Inflatable hot tubs are an amazing invention. They let you enjoy a hot tub at home or on the go. An unfortunate truth about inflatable hot tubs is that the hot tub manufacturer has not designed them for very cold weather. No currently available inflatable spa is rated to work below 40F. How do you make it work better in the cold? One way is by improving the hot tub insulation. Let’s look at a few ideas for insulating an inflatable hot tub.
- Why insulate an inflatable hot tub?
- 13 Tips for Insulating an inflatable hot tub and keeping it hot
- Ground insulation
- Cover Insulation
- Insulating around the hot tub
- Pump and plumbing insulation
- How else can I keep my hot tub warmer?
- Wrap up
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Why insulate an inflatable hot tub?
As stated earlier, inflatable hot tubs are not designed to work in the cold. Even the most premium Intex Purespa is still designed for a max cold ambient temperature of 40F. This is unfortunate since the best time to use a hot tub is when it’s cold out. They have heating that is only strong enough to warm the water temperature 1 to 2 degrees per hour. This is true for every tub made by Coleman, Intex, and Bestway (who make almost every other branded inflatable hot tub).
In cold weather, the hot tub water will cool down much faster while using the hot tub. Some heat is going to be lost by evaporation when the top is off while your using it. There is nothing we can do about that. We can improve the cover with more insulation so the warm water stays warm longer when not in use.
The air jets or bubble jets blow cold air into your hot tub when they are running. You can leave them off but that takes away one of the great parts of using a hot tub. We are stuck with that heat loss also.
A lot of heat is lost through the ground and walls of the hot tub. That is where we can make a difference by adding more insulation to our hot tub.
By adding extra insulation to the inflatable tub it will reduce the time needed to reheat the water between uses. It will also reduce the energy/cost needed to maintain the temperature. No hot tub owner ever thought their hot tub didn’t cost enough. Saving money on heating is a big help.
13 Tips for Insulating an inflatable hot tub and keeping it hot
1 – Hot tub groundsheet
Most inflatable hot tubs come with a ground cloth. These are mainly to protect the bottom of the hot tub from sharp objects and debris on the ground. They do provide a small amount of insulation from the ground. Be sure to use the groundsheet if your hot tub came with it. If it did not, look up the available accessories for your tub and see if you can get one.
2 – Foam sheets
A good DIY option for adding more ground insulation is to use a foam sheet under the tub. Go to your neighborhood Home Depot and find some 1 inch thick foam insulating sheets. Cut the sheets to fit the shape of the bottom of your hot tub. Place these on the ground above the groundsheet and inflate your spa on top of it. Another option is thick foam tiles that are old for flooring. Any kind of thick foam will work as an insulator.
3 – Hot tub pads
A more expensive way to add more ground insulation is to buy a hot tub pad. These are foam or plastic insulating pads you can put under any hot tub. They are designed to insulate your hot tub and do a much better job than a thin groundsheet. If you don’t want to DIY cut a bunch of foam insulating sheets, you can buy a hot tub pad that fits the shape of your hot tub.
4 – Hot tub cover
Every inflatable hot tub comes with an inflatable spa cover that provides some insulation. Make sure you keep it fully inflated. The air gap created by the air chamber provides insulation. Always put the cover back on right away when you are not in the hot tub. Heat rises and an uncovered hot tub loses heat much faster than a covered one.
5 – Thermal blanket across the water under the cover
The insulating cover your hot tub comes with still loses a lot of heat. Lay a space blanket or thermal blanket over the top of your hot tub before putting the cover on. The thermal blanket will trap more steam from leaving the hot tub. It will improve the insulating value of the cover a lot. You don’t need to worry about the thermal blanket growing mold or being wet. The top of your hot tub cover gets wet too and you can clean it off. If your thermal blanket starts getting dirty clean it off or throw it away and start with a fresh one.
6 – Inflatable insulator under the cover
Another option to improve your hot tub cover is adding an inflatable insulator. Putting an inflatable insulator under the insulated cover can double the amount of insulation. These are designed to fit under existing covers between the cover and water. They are run $30-$40 in cost. They will easily make up for their cost in reduced running costs in cold weather.
ALEKO HTRP4BK Inflatable Round Insulator Top for 4-Person Inflatable Hot Tub
- ALEKO’s HTRP4BK Inflatable Insulator Top will retain heat and keep water clean in your personal spa or hot tub when not in use
- Can be used on its own as a hot tub cover or fits underneath your own cover to increase heat retention
- Helps to keep dust and debris out of your tub, so the water will stay beautiful and clear for longer between cleanings
- Material: PVC, Color: Black
- Dimensions: 55 x 55 x 7.8 inche
Insulating around the hot tub
7 – Hot tub jacket around the tub
A portable spa lacks a spa cabinet built around it like a permanent hot tub. The spa cabinet is lined with foam insulation and everything inside of it is covered in spray foam. How do we make our inflatable hot tub better? We wrap it in insulation.
A DIY option is adding an insulation jacket around your hot tub. This can be foam insulation or partial foam insulation using foil or bubble material also.
You can do this with reflective foil insulation. This material has a foil layer with either a foam or bubble wrap layer underneath. Wrap your hot tub with this material. If you want to go fancy, create a cover for it so your hot tub doesn’t look like it is covered in aluminum foil. Make sure your hot tub is leak free before doing this. Water trapped between the insulation and hot tub can grow mold.
A side benefit to creating an insulating jacket is that it gives another layer of protection. It will prevent damage from scratches and punctures.
See the video below to see how to make an insulating jacket for your inflatable hot tub.
Pump and plumbing insulation
8 – Insulate the water hoses
The water hoses are another source of heat loss. Wrapping them with foam will help your hot tub stay warm longer. A good DIY way to do this is to buy a pool noodle or pipe insulation and put it around the water tubes.
9 – Insulate the water pump
The water pump that houses the pump and heater is another source of heat loss. You have to be careful when adding insulation around the pump. I have seen people just throw blankets or foam around it. This works. You have to be careful you don’t block the air vents on the pump which can lead to overheating the pump motors. This can lead to burned out pumps or worse, a fire hazard.
This may work okay during winter and cold temperatures. If you put insulation around the pump in warmer temperatures you risk damaging the pump. If you try this it is best to not block the vents with whatever insulation you choose.
How else can I keep my hot tub warmer?
10 – Add a portable outdoor tankless water heater to supplement heating system.
One of the biggest shortcomings of an inflatable and any portable hot tub is the heating power of the pump. If you can heat 1-2 degrees per hour and you start with water that is 60 degrees, you can do the math for how long it takes to heat. It takes a lot of hours to get it to 104F. If you are handy you can hook up a portable outdoor tankless water heater and a pump to add some extra heating power. As a bonus, it will give you another hot hydro jet if it’s running while you are in it.
First, choose a tankless water heater. You don’t need to go really big. A 1-2 GPH (Gallons per hour) heater is plenty. There are electric and propane versions. Most electric ones need 240 volts and 60 amp circuits. Stick with a propane version. I recommend the CAMPLUX ENJOY OUTDOOR LIFE BD158 1.58GPM Heater.
CAMPLUX ENJOY OUTDOOR LIFE BD158 1.58GPM Outdoor Propane Tankless Water Heater
- 3.0 PSI Low Water Pressure -This tankless propane water heater lights when water pressure between 3.0-110 PSI, 3.0 PSI low water pressure is perfect for campings and remote cabins.
- 1.58 GPM On Demand Instant Water – Rated at 1.58 GPM, this on demand water heater provides endless hot water on demand
- Easy & Safety Installation – It only takes you 5 minutes to get 1.58 gallons per minute of instant hot water.
- Compact Size Portable Design – Weights 14 lbs, this 6L portable water heater is a great partner for camping ,road trips and RV’s.
- CSA certified testing standard ensures your safety
Next, you need a 12 volt pump to circulate the cold water through the water heater. Almost any pump that matches the flow rate and pressure requirements of your water heater will do. If your water heater can only heat at a rate of 1.58GPF, it does no good to hook up a 3GPF pump. It will circulate the water through it faster than it can heat it. I recommend the below pump.
Camplux 12V Water Pump 65PSI DC 1.6GPM
- CE Certification – Can be used for general water transfer, spraying, circulation, filtration, dispensing, small rain system, gas hot water system.
- Self-priming – Allows it to be mounted above tank; able to run dry.
- Built-in 65 PSI pressure switch – It automatically turns on and off as you turn your tap or nozzle on and off.Adjustable CUT-OFF Pressure : default 65 PSI, MAX 80 PSI. It doesn’t mean 6.0L/min jet at 65 PSI
- 1.6 gallons per minute (6.0 liters per minute). 1/2″ male hose thread.
You need a 12 volt power source to run the pump off of. Any outdoor rated 12 volt source works. If you want to be able to control when and how long your pump runs, you can add a timer to the circuit. This requires some wiring skill but not much. See this video for a guide to how to hook up a 12 volt timer.
Kastar AC Adapter, Power Supply 12V 6A 72W
- Kastar AC Adapter 100% Guarantee to work as original LCD adapter, manufactured at the highest quality standards for ultimate reliability.
- Power Input: AC110-240V Worldwide Input Voltage, Please verify carefully that the DC Output (12V 6A) and connector Tip size (in the pictures) match your original adapter before purchasing.
JVR 12V Timer Switch Programmable Digital
- CUSTOMIZABLE: Easily set up to 16 independent ON/OFF schedules , 1 minute to 7 days timing range.
- ENERGY-EFFICIENT: Auto switch on/off the power supply, powered by 12V DC/AC voltage, power off memory function
- AUTO LOCK: Whenever there is no input within 30 seconds, the timer will automatically be locked.
- LCD DISPLAY: Easy to read LCD screen, panel mounted
You need some 1/2″ hose to hook the pump up to the heater and to run between the pump and your hot tub. 20 feet of tubing is good enough for most people. You may need some fittings to make it work. The hose and fittings are available at any Home Depot or Lowes. It may be best to wait until you get your pump and water heater to see what they actually use. Go get your hose and fittings after that.
11 – Keep it out of the wind and in a sheltered location
The biggest heat loss for your hot tub is when the cover is off and water is evaporating out. The more wind is blowing across it the faster this occurs. If your hot tub is exposed to wind it will lose heat much faster with or without the cover. Try to place it somewhere that is sheltered from the wind.
If you don’t have any existing sheltered places to put it, you can use a patio enclosure or tent over it to block the wind. If you are a DIY kind of person, build a greenhouse enclosure to put around and over the hot tub. This will keep the heat from escaping.
12 – Build a heated box for the pump
When you run the water jets, you are just blasting cold ambient air into the inflatable jacuzzi which cools it down very quickly. One way to get around this is to heat the air around the pump. Build a box that is big enough to enclose the pump and house a small space heater. Use the space heater to heat up the pump and surrounding air. You will blow warmer air into the hot tub slowing down the cooling process.
You need to make the box big enough for the pump and heater with room to spare. If you make it too small you are creating a fire hazard for both the pump and the heater. Don’t leave the heater running unattended for a long period of time or you also might come back to a burnt down hot tub.
13 – Maintain your pump and heater
If you live in an area that has hard water, your pump and filter cartridge will get clogged by calcium deposits over time. This reduces the efficiency of your heating system. Keep the filters clear. If your pump and heating elements are getting a lot of build up it may be time to replace the pump unit. A plumber once told me that when they replace a hot water heater in this area, they usually weigh 2-3 times more and have about half the capacity as when they were new due to hard water deposit build up.
Inflatable hot tubs aren’t perfect for winter due to their design. If you are handy there is a lot you can do to make them more efficient and extend their temperature range lower. As they say, if there is a will, there is a way. Good luck on your portable hot tub insulating project this winter. If you are still wondering what inflatable jacuzzi to buy, see our guide to the best inflatable hot tubs for winter.
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About the author
My name is Doug Ryan. I am a homeowner and love having get togethers and finding the best things to make spending time at home easier and more fun. We spend a lot of time at home so why shouldn’t we have a great time there? I decided to start Great Home Gear as a way to share my knowledge and enthusiasm for all things home living with everyone.