I recently noticed that, as winter is approaching, temperatures are beginning to fall and I was wondering what you can do stop a hot tub from freezing in cold weather. This is what I found out:
So, how do I keep my hot tub from freezing? You can stop your hot tub from freezing in three ways. By draining it and winterizing it, using the freeze protection mode, or by running the pump to keep the water circulating and prevent it from freezing.
Letting your hot tub freeze could potentially cost a lot of money to put right. However, with a few easy precautions, you can have peace of mind throughout the coldest of weather.
How to prevent your hot tub freezing in winter?
The best solution is to keep the hot tub open and running. This will mean that you can enjoy using it throughout the winter months. There really is nothing quite like sitting in the luxury of the hot tub outdoors in a winter wonderland or by the twinkling of outdoor lights on a clear winter evening.
If you do keep your hot tub at working temperature then there isn’t a risk of freezing. Depending on the make of your hot tub you might have a freeze protection mode which will operate the pump to keep the water moving when the air temperature dips to near freezing point just to make sure.
If you haven’t got freeze protection then it’s a good idea to set the pumps to come on regularly, particularly during the night when it’s colder, just to be on the safe side. The water won’t freeze as long as it keeps moving. Just make sure that all of the jets are open and that the water is being pumped all around the hot tub. If the water is cold, any static areas will be at risk of freezing.
It’s also really important to have a good quality insulating cover on the hot tub throughout the winter. This will not only keep the heat in but also keep out cold rain and snow and other environmental debris.
The location of your hot tub can also have a big effect on it’s viability and efficiency for winter operation too. Try to position it in a sheltered spot preferably where it will capture as much of the winter sunshine as possible. Keeping the hot tub away from draughts and the prevailing wind by setting up windbreaks and screening works really well. This not only prevents the area around the hot tub warmer but it makes it more inviting for a winter dip!
The other option is to drain and winterize the hot tub. This is only really recommended if you know that you are going to be away for several weeks over the winter or won’t be able to maintain it over the winter months.
Winterizing a hot tub is quite a long process involving draining, cleaning and blowing out the hot tub to make sure that all traces of water are removed. It can be done yourself but is also a big enough job for hot tub service engineers to offer as a paid service.
To be doubly sure and safe you can put a tungsten light bulb in the pump cavity of the hot tub and leave it switched on in very cold weather. Make sure that the bulb isn’t close to anything that can heat up or melt. The small amount of heat the bulb gives out will be enough to ensure that the water doesn’t freeze in it’s vicinity.
Why is freezing so bad for my hot tub?
The main problem is that water expands by 10% when it freezes. If the water isn’t in a restricted place then this isn’t an issue and it just expands to fill the available room. However, if the water is completely filling a vessel it will push and expand and often force it’s way through even the toughest of materials. Think how frost damage can erode and crack even the hardest of rocks and you will realize how powerful it is!
In a hot tub, the problem occurs when water that is left in pipes or in areas of the pump, jets or other restricted area freezes and expands. The chances are that it will split whatever is restricting it causing burst pipes, ruined pumps and motors, and damaged jets.
What temperature should I keep my hot tub over winter?
It makes most sense to keep your hot tub at full working temperature so between 36 degrees C and 40 degrees C. However, if you know that you won’t use it as frequently as in the Summer you may feel you want to lower the temperature a little to save energy and the heat it up again for use. In this case, it’s not recommended to allow the temperature below 30 degrees C.
It’s difficult to decide if this approach is false economy as it will take a lot of energy to reheat to working temperature. You may well be better just leaving the hot tub at working temperature all the time unless you are going to use it very infrequently.
Remember, even if you aren’t using the hot tub you will still need to make your regular maintenance checks. You might have to make a decision as to whether it might be a better course of action to completely drain the hot tub and winterize it.
What to do if your hot tub freezes
If you need to thaw out a frozen hot tub here’s what to do:
- Switch off all of the power. You risk further damage if the pump tries to move frozen water.
- Break the ice on the top of the hot tub and start adding hot water. You will probably need buckets of hot water or, if possible your hose pipe connected to the hot water tap.
- At the same time get some gentle heat inside the cabinet to warm the underneath and the mechanics and pipework. Be very careful if using electrical heat as the chances are that there will be a lot of water around.
- Try to contain as much heat as possible. One technique is to erect a tent around the hot tub if you have one big enough. This will keep the heat in a little and help the thaw. You can also use blankets and tarpaulins to try to keep as much heat in as possible.
- Look for damage. The most likely places are the heater, pump or filter. Look for leaking water and cracks and splits. Pipes will tend to have hairline cracks along them. As the ice thaws you should see water dripping from the damaged parts.
- Once you have got a good idea of the damage then drain the hot tub completely.
If you are sure or are in any doubt that the hot tub is damaged then call out a service engineer to check and make the repairs. The chances are that the damaged parts will be relatively easy to replace. It’s highly unlikely that the hot tub will be totally ruined.
If however, after the thaw, you are lucky and nothing seems damaged then you can start up the hot tub again. Listen very carefully for strange noises and look for leaks over a period of time. Check on the hot tub regularly and if there is anything that doesn’t seem right then switch off, turn off the power and call out a service engineer.
How to keep a hot tub from freezing during a power outage
Luckily these days it’s unlikely that you will be without power for long and, if your hot tub is at working temperature it will be fine for between 24 and 36 hours. Things get a little more problematic if the hot tub is just filled with cold water. It’s possible that if the temperature is very low and the pumps can’t keep the water moving that the pipes will freeze enough to cause some damage within a few hours.
The first thing to do is to keep the cover on your hot tub and to wrap it up further using any insulating material you have. Blankets and tarpaulins are good and if there is a cold strong wind anything that will act as a windbreak will be helpful. Resist the temptation to lift the cover and look inside the hot tub as every time you do this it will let in cold air. You can do buy floating thermometers that connect to an app on your phone if you really want to keep in touch with the temperature of your hot tub without lifting the cover.
You might also want to consider another pre emptive purchase of a battery operated free standing pump if you suffer from frequent power outages during the winter.
If the power is off for a very long time then you might need to take further action. Half draining the hot tub and adding warm water can be effective and you might want to consider introducing gentle indirect heat inside the hot tub cabinet. Hot water bottles can work well as can battery operated lights – just be very careful that the area doesn’t get too hot and bear in mind that it could potentially get wet as well.
As a last resort consider draining the hot tub completely. In this case, you do need to make sure that no water is left in the pipes or the pump as it will freeze.
Once the power comes back on again starter the hot tub as normal. If you suspect that any part of the hot tub has been frozen listen very carefully for strange noises and check carefully for leaks. If in any doubt switch the hot tub off completely consult a service engineer.
Andrew Hind
This post was created by Andrew. Enjoyer of hot tub soaking, fine cheese, music and photography.