There is lots of information out there about what makes a good thermal blanket.
The key to a good blanket, is the quality of how the blanket is made. i.e. If the blanket has less stitching, less parts, how the blanket seams are connected.
Quality makes a good thermal blanket.
The R value or retention rating is an indication of how much the material will retain heat. Almost all thermal blankets are the same or very, very similar.
Microns relates to the strength of the blanket i.e. 4mm heat guard is 4000 micron.
A foam blanket is not as strong as a thermal blanket.
The way the blanket has been made, how easy is the blanket to use, how the seams have been connected, will all make the difference on how you use your blanket. Because all thermal blankets will perform very similar i.e. you will not notice the inefficiency.
PVC pipes/ Boom floating ends
Create drag in the water, can bang around on the pool. Are likely to bend of bow out of shape. You will need to bend down to pick these up. Our Sunbeam boom end is a foam filled end, kind on the pool, it floats and you dont need to bend down to pick it up out of the pool.
Sewn seams
Make sure the seams are running up the length of the blanket. Make sure the seams don't have excess material that might get caught up. Sewn seams will allow water egress, so try to reduce the amount of seams running through out the blanket. Make sure your blanket seams are straight.
Once the blanket becomes water logged, it is difficult to remove the water.
We call our weld seams, seamless. The weld top and bottom create a smooth seam.
Our Heat guard thermal blanket is joined by welded seams top and bottom. Our seams are dead straight. As they are cut and welded on a computer.
Heat guard specifications below:
Blankets shall be fabricated from UV stabilised closed cell cross-linked polyethylene foam laminated between a UV stabilised woven polyethylene fabric top and bottom. Lamination shall be accomplished by flame bonding between the layers. Material shall be manufactured to quality management standard AS-NZS-ISO. 9002
Nominal thickness shall be:
2mm [2000 Microns] or
4mm [4000 Microns] or
6mm [6000 Microns]
Thermal resistance shall be nominally R rating:
[2mm] - 0.08 sqm K/W or
[4mm] - 0.13 sqm K/W or
[6mm] - 0.17 sqm K/W
Wind Retention (Outdoor Pools):
Each blanket shall have fitted along all longitudinal edges effective means of reducing blanket dislodgment or blow off from the pool water surface.
Weighted flexible rope of no less than 20 grams per metre contained within a mesh material, which is double stitched to the blanket edge, will be the minimum acceptable requirement. Mesh material must have specific gravity greater than 1.0