Full Foam VS Thermal Sealed; The Facts
The American National Standard for Portable Spas
Home And Garden Show Wisdom
Water Clarity with the Copper/Silver ionizer and the Calcium test .
Filtration Systems
What Makes a Good Spa.
How we service our customers out of state
Spa Shell Structure: The most important part.
Silly Stuff: Arthritis, Glue Joints and 100% filtering.
Compare spa ideas
Installing an energy efficient spa in the ground.
Installing spas in and on decks.
What is involved in the installation of spas? Electrical GFCI vs. Breakers
About Blower and Pump Clean-out and What is the best filtration system?
More on Full Foam Spa Use
"Spa Covers and Sunlight"
"Heater Problems: Basic Heater diagram
Misconceptions About Spas and How Spas Enhance Your Life
Bromine and Ozone
Air and Jet Therapy
Winterizing Your Spa
Nature2 and Other Ionizers
Filtering Spa Water
Hydrogen Peroxide
Standard Spa Care with Bromine
Insulation, Heat Retention and Freeze damage

 1997 through 2010
Havenmade  Inc.
hot tubs and spas
James Arjuna

Hot Tub Construction: Insulation

Spas And Hot Tubs

copyright 2003 through 2010  Havenmade Inc


Full Foam Spas VS More Modern Thermally Sealed:



This subject runs throughout our entire web site, because it is the  most important design concept a consumer should consider.  The best insulation is the thermally closed design, which is opposite to what is considered "good” by the old time spa sales people.    There is no evidence that full foam has any superior insulation to what has been proven in the side by side independent testing.

The facts are in, and all of the independent testing shows the thermally closed is better. With the Haven DAIT insulation system we have taken the Thermally Closed to the next level.


The Thermal Closed or Thermally Sealed and particularly DAIT equipped spas are far superior to the out of date full foam. (DAIT is only available as standard on the Vista, Paramount, and Super Custom models. You can buy a DAIT system for any model we offer and you can buy it for your spa if it is a thermal pane type of insulation and can be retrofit with the DAIT.)


Full foam (and other silly design concepts) is still here because of consumer's lack of understanding on the subject of hot tubs and spas.  You would have to know almost nothing about natural science to purchase a full foam spa after reading any of the articles on insulation contained in this site. If you don't understand science, then find a friend who does and ask them to evaluate these articles.

"This information on spa design has been "out there" for nearly 14 years.  If you didn't do the research, what else is there to say?"

The only way these other spas could be sold is because the consumer takes a look at the surface of the spa and goes no farther.  The sales persons "stays on the surface" and sells the spa, using the consumer's ignorance (on the subject of hot tubs).  Apparently there are a lot of naive spa shoppers and scientifically ignorant spa sales people.   I am sorry if that offends those who have already made the mistake of purchasing a full foam spa or those who sell them. This information on spa deign has been "out there" for nearly 14 years.  If you didn't do the research, what else is there to say?

When people read my book and go shopping, these sales people are "set way back", because they have no factual answers to give to the consumer about the design of  their  products.  I had one of my customers thrown out of the store for asking detailed questions about that salesman's product.  The salesman could not answer.  He called in to a local radio consumer advocate program and I almost had to lay down from laughing (FOFLMAO). The sales man figgered the customer was a shill from another hot tub store, because consumers are not supposed to know anything about hot tubs.

The first thing you should look for are spas that are NOT full foam or even 1/4 foam filled on the shell..  Only consider spas that are truly thermally closed insulation or thermally sealed.  This is primary to owning a better value. These are made with many layers of modern "space age" materials.

The original concept of full foam, was a cheap way to build hot tubs with a single sheet of flexible cheap plastic shell, (called Rovel or Centrex) stuffed with dense foam to keep it from falling down with water in it.  (Did I tell you just how cheap this is?)  It was developed in Southern California, next to the Mexican border where it never gets cold.  It is really odd to see that same concept being sold today as a “premium” spa in cold climates and to see other companies copy this ridiculous concept because they want to "get in on" some of the profits.  The profits on ths type of spa are evil.  There is no need to sell a cheap product for up to 1300% profit (average is 1010%) over the cost to manufacturer.  It really is a cheaply made product being hyped to for profits because of consumer ignorance.  If this were sold at a price under $3000 that would not be such a poor value issue.  Just the fact that they use plastic control boxes, should be enough to stop a smart person.I am sorry, but if you bought on of these spas, you really got taken advantage of, because of your lack of understanding. Even if they make it for 5 years with no issues, you still were taken advantage of.  Consumer ignorance is common in hot tubs, and the internet message forums are full of these sales peopole protecting their "image" of quality.  Why not sell real quality and not have to put up an image of quality?  HMM? That is a novel idea.  


There have been in the past three independent and separate tests performed comparing the out of date and archaic full foam spas to the, modern and much better, thermally closed.  In all cases the thermally closed has been favored for better insulation.


Each year, we offered the “Spa Challenge” to all the spa companies. We even had the invitation sent out to all manufacturers to participate by an independent company, but absolutely no responses at all.   (Golly gee, I wonder why? ) http://www.spaspecialist.com/SPA_CHALLENGE.html


The first independent test in 1994 that evaluated the rise in temperature the spa water received from two jet pumps in a real* Coleman Spa  that was tested.  There was a temperature rise of 14 degrees, on high speed, just from the pumps over an 8 hour period. These were 1.5 HP pumps by the way; very small horsepower by today's standards. On low speed, with just the filter pump, the rise was 4 degrees over 8 hours. I believe this was conducted at 68 degrees ambient.  68 is considered the average temperature, year round.


In 1996 another test was performed by the Universities of Arizona and Colorado here is a synopsis of the results with my notes in brackets “{}”


"a fully insulated spa {full foam} makes no attempt to recover and use waste heat."  (Tong and Rogers 1996). "...the performance of an insulating system which makes use of a thermal barrier {Thermally Sealed}, generated by waste heat rejected from the motors and pumps, in an enclosed air cavity around the tub is superior to a system which simply insulates the tub directly."
This is because air is 1341 times less expensive to heat than water. And if you are heating the air to form an air barrier to stop the super high watt density or BTU's per cubic foot of water, you will automatically save energy, even if you only have 3/8 of an inch of wood and no thermal foil and no foam insulation at all.  It must be sealed as air tigth as you can.  The value of insulation is measured by the total heat loss from the vessel.


In a recent test done in Alberta Canada, the Thermally Closed Arctic spa came in very high compared to some popular spas.  http://www.spaspecialist.com/AlbertaResearchCouncil.html
(Note the company that lost this test, sued me and my insurance would not fight them, and just settled. Part of the settlement was that I would not publish their company name on my website. So it is clearly blocked out.  I can however, tell as many people in person about this company. If you want to know who they are and what the suit was about, I will glady tell you in a private conversation.)

 One of the things that Haven Spas have is MODERN space blanket technology. There is more insulation in the walls of a Super Custom or SE Haven Spa than in the walls of your house.  R-27 in just conductive readings.  Then we use the radiant barriers , three of them to create a heat reflection back into the spa water.  There is no other spa on earth that has this level of insulation. The total number of layers of modern insulation is in this patteren  A = Air chamber  TF = Thermol Foil  FO= Foam PW = PermaWood. AB = Air Pockets of waht is called bubble air plastic chambers.
FO + A + TF + FO + TF + A + TF + AB + TF+ PW.  It is all done in layers in a very specific way.  Then because the heat saving of this is so intense we must use a vent fan to reduce the insulation in summer or the water gets too hot. So we have a control system that checks the outside air temperature and adjusts the insulation automatically.  http://www.spaspecialist.com/HavenBrochure2003ABK100.pdf



To summarize the differences between the so called “full foam” and the much more modern “thermally sealed”:


  1. Repairs on full foam spas are more expensive because of the labor to dig out all that wasted foam to find leaks. (about 400% more costly than a Haven Spa)  Also the equipment compartment is harder to work in because of limited space.  After the leak is fixed then you have to pay to refoam it. http://www.spaspecialist.com/shopping.html
  2. The full foam spas have plumbing errors in that the pumps are normally placed sideways in the front of the cabinet (in a pretty little box).  This causes these spas to have more turns in the major plumbing pipes to disturb and restrict water flow. It causes a waste of energy. If you have 4 HP pumps and you receive 3 HP worth of energy, what else would you call it? When they add “diverter first plumbing” to this nonsense, it is really sad to see all of that energy wasted like that.  "Clean Plumbing" with as little restriction as possible  is the best
  3. In a Thermally Sealed spa made correctly (like a Haven Hot Tub), the whole cabinet space is utilized to align the pumps to the major plumbing with the least amount of turns.  This also gives better access to the equipment for service.
  4. In Winter, when the power is shut off to the spa for any reason in full foam spas, the equipment in the open box in front is going to freeze quickly, unless the owners of the spa apply heat to that area.  Most of the freeze damage is caused by a GFCI tripping and or a control box failure.  (This design is idiotic for cold climates!) Once the water freezes in pumps and heaters it destroys them from freeze expansion.  Like frozen water pipes in your house that crack and leak.
  5. In a typical full foam spa the equipment is set out in a vented non-insulated box.  This way while the pump is running and the heater is on the cold air is cooling the equipment.   It is basically cooling at the same time it is heating (Isn't that an oxymoron.).  This also causes thermal stress on the plumbing by causing a lot of expansion and contraction to the parts.
  6. In a thermally sealed spa the entire spa is insulated, INCLUDING THE EQUIPMENT.  This gives a much longer time before the equipment freezes….. up to two weeks in freezing winter.  The water vessel is like a huge “hot water bottle” sitting in the middle of a small room.  This makes the Thermally Sealed the only real choice for cold climates.  There is a much longer "down time" before freezing starts.
  7. The Thermally sealed spas have a more even temperature on all the plumbing parts and the pump “wet ends” because the equipment is not subjected to freezing air in winter. It is always warm in the cabinet.
  8. The full foam spas have almost no thermal contact between the water in the vessel and the heat from the jet pumps. That means there is extremely limited heat transfer from the motor heat into the spa water while the pumps are on.
  9. In a thermally closed design with proper use of insulation (Haven Spas), the heat from the pumps is transferred directly into the spa water by the fact that the cabinet is warmed up and the heat is drawn into the vessel from the large surface area of the shell.
  10. In a full foam spa the common problem for jet pumps is they are eventually ruined by heat and lack of proper cooling.  Most all of the full foam spas run the motors at temperatures that exceed the manufacturer's temperature specifications. They are relying on natural convection which cools like crazy in winter, and doesn't cool much at all in summer.   The warm air in summer does not move quickly by natural convection, because it is already hot when it enters and never achieves a consistent velocity.  When most spas operate in summer they are destroying the pumps just from normal use. That is stupid. The manufacturers tell you the perameters that these motors are supposed to operate under; temperature and stress limits are clearly spelled out.
  11. In a thermally sealed spa, the heat is transferred into the spa water, like a huge radiator that cools the equipment in a very direct fashion.  (Two issues are solved by this design, the use of the heat to warm the water and the exchange of heat to cool the motors.) With a DAIT spa the motors are also cooled by a fan system controlled by thermal sensors. http://www.spaspecialist.com/DAIT.html
  12. In the coldest of winter, you can have the air temperature inside the cabinet of a thermally sealed spa warmer than the spa water or very close to the temperature of the water in the vessel.  The heat from filtering can be used to stop all heat losses out of the water vessel on the major surface area.  This is equivalent to 100% immeasurable insulation.  If the air is warmer than the water, the heat from the vessel is not escaping out the sides.  READ.
  13. Typically the method to try and save energy on a wasteful full foam spa is to use a tiny worthless circulation pump that causes poor water quality from weak filtering. http://www.spaspecialist.com/TheMythsOfFiltering.html   The major spa companies use this as a cheap way to save energy, but it causes the consumers to use more chemicals to burn out the contaminants in the disgusting poorly filter water.
  14. In a fully insulated thermal closed spa a full size pump can be used to filter and the energy costs are less, because of the thermal warm air barrier and the heat from the pump stops the use of the very expensive, 6,000 watt electric heater.  Any time you can reduce the use of the wasteful electric heater, you extend the life of the heater and drastically reduce overall energy consumption. The motor heat is enough to stop 90% of the electric heater if you remember to set longer filter times in winter.  (Haven Spas have fully adjustable filter times.)
  15. Full foam spas are very expensive to do any upgrades or add any jets after the spas are finished.  With thermally closed and using a proper foam, you (any one with good knees) can add jets, if you want at a later time.  Suppose the jet manufacturer's come out with a really nice jet that you want; with a Haven Spa or a good thermally closed design, you can put that new jet in for as little as $150.00  (I know I have done this to Haven Spas.) If you do it yourself $20 to $30 in parts.
  16. In a Full Foam spa you cannot operate an air injection system without wasting a lot of electricity. The air entering the water is going to be cooler than the water and causes the electric heater to run for a much longer time with each use.  In a Haven Spa we capture the warm air from the pumps and use that to heat the air entering the air injection pump.  Just remember to run the jet pumps first in winter to warm up the air chamber where the air pump is getting its air.  We have tested this on standard spas at ambient of 68 degrees and the air enters the air pump at 128 degrees F then is heated to over 150 F degrees under the heat and pressure of the air pump. 


So, a well designed, modern thermally efficient hot tub uses the energy of the equipment much more fully and it is less costly to own, in electric use, chemicals because it filters better, and in maintenance or repairs be cause of ease of access.  There is better use of the total energy of the spa, better water flow from the jet pumps, and cleaner water by proper filtering and has full therapy with three types of therapy. Water jets, Air jets and Turbo Air..  The motors last longer because of much better cooling.  And of course an ethical company would only use metal control enclosures for fire protection.


Why would you buy a structural full foam spa?  Anyone who purchases a structural foam,  full foam spa is not educated on spas.  Anyone who "misses the boat" with Haven Spas is just not understanding the whole picture.  Our customers are always calling me and thanking me for this treasure in their life, called a Haven Spa.



*The Real Coleman Spas, that I am very familiar with,  are no longer in existence they have been sold to a company called MAAX and they do not  resemble the original engineered product.

The original engineered product had much stronger 2x4 wooden frames, air injection, the shells were made from Acrylic with Vinyl Ester resin and hand rolled fiberglass.  (Does this sound familiar?) http://www.spaspecialist.com/haven_spas_in_general.html




Size Of Spa VS Energy Use
Jet Numbers in the Brochure
"Modern" Metal Frames
How To BUY Quality
Multiple Pumps
Diverter Valves
Bogus Information
How Spas Filter Economically
What's Involved in Filtering?
Message Board Awareness
The Importance of Engineering
Installing Spas Indoors
Before You Buy any Spa About Controls
Read this about spa controls!!
Before You Buy any Spa
Read this about spa design!!
See the Haven Spas
Check out our very informative Message Board Forum
Hot Tubs and Safety: The US The U.S. Consumer Product Safety Commission
Full Foam and Bad effects on water flow
Electrical Fires

Email us!       Read More down-load a copy of the DAIT brochure in PDF format.