| A lot can be said these days
regarding the ability of a spa to retain heat. However, in the portable
spa market, these days, it is virtually a non-issue.
From Coleman®, to Sof-Tub® to even the
inexpensive Jacuzzi® brand spas at Home Depot. There's hardly a portable
spa manufactured out there that won't retain heat extremely well. So, in
most cases these days, it's definitely nothing to lose sleep over.
|
There are three different ways that heat is transferred:
- Conduction. One surface touching
another.
- Convection. the natural flow of heat through air
movement, and the rising effects of it.
- Radiation. can be easily understood as being the
radiation as felt by the sun, or from a stove burner.
The most commonly used insulation material is an expanding
poly-foam, which is usually yellow to tan in color, and is used by almost every
spa manufacturer. It primarily stops the flow of heat by the prevention
of convection. Without the foam, the heat would transfer from the inside
of the shell to the outside (by conduction), and radiate outward, and be
carried away by air convection. Note that all 3 factors come into play
here.... but by spraying the foam in the cabinet, the chance for
convection is nil.
|
Some spa manufacturers utilize full foam insulation.
That is, foam that fills the spa skirt 100 percent. This is one of the
most effective means of controlling temperature loss, and has been in use for
many years by most nationwide manufacturers.
|
Many other spas (and if you shop around, you'll probably
realize this yourself), are constructed with a thick fiberglass shell, with an
acrylic type of sheet on top of the shell. The thicknesses of these
shells will vary anywhere from 1/8" to as much as 3/4" in some
areas. These shells are generally more expensive to manufacture, and are
usually made in a facility that is dedicated to this purpose....then shipped to
the spa builder/manufacturer for drilling, plumbing, skirting, etc.
Usually what you will find with a spa built in this
fashion, is that all exposed surfaces of the spa shell, plumbing, jets, and
manifolds, will be sprayed with foam, in some areas thicker than others.
Additionally, the foam is used to keep these components "in place,"
preventing the movement of the plumbed parts, and subsequent leak problems from
occuring.
|
Recently, I have begun to see spas built with a new type
of insulation scheme, which is rather remarkable. It uses a laminated
metallic foil/air bubble seal material on the inside of the skirt, and at the
same time uses poly-foam on the spa shell and plumbing. The effectiveness
of this is insulation is extremely good, as the metallic foil contains the
radiation of heat from the spa. Actually, the foil material reflects the
infrared component of heat back into the spa itself, literally creating its own
convection oven effect inside the skirt. The result? Extremely
effective recycling of heat from components such as the pump motor and spa
control system, which is normally lost through equipment
ventilation.
|
What should you buy, then?
As I've said in the buyers guides, buy what you like! All well-made spas
will exhibit superb thermal efficiency characteristics.
Personally, I prefer the feel of the thin shell material used by Dimension One,
Hot Springs, and others, but I also like the ease of service of a full
thickness fiberglass shell with limited foam... and the superb thermal
characteristics of the reflective foil material on a spa skirt...
HA! It's a tough choice! But ALWAYS remember:
Buy what you like folks! They're ALL pretty good!
|
|
