Heat Loss >10 Degrees In 8 Hours

[Vin in NYC]

Hi all,

I hate to have this be my first post, but I wanted to throw this out there before I end up "throwing my tub out there."

We purchased our first tub (Emerald Spas E550) in September of this year and tried to do as much research as possible to ensure our maintenance costs would be reasonable. We're in the NYC area so we can have falls and winters with varying temperatures.

We typically use the tub on the weekends and heat it to 102F. We use it for a half hour and lower the temperature to ~90 when we're done, covering it with the supplied 4"x2" cover from the shop.

When we come out in the morning (about 8 hours later), we find that the temperature has dropped to 90 degrees and the tub is in heat mode.

From what we've been told by a few shops, manufacturers and other tub users, we should not see that sort of heat loss overnight. Typically - we're told - is that 2-3 degrees is the norm when using a good cover and the tub is insulated properly. We've had a few folks tell us 12 degree drops are definitely not normal.

About the tub:
It's on a 240 line in a concrete yard. It has a 4"x2" cover and has the spray foam insulation. It does not have reflective insulation on the panels. We are not running it in economy mode.

We've called Emerald and they said it's not normal; call the shop. Called the shop and they say "it might be normal". They've sent a tech to look at the electrical setup and he said it's fine; the spa is working as expected and there's no anomalies in the setup. They're saying a 10-12 degree drop is normal and it's "the cost of doing business" when it comes to a tub - but I can't justify $200 in increased cost monthly to use a hot tub 8 days a month in the winter. We can't leave the tub at 102 all the time because it would essentially be heating all the time.

My question is - is a 10-12 degree drop normal? Should I try to add insulation myself to the inside of the cabinet? Should I continue to badger the shop or manufacturer? Am I doing something that hot tub newbies shouldn't be doing?

Any help is appreciated and of course, let me know if you need more info.

[TdiDave]

Don't have any ideas to help your problem, but can say I don't see much more than 2-3 drop in 24 hours. I have only had my tub about a month so don't have much to base this on but what you see dosnt sound right.

[Vin in NYC]

Thanks TdiDave. I found that the cover seems to emit heat from the center folding area, so we called the manufacturer. They said that our cover is "commonly used in the southern states" so we're going to invest in a thicker cover. To be continued.

[Dan.The.Spa.Man]

Does it just have blown in foam against the shell and covering some of the pipes instead of a fully-foamed cabinet? If so, and you are turning the temp down to 90 degrees, and it is 20 degrees out at night then I definitely believe that it would cool down to 90 overnight.

[ed3553]

Are you seeing steam come from the seam or where the halfs come together? There is no way this should increase your electric by $200. Your temp drop can be affected by several variables such as wind and temp. Is your compartment door vented? If so try covering the vents to keep the heat in and the wind and cold out. I also think you will find it cheaper to keep it at the same temp all the time.

[Roger]

Are you seeing steam come from the seam or where the halfs come together? There is no way this should increase your electric by $200. Your temp drop can be affected by several variables such as wind and temp. Is your compartment door vented? If so try covering the vents to keep the heat in and the wind and cold out. I also think you will find it cheaper to keep it at the same temp all the time.

It won't be cheaper to keep it at the same temp all the time. But you will not notice any difference as it is so small. Lowering the temp would actually be a few penny's less.