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Product Description

Evaporation is one of the most rapid modes of heat loss from pools and spas; pool blankets were introduced to counter this. Heat$avr® is promoted as a chemical alternative to such conventional covers. It is a liquid comprising around 90% 2-propanol (isopropyl alcohol) and a second unspecified component. When poured into a pool or spa, the liquid spreads across the surface of the water, forming a thin barrier that reportedly reduces heat loss by around 25%. (1)


2-Propanol has roughly double the heat capacity of water; heat capacity is the energy required to raise the temperature of a set amount of a substance by 1°C. At the recommended level given by the manufacturer (approximately 0.5 ppm), however, this is insignificant.


It is, therefore, the second component is the key to the product. The manufacturer advises that Heat$avr should be stored at a minimum of 17°C or a white powdery residue will settle out, implying that the component in question freezes below this temperature. 1-Hendecanol (undecyl alcohol) and 1-dodecanol (lauryl alcohol) are white crystalline long-chained alcohols that have boiling points of 19°C and 26°C, (2) respectively, so both are possibilities. They are insoluble in water but soluble in simple alcohols, explaining the presence of the 2-propanol. When a dilute solution of either is added to water, it spreads across the surface, forming a monolayer (a film one molecule thick). This layer acts as a barrier, restricting evaporation of the water and, hence, loss of heat from the pool or spa.


Precautions and Limitations (1)(3)

The Heat$avr documentation lists a number of limitations to its use and application:

  • Heat$avr must not be applied within 24 hours of shocking the pool or spa water.
  • The container should be examined once a week to ensure that no white powder residue has settled on the bottom. If present, the container should be warmed by placing it in hot tap water. This will cause the white material (the second component again) to pass back into solution.
  • Heat$avr must not be removed from the container when heating. This warning is necessary as 2- propanol is flammable.
  • Undiluted, the liquid is toxic. 

Critical Assessment of Claims

The documentation1 makes a number of claims for Heat$avr.

1. No reaction with normal pool chemicals. Assuming either 1-hendecanol or 1-dodecanol, there shouldn't be any reaction with other pool chemicals at the recommended dosage levels. It should be added, however, that the MSDS for the product does stress that the undiluted liquid may react violently with any strong oxidant, including hypochlorite, chlorine, bromine and hydrogen peroxide, liberating carbon monoxide and carbon dioxide. (3)

2. No effect on ozone. This claim may be interpreted in two ways; either Heat$avr has no effect on pool ozone or it has no effect on atmospheric ozone (i.e. the ozone layer). At recommended dosage levels, both are certainly true. However, the undiluted liquid must not be allowed near an ozonolysis unit (see reactions with strong oxidants, above).

3. Not affected by DE filtration. This is reasonable provided the pool temperature doesn't drop below 17°C. If this occurs, the long-chained alcohol will precipitate out as a white powder and possibly be trapped by the filter.

4. Assists filtration in helping to suspend solids. If the active constituent is 1-hendecanol or 1- dodecanol, then this claim is difficult to substantiate. Both alcohols will act as wetting agents. This may aid flow through the filter but will not floc or suspend solids in the pool water. It is true that organic contaminants will preferentially migrate into this organic phase. However, since Heat$avr only forms a monolayer, and then only at the surface of the water, solid material in the bulk of the water may rarely, if ever, come into contact with this phase anyway.

5. Made of all-natural pure products. Without knowing the exact composition of the product, it is difficult to make conclusive comments on all of the components. However, it is doubtful whether any constituents occur naturally. On the other hand, they may be derived from naturally occurring compounds (for example, by reduction of certain esters or carboxylic acids).

6. Decreases evaporation by up to 25%. On the basis of available data, this would appear to be a reasonable claim. 


This technology is certainly not new; CSIRO developed a similar system to reduce evaporation losses from reservoirs several years ago. However, as the reservoirs supplied potable water, this prior application does lend support to Heat$avr's claims of safety and lack of toxicity at the recommended dosage.


When considering potential cost savings, pool and spa owners need to weigh up the one-off cost of a conventional blanket versus the ongoing cost of adding Heat$avr to the pool. At the time this TIB was prepared, the retail price for 20 litres of Heat$avr was $A350. (4) Based on recommended daily dosages,1 this quantity should last nearly a month for a typical 50 m x 20 m (1,500,000-litre) municipal pool, and over 14 months for a 10 m x 6 m (90,000-litre) pool.


Heat$avr has obvious advantages is that it can be used universally, irrespective of how oddly shaped the pool is, and it does not occupy the deck space needed to store a pool or spa blanket. Its biggest disadvantage may be the onset of cloudiness if the water temperature falls below 17°C, due to precipitation of the active component; this will obviously not be a problem for pools in warmer climates and for spas.



1. Heat$avr Sales Brochure, Hydro Flexible Solutions (Australia) Ltd., PO Box 79, Tewantin QLD 4565.

2. R.C. Weast (ed.), "CRC Handbook of Chemistry and Physics", 57th edition, CRC Press, Cleveland OH, 1976, pp. C-281 and C-326.

3. Heat$avr Material Safety Data Sheet, Flexible Solutions Ltd., 2614 Queenswood Drive, Victoria, BC, Canada V8N 1X5.

4. Jalun Pools Web Site at


The above information is supplied by Bio-Lab and represents its best interpretation of available technical information at the time of preparation. The sole purpose is to supply factual information to Bio-Lab customers. It is not to be taken out of context nor used as support for any other claim not made herein.