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Infloor Radiant Heat issue

124

Comments

  • cattledog
    cattledog Member Posts: 60
    high electricity use when not at cabin

    Hi Ray--



    It's possible that you are incorrectly using the temporary override instead of the hold when you reset to a lower temperature for unoccupied periods.



    https://customer.honeywell.com/resources/techlit/TechLitDocuments/69-0000s/69-2062EFS.pdf



    If there is nothing simple like "operator error" then you may want to have your neighbor go in when you are away, and verify that the place is a cool as you want it to be.



    If the neighbor is not available, then you might want to use Mr Google to find a low cost digital temperature data logger. You could also log boiler on/off time as well, but I can't remember if it is modulating or not and that could be a complexity.



    What is the payback time for the dual use rate to pay for the direct vent propane unit? What is the risk that the dual fuel rate schedule will be discontinued?



    Another thing to think about is if the power company actually uses its dual fuel rights and cuts you off, or limits your power where will you be with a small wall unit? Can you determine the past actions of the power company to see if dual fuel program power cuts are rare or frequent.



    Regards
  • Eastman
    Eastman Member Posts: 927
    If it's holding tempreture more acurately,

    Then I would think the unit is installed correctly.  Cattledog's suggestion seams more likely.  I take it you do not have internet access at the cabin?  There's quite an assortment of thermostats now that would allow you to check on the system and turn the temps up remotely before your arrival.



    Question:  What are the delta Ts across the three system loops?  Someone asked that along time ago and I think it got lost in the dialog.
  • Gordy
    Gordy Member Posts: 9,546
    edited February 2013
    DT's

    I asked it in the hopes of trouble shooting. But at this point with the sporadic short term use it may be difficult to get a steady state sample.



    This was initially to see if loops were all getting decent delta t's. in loops, and main supply/return.



    We know the boiler has a max temp of 135*



    The slab I believe is not insulated.



    Slightly under radiated for the heat loss. No heat in loft area.

    Can't remember what the actual energy audit said.



    We know from the kwh per day (11 avg unoccupied) that there is about 37500 btu's being used per 24 hour period. That's between the boiler, water heater, and any other residual power for fridge etc.



    So that is about 1500 btus per hour average.....rough estimate with out knowing other power draws.



    Don't know the set back being used.



    Looking back at the 2011 bill your not to far off from before you really started to,do something about setting back.......I think.



    458 watts an hour.



    Does not sound like a lot if you break it down that way.



    I know it sounds odd, but I just don't think an electric boiler puts out like a gas boiler if its anything like an electric water heater verses a gas one. But then we are talking recovery rates also in that aspect.
  • SWEI
    SWEI Member Posts: 7,356
    slab not insulated

    in northern Minnesota?  When _was_ this thing built?
  • Gordy
    Gordy Member Posts: 9,546
    SWEI

    Oops it's insulated, under-slab, and perimeter, but it was never said how much. That was many, many posts ago.
  • Eastman
    Eastman Member Posts: 927
    Gordy

    I'm not getting the same result.



    I calculated just over 12,000 btus/hour for the 27 days the place was unoccupied in the last billing period.  That's about 3.5 kilowatts.
  • RCO
    RCO Member Posts: 51
    Patient Group

    I appreciate all of the feedback.  This thread has gone on for a long time and has become quite confusing.

    I'll try to recap briefly, if I can, as to what has been done since the start:

    We took ownership in 12/2010.  Immediately noticed the drop in temp at night of 7 - 8 degrees no matter what the outside temp.  Realtor had contractor check system in January 2011.  Deemed boiler working as it should.  Unhooked outdoor sensor because it was buried in snow and set boiler temp at 130, I believe.  Opinion was that system was not adequate to keep up to temp in place.  Recommendation propane wall unit.  Realized not much space for such.  Then recommended slab thermostat.  Interesting.....is that if we were being controlled during the daytime, I wonder how he operated the boiler??

    We insulated the loft area in the knee walls extremely well as 3 beds are built into the walls.  Didn't do anymore to troubleshoot for the remainder of the winter.  In August, we had a heating tech recommended by boiler wholesaler to inspect system - Thermolec 34,000 BTU boiler with 3 loop system in 720 square foot slab.  Deemed it was working correctly and also hooked up outdoor sensor again.  The contractor recommended electric cove heat or baseboard panels in loft area.  Again system not adequate.  Heating tech noticed control box on outside of house.  Upon further investigation with the electric company, we found that we were being controlled on off-peak service.  No meter so company wasn't aware of it.  But radio controlled controller was shutting our heat down from 7 AM to 11 PM each day.  They removed control box to have service to heat at all times. 

    Heating season of 2011, we noticed that the electric usage was still quite high for the time spent there.  However, the temp was more consistent without dropping as before.  I replaced the mechanical thermostat with a digital unit the end of November of 2011.  Temps seemed to hold steady at set point....couple of degrees higher during the day.  Winter of 2011/2012 was quite mild in comparison to typical winters but still high usage. 

    Acquaintance from that area recommended mini-split system to help lower costs.  He was very pleased with his system.  Contacted 3 contractors for bids.  One contractor is still convinced that I will see a reduction in electric costs and they will help heat the place.  We added cellular shades to all of the 11 windows in the main area. 

    This heating season has been quite high as is shown on the attachment posted a few days ago.  We have been exploring options of supplemental heating for a dual fuel rate.  I tried leaving the temp set higher for the month of October but I believe the usage was higher yet. (Suggestions that it may be better to not set it so far back when we were gone.)  It was S65 higher than last year for that time frame with same rates. 

    We thought seriously about a vent-free system just to enable us to get the dual fuel rate and have for times when we would be controlled.  However, we have had many, many comments that this is not the thing to do because of moisture and potential health hazards.  Also felt we would have difficulty finding someone to install and service.  We have since been exploring the option of a direct vent unit.  Would like to get one that is around 82% efficient....highest that I've seen in researching...to supplement.  Also, this type has a minimal hole size cut through wall incase it is not the answer or need to change system down the road.  We still face the complex issue of somewhere to install such a unit except for the stairway landing which is shown in one of the pictures in this thread.   We do have 2 - 52" ceiling fans which we've not been running on a consistent basis in the winter.  Still trying to figure out how to reverse them for winter use.  They have remotes and no sign of switches on units.  May have figured it out with some help from the company but will check next time up.

    I do know that rates are going to be raised this April but don't know those figures as of yet.  Currently, we are at:  $.0943/KWH for general service.  Dual rate is $.0552 and off-peak is $.0425.  Dual fuel allows company to control you up to a 6 hour time frame generally later afternoon into the evening.  No more than 400 hours during a heating season.  Typically has been about 4 hours at a time this season.  Of course, off-peak is off from 7 AM to 11 PM.

    We only have the word of the GC to go off of when researching construction.  It has R19 in the 6" walls and R38 in the vaulted ceiling.  I know that it should have spray foam insulation in the ceiling but that would be cost prohibitive to do at this point in the game.  The GC also indicated that he was there when concrete was poured and the tubing was insulated underneath and around the perimeter.  To what extent of insulation used, I can't say for sure.  We also know that in speaking briefly to the electrician, he thought the initial idea was to put the loops in a sandbed under the concrete for a heat storage unit.  Therefore, the hookup of control box for off-peak service.  Somewhere along the line there evidently was some mis-communication! 

    As far as measuring temps on the floor in different areas and temps on lines, I've not done any of that to this point.  We are there on such a limited basis.  I did have some concerns about the new thermostat because I don't recall the programming to "hold" status rather than using the factory settings??  Also, I do recall that I needed to select a cycle time frame.  So possibly, I didn't set right??  As I indicated, it has been pretty much spot on accept for this last trip when it was below zero on each evening, it may have varied a couple of degrees.  We were also burning our fireplace which could've been causing more heat loss than any good. 

    We did have the electric company do a heat loss calculation based off the dimensions and info I gave them.  The heat loss is at around 32,800 I believe.  I'm attaching that as well.  Can't recall if I did that earlier or not.  But it seems that the existing boiler system is probably marginal in handling that loss.  Typically, we notice when temp is at 69 by thermostat, outside wall (north wall) where indoor/outdoor thermometer is located; the temp is 64 or 65 on that wall area.

    Anyway, we typically have the temp set at mid to upper 50's when not there.  Again, the only other appliance drawing electricity would be the fridge which is 4 years old so energy efficient.  We turn off water heater and water pump.  The summer usage for the past 2 summers we've owned it has been very consistent at an average of 190 KWH per month over that period.  So it gives us a pretty good idea as to what we're using for heat. 

    As mentioned many times throughout this thread, the objective is to lower our heating costs.  We just received a $5200 bid for installation of an 80,000 BTU propane boiler from the contractor that was out 2 weeks ago while we were there.  I understand that a bigger system.....probably not quite this big...would generate more heat.  But my thought is that unless we spend more money to add additional radiant options, we'll not get much more, if any, heat out of our floor to heat the place any better.  It's really an unknown how long we would see a payback in this expense as well as possible remodel plans down the road. 



    Thanks again for all the feedback.
  • Gordy
    Gordy Member Posts: 9,546
    edited February 2013
    Watts the btus

    He's averaging 110000 watts a day that's 11 kw



    1kw= 3412 btus



    11x3412=37532

    37532/24=1563.83 btus per hour





    The 458 must have come out of my arse sorry about that one.

    I did not average the whole billing cycle. The11kw looked pretty much unoccupied avg. that's what concerns me is the unoccupied periods.





    Like I said rough average we do bot know temps outside or indoor setpoint in unoccupied periods.
  • Gordy
    Gordy Member Posts: 9,546
    edited February 2013
    Slab insulation RCO

    Is there snow melt around the perimeter of the foundation?



    A SLIGHTLY bigger boiler will allow higher supply temps to the slab verse the 135 you are bound to now





    I know one thing it's a long scroll,to the bottom of this thread every time I open a PDF, or do a post.
  • Eastman
    Eastman Member Posts: 927
    factor of ten

    110,000 is 110 kilowatts
  • RCO
    RCO Member Posts: 51
    Snow Melt

    Gordy

    No, I don't notice snow melt as I particularly looked for that last time up.  Will check agaiin the next trip as they've received more snow.....about a foot.

    Thanks!

    Ray
  • RCO
    RCO Member Posts: 51
    Snow Melt

    Gordy

    No, I don't notice snow melt as I particularly looked for that last time up.  Will check agaiin the next trip as they've received more snow.....about a foot.

    Thanks!

    Ray
  • Gordy
    Gordy Member Posts: 9,546
    Your right

    I was looking at the demand column on RCO spread sheet thinking that the 11 was kwh. Now I looked at the billing. Sorry
  • Eastman
    Eastman Member Posts: 927
    Doesn't that seem high?

    For being unoccupied?
  • Zman
    Zman Member Posts: 7,610
    Blower door?

    ME mentioned a blower door test earlier in the thread. An IR camera would not be a bad idea either.

    It seems as though the system is working as designed. A typical radiant system like yours will emit somewhere around  30 btu/foot. Judging by your energy bills, it is doing exactly that. There seems to be a lot of talk about a bigger boiler. I think the one you have is oversized compared to the capacity of your slab to emit. You could put an amp meter on the boiler if you want to see what is really going on.

    You could certainly put in a propane boiler and reduce your energy bill 30% or so. www.eia.gov/neic/experts/heatcalc.xls . You would however have to add some radiation to get any more heat.



    The real Elephant in the room is, Where is all the heat going? The kind of heat loss you are seeing is unheard of. Has the meter been checked or replaced? You could throw an amp meter on the main an "clock" It. 



    I think the next steps should be to verify that the meter is correct. Then do a blower door and IR camera survey.



    Carl
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • RCO
    RCO Member Posts: 51
    More Info

    Just wanted to give you one more piece of information to help this thread keep going!!!  Just happen to have all of the usage by day from time we took ownership.  I've also highlighted the days we were there and set temps as best as I can recall. 

    If I understand correctly, I'm getting the consensus that we are using too much energy even while away to keep the place to temp.  So, if that is the case, my best bet is to have some testing done to see where the heat is going??  I'll need to do some checking to find out who can do this for me up there. 

    I did find out yesterday that the new rates are going to be as follows:  $.1053 / KWH - general service, $.0602 / KWH - Dual Fuel, and $.0445 / KWH - Off-Peak.  So we will be taking a $.011 increase per KWH from what we are currently paying. 

    I've been looking at the Rinnai energy efficient direct vent heater.  I've attached a couple of pics that show where we'd like to mount this if we decide to go this route.  I'd prefer the larger, 36,500 unit but the 20,700 unit (29.5" wide with 2" clearance on each side as space is 36" wide on landing between wall and stair) would fit better in this space.  The 1st picture is of the bottom landing of the staircase and would blow heat towards the main living area....sectional, fireplace, and the dining area off to the right of the heater.  Again, this would be done after making sure we have the other issue covered in checking out the 1st issue.  The 2nd picture shows the utility closet that is directly behind the wall on the landing.  I believe the Rinnai has an extension kit that would allow for venting from the unit back to the outside wall (which would be along the right side of the picture). The vent in the picture was just installed in November of 2012 as we thought we might as well release some of the warm air that was trapped in the closet area. The Rinnai units appear to be the most energy efficient units @ 84% according to their brochure.

    Thoughts??
  • Zman
    Zman Member Posts: 7,610
    Red flag

    I think your energy usage is a major red flag.A heat loss over 25 btu/foot on the coldest day is cause for concern. 25,000 btu/hour / 3415 = 7.32 KW/hour or 175 kw in 24 hrs. That would be with the home at 70 degrees on the coldest design day. The days you are not there with the temps turned down should be a fraction of that. Those are the numbers that are most alarming.

    I would have a blower door and IR survey done.



    Carl
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • RCO
    RCO Member Posts: 51
    Thermostat

    I found an issue with the t-stat. First the Honeywell model is a111 not a 221. It is a basic non-programing for time of day settings. The only settings to program are Fahrenheit and Celsius and cycling frequency. That last item had me thinking about the stat since our last trip up. I checked it when we arrived this weekend and sure enough I had it set incorrectly. The instructions are basic and brief but somehow I had set the stat at number 5 which is for a gas or oil furnace @ every 12 minutes! I think it should be set at 1 which is for gravity / steam setting for 60 minutes.



    Th instructions don't go into detail on cycling control but I would assume this would have some impact on operation?? Possibly the boiler running to short a period more frequently??



    Thanks!
  • Gordy
    Gordy Member Posts: 9,546
    Setting

    Basically that setting is what takes the place of the anticipater on the old mercury t stats. This controls how much variation from setpoint is allowed. It does not mean your heat source will run every 12 or 60 min. It still needs a call for heat. It just decides how much below setpoint before it calls, and how close to setpoint before it shuts down. I do not think this would effect energy use to much at least to the extent your seeing.



    I should note I have a LUX t stat with the same feature. Why they call it cycles per hour I don't know. And my description of its function may be a little off.
  • cattledog
    cattledog Member Posts: 60
    electric boiler cph

    Ray-



    With an electric boiler, you are always nominally 100% efficient. I can't really think of a situation where overall system efficiency would be significantly decreased by shorter cycle times. Keeping the slab stable and not having large swings around set point is good.



    If you are only setting back to 55 unoccupied, you can go lower if you can arrange for turn up before arriving. I would also try and get the heating degree day data to go with your unoccupied and occupied usage to try and understand better if you really have high usage unoccupied, or are just paying the price for a cold Minnesota winter.
  • SWEI
    SWEI Member Posts: 7,356
    thermostat should

    really be a high limit controller if the ODR is setup properly.  It should turn off the boiler when your fireplace or woodstove elevated the space temp a few degrees above the indoor setpoint.
  • Gordy
    Gordy Member Posts: 9,546
    edited February 2013
    HDD

    Ray,



    What is your location in northern Minn.?



    Like to put some HDD to the usage to clarify things. If you don't mind.



    You have provided a lot of usage information but no real temps for the days. This can tell a lot about the structure your heating.
  • RCO
    RCO Member Posts: 51
    Location

    Gordy - We are near Park Rapids, MN   56470.  My wife had the local gas company that sells/installs Rinnai heaters bring out a unit to see how it fit on our bottom landing to the stairway.  I've attached some pictures of the unit as it will be sitting if we go this route.  It's only a 20,700 BTU unit but have heard good reviews on this brand.  It fits the space nicely and can be vented out approximately 10 foot to the right of heater.  It is situated in a fairly good area.  We would probably be controlled mostly for 4 hour periods during peak demand times.  The cost of this unit, vent kit, and installation will be around $2100 with gas line, tank, etc behind garage.  Will cost $200 - $300 for wiring 2nd meter.  Shouldn't take long for payback on the savings for dual fuel rate.  I really can't think of a better option with quicker payback at this point.  Just concerned that this size heater will do the job.  I can't imagine the slab losing too much heat in the 4 hour span. 

    Thanks!

    Ray
  • Gordy
    Gordy Member Posts: 9,546
    Different perspective

    Ray,



    Lets look at the boiler. It's 34,120 btu. So that is 10 kw consumption while on.



    If the boiler ran 6 hours a day. That would be 60 kw used in 24 hours. 6.60 a day at .11 cents a kw.



    That would be 198.00 a month. So you could do some deductions to,figure how much your boiler actually is on. I like my lux thermostat it tells how many hours in a 24 hour period there is a heat call which you can only go back to the day before, but it has a total also from the point of time its reset. You can figure out from there how much the boiler is actually on.





    From that info you could calculate degree days per sf. Knowing how much electricity is actually being used by the boiler to heat the space. If your in the 5 btu per degree day range the dwelling is not to bad for insulation. But you would need to do,those calculations at set point while occupied. To get a real good number.
  • RobG
    RobG Member Posts: 1,850
    Clearances For Stairways

    Before jumping the gun, I would contact the local building inspector to find out if the Rinnai unit will work in that location regarding clearances. (I doubt that it will).

    If it were my house, I would put in a Mini-Split. The unit(s) could be left at 50 degrees while unoccupied and turned up prior to occupancy. Then use the electric boiler as a back up. A heat pump is ALLOT cheaper to operate than an electric boiler, and you would have A/C. When funds permit, you could change out the electric boiler for a propane boiler to get the dual fuel rate. Until then, a heat pump would save  you allot of money on electricity.

    Rob
  • Gordy
    Gordy Member Posts: 9,546
    Heat pump

    It was -14 there this morning how do you suppose a mini split would fare with those temps Rob. Not questioning just asking.
  • RCO
    RCO Member Posts: 51
    Options

    I appreciate the feedback.  I'm growing weary of all of my research and analyzing this current system and structure.  I've not been able to find anyone local to really give me much help in a solution that will ultimately save $$ in operating costs in a reasonable amount of time frame. 

    I had a contractor I'd been in touch with who was kind enough to stop by on Saturday AM up there.  He builds energy efficient homes and has them tested  quite frequently for efficiency.  Obviously, I can't go back and redo insulation to make it more air-tight as it would be cost-prohibitive.  I had mentioned my thermostat finding and his suggestion was to install a simple slab stat to control the boiler system.  Then no matter what other type of heating supplement I was using, it would always maintain the slab setting to how the thermostat was set in conjunction with the outdoor sensor.  He thought the gas supplement wasn't a bad idea.  He didn't mention any huge, noticable areas of loss.  There is no sign of ice forming on the roof....snow is intact all over roof line with no signs of melting so I'm guessing we're not losing much heat that way.  I'm not saying it's completely air-tight as I know there are areas that could use more insulation.  Also the foundation area does not show any signs of melting so slab must be insulated in that area as we're told. 

    I'm thinking that my best option at this point is to go the supplemental gas heater route.  First of all, we don't spend a lot of time up there see how the system works for long periods of time at the higher, steady set point.  Secondly, we don't want to spend a fortune to possibly get a cheaper cost in a gas boiler setup.  Lastly, I would prefer to see savings right away which we would do so in cutting our electric rate between 40 - 45% on our heat. 

    I'm not sure on codes but the Rinnai unit needs to have 2" clearance on each side from any combustibles....no problem.  10" above the unit....no problem.  And 40" in front of the unit...again, not an issue.  It takes up approximately 10" of space on the landing and still leaves sufficient room to go around it up the stairs. 

    Thanks!

    Ray
  • Gordy
    Gordy Member Posts: 9,546
    Stairway access

    Would be an issue if its a 36" stairway you would lose 10 " of that unless you mount it 7' off the floor, or more.
  • Bob Gagnon plumbing and heating
    Bob Gagnon plumbing and heating Member Posts: 1,373
    Radiant Heat Issues

    If your cabin seems to have no problem heating up during the day, could solar gain be shutting down the radiant system, in the afternoon, and it has a hard time catching up because of the high mass slab? Have you checked for melting snow around the foundation? That could be the cause of the high heating bills, if the slab or perimeter insulation wasn't installed correctly. Thats my guess.



    Thanks, Bob Gagnon
    To learn more about this professional, click here to visit their ad in Find A Contractor.
  • Ericjeeper
    Ericjeeper Member Posts: 179
    Looking for a cheaper way to heat the outdoors.

    I have read through most of these post, You are simply loosing all of your heat out through those windows. granted they are pretty. But I would opt for some better glass. look for a triple pane, non conductive spacer system with Krypton gas.

      On a sunny day those windows are working in your favor but once a cloud or night fall rolls in. Your system falls back into catch up mode.
  • Eastman
    Eastman Member Posts: 927
    edited April 2013
    RCO...

    Love to dig this thread up and keep it going....

    First off, I can't remember everything anymore that has been discussed/not discussed  --I hope you don't loose your cool if it sounds like I'm rehashing issues you're already aware of.  I just don't want to leave something out that you might find important.



    Subject:  Are the fuel costs listed on your heat loss correct?



    I looked at your heat-loss-analysis.pdf.  Are the energy costs listed there correct?  Your freedom heating amount was $0.065 per kwh.  LP was listed at $2.05 per gallon.  Which is equivalent to about $0.075 per kwh.  (1 gallon of LP utilized at 100% efficiency has energy content of about 27kilowatt hours which, when you do the math that equates to $0.075 per kwh.



    So, just from an energy cost perspective you are getting a better deal with the electricity.  Installing the Rinnai unit and *not* using it is the best way to go here.  Then you can get the duel fuel rate which pushes the electricity price even farther down to $0.055 per kwh.  Now, If I remember correctly, it sounds like the utility shuts off the electric heat for a few hours in the late morning?  That is typically when a slab system is in the process of overshooting the desired temperature.  (Just like the undershoot in the evenings; slab and environment are out of sync)  So that is really a perfect scenario for making the most of a duel fuel system.



    Are you still experiencing a lack of heat in the evening?  If it were my place, I would install the LP unit merely to get the better rate, and use the fireplace or some other type of electric resistance heater for the evening auxiliary requirement.  Once again, purely from a cost perspective based on the rates provided by the utility, it's clearly better to use an electric resistance heater rather than LP.  However, personally, I would much rather upgrade the fireplace to a level suitable for daily practical use.  Your fireplace is really right where the heater wants to be, and given the way you use this place as a north woods retreat of sorts, it seems only natural.  Of course you would for sure want something that gets its combustion air from the outside and is reasonably efficient.  A third option, would be a cheaper gas wall furnace that is capable of running with or without the fan in case of a power outage.  Not as efficient as the Rinnai but it would give you peace of mind in case there's an extended power outage.  They're tall and skinny; consider putting one in the corner behind you're dinning table.



    New topic:  Here's my thoughts on where the heat is going. 



    #1.  Smaller homes require more btu's *per* square foot to heat.  Not total but more per square foot.



    #2a.  I really don't think you are reducing the heat far enough to get any significant saving while you are gone.  The house is in a really cold winter environment.  It's architecture and solar orientation are not helping.  When its -14 degrees outside, a setback from say 70 to 55 doesn't help that much.  I checked your billing information over one of the colder months and compared it to the heat loss information using a correction factor based on the average temperature at a nearby town during that time period.  *I got a decent match.*  Heat loss is proportional to the delta T between the indoor and outdoor temps.  The colder the environment is, the larger the setback required to achieve a noticeable percentage of savings on one's bill.  On the other hand, the good news is it wouldn't cost much more to actually live there. 



    #2b.  You're setting the thermostat back while you're gone but not the system supply water temperature.  Higher water temperatures imply higher thermal losses into the ground.



    #3.  Too much inherent system lag due to thermal inertia:  A small home needs a responsive heating system, particularly ones with extra windows and cathedral ceilings. Changes in outdoor temp or solar gain quickly translate into significant heating or cooling demand changes.  If the system can't modify it's output quickly enough it falls behind or overshoots.  Typically the occupant is forced to increase the thermostat setting and water supply temperature all day to maintain a minimum comfort level.  This in turn increases thermal losses through the slab and rest of the building envelope.  --Ultimately increasing your power bill.  Have you considered getting an internet connection?  There's a lot of thermostats on the market that can be controlled remotely, but more importantly, I believe there are units that are capable of receiving weather forecast data from the National Weather Service.  With this information, a slab system would be able to predict future demand changes instead of responding to them after the fact.  That would be a major improvement for you.  At a minimum though, I suggest adding an auxiliary heat source that can react quickly, with the floor temperature maintained for even base load.  That would give comfortable even floor heating with a faster response to occupant demands and changing weather.  With such a configuration you should be able to reduce your supply water temperatures and prevent some heat loss into the ground.



    #4.  Possible unresolved system issue, control issue, or lack of insulation.  Can you check the flow rates through the pex loops next time you're there?  Low flow may indirectly result in additional heat loss into the ground.









     
  • RobG
    RobG Member Posts: 1,850
    Another Idea

    How about using a glycol solution for the radiant, install a tankless gas water heater (you will now get the dual fuel rate). A tankless water heater can be drained down in under a minute. Get a good plumber over to show you how to drain down and winterize the rest of the plumbing system. In a small place like that, draining the system should take no more than 15 minutes. Then you can just kill power to the home while it is unoccupied. USING NO FUEL!.

    Just Another idea.

    Rob 
  • Eastman
    Eastman Member Posts: 927
    Have you ever

    used any kind of system that can receive weather prediction data over the net?  I see Mr Pex is advertising a new system that "recieves a constant stream of weather forecast information from the National Weather Service."  I assume it uses an internet connection for this.  That seems like the best way to run a slab system.
  • RCO
    RCO Member Posts: 51
    Thanks for Continued Suggestions!

    I appreciate the continued support with suggestions and opinions.  I can update you to the fact that I have had the Rinnai heater installed a few weeks back in the location show in the previously attached photos.  I'm pleased with the quiet operation of this unit.  Although we don't use it much.  I'm waiting for the snow to leave and ground to thaw so I can get an electrician in to hook up the radiant system to the 2nd meter for the dual fuel rate.  As close as it was to spring and that fact that the electrician would need to make 2 trips ( 1 to do a temporary connection at the meter post and then come back to dig the line in from the 1st meter to the 2nd), I decided to wait to save on labor and 2nd trip charge. 

    So starting next fall when heating is needed, I will be on a dual fuel rate.  I'm anxious to see how this works for us. 

    I've read the comments concerning the windows and loss of heat.  We know that we have to deal with this issue.  Actually we are not getting much heat gain when we are not up there as we have the cellular shades down and curtains drawn shut. I actually work for a storm door and window company.  I've had thoughts of installing storm windows on the Andersen units to help.  We now offer Low-E storm windows.  At my cost, I could purchase 13 windows for roughly just under $1000.  I guess I'm not sure how long the payback would be on those??  Our information tells us that we can increase insulation over plain glass by up to 69% with the addition of a storm window with Low-E glass.  As we currently have thermal pane Andersen units, we of course do not have storm windows on them as the unit comes with a full screen that snaps into the frame on the outside of the window.  The storm window I'm looking at is our top of the line unit as we have Low-E availablity in the 3 series of our storm windows.  However, the best series is the only one that offers a color that would most closely match the exterior of the place.

    So, that is where things stand right now.  I'll report back next heating season as to how things are going.

    Thanks!

    Ray
  • Eastman
    Eastman Member Posts: 927
    What about the flow rates?!

    Can you check the flow rates?  You shouldn't have to wait more than a few seconds for the manifold readings to stabilize.



    And while I have your attention, seems like there has been several suggestions for internet controllable thermostats.  Is there some reason you are not considering this?  How much is a cheap dial-up connection in that neck of the woods?
  • RCO
    RCO Member Posts: 51
    Update on Heating System

    Just an update on my heating situation.  I now have my electric boiler connected to a 2nd meter for dual fuel rate @ $.0602 per KWH compared to the general which is at $.1053 per KWH.  I've not been up yet to use or has there been weather at this point to need the heat.  The electrician set the thermostat for the boiler at 50 for now and the Rinnai heater at 45, I believe.  Plan on heading up there this next weekend.

    I have been investigating thermostats that I can remotely control.  However, it appears that most all require an internet connection.  As we don't have a phone nor satellite there, it would definitely be an added expense per month...probably in the $50 range.  Which wouldn't make sense at this point.  I've started looking into it because my dependable neighbor is going to be moving to town next spring....bummer!  This will make everyone on our road seasonal. 

    I've done some reading on the Nest thermostat.  Although it also requires Wi-Fi connection to use remotely.  However, it does indicate that it works well with radiant heat.  I guess worse case scenario is that we can leave at 58 and use the gas heater and infrared to heat place up quickly when we arrive in  the winter. 

    I'll keep you posted as to how the new system works and costs for this heating system.  Hopefully, we'll realize some significant savings in our electricty bill.

    Thanks!
  • NYplumber
    NYplumber Member Posts: 503
    wood stove

    I recently spoke to a customer of mine with a small cottage in a very cold climate. He has electric baseboard as the built in heat source. He says his wood stove is the key to bringing the place up to temperature
    :NYplumber:
  • Eastman
    Eastman Member Posts: 927
    Post #159

    The detailed energy usage history available with nest along with it's integrated occupancy senor are excellent features.  However, I believe the usage history requires the device to be in communication with a nest account at nest corporate.  In other words, that feature probably requires an internet connection to really make use of.  I don't think it is directly accessible from the device.  (Somebody step in and correct me if I'm wrong.)



    Regarding the "True Radiant" feature.  I can't see how the device could have a chance of accurately predicting the response time of your slab unless an ODR is installed on the heating system.  It could certainly learn what is required if the weather remains steady, but that doesn't seem like a realistic expectation.  Does the nest monitor the outdoor temperature?  Likewise, your infrequent cottage usage pattern would probably exacerbate such algorithmic learning problems.
  • nicholas bonham-carter
    nicholas bonham-carter Member Posts: 8,578
    Extra source of heat

    No one has mentioned an additional heat source--get more dogs!!--NBC
  • nicholas bonham-carter
    nicholas bonham-carter Member Posts: 8,578
    Internet thermostat

    Maybe you and your neighbors could share an internet connection for the remote monitoring.--NBC

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