Are you planning to purchase a hot tub for your home? Also, wondering how long it takes to heat up. Or, maybe you already have a hot tub but want to know if there is anything you can do to speed up the heating process.
Well, you have come to the right place! In this post, I will dive into the factors that affect hot tub heating time. Also, I will provide you with some tips to make the most out of your hot tub experience.
Whether you are a hot tub newbie or an experienced user, this post will surely provide valuable insights. So, let’s jump in and find out how long a hot tub takes to heat!
It depends on a few factors, like the size of your hot tub and the temperature you want it to reach. Generally, it takes between 4 and 8 hours to heat up to a comfortable temperature of 100° F to 102° F. If it is the first time you are turning on your unit, it may take up to 24-48 hours before it reaches optimal temperature.
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When it comes to answering the question, it depends on many things.
It depends on your tub’s water heater if you are trying to heat your tub for the first time. If you have a high-quality water heater, it will take less time to heat your tub’s water to go from cold to the ideal temperature.
Usually, water heats up by 5° F to 10° F almost in an hour. Heating your hot tub to the desired temperature from 100° F to 102° F can take 4 to 8 hours.
Also, it is a basic thing for hot tub owners or those who have changed their tub water often to know how long a hot tub takes to heat.
However, there are many things to know about it, including how to speed that up, and you should never leave your hot tub running.
Estimated Heating Time for Different Situations
- Heating After Refilling: It can take 12-24 hours to reach a comfortable temperature.
- Heating With Hot Water: It can take 4-8 hours to reach 100-102 degrees Fahrenheit.
- Heating With Cold Water: It can take up to 20-48 hours to reach a safe and comfortable temperature of 100-102 degrees Fahrenheit.
Electricity Usage
A hot tub with a 120-volt heater will consume about 2 kilowatts per hour during the heating process. This means that heating your hot tub could cost anywhere from 8-40 dollars, depending on the time needed to heat it.
Hot Tub Covers
Using a hot tub cover while heating can help keep the heat in and reduce the time needed to heat your hot tub by up to 25%.
Factors Affecting Hot Tub Heating Time
- Air Temperature – The temperature of the air outside your hot tub can affect the time it takes to heat up. Warmer air will help to heat the water faster than cooler air.
- Hot Tub Size – The size of your hot tub will also determine how long it takes to heat up. Larger hot tubs will require more time to heat up as more water needs to be heated than smaller tubs.
- Insulation – If your hot tub is well insulated, it will help to keep the heat in, allowing the water to heat up faster. Poorly insulated hot tubs will take longer to heat up and may not maintain their temperature as well as well-insulated ones.
- Water Temperature – The temperature of the water when you start heating your hot tub also determines how long it takes for the desired temperature to be reached. If your water is already warm, it may take less time to reach the desired temperature than if it is colder.
- Hot Tub Heater – Different types of hot tub heaters will also affect heating time. Some heaters can more quickly and efficiently heat your water than others. So consider buying energy-efficient models that can help you save money in the long run while also heating your water faster!
Tips You Can Follow to Make Your Hot Tub Heat Up Faster
Depending on location and the external temperature, heating your hot tub can take anywhere from three to eight hours.
To speed up the process, ensure your hot tub is in good working condition and set the thermostat to a lower temperature.
Running your hot tub for the first time can take up to 48 hours before it reaches an optimal temperature. For outdoor hot tubs, the external temperature plays a role too.
So the warmer it is, the quicker your hot tub will heat up. However, with a few simple steps, you can enjoy your hot tub in no time!

Cover Up Your Hot Tub
A hot tub cover keeps the heat inside the tub. Without the cover, your hot tub’s heater will work harder and take more time to heat the water because heat can escape from the surface.
That is why you should resist the urge to leave the cover off while the water is heating, as it can prevent the heat generated inside the hot tub from escaping.
Turn The Jets On
A hot tub jet has a hose that is installed on the jet body (holder) of your tub. You can get help spreading the heated water equally throughout the tub by turning on the jets.
This will impact the water and remove any cold water pockets or areas in your hot tub that might not heat evenly if left still. So, turning jets on can help heat the tub water faster.

Consider a Floating Thermal Blanket
Floating thermal spa blankets are insulated floating sheets. You can use them directly on the surface of the water.
Stacking a thermal spa blanket under your hot tub cover will add a layer of protection. So this will prevent heat from evaporating from the surface of the water turning. So water will be hated faster (especially during the winter months).
Put A Pop-up Canopy Tent Around The Tub
A canopy tent has many advantages to protect your hot tub. For instance, if you have an overlooked garden, it will give you additional protection against weather damage and privacy from your neighbors.
A canopy over your hot tub will ensure less heat escapes from the area nearby while it is heating, much like keeping your hot tub cover on.
Use A Portable Immersion Heater
Small electric heaters, known as immersion heaters, are plugged in and submerged in water. They can significantly speed up the heating process when combined with the hot tub’s standard heater.

Remember that for the best results, you should look for a heater of at least 1500W. Premier Line 742G Bucket Water Heater is appealing to us. This immersion heater can heat up to five gallons of water in minutes.
You can read How Many Gallons in a Hot Tub? (Easy Formula)
Note: The time it takes for your hot tub to heat up will be even shorter if you buy multiple immersion heaters to use simultaneously.
Bottom Line
Most mainstream hot tubs are made with built-in thermostats, highly insulating covers, and materials to maintain their temperature permanently. Cheap hot tubs often have disappointingly high operating costs because they cannot maintain their heat well.
The time it takes to heat your hot tub from scratch (for instance, the first time you use it or after cleaning or service) depends on the water heater in your tub. The shorter the time it takes for the water to warm to the ideal temperature, the more powerful your water heater is.
When you are heating your hot tub for a longer time, check the heater and the air temperature because excess humidity can reduce the effectiveness of your heating element by causing it to overheat.