How Many Solar Panels to Run a Hot Tub?

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In an area with high sun peak hours, fewer panels would be needed to run the same hot tub as in a place with lower sun peak hours. Still, how many solar panels does it take to run a hot tub? There is an easier way to calculate precisely how many solar panels will be needed to run a hot tub at one home. The tools are widely available, and most do not have a cost to use them. 

The steps to figuring out how many solar panels to run a hot tub are:

  1. Calculate the amount of power the hot tub needs to work
  2. Calculate the amount of solar power the location of the hot tub needs to work
  3. Calculate the amount of energy the solar panel array will produce.
  4. Discover the difference between the production and the need
  5. Install the correct solar panel heat transfer system to counter the electric heater

A solar panel heat transfer system is used to heat a hot tub with an electric heater. Two primary methods by which these systems are considered are: adding additional panels to a home solar system to counter the cost of the hot tub, or setting up a solar system independent of the home system to lower the cost of operating the hot tub on the home system.

Solar Panels to Run a Hot Tub

Installing a Solar Panel Heating System to Counter the Electric Heater

A separate solar-powered heat transfer system for the hot tub is one of the many popular choices. Several options are available, but the most common choice is the silicon solar heating mat that is easily installed. The mats come in different sizes, but the most commonly needed size is an eighty-square-foot mat rated to heat up to five hundred gallons. 

Installing the Mat is Easier than Installing the Panels:

  1. Pick a good location to place the mat. An area that gets plenty of sun and room. 
  2. Set the angle between thirty and forty-five degrees to capture the most solar rays. 
  3. Build the rack out of stable, water-resistant material, such as treated metal or wood. 
  4. Mount the panel to the rack. 
  5. Connect the pipe fittings and check valves. 

Depending on the kit purchased, the fittings may or may not come with the equipment. Different kits are available, but primarily they all work the same way. The heat transfer will occur during peak sunlight; this system alone does not store electricity. The solar panels and batteries need to be wired into the home in a more traditional design to store electricity. 

These do-it-yourself kits also do not allow for usage after the sun sets for the evening, so the water will only be preheated, and then to maintain the temperature, the electric heater would need to be used. However, these kits made to counteract the electric cost of running the pre-installed electric heater do help bring down the cost of ownership. 

How Much Power Does a Hot Tub Need to Work?

Hot tubs are available in many shapes and sizes; however, on average, a hot tub holds about three hundred gallons of water and is a stationary appliance that plugs into an outside outlet, usually on the back porch. To lower this cost of electricity, homeowners must first calculate the electricity needed to power the hot tub for one hour. 

An average size hot tub will take between 500 to 6000 watts of electricity to heat 300 gallons of water. The water pump also consumes around 1500 watts of electricity to work. 

Several factors must be considered to calculate the exact amount of solar panels needed to run the hot tub: 

  1. Consideration must be given to the battery setup if anyone plans to use the hot tub after dark. 
  2. If running a separate system entirely for the sake of the hot tub, then a proper solar-powered battery system should be a part of the plan. After all, solar panels only work when the sun is out in full swing. 
  3. There are different battery types to consider, and one should research those accordingly for the proper setup. 
  4. The hot tub will have to have a steady electricity source to maintain the water’s temperature where it is set. 
  5. There are cost-effective alternatives to using electric heaters through solar; these options should also be well-researched as they all work differently. 

Now, let’s move on to how your location and what the weather is like can affect the number of solar panels you will need 

How Do Location and Weather Affect the Number of Panels Needed? 

Find the Peak Solar Hours of Your Location

Use an online solar map to find where the panels will be set up and grab the peak solar hours. These maps help in calculating the estimated output of each solar panel. 

For example, suppose the location is in Texas. In that case, the map states that Texas gets almost five peak sun hours per day, as indicated by the Global horizontal irradiation levels on the Global Solar Atlas Map. 

Do the Math

Multiplying the daily peak hours by the average of the solar panel’s output will give the expected daily production of that specific solar panel.

If the location is in a low-output area, such as Alaska, or a high-output place, such as Lancaster, Ca, reduce, the number of solar panels needed to complete the same output will vary. A person will need fewer panels in Lancaster to heat the same amount of water compared to Alaska. 

Take Into Account the Weather

The weather is another primary consideration for utilizing a solar panel. Things such as rain, overcast, and fog often affect the solar rays in the area. Extreme weather conditions, such as hurricanes or tornadoes, will necessitate special precautions to secure the equipment to a stable foundation.

In some extreme weather conditions, such as sand storms in desert areas or snow storms in the northern hemisphere, equipment can be damaged or stop producing entirely. The terrain is also a consideration, as some areas facing southern directions receive the least amount of solar radiation to convert into electricity.


A global sun map will help with the planning portion of setting up a system. These maps help you find the best angle and tell you how much energy a particular solar panel is likely to produce. Unfortunately, the D.I.Y. kits mainly do not have the resources to store the added amount of electricity, but I am sure some home engineers could conquer that feat. 

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