spa blanket

[Bonibelle]

I finally got around to putting my blanket on the spa but I am not sure if it is supposed to be cut to fit exactly the contour of the tub so it lays on the top of the water, or should it overlap a bit to fit the insulating cover? I don't want to cut it too small and defeat the purpose. :-/

[Vinny]

If you're using the velcro then cut it to fit the cover. It'll "seal" the tub and the cover will keep it in place.

If you want it to float on the water then cut it to the contour of the tub. I guess you can cyt it a little larger and have the edges curl up a bit.

I cut mine to fix "exactly" (OK not exactly - I had cut it not too good) and I have neck jets so I even cut it to make the neck jets not spill onto the blanket.

[Bonibelle]

Thanks, Vinny, I am going to try the velcro, my hubby doesn't want to punch holes in my cover.

[Gomboman]

Are there any documented energy studies regarding the benefits of spa blanket? I would even settle for a home study. I can't imagine a spa blanket could add any substantial insulating properties in addition to a modern insulated cover. I would love to be proved wrong though. If I could save $10/month or more I would give it a try.  

[Bonibelle]

Gombo, Any savings would be great to me at this point but I was also looking for protection of my spa cover
from ozone and chemicals. Funny, while I was waiting in the line at the grocery store the other day, I picked up one of the special outdoor magazined that Better Homes and Gardens puts out this time of year. There was an article about hot tubs, as they are becoming as popular in some places as swimming pools. Anyway the article claimed that the spa blanket DOES make a difference as far as insulation. Now would not be the time for me to try to do any sort of experiment as our weather has warmed up and I think the effect of the blanket would be minimal

[drewstar]

Are there any documented energy studies regarding the benefits of spa blanket? I would even settle for a home study. I can't imagine a spa blanket could add any substantial insulating properties in addition to a modern insulated cover. I would love to be proved wrong though. If I could save $10/month or more I would give it a try.  
 
 

I had the same thought, and noticed that many of the companies selling blankets aren't pushing them so much as "energy saving"  but  the big selling point is to help protect the underside of the cover from the effects of chemical off-gassing.  The energy savings point seems to be a secondary feature?

[Bonibelle]

Drew, I didn't buy the magazine, but I will see if I can find it again. I think they did  have info about the R-factor of the spa cover and the increase in the R-factor by adding the closed cell foam blanket. They said something like the greatest heat loss occurs through the spa cover....and how the blanket offers additional insulation. I will look for it today.

[Bonibelle]

OK, I found the article (only one page). It claims that most spa covers have an R factor of about 12. The addition of a closed cell blanket is supposed to increase the R value to 16. Today, I turned my heat way down and the tub only dropped 1 degree. I don't know if that is a big deal though since it was about 70degrees this afternoon..I figure it can't hurt and I will take any energy savings that I can get.

[Vinny]

I think the energy savings come from IF the blanket seals the water completely since dry air conducts heat slower than moist air. And the fact that convection currents are off the water.

I will say that I believe these savings are minimal and shouldn't be the reason for the blanket.

I purchased the blanket to be my sacrifice for the chemicals. As I've said I have about 95% of the water covered so that's 95% less water surface for ozone and chlorine off gassing to affect my cover. I also got away with not filling up the spa too often during the winter. Reading that people put water into their tub every week during the winter, I went 3-4 weeks. I don't use the tub every day but do use a suit when I go in and it takes out some water when I get out ... If that's any indication of less water evaporation, then there's some proof of something.

I originally was going to put the blanket onto the cover as was discussed here in the past but my cover isn't "the very best", it's nice but it does have some gaps and I thought that I should have something closer to the water. Once this cover goes and I buy a better cover I might not use a blanket.

[drewstar]

I think the energy savings come from IF the blanket seals the water completely since dry air conducts heat slower than moist air. And the fact that convection currents are off the water.

I will say that I believe these savings are minimal and shouldn't be the reason for the blanket.

I purchased the blanket to be my sacrifice for the chemicals. As I've said I have about 95% of the water covered so that's 95% less water surface for ozone and chlorine off gassing to affect my cover. I also got away with not filling up the spa too often during the winter. Reading that people put water into their tub every week during the winter, I went 3-4 weeks. I don't use the tub every day but do use a suit when I go in and it takes out some water when I get out ... If that's any indication of less water evaporation, then there's some proof of something.

I originally was going to put the blanket onto the cover as was discussed here in the past but my cover isn't "the very best", it's nice but it does have some gaps and I thought that I should have something closer to the water. Once this cover goes and I buy a better cover I might not use a blanket.

I've been midly curious about the blankets for a while now.    

However, I keep stumbling over the off gassing.

Does the blanket REDUCE off-gassing?

or does it trap the gas under the blanket until it's removed (do you notice a stronger chemical smell when lifting the blanket?)

Just divert the gas to have it escape off to the side?

As far as ozone goes, I thought  it was so quickly converted back to 02, that once the treated water entered the tub via the contact chamber,  the ozone's ability to oxidize  had been completed?

Or am I just being a wet blanket?  

[Vinny]

I "think" it traps the gas under the blanket or makes the gases travel horizontally thereby eliminating immediate off gassing. I usually wait 5 min for regular dosing and usually an hour during shocking before closing the cover. I do smell chlorine sometimes when I lift the cover but since I've had the blanket since pretty much day one, I can't compare it to a non blanket.

As far as ozone ... I have softened my stance on it's effectiveness but I believe most of the ozone is unused, at least in a tub without a mixing chamber (mine). Not all ozone is used up even in a commercial drinking water application, which by the way is vastly different than a spa's.

[Bonibelle]

I opened my tub this morning and I didn't notice any stronger smell of chemicals (I use bromine) then usual.
I have to say I think there is some insulating value, maybe because I am hoping that there is, but it does make sense since the blanket is on the water surface and there is a layer of warm air trapped above it between the blanket and  the spa cover. I guess assuring that the entire surface of the water is covered, is the ticket to getting the least amount of heat loss. I think winter time would be the best time to test that.