cold" air. My theory is that previously scorched air got some surroundings a bit warmer and that extra radiant kept occupants "feeling" warm at same temperature that tepid air replacement did not.
  • rb_6
    rb_6 Member Posts: 222
    Hi Jumper et al,

    Sidebar, I use the following classification systems for cold climate homes (old or new):

    Terrible: built to Code, >30 Btu/hr/ft2
    Traditional: built to Code, 20 to 30 Btu/hr/ft2
    Transitional: built to above Code, 10 to 20 Btu/hr/ft2
    Terrific: built to future Codes, <10 Btu/hr/ft2

    Over 60% of our projects on the books these days are ‘terrible’ and ‘traditional’ homes being modernized.

    Re: new construction the practice is somewhat like owning a RollsRoyce to drive next door.

    Well as per above, that all depends on how one defines ‘new construction’…even today with all that we know, consumers still end up with ‘Traditional’ and ‘Terrible’ new homes. But yes…when you get down into the fluxes of <5 Btu/hr/ft2 with small loads there are other options for heating…

    For the OP, as you and others have already discussed…go radiant ceilings or design for lower temperatures…

    Ok…I apologize for hijacking this thread...time for me to move along.

    Have a Happy Easter weekend all!
    Mark EathertonRich_49
  • Gordy
    Gordy Member Posts: 9,546
    We missed the boat in the grand housing bubble to really make a dent in energy savings for homes. Codes were slow to catch up, and even at best mediocre in the insulation requirements to satisfy builders, and consumers appetite for affordable housing.
    rb_6Rich_49