Skip to Content

What Size Gas Line Do You Need for a Pool Heater? (Answered)

An additional comfort or luxury, however you label it, installing a pool heater to your pool can increase the quality of the pool to a great extent. It will allow you to take advantage of the facility even in the cold winter days. 

But if you are expecting the best possible coziness and warmth from the pool water, you have to concentrate on your pool heaters installation.  

You may know that pool heaters mainly run on gas. Thus the heater to get power will need to be connected with a gas line. But you can’t just use any size of line for your pool heater. Depending on the pool heaters size and capacity you have to choose the right size of gas line. 

If you are planning to install a heater to your pool and currently looking for a pool heater, we are here for you. Let’s explore what size of pool heater you will need, and what size of gas line will be needed for that pool heater.

What size gas line do you need for a pool heater? 

The temperature of the pool is maintained by the pool heater. This heating procedure is conducted with the help of gas through gas pipe lines. A small pool heater, such as 260k BTU needs at least 1-1.25” gas pipe line. Whereas bigger pool heaters, such as 400k BTU heaters need pipe sized at least 1.5”. 

However, there are pool heaters in different sizes which are required for pools of different sizes. As different sizes of pool carry different amount of water, the power of heater required for different pool varies accordingly. The frequency of heating also determines the required capacity of pool heater. Different capacities of pool heaters are described as follows-

150000 BTU pool heater:

A pool with a surface area of 250 square feet normally contain 5K gallons. For such type of pool, a heater with the capacity of 150K BTU is used. Heater with low capacity takes longer time to raise the water temperature. Pool with a 150K BTU heater may take around 3.5 hours to raise each degree of temperature. 

200000 BTU pool heater:

A pool with a surface area of 350 square feet normally contain 10K gallons. For such type of pool, a heater with the capacity of 200K BTU is used. This pool heater may take around 2.5 hours to raise each degree of temperature. 

250000 BTU pool heater:

250K BTU pool heater is used to raise the temperature of around 10K- 15K gallons of water. It may take a surface area of around 400- 450 square feet. The required time for raising each degree might be less than an hour. 

300000 BTU pool heater:

Pool heater of this capacity is normally used for pool with a surface of up to 500 square feet and it contains almost 15K – 20K gallons of water.  Pool heater with such capacity can raise the temperature of 20k gallons of water more than 2 degrees in an hour.  

400000 BTU pool heater:

400K BTU pool heater has better capacity than the previous one. It is normally used for a surface area of up to 800 square feet. A pool of around 800 square feet surface can contain water about 40K gallons. To increase the temperature of such quantity of water, 400000 BTU pool heater normally takes around 1.5 hours to increase 2 degrees of temperature.  

Can I use flex gas line on pool heater? 

No, you cannot use flex line on pool heater. You have to use rigid pipe for connecting gas lines to the pool heater considering safety.

Flex gas lines are basically corrugated stainless-steel tubing (CSST) made of stainless steel and coated with yellow casing. The casing may also be in black. These lines are extremely flexible in nature. These are normally used for interior appliances such as stove, fireplace, furnace, and basically carrying natural gas. They have a tendency of diminishing the gas flow which will create an issue in the pool water. Due to the thickness of this pipe, there are changes of causing fire to the pool heater.

So, flex lines are discouraged to use on pool heater. Rather, rigid pipes are normally used in the pool heater. A union is also used in the hard pipes for easy disconnection. 

What are the gas line requirements for pool heaters?

A pool heater is installed through gas lines for maintaining water temperature. Determining the proper heater and gas lines for your needs will ensure that your heater functions well when you need it and that you can use your pool for longer periods of time. The capacity of pool heater is determined based on pool size and the water contained.  

For connecting a natural gas lines for a pool heater, following variables need to be maintained- 

Location of the pool and heater:

The length and measurements of the gas line depend on the location of pool and pool heater. Distance between pool and pool heater can identify the gas line pipe length.

Proximity to the meter and main gas line:

Distance of main gas line and meter from the pool heater determine the required length of gas line for connecting the heater with the pool. This should be measured accurately to avoid any unpleasant incident. 

Size of the pool and heater:

The width of gas pipes depend on the size of the pool. The pool size represents the contained water and capacity requirement of pool heater. The width of pipe depend on the heater capacity. So, before identifying gas line width, size of pool and heater need to measured.

Location of any existing gas lines and electricity:

To avoid collision among other gas lines and electricity lines, existence of any should be ensured. Otherwise, there might occur accidents.

How much does it cost to run a gas line to a pool heater?

Installing heater line to a pool increase the level of comfort in the water. If you are installing one, you might be aware that, a pool heater runs on gas. So, to operate the pool heater you will need to run a gas line.

If you need a new gas line for the pool heater, it will cost you around $350 to $800 depending on your requirement. Then if you will need electrical connections added to the Heat pumps and electric resistance heaters. To install the electrical circuit, you will have to spend something between $500 to $2100.

Now you will require the work from a plumber, depending on the expertise of the plumber, he will charge you nearly $350 to $800. However, if you will run existing hookups, it will require $500 to $1500.

How to size gas line for pool heater?

The need for a perfectly sized gas pipe is to get the required amount of gas your pool heater need to operate the heater and not to buy an unnecessarily oversized and expensive line. If you by a thinner pipe, the heater will not run properly due to the smaller supply of gas. If you buy a wider gas pipe which supply more gas than heater needs, will be expensive but not increase the heating.

If you want to measure your gas line size needed for the pool, you may follow this steps-

Size of the pool:

The size of the pool heater and the gas line depends on the size of the pool. In this case, size of the pool is an independent variable. The pool size represents the contained water and capacity requirement of pool heater and the width of pipe depend on the heater capacity.

Energy consumption of the heater:

There are many types of pool heater who have unique capacity and energy consumption rate. Distinguishing the heater based on their energy consumption can give you figures to calculate the size of the gas pipe. Based on the energy consumption rate labelled on the pool heater, you can find the appropriate size of the gas line.

Size of the pipe:

Size of the pipe depends on the pool size and the energy conversion of the pool heater. Finding from previous steps will give you appropriate gas pipe size.

Final Thoughts 

Pool heaters primarily run on gases. As the heaters come in different sizes and capacities, the gas line required for their operation varies accordingly. A larger pool heater capable of heating a large pool will need a wider gas line than a smaller one. Usually, the gas lines are between 1″ and 2″.