Hot Tub Forum
General => Beating a dead horse => Topic started by: benalexe on June 22, 2008, 06:14:18 am
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I was recently in a dealer who carried only full foam tubs and he was saying that the cheaper ones are thermopannel and the LIPA (Long Island Power Authority) has tested the full foam and showed they are very very energy efficient. I thought the thermopannel were effficent too until he told me he raw hard data.
Just wondering if anyone else had any thoughts.
FYI the spa I also saw did not have an air blower. I personally would really miss it.
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This question is the reason the Dead Horse section was created.
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wmccall....but for incoming freshmen it's a new question!
(http://i269.photobucket.com/albums/jj72/MWSPHOTO/deadhorse.gif)
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I was recently in a dealer who carried only full foam tubs and he was saying that the cheaper ones are thermopannel and the LIPA (Long Island Power Authority) has tested the full foam and showed they are very very energy efficient. I thought the thermopannel were effficent too until he told me he raw hard data.
Just wondering if anyone else had any thoughts.
FYI the spa I also saw did not have an air blower. I personally would really miss it.
The war is about to start again. You can look at some of the older pages and fine whole threads on this. In a nutshell the dealers that sell thermopane will say they are better and the dealers that sell full foam will say that they are better. As I am not a dealer or a energy expert (nor do I want to spark the war again) I will refrain from adding my opinion to this question.
Dave
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I think I can sum up this argument with a few points.
Full Foam:
1. full foam does a good job of keeping heat from leaving through the bottom of a spa.
2. Full foam does a great gob of keeping the pipes secure. Secure pipes move less. The less a pipe moves the less leaks you will have.
3. Full foam makes it a bitch to fix a leak (most spas have a 5-7 year warranty against leaks, so that is the repairman's problem.
Thermal Pane:
1. Thermal Pane does a good job of keeping heat from leaving through the bottom of a spa.
2.Thermal Pane leaves the pipes open where it is easier to find and fix leaks. (since the pipes are hanging and can move they will weaken the glue and clamp joints much faster...so there will be more leaks to fix.)
The truth:
1. Heat rises. It finds the path of least resistance to escape.
2. In an average climate you loose 90% of you heat through the cover (or where the cover meets the spa)
3. If I were a customer concerned with energy and heat loss, I would spend more time making sure I get a GREAT cover and not being so concerned with "marketing hype"insulation methods.
For the record I own a full foam spa from Jacuzzi. If I found a spa that I love, I would have no problem owing a Thermal Pane spa.
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Micah hit it on the head.
I was going to say the last paragraph. Now I do live in Vegas but I bought a spa blanket from Dr. Spa and my heater does not come on very often. Of course it is 108 degrees outside but the blanket keeps the heat in the tub during the evening. Heat rises, do you insulate the attic or the basement of your house? I'm no engineer but full foam vs. cabinet insulation is the insulation in the walls of your house. Full foam helps keep the pipe joints in place. Pane insulation helps access the pipes. I'll bet you won't see much difference in heating costs between the two.
See I almost said the same thing Micah did, I should have just said ditto.....
Scott ::)
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Unless you get a T-P spa that isn't sealed tight. The cheap T-P spas aren't sealed. Arctic does a good job of sealing everything so the T-P works for them better than the cheap ones.
If you get a cheaply foamed spa the same thing can happen. Some foam is such low density, it doesn't do much good.
Either way, if you go with a high quality spa, you'll have good insulation.
I do still have my preference, but I won't go into that here.
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The truth:
1. Heat rises. It finds the path of least resistance to escape.
2. In an average climate you loose 90% of you heat through the cover (or where the cover meets the spa)
Sure sounds good. Unfortunately, it is completely wrong. Heat goes in any direction from warm to cool (hot to cold). Any direction.
Hot air rises, but that is not germane to this discussion. But don't feel bad, it comes up every time this discussion does.
So does the analogy comparing insulation in a house attic. No connection whatsoever. One is a box of air at 72F, the other is a box of water at 102F with air spaces around it.
If you take a poorly insulated tub and put a great cover on it, you will still pay a fortune to keep it hot. You will also hear a lot more noise, and have the plumbing rattling around when the pumps start up.
Also - the less dense foam insulates better than the more dense foam. More air.
8-)
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When water is hot, the molecules are hot so they want to get away from each other and expand. Also as temperature rises, the molecules go crazy in the sense that they move faster. That's why when water is heated, it rises, and boils.
I love having this conversation. Have we talked about this before?
I kid, I kid, quote from Triumph the dog.....
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I suggest pouring a tall drink, get a snack, find your most comfy chair (although you didn't sit in it prior to buying it ;) ) and search the PAGES of debate on this subject over the past 5 years on here benalexe...
nuff said...
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Sure sounds good. Unfortunately, it is completely wrong.
If you take a poorly insulated tub and put a great cover on it, you will still pay a fortune to keep it hot.
8-)
So the study that shows that in an average climate (Southern California to be exact) you loose 90% of your heat through the cover or where the cover meets the spa. Are you saying that is incorrect.
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So the study that shows that in an average climate (Southern California to be exact) you loose 90% of your heat through the cover or where the cover meets the spa. Are you saying that is incorrect.
SO CA is an "average" climate? :-?
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Study? What study?
As chas says, HEAT does not rise. Heated substances though do rise. Air or water, when heated expands. This make it lighter than what's around it, and it rises. This, is called convection. Once that heater "substance" hits a solid barrier, convection ends, and conduction take over. Heat will conduct rather equally in all directions. Hence the reason homes floors are insulated :)
Now, as for more heat escaping through the cover compared to the sides of a spa.... well, figure out the R values. The average cover is R-12 - R-14. Put 6" - 10" of full foam insulation around a spa and yeah, way more heat will travel through the thinner cover.
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I suggest pouring a tall drink, get a snack, find your most comfy chair (although you didn't sit in it prior to buying it ;) ) and search the PAGES of debate on this subject over the past 5 years on here benalexe...
nuff said...
That's what I tried to say earlier!!! ;D
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Now, as for more heat escaping through the cover compared to the sides of a spa.... well, figure out the R values. The average cover is R-12 - R-14. Put 6" - 10" of full foam insulation around a spa and yeah, way more heat will travel through the thinner cover.
It all depends on the combination of your spa. If it is a well insulated spa with a cheapo low R cover then sure, you'll lose a great deal of energy out of the top. If however, you have a great cover and poorly insulated sides then much more of that energy loss will be out the sides than in the previous example.
You don't just need a good cover, you need a well insulated spa in ALL directions.
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I was recently in a dealer who carried only full foam tubs and he was saying that the cheaper ones are thermopannel and the LIPA (Long Island Power Authority) has tested the full foam and showed they are very very energy efficient. I thought the thermopannel were effficent too until he told me he raw hard data.
Whee! Arctic dealers must love this kind of argument!
However, the part about "raw hard data" really caught my attention. I want it, I want it! Get that dealer to provide you the data, in print or via a web site. Share it with us. Data (and details of how the data was obtained so its validity can be determined) is the best starting point for a discussion.
Meanwhile, for the only independently obtained comparative data (comparing different brands) I've seen in five years on the job, go to http://www.arcticspas.com/index.php/en/custom_content/12/12/. This is the only test I've seen where the independent lab conducting the test is identified (others just say "an independent research organization" and won't even respond to polite emails asking 'who did your study' Though maybe I'd get a reply if my email didn't go out over an Arctic Spas logo ::) 8-))
For discussion of the weaknesses of both these studies, and my defense of them, hunt through the "Beating a Dead Horse" forum. A search for "ARC Study" or "Arctic Study" will probably turn up more information.
Meanwhile, the Canadian Office of Energy Efficiency continues to move towards developing Canadian test standards (you know, Canada, where the mean annual temperature averages 7C/45F and winter temps are somewhat colder?)
Please shift the thread to BADH.
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I found the raw data interesting to since I have dtat from Clearwater showing that good thermopane is better insulating than full foam.
I think many others have hit the nail on the head, a quality tub, with quality insulation and cover are all going to be very close on how well they insulate.
As far as being more quiet when full foamed, my tub is very quiet with thermopane. Then again the thermopane is 2 inches thick and surrounds all 5 sides of the tub, again, quality plays an important role.
Hard facts that would impress me are those from previous customers that have actuall electric bills to show. Ask other owners of the brands you are looking at...
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I used to own an Emerald (a TP tub). One thing I know for an absolute fact is that I will never own a thermopane tub ever again.
Reason why? My own "raw data" in the form of a sky high electric bill. The Emerald more than doubled my electric bill.
Keep in mind that I live in Michigan. My wife and I were the only ones who used it so the cover was on most of the time.
I bought the tub new and ordered it with as much insulation as I could plus Reflectix. When the electric bills started rolling in I went to Home Depot and bought a box of Husky garbage bags and faceless fiberglass insulation. I filled the bags with the insulation and lined the interior with them. Royal Spas uses this same method except theirs hangs neatly inside.
I prayed to the hot tub gods for lower electric bills but they ignored my pleas. The DIY insulation did nothing for my energy costs. I sold that Emerald and we don't miss it one bit.
Now the only hot tub I will buy is a full foam. I will be looking for one with a good base. I won't settle for one that is "sealed" with just a poly sheet. I think that is just a way for a manufacturer to cheap out.
I can see a Jacuzzi 345 in my future but no Colemans or Arctic or Royal or Spa Crest. No thermopane ever again.
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I used to own an Emerald (a TP tub). One thing I know for an absolute fact is that I will never own a thermopane tub ever again.
Reason why? My own "raw data" in the form of a sky high electric bill. The Emerald more than doubled my electric bill.
Keep in mind that I live in Michigan. My wife and I were the only ones who used it so the cover was on most of the time.
I bought the tub new and ordered it with as much insulation as I could plus Reflectix. When the electric bills started rolling in I went to Home Depot and bought a box of Husky garbage bags and faceless fiberglass insulation. I filled the bags with the insulation and lined the interior with them. Royal Spas uses this same method except theirs hangs neatly inside.
I prayed to the hot tub gods for lower electric bills but they ignored my pleas. The DIY insulation did nothing for my energy costs. I sold that Emerald and we don't miss it one bit.
Now the only hot tub I will buy is a full foam. I will be looking for one with a good base. I won't settle for one that is "sealed" with just a poly sheet. I think that is just a way for a manufacturer to cheap out.
I can see a Jacuzzi 345 in my future but no Colemans or Arctic or Royal or Spa Crest. No thermopane ever again.
That’s fine that you don't want to buy a TP spa again, but I can tell you that comparing Arctic's insulation method to Emerald’s is like comparing apples to oranges. I have said this on here before, but Arctic doesn’t even refer to their spas as using Thermo Pane insulation. Arctic Spas are built differently than any other TP spa out there, and that is why they are as energy efficient as any FF spa. They've got the "raw data" to back it up. See the link that Tom so kindly referenced.
Why didn't you just go with the Emerald full foam option Chubby?? :-?
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What % of spas on the market are TP and what % are FF? Anyone know?
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Please shift the thread to BADH.
I'm watching, but for now, there is a little bit of originality this time, and I don't want to sqaush the enthusiasm of our newer members, but it will eventually get shifted there.
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As far as I know, Emerald does not offer a full foam option. Back when I was ordering mine a full foam option was never mentioned. I have not been to the Emerald website or read one of their brochures lately so fo all I know they may offer it now.
One thing I think Emerald (and Arctic and Royal) does a wonderful job with is their fiberglass shell. No doubt they are strong. They will never have structural issues. Wish I could say the same of their insulating method. I guess there is good reason why most of the major manufacturers use full foam.....It Works!
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As far as I know, Emerald does not offer a full foam option. Back when I was ordering mine a full foam option was never mentioned. I have not been to the Emerald website or read one of their brochures lately so fo all I know they may offer it now.
One thing I think Emerald (and Arctic and Royal) does a wonderful job with is their fiberglass shell. No doubt they are strong. They will never have structural issues. Wish I could say the same of their insulating method. I guess there is good reason why most of the major manufacturers use full foam.....It Works!
As far as I know, Emerald does not offer a full foam option. Back when I was ordering mine a full foam option was never mentioned. I have not been to the Emerald website or read one of their brochures lately so fo all I know they may offer it now.
One thing I think Emerald (and Arctic and Royal) does a wonderful job with is their fiberglass shell. No doubt they are strong. They will never have structural issues. Wish I could say the same of their insulating method. I guess there is good reason why most of the major manufacturers use full foam.....It Works!
Again, please don't lump Arctic Spas in the same category as the TP spas. They are not TP. Like I said before, in a third party independent test, Arctic Spas ranked right up there with some of the top FF spas, and even tested better than most. They are as energy efficient as any FF spa, even in cold weather climates like Michigan.
Here is how Arctic Spas are insulated:
(http://www.lushingtongardenrooms.co.uk/hottubs/heat1.jpg)
(http://www.arcticspa.lv/lat/img/models/heating.jpg)
Here is what your old spa used for TP insulation:
(http://www.emeraldspa.com/features_and_options/images/insulation_inset_1.jpg)
Again, there is no comparison. That is fine that you don't want to buy a TP spa like that again, as I wouldn’t either. But hopefully you can see now that there is no comparison between Arctic Spas and your old spa! They do it differenty than the other guys!
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Again, please don't lump Arctic Spas in the same category as the TP spas. They are not TP. Like I said before, in a third party independent test, Arctic Spas ranked right up there with some of the top FF spas, and even tested better than most. They are as energy efficient as any FF spa, even in cold weather climates like Michigan.
I wouldn't own a thermopane because IMO they just don't work as well as FF at avoiding heat transfer even if they promise their method works great and explain the theory. I do agree that Arctic is a different story because they don't follow the standard thermopane method and I can see why they don't like to get lumped in with the standard foil barrier methods.
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We are looking at a Sunrise that has neither Thermal Pane or Full Foam. It has Roxul insulatiion. It is a multi-layered instulation. Supposed to be much easier to work on if problems arise plus be great at insulating. It seems to me that full foam can be a major headache to repair...somtimes even having to send the hot tub out??? Is this true?? I know most have a 5 year warranty but lets's face it, you will probably have your hot tub a lot longer than that....so then what? I'm a newbie trying to figure it all out. Any truth to any of this stuff?
crystal777
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We are looking at a Sunrise that has neither Thermal Pane or Full Foam. It has Roxul insulatiion. It is a multi-layered instulation. Supposed to be much easier to work on if problems arise plus be great at insulating. It seems to me that full foam can be a major headache to repair...somtimes even having to send the hot tub out??? Is this true?? I know most have a 5 year warranty but lets's face it, you will probably have your hot tub a lot longer than that....so then what? I'm a newbie trying to figure it all out. Any truth to any of this stuff?
crystal777
I've never heard of Sunrise Spas but from their site I can see that they are a thermal pane spa even though they say otherwise for some reason. Also, most leaks down the road are in the equipment compartment (at the pumps, heater, etc.) so I wouldn't worry about the salesmanship you're being fed about imminent leaks and foam digs (and sending out a tub for leak repair is very rare so they're reaching). Leaks occur from poor quality so you're better off worrying about how well your spa is made, whether it insulates well and that you're buying from a manufacturer known for backing their warranty (most all warranties look alike, not all spa makers take care of their customers the same way).
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I used to own an Emerald (a TP tub). One thing I know for an absolute fact is that I will never own a thermopane tub ever again.
Reason why? My own "raw data" in the form of a sky high electric bill. The Emerald more than doubled my electric bill.
Keep in mind that I live in Michigan. My wife and I were the only ones who used it so the cover was on most of the time.
I bought the tub new and ordered it with as much insulation as I could plus Reflectix. When the electric bills started rolling in I went to Home Depot and bought a box of Husky garbage bags and faceless fiberglass insulation. I filled the bags with the insulation and lined the interior with them. Royal Spas uses this same method except theirs hangs neatly inside.
I prayed to the hot tub gods for lower electric bills but they ignored my pleas. The DIY insulation did nothing for my energy costs. I sold that Emerald and we don't miss it one bit.
Now the only hot tub I will buy is a full foam. I will be looking for one with a good base. I won't settle for one that is "sealed" with just a poly sheet. I think that is just a way for a manufacturer to cheap out.
I can see a Jacuzzi 345 in my future but no Colemans or Arctic or Royal or Spa Crest. No thermopane ever again.
I guess I should be thankful I bought an Artesian vs the Emerald I was looking at!
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I wouldn't own a thermopane because IMO they just don't work as well as FF at avoiding heat transfer even if they promise their method works great and explain the theory. I do agree that Arctic is a different story because they don't follow the standard thermopane method and I can see why they don't like to get lumped in with the standard foil barrier methods.
Clearwater does their spas like Artic. It works great if done right.
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Clearwater does their spas like Artic. It works great if done right.
I didn’t know Clearwater sprays a foam barrier along the bottom and along the insides of the cabinet walls like Arctic does? I assumed they used the standard thermo pane design of applying foil backed bubble wrap or foil backed foam to the cabinet walls.
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Clearwater does their spas like Artic. It works great if done right.
I believe that there are now several brands using this method. There are also quite a few brands 'borrowing' our trademarks; this helps keep our lawyers employed.
Still, imitation is the sincerest form of compliment.
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I was wrong, Clearwater does not spray, nor do they use bubblewrap. It is a 2 inch thick foam that they use for floating islands, and in construction. It has borates infused into the foam to eliminate bugs and rodents. It is foiled on both sides. It is placed on the floor and on all 4 walls of the cabinet, All 5 pieces touching tightly together. We brought it to an insulation guy(not a spa industry guy) and he stated it had an R 50 factor.....now that does not mean the tub as a whole is R 50, so lets not start down that road.
My point I guess is that a dead air space...a tight one with no gaps....with a high quality high R factor insulation works great. Add a 5 inch 2 pound quality cover.... My tub is very effcient. Why waste the heat pumps produce. I have 5 pumps and the other night, 50 degrees outside and all pumps going, my tub heated up 2 degrees in less than an hour from the heat produced by the pumps, heater never came on.
I had a full foam tub, a hawkeye and it cost me much more to run. The cabinet was always warm to the touch. Once you heat the foam up till it reaches the outside of the cabinet it starts "leaking out, kind of like a coffee cup. Now if the cabinet was lined with the foil to reflect the heat back, then filled with foam I think it would be great for insulation purposes.
Still have my gripes about repairs, I guess we have been the unlucky ones that have worked on all the full foam tubs with leaks other than in the control box. We have done a ton of them, multiple brands.
A quality tub is a quality tub....the high end tubs all seem to cost about the same to run, full foam or not, it just depends on how they are built
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My point I guess is that a dead air space...a tight one with no gaps....with a high quality high R factor insulation works great. Add a 5 inch 2 pound quality cover.... Why waste the heat pumps produce. (My emphasis - TG)
An excellent brief summary of the benefits of perimeter insulation. Conserving energy from the pumps has been part of our system since 1997 (we call it "Free Heat(tm)")
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I always tell myself: "I'm just gonna look at BADH, I won't post, I won't post, I..."
I can't resist pointing this out though. (Even though I sell and service FF spas).
The reason (IMO), that Arctic is doing a much better job than any others (which I'm aware of), was stated earlier, sort of.
Heat will, like many things, follow the path of least resistance. So, by putting the high R-value foam on the cabinet, and not much on the shell, the least resistance is toward the plumbing and shell (where your water is). This will effectively recycle the heat from pumps.
Other TP brands I have worked on put more insulation on the shell than the cabinet, therefore making the recycling aspect less effective (least resistance becomes outside of the spa).
I hope I don't ruffle too many feathers with this part:
I live in Montana, it gets kinda cold here (if you've never visited). The ONLY TP spa I would consider at this point is Arctic.
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Clearwater does not put insulation on the shell either. My point is there are a few good TP companies which have their other advantages.
It still all comes down to quality building and service. Not all in how many can we sell, but how many customers are completely happy.
I live in NH, also very cold as with Washington where Clearwater is made, and Canada for Artic who has all of us beat on "coldness" :D (I went on vacation to the coast of Canada in August and froze my butt off!)
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Clearwater does not put insulation on the shell either. My point is there are a few good TP companies which have their other advantages.
It still all comes down to quality building and service. Not all in how many can we sell, but how many customers are completely happy.
I'm in complete agreement with both of these points.
I have zero exposure to Clearwater, please pardon me for leaving them out.
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Forget about insulation value, I see way more leaks with TP spas than FF spas and when I do fix FF leaks it is no big deal as some try to preach.
I am only a service person and from what I have seen through the years FF is how I prefer a spa to be.
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Forget about insulation value, I see way more leaks with TP spas than FF spas and when I do fix FF leaks it is no big deal as some try to preach.
I am only a service person and from what I have seen through the years FF is how I prefer a spa to be.
This is turning into a good discussion. Since Arctic uses access and ease of repair as a sales argument, I'm interested in comments of this type.
Gary, have you had the opportunity to work on an Arctic Spa? We really don't follow the usual TP construction, and other technicians report the reverse, that they prefer to work on an Arctic to FF types. Perhaps this is just a variation in individual experience? I do know that in our factory service training courses, we have techs with a lot of experience with other brands who comment on how easy it is to service our spas by comparison. At that point, though, they wouldn't have much experience about relative frequency of repairs.
Would this vary with location or climate, do you suppose? I remember one tech from Alaska, who makes a good living fixing frozen spas, saying that Arctic was the only one that made sense from his perspective.
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Have never worked on an Artic nor see one up close, not much a dealer base in the deep south.
If and when a spa does leak a non full foam spa is easier but as I stated fixing a full foam is not a big deal either.
If they are sealed up tight and it appears Artic does then I would think it would be insulated just fine.
The other thing that bothers me though is the heat, to lower the life and any electronics just add heat or moisture or a combination of the both. If you seal it up tight the pumps, circuit board will all run much hotter than they were intended. That is why some manufactures of TP add vents that the owner can open if it gets too hot in there. The pumps themselves have fans built into the to remove heat, so if it is a sealed environment it will just recycle the hot air. All kinds of electronics have built in fans, they are not doing it for no reason.
For this reason alone I would never recommend a TP style spa to someone.
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Have never worked on an Artic nor see one up close, not much a dealer base in the deep south....The other thing that bothers me though is the heat, to lower the life and any electronics just add heat or moisture or a combination of the both. If you seal it up tight the pumps, circuit board will all run much hotter than they were intended.
Your being in the deep south does indicate a regional influence. As their name implies, Arctic Spas were engineered for cold climates, and a lot of that engineering is redundant in your service area. Many who think we are an ordinary TP-type spa are not really familiar with our product. I invite you to check www.arcticspas.com (and oh, how I hope our new site gets finished soon!)
Obviously, we've considered the heat issue, and our components are spec'd for the required internal operating conditions. Our pump motors, for example, are IP55 (sealed against moisture and air infiltration) and use an aluminum housing with an external fan driving air over cooling vanes. Electronics are spec'd appropriately as well.
Although we have few dealers in the American south, we have dealers in Australia, the Canary Islands, and Cyprus, to name a few hotspots. For warm climates like that, in what I consider a monumental irony, we remove two of the insulated doors and replace them with screened, louvered doors to permit cross airflow, or we install our patented Chiller to help keep the interior cold. The irony is, of course, that we devoted a lot of R&D time to keeping the heat in during a Canadian winter, only to have to find ways to keep it out in more southern latitudes.
Often mentioned in this context is the myth that "In a TP tub, the unsupported hoses flop around, which causes them to work loose and leak." Could be true in some, not so in ours. The simple answer is to remove a couple of the access panels and point out that the hosing is spot-tacked where necessary so it is hardly "unsupported". A more fun answer is to hand the person a three-foot piece of the heavy hose used in our products and say, "Here you go, flop it around." It takes real effort to bend the stuff; it doesn't need a lot of support.
I hope that addresses some of the concerns you raised in your post.
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Very well explained Tom. Funny how different our experiences are in different climates on the repair aspect. I will also add that for us, in the cold weather, digging in foam for a leak sucks when it is zero outside. I will also add with Clearwater we have never had to address a leak in the plumbing(keeping fingers crossed!) We have had to replace many light lenses last year(light lens manufacturer issues), very glad it was not a full foam tub for those! Clearwater also spot glues the plumbing where needed and uses decremeted clips for the plumbing to the jets. It still comes down to a quality built spa with a company and dealer that back it!
As well as my tub is insulated, we are having serious heat creep here right now, but only have to deal with it for a month. I can see in the south how this would be a disadvantage. I have the tub set for 98, it wont go below 100 and creeps to 102 when we use it. We have to take 2 doors off to let the heat out this time of year.
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The war is about to start again. You can look at some of the older pages and fine whole threads on this. In a nutshell the dealers that sell thermopane will say they are better and the dealers that sell full foam will say that they are better. As I am not a dealer or a energy expert (nor do I want to spark the war again) I will refrain from adding my opinion to this question.
Dave
Is it any indication as to what the better solution is when I have not visited a single dealer that sells anything other than Full Foam?
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The pumps would have to bring the cabinet air temperature up to a level "above" the temperature of the thin foam, plumbing, vessel shell, and water for the heat to travel through the air by convection, transfer to the thin foam and plumbing and on through the shell and into the water by conduction. I would venture to guess that, especially in colder climates, the pump or pumps heat energy input would be hard pressed to reach and/or maintain a temperature high enough for this theory to work.
I point out again that an Arctic has NO foam on the shell. A temperature gradient of only one degree is sufficient to transfer energy from the cabinet air into the water through the uninsulated shell. Some heat is transferred by radiation, I expect. Provided the cabinet is sufficiently insulated to prevent heat loss, energy will transfer into the water, reducing (but not eliminating) the time the heater is required to run.
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Anybody out there? Is this thread still alive?
Anyways, I am struggling with the question of FF vs TP question. The consensus of the thread seems to be FF offers more advantages at higher cost. Does a third method of insulation exist where TP is used with fully sealed air cavity between shell and skirt?
I would like to have a hot tub with the highest R-value. I have not seen any published R-value information. Has any research institute or public agency attempted to assemble this data?
I am particularly interested in the R-value of the sides between the shell and the skirt. I have already settled in my mind that the top is where approximately 70% of heat would be lost (with no insulation whatsoever). Any cover that forms a full contact seal with the rim and provides several inches of foam insulation over the top will prevent most heat loss from this source. The heat loss from the bottom is solved by resting on a thermopane panel.
This leaves the sides for which I have not resolved the question of the "ideal" insulation method.
I accept that FF may result in higher repair cost if a leak occurs (which is less likely to occur since additional pipe support is provided by FF and longer time to freeze pipes during periods of no power).
It seems to me that a third option may exist where the air cavity between the shell and the skirt is fully sealed. The air serves as the insulation with some TP under the skirt.
Does anyone know if it is reasonable to expect a fully sealed air cavity between the shell and the skirt? If this method was relied upon for a superior R-value then no leaks in the air cavity could be tolerated since any cold air intrusion would significantly reduce the effectiveness.
If I am allowed to wish, then I would like to see comparisons of infrared thermography scans using various techniques of insulation (to go along with my wish of tabulated R-values for each model).
I may just give up and design-build my own hot tub.
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The dilemma would be cooling of the pump motors. I purchased a partially foamed tub (Great Lakes) and actually removed some foam from beneath the entry step (the pump motor was located right under it.) Then fully sealed the cabinet walls with reflextics 2 inch insulation. Shiny silver side facing the vessel. My thoughts here were it would reflect any warmth back to the vessel. Then I designed and installed a thermostatically controlled 110V actuated 2 damper and fan system for incoming vent air and out going waste air. The dampers were ducted so the incoming air went across the pump motor down low and the outgoing air was drawn from the top on the opposite side. The fan was on the outgoing duct/damper to create a positive flow in and across the motor. It was set for 115 degrees which was slightly lower than the motor manufactures maximum safe operating range. I live in Northern Minnesota so the system seemed to save on some dimes. The funny thing is all the components and labor added up to about a 10 year ROI with the minimal cost to operate savings that was realized. Instead of a 50 dollar bill to operate on a particular cold month it was a 40 dollar bill. I have all the KWH data to prove the savings as the spa was metered. I believe the pumps running at max temp may cause premature failure. Never kept the tub long enough to know. The new owners lived far enough away that they never called me for service. I do know it is or was still running about a year ago which would make the tub about 9 years old. Not sure if a new pump was ever put in it but their life expectancy on that value brand was likely only 5-6 years anyway.
Any way just some thoughts for you.