Swimming Tricks

How Long Does It Take To Heat A Pool?

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So, how long does it take to heat a pool?

Many people are curious about how long it takes for a pool to heat up as the pool season approaches. For anyone who wants to use their pool all summer long, this is a crucial question. When estimating how long it will take for the temperature of your pool to reach the desired levels, a number of different factors are taken into account.

A heat pump will generally heat a pool within 24 to 72 hours by 20 degrees But this will depend on things like the heater’s BTU output, the size of your pool overall, and the amount of water in it. A heat pump can heat smaller pools, like spa pools, in 45 to 60 minutes.

This demonstrates the significance of understanding your pool’s volume as well as the BTU rating of your pool heater. You can calculate how long it will take to heat your pool if you have this information.

How Long Does It Take To Heat A Pool?

The Short Answer

The short answer is that, for a standard 32 m2 pool, from a cold water standing start at the beginning of the swimming season, a swimming pool heat pump can heat your pool to a swimmable 28ᵒ Within 12–48 hours, C.

Whether or not you have a pool cover affects how long it takes for the pool heat pump to heat the water.  Furthermore, where you reside affects this:  if you live in If you live in Melbourne, it might take an extra day or two; if you live in Sydney, you might only need 24 hours or less.

The reason for this is because pool heat pumps are capable of warming the water of an average 32 m2 (42,000 litre) backyard pool by around 0.5ᵒ C per hour.

The Longer Answer

The more complicated response is that the length of time needed for a swimming pool heat pump to raise the water’s temperature to 28° C depends on the water’s initial temperature.

And it depends on the rate at which your pool is actually losing heat.  Your pool is losing heat to the atmosphere even though the pump is bringing warm water in at one end.  As a result, an exposed pool will gain heat more slowly than one that is covered.

Furthermore, geography and climate are important.  This is so because wind speed, air temperature, and humidity all have an impact on how much heat the pool heat pump actually transfers to the water in a given hour.

Factors That Affect The Pool Water Heating Time

The length of time that a heat pump must run depends on a few factors. In order to get the desired temperatures, there are a number of factors to consider when heating a pool, including the pool cover, the size of the pool and the heat pump, the surroundings, the dimensions, the weather, and the volume of the water. 

Since the heat pump does not produce its own heat, keep in mind that its operation and runtime are influenced by the weather. In light of this, it is challenging to determine a heat pump run time for all pool heaters.

Climate And Geography

Heat pumps, as was already mentioned, are unique appliances because they hardly produce any heat. It uses air that is pulled in from the surrounding atmosphere to warm the water. Pool owners in colder climates should be aware that they face challenges because of the climate. Heat pumps function best at temperatures over 50 degrees Fahrenheit; below that, they are ineffective. 

This means that in order to warm the pool appropriately, you must run the heater for a longer period of time. It is therefore imperative that you take into account the climate in your area before you purchase a heat pump, especially during the cooler seasons. 

Pool Size

Although it should go without saying, there are still some people who will fail to notice it. In general, it takes more time for the heat pump to run to the desired pool temperatures the larger the water body. 

A powerful heat pump is necessary to quickly warm a large pool; otherwise, it will take longer and may not be as effective. However, a small heat pump can perform the task comfortably with a small pool size. But keep in mind that the present weather also has a significant impact. 

Heat Pump Size

British Thermal Units (BTU) per hour are used to determine the size of a heat pump. Pool water will warm up by 0.6°C for every unit of BTU, and a gallon of water weighs the same as 8.34 pounds.

As a result, 8.34 BTUs will raise the temperature of a gallon of water by 1°F (0.6°C). In an effort to save money, some consumers purchase underpowered pumps, but you’ll go bankrupt if you do. The pool may require more run time to warm up, and they frequently have high operating costs. Efficiency declines as running time increases. Therefore, you ought to invest in a gas heater. 

So the heat pump has a significant impact on the duration of the heat. In light of the fact that higher unit counts require more heating energy, heat pumps run for shorter periods of time.

Pool Covers

For energy conservation, some pool owners use covers. It’s a fantastic way to stop evaporation, which affects most pools to the tune of 75% and is the main cause of heat loss. As a result, the covers will help to keep the heat in the pool by reducing the rate of evaporation and acting as a barrier between the water and the outside air. Additionally, you save money and time by cutting back on heating requirements.

In some cases, if you use a pool cover effectively, you might be able to heat the water using a small pool heat pump. Because pools lose heat quickly when left uncovered, they typically gain heat more slowly than covered pools. While you’re at it, make sure to purchase a top-notch cover that will help you prevent up to 75% of heat loss from your pool.

Water Temperature

The initial pool water temperature plays an important role in calculating the heat pump run time. However, it wouldn’t take long for the pool to reach 80 degrees if it had been comfortably sitting at around 70 degrees during a warmer season.

Keep in mind that the heat pump will need to run for a longer period of time the greater the difference between the starting and desired temperatures. 

People opening their swimming pools after a cooler season are probably on the chilly side. It implies that it will take longer to heat up the pool to a pleasant temperature and take a dip. 


Are You Buying A Heater Or A Heat Pump?

A few factors influence how long it takes to heat your pool. Have you made a decision regarding whether you want a heater or a heat pump? Although they both heat your pool, they do so in very different ways. Let’s dig in.

Instead of producing heat on their own, the heaters in thermal pools take heat from the surrounding air and use it to warm the water in the pool.

This might be a problem if you live somewhere particularly cold. When the temperature is above 50 degrees Fahrenheit, heat pumps perform best. Below 50 degrees Fahrenheit, heat pumps cannot operate effectively.

Pool owners consequently need to run their heat pumps for longer periods of time to warm the water. Therefore, before investing in a heat pump, it’s crucial to consider the average temperature in your area, particularly during the winter.

If your heat pump is too small, it will need to operate harder to heat the pool. Lower efficiency and higher operating costs follow from longer running times. In a nutshell, it’s a lose-lose scenario; choose a gas heater in its place.

Which Is Preferable, Day Or Night For Running A Pool Pump?

This is a question that many people have because it leaves people uncertain about which course to take. You should be aware of a few things, though.

A great alternative is to run your pool pump at night, but this isn’t necessary and could end up costing you money and time. It would also assist in the formation of algae since they require heat to develop,

The best way to use your pool pump is to leave it running at a particular temperature for a predetermined period of time. Therefore, if you want to use the pool in the afternoon, you can run it at a certain temperature for at least an hour, then store the energy by covering it with a solar blanket.

Is It Ok To Leave The Pool Heater On All Night?

Whether or not you leave your pool outside overnight has an impact on both the size of the heater and how much it costs to heat your pool. Depending on how much swimming you do in your pool, people typically recommend keeping the water between 78 and 82 degrees Fahrenheit.

However, if you keep your pool at a temperature of around 78°F, you’ll use less energy and keep kids and the elderly safe.

However, if you want to use the pool in the morning, turning off the heater at night wouldn’t be a good idea because the pool’s temperature would drop quickly at night, requiring a higher heat rate when you want to use it.

What Are The Operating Costs Of A Pool Heater?

What are the costs associated with operating a pool heater? This is a question that many people with pool heaters or those considering adding one to an existing pool may have.

Propane Heaters

For every 100,000 BTU, propane pool heaters burn approximately 1 gallon per hour. That works out to 4 gallons per hour for a 400,000 BTU heater. Currently, the price of propane is between $4.50 and $5 per gallon, but this could change.

You should ask your service provider since prices can change.

Without a solar cover, a 10–12K gallon pool needs to be heated in the range of 8–14 hours. By adding a solar cover to your pool while it is being heated, you could significantly increase the efficiency of the heating process.

Natural Gas Pool Heaters

Natural gas heaters, also referred to as NG or NG heaters, use approximately 1 therm per hour for every 100,000 BTU. 400,000 BTU pool heaters typically produce four therms per hour.

Currently, a therm of natural gas costs about $1.50 in the United States. Using natural gas, it typically costs $7.00 to heat a pool for an hour.

Natural gas needs 8–14 hours to heat an average pool (10–12K gallons) without a solar cover. By covering your pool with a solar blanket while it’s being heated, you could significantly improve efficiency.

Heat Pumps

For every 100,000 BTUs in a heat pump, approximately 5,000 watts, or 5 kilowatts per hour, are required. That amounts to 5 kilowatts per hour for a heat pump of a typical size of 100,000 BTU.

Around $.16 per kilowatt-hour is the standard price for electricity in my area. Double-checking your utility provider’s rates is advised if necessary as they are the ones that govern electricity.

According to our example, it will cost about.80 cents to heat a pool with a heat pump for an hour. Without solar protection, a typical pool (10–12K gallons) should heat up at a rate of 1–1.5 degrees per hour.

A solar blanket over your pool will improve its effectiveness, as it does with other heaters.


So the next question is, how long does it take a heat pump to heat pool water? Is one of the things that most people have always wanted to know, and with the help of this guide, you can now estimate the heat pump’s run time based on the information provided. Nevertheless, bear in mind that each swimming pool’s environment has a different impact on how long the heat pump runs.

Despite the fact that these variables will have an impact on the heating time, you must make sure that the heater and the pool are in good working order. So make sure to plan yearly maintenance visits to keep them in top condition; you’ll end up saving a ton of time and money.