BUYER'S GUIDE: How Many Panels Do I Need?

Step-By-Step Instructions For Sizing Solar Pool Heaters

How Many Panels Do I Need?

Which Brand Is Best Is The Best?

Step 1 - Overview

A few different variables should be considered when selecting a solar pool heating system to match your swimming pool. The primary factors are; your location (climate), pool size (surface area), and heating goals (how long your looking to extend your swimming season).

Understanding exactly what your goals are will help determine how many panels you need and which system to ultimately select. Solar pool heaters are available in a couple different types, each with its own advantages and "ideal fit".

Because solar pool heating systems are dependent on weather and sunlight, these figures can only be used as an estimation, they cannot be guaranteed.

Step 2A - Measure Your Swimming Pool

Solar pool heating systems are sized based on the surface area of your swimming pool, rather than its volume. This is because the primary source of heat loss occurs through evaporation at the surface.

If you have a geometrically shaped pool, this calculation is quite easy. If however, your swimming pool is a "freeform" shape, or a "kidney" shape, this calculation can be a bit more difficult.

*For pools matching this second classification, see our step-by-step instructions for using Google Maps to measure your pool (Step 2B).

Formulas for Geometrically Shaped Pools

  • Circular: πr² (radius being half the diameter of your pool, π=3.14)
  • Rectangular: L x W (length x width)

Step 2B - Measuring Pool With Google Maps

  1. How to Size Your Siwmming Pool with Google Maps:
  1. Type your address into the search bar and hit enter.
  2. Click the small image labeled “Satellite” in the lower left-hand corner of the map.
  3. Zoom into your address with either the mouse wheel or the (+/-) buttons located in the lower right-hand corner.
  4. Right-click on any portion of the border of your pool. Click “Measure distance”.
  5. Continue to click on multiple points, essentially creating an outline of the diameter of your pool, clicking every time the direction changes (you’re essentially creating an outline around the pool with each click of the mouse).
      • To Edit Your Selection: You can move a selected point by clicking on the node, holding the mouse button, and moving it to the desired location. You can also erase and start over by right clicking anywhere on the screen and hitting “clear measurement”.
  6. Once you have gotten all the way around your pool, make a final click on the very first point you made, thus completing the border. When you make this final click, the bottom of your screen will show the “total area” of your pool. This is the surface area that will be used to calculate what size system you need.

 


Google Maps Example Pool Measurement

 

This tool also works well for measuring available roof space. (Satellite imaging provides pretty accurate measurements; however, they are not always 100% accurate and roof measurements should always be double checked by hand if possible).

Step 3 - Calculate Solar Coverage "Offset"

Generally speaking, solar pool heating systems are sized anywhere between 50%-100% of a swimming pools total surface area. IE: “50% offset” means you are matching 50% of your pool’s surface area to the total surface area of all your solar panels.

If your pool has a total surface area of 400 square feet, 50% offset means you will need a total of 200 square feet of solar panels to heat it.

As a reference; a single 4'x12.5' solar panel has a surface area of 50 square feet, so a system with (4) 4'x12.5' solar panels has a total surface area of 200 square feet.

  • 3-4 Month Swimming Season: If you are only looking to add some additional heating during the summer months (3-4 months of warm swimming pool temperatures), 50% offset should be sufficient.

 

  • 4-6 Month Swimming Season: If you are looking to heat your pool into the shoulder months (4-6 month swimming season), you will want to aim in the 60-80% range.

 

  • 8-10 Month Swimming Season:If you are looking for a full spring-fall season extension (8-10 month swimming season), you will want to aim for 85%-100% offset.
  • Example #1
  • Example #2
    • Swimming Pool Size: 16' x 32' (rectangle)
    • Surface Area (Swimming Pool): 512 square feet
      Desired Heating Goal: 4-5 month swimming season
      Solar System Offset: 75%
    • Rec. Surface Area (Solar Panels): 384 square feet
        • Swimming Pool Size: 16' x 32' (rectangle)
        • Surface Area (Swimming Pool): 512 square feet
          Desired Heating Goal: 8-9 month swimming season
          Solar System Offset: 85%
        • Rec. Surface Area (Solar Panels): 435 square feet

Step 4 - Climate Considerations

When it comes to location (climate), you will want to consider how cold/long your winter months are. Solar systems only work when the sun is out and shinning, they also need to be winterized (drained & isolated) for the winter months when temperatures drop below 42 degrees. They also need to be isolated when pools are shut down for the winter.

For this reason, not all climate zones are capable of achieving a full spring through fall season extension. If you live in one of these colder climates, you will not be able to run your solar heater during these cold months when temperatures drop near freezing or below. If you are only able to keep your system running for 4-6 months a year, 50%-80% offset will be more than sufficient.

Step 5 - Optimizing Efficiency

Other factors to consider are what direction the panels will be facing, how they are plumbed, and the amount of sun exposure each day. Solar pool heating systems will perform at optimal performance when the system is facing south, plumbed in parallel (if possible; to achieve a higher flow rate), and the system has full exposure during the day.

If the panels are installed on a ground structure (ground rack), you will want a solid substrate beneath the panels to keep any wind from passing through the riser tubes (reduces wind load on the panels & restricts heat loss). Also, be sure the system is never installed at a pitch greater than 45 degrees (the angle the sunlight hits the panels does make a difference; efficiency nearly drops off the map once the pitch exceeds this maximum).

Need Help Designing / Sizing Your System?

FOR A MORE ACCURATE ASSESSMENT SPECIFIC TO YOUR HOME & NEEDS

Please feel free to message us with your address, pool heating goals, and where you are thinking of installing the system. We can look into the conditions specific to your area and provide a much more accurate idea of what will work best for you, or some ideas to help you along.

We also employ trained solar analysts that are available by phone Monday-Friday, 9AM-5PM (PST) that are more than happy to help fit your home with the ideal heater.


WHICH BRAND IS THE BEST?

Need Help Deciding Which Brand To Select?

Let's Dive In!

Panel Types - Overview

Solar pool heating panels are available in a few different types, solid-body, separated tube, and glazed. Each type has its own advantageous and fits better with different climate zones, roof types & heating goals. Below is a general overview of each panel type. A detailed breakdown will follow with a dedicated section allocated to each.

  • Solid-Body: Ideally suited for those in windy climates zones who want to maximize heating performance. These panels do require multiple lines of strapping to secure to mounting surface, however they are the best low cost option for maximize heating results.

 

  • Separated Tube (ST): Ideally suited for those in colder climates needing an improved resistance to freeze damage. Separated tube designs contain thicker riser tubes that are far more resistant to cold weather damage. These systems are also ideally suited for those in low wind climates looking for an extremely durable system that will last through the ages without much hassle. These systems do tend to be a bit more expensive, however they generally carry much longer warranties.

 

  • Glazed (Insulated): Ideally suited for those in cloudy, windy, coastal regions that are looking to maximize heating performance, while also achieving improved freeze resistance and durability. These systems have a specialized acrylic glazing that encapsulates the riser tubes. This glazing creates a greenhouse effect to preserve heat in the collector as temperatures cool down. This glazing also works to eliminate any heat loss that can occur from wind passing through the riser tubes. These systems are extremely durable, maximize heating efficiency, and provide an an aesthetic appeal that no other system can match. These systems also carry some of the industries longest & most comprehensive warranties.

Panel Type By Climate

Minimal Wind OR Harsh Winter

Separated tube designs are the ideal selection if you are located in a climate void of frequent wind. These systems provide efficient heating and are extremely robust, requiring little maintenance throughout the life of the panel. These systems also carry the industries longest warranties.

Brands: SwimJoy | Heliocol

 Moderate Wind OR Mild Winter

Solid body panels retain heat more effectively than separated tube designs and will provide better heating performances in windy climates. These systems do require tie-down strapping to keep them secure. Also, these panel types do tend to have thinner riser tubes that are more susceptible to freeze damage over time.

Brands: FAFCO | SwimEasy

Heavy, Storm-Force Winds

Separated tube panels are designed to withstand violent storm winds; these panel types will however suffer a larger degree of heat loss from these conditions than a glazed or solid-body panel. If you're in this climate and need to maximize heating performance, you will want a glazed (insulated) panel.

Brands: SwimJoy | Heliocol

Glazed (insulated) panels provide the best heating performance in windy conditions and are designed to withstand storm force winds. This panel type also maximizes efficiency in cloudy climates that receive less sunlight (acrylic glazing generates a greenhouse effect to preserve energy).

Brand: SwimLux

Cloudy, Coastal OR Northern States

Glazed (insulated) panels provide the best heating performance in windy, cloudy, and coastal climates. They are extremely freeze resistant and an ideal panel type ideal for cold weather climate conditions. This panel type also maximizes efficiency in regions that receive less sunlight (acrylic glazing generates a greenhouse effect to preserve energy).

Brand: SwimLux

Type 1 - Solid Body

Solid-body panels are constructed so that each riser tube is connected to its adjacent riser tube, either directly, or through a thin strip known as a "web". Essentially these panels do not allow air to pass between the riser tubes, thus restricting the amount of heat loss that can occur from the wind.

These panels attach with rubber coupling hoses, an industry standard that is well known and easy to work with. Installations are generally pretty simply and can be completed rather quickly. These panels do require body straps across the length of the panel to keep them secure. Also, the riser tubes on these panels are thinner, so the panels are less resistant to freeze damage. This panel type is not well suited for tile roofs.

PROS
  • Easy Installations
  • High Heat Output (Especially in Windy Climates)
  • Great Cost Value
CONS
  • Requires Tie-Down Strapping
  • Higher Susceptibility to Freeze Damage
  • Not Well Suited For Tile Roos
PROS
CONS
  • Easy Installations
  • High Heat Output (Especially in Windy Climates)
  • Great Cost Value
  • Requires Tie-Down Strapping
  • Higher Susceptibility to Freeze Damage
  • Not a Great Fit For Tile Roofs
Visual Examples
SwimEasy Tube & Web Construction
FAFCO Solid Body Panel Design
Solid-Body Brands

Type 2 - Separated Tube (ST)

Separated tube designs are constructed with each individual riser tube being "separate" from all the others. IE: Each tube is free across the length of the panel and not joined to either tube next to it. This design allows air to pass through the body of the panel.

Separated tube designs do not require any tie-down strapping; this feature reduces the overall number of penetrations required for installation. Because they allow wind to pass through the body of the panel, they are far more stable in climates with violent storm winds.

On the performance side, these panels do heat more efficiently in low wind climates. This is because separated tubes allow air in-between the riser tubes, which leads to heat loss as the air moving through the panel will strip some heat.

Separated tube designs do generally have much thicker riser tubes, making them ideal for areas with cold winter conditions (thicker riser tubes are less susceptible to freeze damage). *These systems do still need to be winterized properly, however are more resistant to this type of damage.

The separated tube systems we carry utilize a specialized clamping system to connect the panels together & make attachments to the supply and return PVC plumbing. This clamping system eliminates any gaps between panels, minimizing the space required for installation (also leads to a more appealing appearance). The downside to this clamping style is on the installation side; these systems can take longer to install.

Separated tube designs are generally far more robust and, in our experience, incur fewer pin-hole leaks across the lifespan of the panel. These systems are also protected by longer warranties.

*This panel type is far better suited for installation on a tile roof.

PROS
  • Virtually Indestructible
  • Minimal Roof Penetrations
  • Freeze Resistant
  • No Gap Between Panels
  • Wind Lift Resistant
  • Industry Leading Warranty
CONS
  • Susceptible to Heat Loss in Windy Climates
  • Timely Installation
PROS
CONS
  • Virtually Indestructible
  • Minimal Roof Penetrations
  • Freeze Resistant
  • No Gap Between Panels
  • Wind Lift Resistant
  • Industry Leading Warranty
  • Susceptible to Heat Loss in Windy Climates
  • Timely Installation
Visual Examples
Separated Tube Solar Panels
Heliocol Solar Panels
SwimJoy Pool Solar Panels
Separated Tube Brands

Type 3 - Glazed (Insulated)

Glazed, or insulated solar panels are separated tube designs with an acrylic glazing encapsulating the riser tubes. This glazing essentially enables these panel types to deliver the best of both worlds. These systems are extremely durable, highly freeze resistant, and eliminate heat loss from wind. These panels also activate a greenhouse effect within the glazing that preserves energy within the collector. These systems are extremely efficient and provide the some of the best heating performances in the solar pool heating industry.

These systems stand out most in cloudy, windy, coastal, or northern states that are looking to maximize every bit of heating performance, while also achieving improved freeze resistance and durability.

Glazed panels are designed to be extremely resistant to violent storm winds. The panels are designed with a strapless mounting method that eliminates the need for tie-down strapping, reducing the number of penetrations required for installation.

Glazed panels are highly used for their aesthetic appeal. These systems are installed almost without question when appearance is a primary factor in the decision.

Another benefit of a glazed panel is from the additional layer of protection to the riser tubes by the acrylic glazing. Pinhole leaks can be caused by wild animals/rodents walking across the panels. This is especially true if the panels are being installed near the ground or near a wooded area. The glazing material provides a solid surface to protect the riser tubes.

Like the separated tube panel type, glazed panels also carry one of the industries longest & most comprehensive warranties.

PROS
CONS
  • Warmer Output at Lower Ambient Temperature
  • Minimal Roof Penetrations
  • Maximizes Limited Roof Space
  • Added Layer of Protection Around Riser Tubes
  • Aesthetic Appearance
  • Industry Leading Warranty
  • Timely Installation
  • Cost
PROS
  • Warmer Output at Lower Ambient Temperature
  • Minimal Roof Penetrations
  • Maximizes Limited Roof Space
  • Added Layer of Protection Around Riser Tubes
  • Aesthetic Appearance
  • Industry Leading Warranty
CONS
  • Timely Installation
  • Cost
Visual Examples
Glazed Solar Panels
Collector Tubes Extruded in Special Glazing
SwimLux Glazed Solar Panels
Glazed (Insulated) Brands

COMPARE BRANDS

COMPARE BRANDS

*Side-by-side comparison tool available on large screen displays.

Tablet & mobile displays limited to single brand viewing.


COMPLETE D.I.Y. SYSTEM KITS

Take The Guess Work Out!

LOOKING TO REPLACE MULTIPLE PANELS OR INSTALL A BRAND NEW SYSTEM?

Take the guess work out with our wide selection of DIY Kits. These products are bundled together with large discounts to save you money. When coupled with one of our promotional coupons, these products may be purchased for up to 40% OFF MSRP.

Each of our DIY Kits include everything you need to:

  • Install the selected number of solar panels in a single row.
  • Mount each solar panel to your preferred installation surface (roof or rack).
  • Make water connections to and from each panel.
  • Make water connections to the systems’ supply and return plumbing lines.
    • Enable gravity drainage of the panels and piping.

LOOKING TO REPLACE MULTIPLE PANELS OR INSTALL A BRAND NEW SYSTEM?

Take the guess work out with our wide selection of DIY Kits. These products are bundled together with large discounts to save you money. When coupled with one of our promotional coupons, these products may be purchased for up to 40% OFF MSRP.

Each of our DIY Kits include everything you need to:

  • Install the selected number of solar panels in a single row.
  • Mount each solar panel to your preferred installation surface (roof or rack).
  • Make water connections to and from each panel.
  • Make water connections to the systems’ supply and return plumbing lines.
    • Enable gravity drainage of the panels and piping.

COMPLETE D.I.Y. SYSTEM KITS

Take The Guess Work Out!

LOOKING TO REPLACE MULTIPLE PANELS OR INSTALL A BRAND NEW SYSTEM?

Take the guess work out with our wide selection of DIY Kits. These products are bundled together with large discounts to save you money. When coupled with one of our promotional coupons, these products may be purchased for up to 40% OFF MSRP.

Each of our DIY Kits include everything you need to:

  • Install the selected number of solar panels in a single row.
  • Mount each solar panel to your preferred installation surface (roof or rack).
  • Make water connections to and from each panel.
  • Make water connections to the systems’ supply and return plumbing lines.
    • Enable gravity drainage of the panels and piping.

LOOKING TO REPLACE MULTIPLE PANELS OR INSTALL A BRAND NEW SYSTEM?

Take the guess work out with our wide selection of DIY Kits. These products are bundled together with large discounts to save you money. When coupled with one of our promotional coupons, these products may be purchased for up to 40% OFF MSRP.

Each of our DIY Kits include everything you need to:

  • Install the selected number of solar panels in a single row.
  • Mount each solar panel to your preferred installation surface (roof or rack).
  • Make water connections to and from each panel.
  • Make water connections to the systems’ supply and return plumbing lines.
    • Enable gravity drainage of the panels and piping.

Heliocol Solar Pool Heating
Heliocol Roof Mounted Solar Pool Heater
Rating Category Rating Score

Life Expectancy

Ease of Install

Freeze Resistance

Heating Performance

Low Wind Climates

Heating Performance

Windy Climates

Recommended Flow Rate

3 - 7 GPM

Operating Pressure

90 PSI

Ideal Roof Type

Shingle or Tile

Ideal Climate

Low Wind / Any Winter

Warranty

12-Year Full / Lifetime Limited

Rating Category Rating Score

Life Expectancy

Ease of Install

Freeze Resistance

Heating Performance

Low Wind Climates

Heating Performance

Windy Climates

Rec. Flow Rate

3 - 7 GPM

Operating Pressure

90 PSI

Ideal Roof Type

Shingle or Tile

Ideal Climate

Low Wind / Any Winter

Warranty

12 Year Full / Lifetime Limited

FAFCO Solar Pool Heating
FAFCO Metal Seem Mounted Solar Pool Heater
Rating Category Rating Score

Life Expectancy

Ease of Install

Freeze Resistance

Heating Performance

Low Wind Climates

Heating Performance

Windy Climates

Recommended Flow Rate

3.2 - 4.8 GPM

Operating Pressure

30 PSI

Ideal Roof Type

Shingle

Ideal Climate

Moderate Wind / Mild Winter

Warranty

12-Year Limited

Rating Category Rating Score

Life Expectancy

Ease of Install

Freeze Resistance

Heating Performance

Low Wind Climates

Heating Performance

Windy Climates

Rec. Flow Rate

3.2 - 4.8 GPM

Operating Pressure

30 PSI

Ideal Roof Type

Shingle

Ideal Climate

Moderate Wind / Mild Winter

Warranty

12 Year Limited

SwimEasy Solar Pool Heating
SwimEasy Roof Mounted Solar Pool Heater
Rating Category Rating Score

Life Expectancy

Ease of Install

Freeze Resistance

Heating Performance

Low Wind Climates

Heating Performance

Windy Climates

Recommended Flow Rate

3.5 - 5 GPM

Operating Pressure

50 PSI

Ideal Roof Type

Shingle

Ideal Climate

Moderate Wind / Moderate Winter

Warranty

5-Year Full / 10-Year

Rating Category Rating Score

Life Expectancy

Ease of Install

Freeze Resistance

Heating Performance

Low Wind Climates

Heating Performance

Windy Climates

Rec. Flow Rate

3.5 - 5 GPM

Operating Pressure

50 PSI

Ideal Roof Type

Shingle

Ideal Climate

Moderate Wind / Moderate Winter

Warranty

5 Year Full / 10 Year Limited

SwimJoy Solar Pool Heating
SwimJoy Roof Mounted Solar Pool Heater
Rating Category Rating Score

Life Expectancy

Ease of Install

Freeze Resistance

Heating Performance

Low Wind Climates

Heating Performance

Windy Climates

Recommended Flow Rate

3 - 7 GPM

Operating Pressure

90 PSI

Ideal Roof Type

Shingle or Tile

Ideal Climate

Low Wind / Any Winter

Warranty

12-Year Full / Lifetime Limited

Rating Category Rating Score

Life Expectancy

Ease of Install

Freeze Resistance

Heating Performance

Low Wind Climates

Heating Performance

Windy Climates

Rec. Flow Rate

3 - 7 GPM

Operating Pressure

90 PSI

Ideal Roof Type

Shingle or Tile

Ideal Climate

Low Wind / Any Winter

Warranty

12 Year Full / Lifetime Limited

SwimLux Solar Pool Heating
SwimLux Pergola Mounted Solar Pool Heater
Rating Category Rating Score

Life Expectancy

Ease of Install

Freeze Resistance

Heating Performance

Low Wind Climates

Heating Performance

Windy Climates

Recommended Flow Rate

4 - 5 GPM

Operating Pressure

90 PSI

Ideal Roof Type

Shingle or Tile

Ideal Climate

Any

Warranty

12-Year Full / Lifetime Limited

Rating Category Rating Score

Life Expectancy

Ease of Install

Freeze Resistance

Heating Performance

Low Wind Climates

Heating Performance

Windy Climates

Rec. Flow Rate

4 - 5 GPM

Operating Pressure

90 PSI

Ideal Roof Type

Shingle or Tile

Ideal Climate

Any

Warranty

12 Year Full / Lifetime Limited


Which Solar Pool Heater Should I Buy?

Learn From The Experts

Which Heater
Should I Buy?

Learn From The Experts