Hot Tub Forum
Original => Hot Tub Forum => Topic started by: Steve on September 08, 2004, 12:01:41 am
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I was speaking to someone very knowledgeable in our industry today. One of the comments he made was that all spas are comparatively efficient with the cover on.
Do you feel this is a fair statement?
Steve
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My guess is that for most spas of similar size...that it would be true of quality tubs...that yes the cost to run the spa would be of a comparable price....how ever some spas of some of the major manufactures do require to step up to 60 amps while other in the same class or size of spa will off of 50...
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Mom always said, "wear a hat, you lose most of your body heat through your head."
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that all spas are comparatively efficient with the cover on
I have to disagree with this. Not that I have any specialized education in this, but I do have some empircal support for my postition.
As a service technician, Ive had the opportunity to own a number of different spas.
One of my first was a 110v API - a now defunct company that produced spas in the late 80's. The shell was insulated as I recall with about 4" to 5 " of foam and wasnt a full foam spa, The cabinet while complete was not insulated. This spa ran frequently to keep temps into the 102-103 degrees F range. My first power bill was up more than $40.00 just to operate the spa.
Later on I aquired a 1990 HotSpring Prodigy, which is also 110v. The percievable difference though is this spa is full foam, runs a small circulation pump, and only cost me $10.00 a month to run.
I think there's more to a spa's energy efficiency than a good quality 'hat'... er, a spa cover.
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So if this is a true statment then there is no need to own both a heavy winter coat and a light fall jacket. Just get lighter and heavier hats!
Steve, does the guy that told you this go sking in speedos and tank tops as long as he has his stocking cap on?
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Stuart
I just lost my breakfast at that thought :o :o :o
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Mom always said, "wear a hat, you lose most of your body heat through your head."
There is an assumption in that old saying that you've already bundled up with an approprite coat and merely need to be reminded about the head!! Mom would have had a fit if you didn't have a heavy coat on as well.
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There is an assumption in that old saying that you've already bundled up with an approprite coat and merely need to be reminded about the head!! Mom would have had a fit if you didn't have a heavy coat on as well.
Of course not, but the statement doesn 't imply that a cover is the only needed insulation. But the best insulate spas aren't going to do nearly as well with no cover or a poorly fitting cover.
Steve didn't state where in the industry the person who said it works. I would consider it a valid argument for a good quality cover without starting the old Thermopane/Full foam argument for the umpteenth time.
Of course Steve did say, "Is this a fair statement" Fair, I guess not, but it does have some validity.
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Awfully extreme wording, to me. All??? Some, most, many, may have been better qualifying words to use.
But what do I know? Just an observation on the statement!!!
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No Steve I do not buy that statement.
IMHO,
While a good insulating cover is important, the vessel (The Hot Tub) itself acts like a huge heat sink, pulling heat right through it. Fiberglass and acrylic are very poor insulators of heat. If you have ever owned an uninsulated fiberglass truck canopy you will find that it sweats because fiberglass is a very poor insulator. The same thing happens with boats. That is why the inside walls of fiberglass boats are insulated with a very fiborous carpet to insulate it and increase its evaporative qualities to prohibit sweating caused by the conductive qualities of fiberglas transfering the cold temperature of the outside water.
So the more foam insulation on the underside of a spa the better to stop this transfer of heat loss and the more efficiently the tub operates.
In very cold climates, like the northern part of the US and all of Canada this is a very important factor to consider.
Of course because of the evaporative properties of hot water, the surface presents the greatest heat loss of all, so a good quality thermal cover and an insulating blanket are your best defense from losing surface heat energy.
Beyond the heater, there is only one other factor in operating costs and that is the size and number of electric pumps. The fewer pumps the less it costs to operate.
Regards, Zz
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Awfully extreme wording, to me. All??? Some, most, many, may have been better qualifying words to use.
But what do I know? Just an observation on the statement!!!
I think Steve was intentionally being as vague as the person he quoted. He may have more for us later and this was a feeler.
Bill
Always the conspiracy thinker
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No Steve I do not buy that statement.
IMHO,
While a good insulating cover is important, the vessel (The Hot Tub) itself acts like a huge heat sink, pulling heat right through it. Fiberglass and acrylic are very poor insulators of heat. If you have ever owned an uninsulated fiberglass truck canopy you will find that it sweats because fiberglass is a very poor insulator. The same thing happens with boats. That is why the inside walls of a fiberglass boats are insulated with a very fiborous carpet to insulate it and increase its evaporative qualities to prohibit sweating caused by the conductive qualities of fiberglas transfering the cold temperature of the outside water.
So the more foam insulation on the underside of a spa the better to stop this transfer of heat loss and the more efficiently the tub operates.
In very cold climates, like the northern part of the US and all of Canada this is a very important factor to consider.
Of course because of the evaporative properties of hot water, the surface presents the greatest heat loss of all, so a good quality thermal cover and an insulating blanket are your best defense from loosing surface heat energy.
Beyond the heater, there is only one other factor in operating costs and that is the size and number of electric pumps. The fewer pumps the less it costs to operate.
Regards, Zz
Personally, I agree with ZZ. I would add one more item for consideration: Heat will travel in any direction: it always goes from hot to cold.
The idea that 'heat rises' is incorrect. Hot air is lighter than cold air, and hot air rises (unless you put it into air that is hotter still...). I think that is where the false idea that a spa's cover is the most important part of the insulation comes from. If you put a 6" thick cover on an in-ground spa, and shut off all motors and heaters, it will be cold in a couple of days. Do the same with a full-foam spa and it will lose only a couple degrees per day. It may take it weeks to get cold.
And before anyone tells me to go stick my hand over a candle: I know that the heat from an open flame also tends to go straight up. But the radiant heat from a campfire goes in all directions, including down into the ground.
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From a thermodynamic standpoint, the rate of heat transfer is a direct function of the difference in temperature between a fluid, and the boundary layer of the material which surrounds it. Yes heat radiates in all directions. However, as those of us who have held a foam cup of liquid ( pick your liquid ) can attest, the boundary layer of the foam, nest to the liquid warms to a temperature near the liquid, and resists further transfer. If the top is open, thermal flow will keep a continuous supply of cooler gas close to the liquid, and a majority of energy will be lost from the top. Lids and other devices retard this transfer by restricting the thermal flow.
BobB
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lol...did I mis read this question or statement...I thought what was being asked or suggested was that most spas of same size cost the about the same (energy) to operate....did I totally miss it...
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Taking the devils advocate...I would be a little more likely to agree. Look at the way we build houses. The attic is insulated and the walls are insulated...but not the basement floor. Heat rises, otherwise hot air balloons would be less enjoyable. IMO.
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Taking the devils advocate...I would be a little more likely to agree. Look at the way we build houses. The attic is insulated and the walls are insulated...but not the basement floor.
No comparison. Houses are not filled with water, and the whole house is the living space, the walls are all we have to keep in the heat. By contrast, the spa is a container of water, and the air space, if there is one, is designed as part of the heat retention system or insulation scheme. My house has no insulation in the walls, and very little in the attic becuase I live in paradise. The house I'm building up in the mountains will have insulated floors. Your next statement; Heat rises, otherwise hot air balloons would be less enjoyable. IMO.
Is incorrect. Heat doesn't rise: it goes in any direction from hot to cold. Any direction. The reason a hot air balloon rises is because HOT AIR is less dense than cold air, and yes, HOT AIR will rise above cold air. But that is not synonymous with heat rising. In fact, if you looked at a hot air balloon with thermographic imaging equipment, you would see it 'bleeding' heat in all directions. And you would see huge convective currents moving about inside of the envelope.
A tub keeps its heat best if it keeps all forms of heat transfer to a minimum - in all directions. I will say that in my experience 4 to 6 inches of foam insulation is about all that is needed. Going beyond that will not get you a spa that will keep the heat in better. Insulating the bottom of a spa is important: if you don't believe that try to keep an in-ground tub warm for a week with the pumps/heat off and the lid on.
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Houses are not filled with water, and the whole house is the living space,
unless you live in FL......
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Ah, you guys are great! And may I add somewhat predictable too! ;D (said respectfully)
The lovely Lori brings up a valid point. In attempting to recall his exact words, I changed that word a number of times prior to posting. I'm almost certain, but he might have said most as well. ??? Let's go with that instead maybe... ;D
As my friend Bill (careful, I'm filming you over your left shoulder as you're reading this ;D) mentioned, there is a reason. Now, I have to be careful as most know me as this FF advocate that excepts no other alternative but it opens up dialog if nothing else.
As the intelligent ZZ mentioned, heat does travel through acrylic ( and fiberglass as well) quite easily as it's a poor insulator in itself. What if there was a small area underneath the acrylic that utilized the heat transferred from the tub itself and back when the pumps were running? Pumps do generate about 120 degrees on high speed and would this area not help with proper heat induction?
I have always disagreed strongly with companies like Arctic that want to take a design and try to heat a very large area with pumps that run usually 4 hours a day generating 112 degrees on low speed. It's far too large an area to trap heat effectively in cold climates. But what if the majority of the spa was foamed with this small area directly under the entire shell allowing the induction of heat? It makes great sense to me though I have nothing to back up any words of superiority at this point. ;) I’ll letcha know if that changes!
Both acrylic and fiberglass allow the induction of heat effectively. This is an instance where allowing the transfer/induction of heat when the motors are running on a high speed and generating 120+ degrees, to help in the efficiency of the spa once the cover is off. (practicing my sales presentation on you guys! ;) ;D )
Understanding that the majority of the heat is lost in surface area once the cover (hat) :) is removed, this application in a small area under the acrylic is functional. It's also the area where the plumbing is for easy access and heat transfer. In the Hydropool spas, this design is standard and for one, I really like it. It's not a real stretch from Beachcomber with the slight variation of not allowing wasted heat when the pumps are running on high speed and the cover is off.
Getting back to my question though, I do believe that if you took the top 10 manufacturers in the spa industry and ran them all side by side, the operating costs won't vary more than a few bucks a month with the covers left on the entire time in the same conditions. I do believe that to be quite accurate and have always felt that way.
Just pondering benefits of alternate methods that we as salespeople are trained to disclaim without sometimes taking the time to consider. I'm as guilty as anyone in that regard though Arctic still sucks! lol... ;D
Steve
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I think you have to make assumptions with Steve's statement. Two assumptions that should be made IMO are: 1) your talking about tubs of the same quality and 2) the tubs' sides are insulated to some extent.
As Bobb stated there are laws in thermodynamics (unfortunately I didn't study it so I can't elaborate) and all things must follow these laws just as they do in physics (I did study this).
Heat does radiate (radiant heat) in all directions but hot water does rise as hot water is lighter than cold water (oceans and lakes) and some 2 story houses are warmer on the 2nd story than the 1st, this property of water and air is called stratification.
As huh? stated we insulate attics and walls. The recommendation has always been to add insulation in the attic to slow the flow of heat upward.
Also, there is a law of diminishing returns when it comes to insulation. A blanket statement that if Y" of insulation is good then 2 x Y is better is wrong. Without knowing at what point the insulation isn't being efficiently used could end up wasting more money insulating than saved in heat retention.
So after all that said I guess my answer to that comment would be - Yes, this is a fair statement.
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Steve,
I thought I knew where you were going when you started this but now you brought in the top 10 manufactures.
Please stick to one debate at a time! ;D
Vinny
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Rule #1 Vinny... Never follow me cause one never knows where I'm going... ;D
Steve
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I can answer this question, hey that degree in chemical engineering comes in handy once in a while.
heat loss is calculated using the following equation
q= K(eff) A dT
q= heat loss
K(eff) = Thermal Conductivity
A = surface area
dT = Temperature differential
simple enough. The trick of minimizing heat loss is to minimize the K(eff) or the surface area. Temperature is generaly beyond our control, unless the tub is in a house.
1) all materials have thermal conductivity (TC) coefficients. If the hot tub was made of aluminium (very high TC) for example there would be very little to restrict the flow from hot to cold. The comment about the shell being a realtively poor insulator (e.g. high TC) is true, relatively.
2) most insulation materials attempt to trap air which has a very low TC coefficient. This is called for lack of a better word creating "dead-air". Thus increasing the thickness of foam or using foam made from a material that has a low thermal conductivity coeffiecient is important. As anyone with an attic knows, increasing the thickness of the insulation decreases the Thermal Conductivity.
3) in order to calculate the effective Thermal Conductivity it is related to the inverse sum of the indivdual layers
1/Keff = 1/K1 + 1/K2 + 1/K3 +++ 1/Kn
where K1 and K2 represent the thermal conductivity of each layer of insulation.
if i remember my thermo correctly.
1/Keff is basically the R value of insulation.
4) so the base of the tub gets insulated but is is also the space to the outside and the wood or plastic that is in part of the tub, and the base.
5) A hot tub that is molded with minimal nooks and crannies is therotiacally a bit better as the surface area is minimized when the insulation is applied.
6) The top is another consideration. Although we have an air pocket above the water this air is not truly "dead air" so its insulation effects are less. The cover and thickness of the insulation are what minimzes heat-loss.
7) so the key to minimizing heat loss is placement of the tub in a wind shielded area, and minimizing the losses from the bottom. So there will be a difference if you locate the tub on a deck or ground.
that stated, I need to determine the allowable heat loss from a can of beer using a foam insulator.
;D
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God I hated math!!! :P
I have enough problems balancing my checkbook. Maybe because I don't have any money in it. Somedays I can't afford to pay attention. ;D
When I get my tub, I just want it to work. Period
r100rs
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When I get my tub, I just want it to work. Period
r100rs
You are 100% correct r100rs and my post wasn't meant to cloud the real benefits of ownership, but rather open up a debate for those of us hardheads who take it to a level most don't care the least bit about (nor need to)! ;D
Steve
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Well, FWIW I was doing ok with this thread, (enjoyed the hot air ballon ride - nice explanation Chas!) until Shut_Down told me to calculate heat loss thus: q= K(eff) A dT.
After I thought about it a while, yeah I can follow that. But the next step was a little tougher ("the effective thermal conductivity is related to the inverse sum of the indivdual layers thus: 1/Keff = 1/K1 + 1/K2 + 1/K3 +++ 1/Kn.") Now that made my eyes kinda glaze over and they still aren't focusing quite right.
But you landed me safely again with ". . .to determine the allowable heat loss from a can of beer using a foam insulator.") Now THAT I can work with and I've decided to design & market a beer cozie using the thermo-pane design. I figure I'll capture the "other half" of the can cozie market. (and I think that's pretty broad minded of me considering I've always been a full-foam cozie kind of guy.) ;D
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LMAO!! :D Great post UTS! See...we can all change.
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(http://larissmix.typepad.com/cozy_of_the_week/images/40cozy.jpg)
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Rule #1 Vinny... Never follow me cause one never knows where I'm going... ;D
Steve
That is why I replied to the statement, not the content, so to speak!!!
wmccall, I knew the other shoe would drop, but I figured I would bait Steve a little!!! Hey, why not, he baited the other professionals on here!!!
LOL!!! Gotta love ya, Steve!!! ;)
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Taking the devils advocate...I would be a little more likely to agree. Look at the way we build houses. The attic is insulated and the walls are insulated...but not the basement floor. Heat rises, otherwise hot air balloons would be less enjoyable. IMO.
Well speaking from years of experience within the housing industry. Chas said it correctly, warm (hot) air rises whereas heat goes from hot to cold.
In North America we have strong building science but terrible application of that science. We fill attics (typically R-40) and have OK walls (typically R-20) but nothing in the basement. Over 20% of the heat loss occurs through the foundation. And so it is very important to have full height insulation and even more important to have underslab insulation. The same principle applies to hot tubs. Although a cover is extremely important in that it provides a barrier to heat loss, insulation in a hot tub in the wall structures and underneath is equally important. Thermodymanics 101
Now in re-reading Steve's original post ''all spas are comparitavely efficienct with the cover on'' I tend to dissagree. Because of the heat loss that can occur due to poor insulation in the walls or the underside of a hot tub.
But then again, we can all get in on the beer cozie thing and make millions. UTS can we buy shares?
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I am a neophyte spa'er, tubber' darn it, I don't even know what you call folks who like to hang out in hot tubs.
As a high school science teacher, I am impressed with the professional analysis of thermal coeffiecients and more so with the discussion on air pockets. I am waiting for the heat vector analysis and I'll be set.
I must say though as an avid home brewer.....that after all of this discussion, I most strongly concur with those of you who just want to relax w/ a good beer or a great wine and a warm spot w/ a great view.
This is a great forum that has helped me a lot, I have learned a ton and most definately saved myself from hot tub hysteria brought on by the purchase of a poor system. That being said, I am still looking for the best tub.....
Keep that info comin'
Mac
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Are you going to put your tub out in a scalar field?
;)
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Only if you're looking to determine the temperature distribution throughout space.
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Color me stupid, but as this relates directly to hot tubs, I think it is relatively harmless.
There are always assumptions to be made. So assuming we are talking about any of the many favorably looked at brands, most heat will be lost from an ill fitting top, assuming the top is not ill fitting, there will be little heat loss when the tub is not in use and is properly closed.
Thus the original statement - too me is accurate and harmless (unlike the current political administation - not that the alternative is any better).
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NEWS FLASH!
At 9:53 am, DooDoo asked about buying shares in my soon to be "Thermo-pane Beer Kozie" company. I'm happy to report the following progress: Initial offering structured and have applied for listing on the New York exchange. Ticker symbol took some thought (wanted it to suggest "Beer" and "Kozie") and we applied for "BKZ" The rep from Securities Exchange Commission asked, "Why BKZ?" and I said, "BeKauZe."
We are still in the product R&D phase (thank you Chas for your photographic submission, we'll let you know.) Still looking for a manufacturing facility. Confident I can convince Steve to handle distribution and will look to DrSpa for web outlet. DooDoo, please forward $1000 (paypal or unmarked bills) so I can reserve the first block of shares in your name. Thank you all for your support and we'll keep you posted.
THERMOPAIN, THE OTHER CAN KOZIE
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Chas,
"No comparison. Houses are not filled with water, and the whole house is the living space, the walls are all we have to keep in the heat."
I'm not comparing living spaces but insulation. Besides the walls (insulation) of the cabinet, what else holds in the heat of the tub.
"My house has no insulation in the walls, and very little in the attic becuase I live in paradise."
What do you want, a cookie? Mine has insulation and a few 14ers nearby, also paradise.
"The house I'm building up in the mountains will have insulated floors."
At least your feet will be warm. You will, of course be insulating the walls and attic too, right?
"...and yes, HOT AIR will rise above cold air. But that is not synonymous with heat rising"
Hot air will rise...not synonymous with heat rising. (insert my handle here)
"The reason a hot air balloon rises is because HOT AIR is less dense than cold air"
Finally something I agree on.
"Going beyond that will not get you a spa that will keep the heat in better"
I agree again
"Insulating the bottom of a spa is important"
and again
"if you don't believe that try to keep an in-ground tub warm for a week with the pumps/heat off and the lid on."
Bad comparison. Where I live our "freeze line" is 28". Because of that, we build foundation walls graeter than 28" deep, typically 4'(for acces reasons and without a basement). At 4' deep (no mater location, ie. paradise, boston, LA, alaska) the temperature of the soil will not vary much from 54 degrees. Where I live we do insulate concrete walls, but not floors. I believe that an in-ground hot tub with insulated walls (and cover) protruding into the 4' point would not require an insulated bottom. However, with a spa sitting on a slab above ground or any deepth less than say 4', I would recommend an insulated bottom.
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I came up with a great idea - a full foam thermo-pane tub.
This is for use with U.T.S. thermo-pane beer kozie.
This is how it works: You build a structure and you get the shell with the plumbing and put R-40 insulation around the whole shell parameter. Next build a 2x4 frame and add 14 inches of dead air space. this is where any and all motors will go. Finally, you enclose all of the above in plywood and you add another R- 40 to that parameter. Of course you have the choice of skirting materials.
OK it does sit about 6 1/2 feet tall and the cabinet is 6 feet bigger than the shell but NOBODY will beat the insulation value. Now for the cover ... anyone have a hoist!
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Here's another idea for building that spa.
Full foam the cabinet from outer wall to shell, wrap the entire spa just inside the cabinet and on the bottom with a LOW E wrap for the "closed cell" effect, make it so that the when the motors are running you have tubes that pull that heat out on a venturi back into the water to not lose it.
Great idea! Wait, that’s already being done! It's called a Marquis! ;D :D
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Stuart,
That idea won't work because I know that the foam has to put on from the shell to the cabinet NOT the cabinet to the shell as you stated! :D
And besides I'm still waiting for all you professionals to come up with who's the top 10 TP manufacturers and top 10 FF manufactures and which manufactures in either category is better than the other manufacturers in the other category and if we can mix and match different tubs with different covers to achieve the desired result. ??? Whatever that may be.
I think this is where Steve was going when he started this thread! ;D
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Vinny,
The process can and does work! I put the steps in the wrong order so I will elaborate; They tack the "Low E" wrap around the inside of the cabinet and then foam the entire cavity, finally they save the excess from the bottom of the spa and put another sheet of "Low E" on the bottom before sealing it off with a DuraBase.
As far as the to ten in each category I don't think I could give you ten top spas with TP and would have a difficult time justifying 10 in the FF either (although I could come up with more FF than TP).
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Stuart,
I was only goofing in the whole last post. I know Marquis uses some kind of wrap in their insulation system, where they put it I didn't know. It was my stupid attempt at trying to be funny.
Actually I think Coleman and I know Emerald uses aluminized "bubblewrap" as some of their insulation. Emeralds is an optional insulation package. The aluminum reflects the radiant heat back as does the low-e coating (I once saw low-e paint for attics and walls being advertized - I thought it was an interesting idea). Only thing it's the last process, not the first.
You guys do a great job in helping us non professionals out, but I do chuckle about the FF vs TP debate and the 'what's the best'. At times it seems to get so heated. Hopefully you all sell products that you believe in, so "the best" should be your product or products.
My personal belief is that all quality tubs will operate efficiently and effectivly but feels differently to different people.
Vinny
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Vinny,
Sorry for not catching it as a joke, I just finished another fair and it has been a very hard show season. I feel like I have been in a yearlong debate and have a problem stepping out of that mode.
Funny story for you though to let you know how punchy I am;
After 3 weeks of selling 16 to 18 hours a day I was working with a couple on a spa, they were quite challenging and would ignore half of what I said or cut me off, I had just gone through all of the colors available when she asked "Can't you get this in a Purple color?" I looked at her for a long moment and stated "Yes, it does come in purple, in fact the whole warehouse is full of purple spas but I really didn't want to sell you one so I kept that little secret from you!!"
After a bit of groveling on my part they bought a blue spa from me.....
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Maybe you can look into that low e paint ... it may come in purple!
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lol at the responses,
even, engineers are allowed to relax and drink their beers in the hot tub while pondering the elegance of the combination of pumps, water, chemistry, plastics and heat loss.
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Steve, I think you need to read back in my post's before I bought my tub. Not on this board though the other one, pooh and spit. I asked and asked and made plenty of assumptions regarding what style of insulation to choose because of my theorys and convictions regarding how much foam and how to utilize waste heat and how I wanted a combination of the 2 types of insulation and some minor modifications to achieve what I feel is a better insulation method than both FF or TP. Now your talking about it...LOL I have a sweet spot I call it where most of the waste heat is generated and transfered into the water. I also have a thermostaticly controlled cooling fan and gravity dampers allowing venting in the summer yet seal tight in the winter. I have 4-8 inches of foam on the entire shell (except the equipment area) supporting the plumbing. Reflective R-12 surrounding the entire cabinet with sealed seams (including the access door), Ducting to force air over the motor when cooling is required, or air is called for in air blower operating. And it works very very well. The foam acts to preserve heat during non fitration times and the R12 reflective acts to force feed the vessel heat during filtration. Even during below freexing temps (down to about 10-20 degrees F) I still can see some temp creep. Below 10-20 F heater use is still required but reduced, unless I up filtration times but that to me don't seem that smart (premature motor failure) at the cost of saving a less expensive heater element. Just so you know Steve I agree with your orininal statement a few cents per day difference on just about all brands as long as the covers are equal. I ride my bike to work one day a week to pay my tub electricity bill any way, so my tub cost's 0 dollars to operate per month!!
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Chas,
"No comparison. Houses are not filled with water, and the whole house is the living space, the walls are all we have to keep in the heat."
I'm not comparing living spaces but insulation. Besides the walls (insulation) of the cabinet, what else holds in the heat of the tub.
The lid. But my point is that a house is a house, and a spa is a spa. There are very few similarites, or direct comparisons. "My house has no insulation in the walls, and very little in the attic becuase I live in paradise."
What do you want, a cookie? Mine has insulation and a few 14ers nearby, also paradise.
Sure - I'll take a cookie. Home-made, chocolate-chunk, Tollhouse recipe would be fine. I have milk. What are (is) 14ers ?? "The house I'm building up in the mountains will have insulated floors."
At least your feet will be warm. You will, of course be insulating the walls and attic too, right?
Yes - we are building the walls with 2x6 to allow 5" of insulation in the walls, and we will insulate the attic heavily. My point was that since heat does in fact go in any direction from hot toward cold, the insulation in the floor is valuable in keeping the house cool in summer and warm in winter. "...and yes, HOT AIR will rise above cold air. But that is not synonymous with heat rising"
Hot air will rise...not synonymous with heat rising. (insert my handle here)
The point here - and I admit I may not have made it perfectly clear - is that hot air rises, but HEAT will go in any direction. This cannot be stressed enough: heat is heat and air is air. Becuase hot air rises, people think that heat only goes up. That is simply not true. Heat can and does go in any direction, but always goes from hot toward cold. Sitting in front of a fire should tell you that: the warmth you feel is not connected with hot air rising: it is radiant heat, and it radiates in all directions. The fumes from the fire go up the flue because it is hot air. "The reason a hot air balloon rises is because HOT AIR is less dense than cold air"
Finally something I agree on.
Well, the other things I have mentioned are physical laws. If we disagree on those, one of us is wrong. I think its a matter of me not making my point clear. Which is also related to hot air... Bad comparison. Where I live our "freeze line" is 28". Because of that, we build foundation walls graeter than 28" deep, typically 4'(for acces reasons and without a basement). At 4' deep (no mater location, ie. paradise, boston, LA, alaska) the temperature of the soil will not vary much from 54 degrees. Where I live we do insulate concrete walls, but not floors. I believe that an in-ground hot tub with insulated walls (and cover) protruding into the 4' point would not require an insulated bottom. However, with a spa sitting on a slab above ground or any deepth less than say 4', I would recommend an insulated bottom.
Most in-ground tubs are not insulated at all. Some are, but the insulation gets soaked early on, and is of no use from that point. So - you have hot water sitting in almost direct contact with the planet. And since we now all agree that heat will go in any direction (from hot to cold) we see that the heat will transfer from the hot water into the soil from all the walls and bottom. Also, most in-ground tubs don't have insulated plumbing, so when the pumps are on those pipes are giving up heat from the water. The thing that clouds this issue here is that most in-ground tubs have huge gas-fired heaters, which can re-heat the water in minutes. So it doesn't matter if the tub drops 10 degrees overnight - it can be hot again in the time it takes to turn the heater on, go lift the lid and get in. Give or take ten minutes if the heater is a bit smaller.
But a self-contained spa is designed to keep the heat in and keep the water at a stable temp, so it needs to be well insulated on all sides. And in my opinion, it should have an insulation scheme that allows it to keep its heat in if the pumps are running or not. So my favorite system doesn't count on the cast off heat from the pumps - rather it recycles that heat only when the jets are on.
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Thus the original statement - too me is accurate and harmless (unlike the current political administation - not that the alternative is any better).
Yea, that is what I was trying to say. Damm Alzhiemers anyhow!
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What if there was a small area underneath the acrylic that utilized the heat transferred from the tub itself and back when the pumps were running? Pumps do generate about 120 degrees on high speed and would this area not help with proper heat induction?
But what if the majority of the spa was foamed with this small area directly under the entire shell allowing the induction of heat? It makes great sense to me though I have nothing to back up any words of superiority at this point. ;) I’ll letcha know if that changes!
Both acrylic and fiberglass allow the induction of heat effectively. This is an instance where allowing the transfer/induction of heat when the motors are running on a high speed and generating 120+ degrees, to help in the efficiency of the spa once the cover is off. (practicing my sales presentation on you guys! ;) ;D )
Steve
You know come to think of it my caldera is FF but for the space right next to the pumps and heater.
So if I understand you right Steve there is a manufaturer that has already thought of this.
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Chas,
Sorry, I didn't get the point you were making. I understand the radiant heat thing as well. Chocolate chip is my fav too. 14ers refer to the elevation of mountains. With the rockies in my back yard, my paradise is a little colder than yours. What do ya say, lets forget about the Hot air balloons and grab one of the aformentioned coozies. I thinks its almost beer:30 anyway. Thanks for the discusion. 8)
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Chas,
Chocolate chip is my fav too. 14ers refer to the elevation of mountains. With the rockies in my back yard, my paradise is a little colder than yours.
AH! Real mountains. I've seen pictures of those. Yeah, our place is at about 25 feet: 70 degrees just about year 'round. Now, the mountain house will be at 5500 feet - snows several times each winter. But we get to choose when we go there!! What do ya say, lets forget about the Hot air balloons and grab one of the aformentioned cookies.
I'm with you!
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Little different here. My house is at about 5000 feet and my mountain house is at 8900 feet. Ever have that asmatic feeling by just sitting around?
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Little different here. My house is at about 5000 feet and my mountain house is at 8900 feet. Ever have that asmatic feeling by just sitting around?
LOL..the Rockies. You want cold come to Northern Minnesota, and snow sheesh up to our eyeballs most years. The worst part about the cold here is it is relentless. Minus 20 for 3 weeks then a break and a warm spell to 0. Then back to minus 15 and then t-shirt weather at 10 above. Then minus 30 and a warm sunny week with highs in the minus 5 range. For 2-3 months straight. Then we get minus 5 for lows to freezing for highs for another 1-2 months before and after the bad stuff. But boy the summers can be nice albeit short.
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Too da_mn cold for my blood. I was refering to the altitude.
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You want cold come to Northern Minnesota, and snow sheesh up to our eyeballs most years. The worst part about the cold here is it is relentless. Minus 20 for 3 weeks then a break and a warm spell to 0. Then back to minus 15 and then t-shirt weather at 10 above.
Dang! I'm going to have to go get in my spa just to get over the chill of thinking about that! :o
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Yea maybe I shouldn't of brought that up! Sigh...it's right here now. Had a couple freezing nights already so it won't be long...........gulp.
They say it makes you hardy, I think it makes you cold.
I do love to ice fish and snomobile though.
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That sounds terrific right now compared to Florida--both Bonnie and Frances skirted us here in the Panhandle and Ivan has us right in his sights. Could I send my tub up there for safe keeping?
8)
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WSD,
I'll make sure it gets plenty of use ;D
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NEWS FLASH!
At 9:53 am, DooDoo asked about buying shares in my soon to be "Thermo-pane Beer Kozie" company. I'm happy to report the following progress: Initial offering structured and have applied for listing on the New York exchange. Ticker symbol took some thought (wanted it to suggest "Beer" and "Kozie") and we applied for "BKZ" The rep from Securities Exchange Commission asked, "Why BKZ?" and I said, "BeKauZe."
We are still in the product R&D phase (thank you Chas for your photographic submission, we'll let you know.) Still looking for a manufacturing facility. Confident I can convince Steve to handle distribution and will look to DrSpa for web outlet. DooDoo, please forward $1000 (paypal or unmarked bills) so I can reserve the first block of shares in your name. Thank you all for your support and we'll keep you posted.
THERMOPAIN, THE OTHER CAN KOZIE
UTS. Put in the mail this morning an envolope containing the money. Bank was closed, so took some $1000 from the kids' Monopoly game.
Cheers!