How To Keep A Hot Tub From Freezing (6 Easy Steps)

Patricia Oelze
by Patricia Oelze

Hot tubs are great for relaxing after a long hard day at work. They can also be beneficial for fibromyalgia, low back pain, and arthritis. But the damage that can be caused by your hot tub freezing in the winter is not so good. Because water expands to around 10% of its volume when it freezes, pipes and other equipment can crack or break due to the expansion. But there are many ways you can keep your hot tub from freezing.

To keep your hot tub from freezing, you can cover it with a thermal blanket, putting it on “freeze protect” mode if available, or winterizing it. To winterize your tub, turn off the circuit breaker, drain out any water, and fill it with hot tub antifreeze. Do not drain any water under freezing temperatures.

First, you have to decide whether or not you are going to want to use your hot tub during the winter. If not, you can just winterize it and not worry about it until the winter is gone. But if you may want to use it, you can take a few steps to keep it from freezing up on you.

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How to Keep a Hot Tub from Freezing

Step 1: Shutting Off the Jets

If you do not shut off your air jets after each use, you are letting in some ice-cold air into the water that will freeze it even with a cover on it. Even if you turn on the heater periodically or have it set to turn on at certain times, the motor and heater will have to work extra hard to heat the water if there is icy air coming through the jets.

Step 2: Keep a Full Tub

Some people think that draining your tub will protect it from freezing. But the opposite is true. The only way you should ever drain your tub for winter is if you are going to winterize it.

Having a full tub keeps the water warm longer. Similar to having a deep lake, only the top of it actually gets cold enough to freeze, and you can control that with a thermal blanket or insulated cover. Keep the tub full and check on it at least once a week.

Step 3: Quality Insulated Cover

A good insulated cover will keep the heat in and the cold out. Do not just get the cheapest one you can find. After all, you spent a chunk of change on that hot tub, make sure you spend a bit more to protect it. Unless you want to have to replace it, which will cost you more. Insulated hot tub covers come in many materials and thicknesses.

They have some that cover the entire tub, which is recommended. You should also get one with the thickest and densest foam to keep it protected from the elements. They also come in all sorts of shapes including round, oval, square, rectangle, octagon, and elliptical. You can even have them custom made to fit your spa perfectly.

Step 4: Floating Thermal Blanket

Actually, if you live in a really cold area, it is best to have both a floating thermal blanket and an insulated cover. The cover will keep the warmth in, but the blanket can help your tub retain 95% of that heat that would evaporate without it. You do not want all that heat from your insulated cover to be wasted.

A floating thermal blanket (or spa blanket) is a thick plastic sheet that is custom cut to cover the entire surface of the water. It is a form of insulation similar to the insulation in your home that keeps cold air out and the warm air in. It also saves you on your heating bill because you do not have to use as much energy to heat up the tub when you want to get in.

Step 5: Timer or Automatic Thermostat

Most hot tubs have a timer or automatic thermostat that will run the heater when it gets too cold. The best kind is the one that can automatically monitor the temperature of the water and kicks on when needed. It reads the temperature of the water at all times and is set to turn on the heaters when it drops below a certain temperature.

The other kind is just a timer that you can set to turn on to circulate at certain times to keep the water from freezing. Because moving water is less likely to freeze than standing water, setting it to turn on for 15 minutes every hour will prevent it from freezing.

Step 6: Space Heater

You can get a ceramic heater and put it in your tub’s equipment bay or somewhere else close enough to keep it warm. Keeping it near the hoses and pipes will help prevent them from freezing if the temperature drops too low.

However, do not put it too close to any wires or PVC pipes that can be damaged by high temperatures. You do not want to melt the pipes or hoses either. It does not have to be a ceramic heater, but it needs to be safe and you should check on it daily.

How to Winterize a Hot Tub

If you are totally sure that you are not going to be using your hot tub this winter, you may as well go ahead and shut it down for the winter. But there is a process of winterizing. Follow these easy steps.

  • Before doing anything to your hot tub, make sure you turn off the power at the circuit breaker. This is a must, no matter what you are doing to your tub.
  • Take off the access door to get to the hot tub equipment. It is typically on the side of the tub.
  • Hook up a garden hose to your drain hose. Allow it to drain as much water as you can get out of the tub.
  • Loosen the connections on all the water lines.
  • Take the drain plug out of each pump to drain the water.
  • Use a shop vac to get the water out of the lines. Use it to get the excess water from the tub too.
  • Put the drain plugs back on.
  • Pour a gallon of hot tub antifreeze into the top of each of your pumps.
  • Add another gallon of antifreeze to the filter cavity.
  • Put the access cover and hot tub cover back on.

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Related Questions

What do I do if my hot tub freezes?

If your hot tub does freeze, do not panic. You can thaw it out and hopefully, there will not be too much damage. Here are some tips on thawing out your hot tub.

  • Get a heat lamp and place it next to the pump. You need to thaw out the pump first so you can get the lines thawed out. It may take several hours. If your hot tub is not enclosed, pitch a tent over it to hold in the heat.
  • You can also use a space heater like the ceramic heater mentioned above to thaw out the pump and pipes.
  • If there is water in the tub, do your best to make a hole in the middle of the frozen water. You can pour warm water in the middle to get it started. Do not get any on the shell of the tub or it can cause it to crack.
  • After you get the water defrosted, open the drain valve, and let the tub empty. You can also use a sump pump.
  • Once the tub is empty, check to see if anything is damaged and fix it or call a hot tub professional.
How much does it cost to replace freeze damage?

Depending on how much damage is done and what the damage includes, you can expect to pay anywhere from $200 to $2,000. Obviously, if the cost is too high, it may just be cheaper to get a new one. However, take a look at the most common fixes and how much they cost.

DamageAverage Cost
Hose repair or replacement$75 to $150
Heating system repair$150
Pump repair$200
Pump replacement$500
Electrical work$750 to $1,000
Shell repair or replacement$500 to $2,000
Patricia Oelze
Patricia Oelze

I am a DIYer who loves writing about anything home-related. When I am not writing, you can find me studying for my PhD in Psychology, photographing nature, and swimming at the lake with my grandkids.

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