The practice of adding a layer of insulation on bathtubs for energy-efficiency reasons is relatively new, but one that’s starting to be commonplace.
In the olden days before climate change and energy-conservation awareness were big topics, you’d swim in an uninsulated bathtub however you pleased and never feel bad about it.
Today, bathtub insulation is a priority and isn’t just limited to energy conservation but sound management as well.
See Also: Can You Replace A Bathtub In A Mobile Home?
But, Is It Worth Insulating A Bathtub?
Yes, certainly. Unless you have a solar-powered water heater in place, every drop of hot water used at home is either heated with gas or electricity – you don’t get these for free. Nonetheless, tub insulation is cheap and has no known drawback.
The Cost of Installation Is Lower Than Long-Term Cost of Wasted Heat Energy
The most obvious reason why you’d add a layer of insulation is to boost the energy efficiency of your winter bath and, of course, save money on your energy bills.
No season sees a spike in energy bills like winter. That’s partly because you take a warm bath more often around this time than any other part of the year.
Unlike hot tubs that come with a coil element somewhere in their structure to do all the heating, bathtubs rely on you to heat your water manually or link them to the water heater.
Oftentimes, you take a few minutes to boil a kettleful or potful of water before pouring it into the bathtub.
This means your bathtub deserves insulation more than a regular hot tub (a fancy cousin of your bathtub which often comes with factory-installed insulation, by the way).
Your bathtub water starts to cool immediately after you pour the first kettle.
You might want to preheat the surface of the bathtub to prevent the water from cooling too fast once it hits the surface.
If you want to skip the manual part, the trick is to adjust the bathtub’s faucet to the hottest settings for, say, 5 minutes, drain the water, before filling the tub at the right temperature.
Even more thoughtful, you can hold your hot space heater above or inside the bathtub for 10 – 15 minutes before filling it with hot water. Still, you need insulation to keep it hot for a long time.
Need for A Sound Dampener
When all is well, you just climb inside, soak, and leave without placing a rock under the tub.
However, as the tub ages, it starts to feel shaky and flimsy on the slightest movements you make from inside.
The best way to stop these movements (plus the creaking sounds that come with it) is to add a layer of insulation between the tub and the wall or floor.
Anything denser than fiberglass can do. Such insulators as polyisocyanurate foam (or spray-on Great Stuff) can be a great start.
Polyisocyanurate foam is particularly competent for the job because it establishes a firmer yet spongy bond with the wall.
You can combine it with any other appropriate foam to enhance its effectiveness.
Alternatively, you can press soundproofing batts between the studs. Make sure they fit tightly.
Do You Insulate the Entire Tub?
Absolutely not. It would be near impractical to install any kind of insulation material over the whole exterior of the tub.
Most bathtubs come in curvy shapes – adding foam or paneled insulation materials would be super difficult.
It would be more expensive if you tried because you’d end with something boxy and thick, like a commercial hot tub.
The best approach is to add your insulation material on flat surfaces in contact with the bathtub, that is, the floor and the wall.
It just so happens that your bathtub loses more heat to these surfaces than to the air which is a good thing as it makes your installation job a little easier.
Note that it isn’t entirely impossible to insulate the entire exterior surface of your bathtub.
I’ve seen worse – panels of Styrofoam glued on the surface, batts or Anticon (batt and foil) delicately held in place, etc.
For the sake of the beauty of your bathroom area, don’t go that far.
When Do You Insulate Your Bathtub?
The best time to insulate your tub is during installation, bathroom remodeling, or replacement.
However, it’s still OK to dismantle a tub just so you can add a layer of insulation and the wall and beneath it, but it’s costlier that way.
Also, hire the most experienced and qualified professional to spray the insulation material, preferably polyisocyanurate (we’ll explain later why just this specific material).
Please imagine what would happen if insulation was installed inappropriately and resulted in mold and leaks!
How About Outdoor Bathtubs? Is It Worth Insulating Them?
A big “yes” to that as well – it makes sense to insulate your outdoor tub.
The objectives are the same: to boost energy efficiency and remove movement noises. In fact, they are the easiest to insulate because they don’t sit on a permanent floor like your bathroom’s.
However, you will need a slightly different class of insulators perfect for outdoor conditions.
Remember that your outdoor bathtub may come into direct contact with snow in the winter.
Make sure your insulator has thermal insulation properties as well as anti-reflective characteristics if you want to keep energy wastage to a minimum and even boost the lifespan of the tub.
What Are the Best Insulation Materials for Tub Insulation?
Virtually any spray-on foam will work for your tub. For indoor bathtubs installed in your bathroom, however, I’d recommend polyiso foam (a spray-on foam).
Besides the fact that Polyiso works with virtually any kind of surface you’d find in a modern bathroom (doesn’t matter your tub is sitting on bare concrete or structural surface), the material comes with an R-7 thermal insulation value – just the right value for the job. Spraying polyiso foam is a skill-intensive task, so don’t even think about DIY.
And because it is dense, it won’t create hollow sounds with your wall or floor.
Polyiso is also known to establish a bond with surfaces (in this case, the wall or floor of your bathroom). As such, it tremendously cuts air movements within.
Another advantage of Polyiso is that you can easily combine it with rigid foams (the likes of regular Styrofoam used in packing) if you feel like it although pretty any other spray-on foams work harmoniously with rigid foams.
For outdoor bathtubs, go for both partial and full foams, thermal wraps, FiberCor insulation, or Multi-density foam.
Note that some of the materials used to make bathtubs come with insulation properties, but you can’t count on them because their R-value doesn’t fit the purpose.
Conclusion
So, is it worth insulating your bathtub?
Absolutely. Unless you have a solar-powered water heater in place, every drop of hot water used at home is either heated with gas or electricity.
Every degree Fahrenheit used to heat the water needs to be accounted for or else you will end up with a bloated electricity bill with nothing to show for.
Virtually any spray-on foam will work for your tub. For indoor bathtubs installed in your bathroom, however, I’d recommend polyiso foam (a spray-on foam).
Related
References
http://www.korraware.com/html/news/bath_ware_knowledge/981.html
https://dengarden.com/remodeling/Insulating-a-Bathtub-How-To-and-Photos
