Keeping the pool warm will generally result in more fun in the water for everyone.
While pools may be heated by gas or electric heaters, there are also many pools that rely solely on the sun.
If you’re looking to keep your pool warm without breaking the bank on a gas or electric heater, solar covers or solar rings should be top considerations. These are two options that nearly all pool owners can benefit from in trying to heat the pool without a heater.
But, which one is the best? Each of them have unique pros and cons that should be considered before jumping into a purchase.
This article will provide a detailed comparison of solar rings vs solar cover.
Solar covers are often sized to provide a close fit to the pool to ensure maximum effectiveness. They can be trimmed in order to meet custom pool layouts.
Solar covers have a variety of styles with the most common being the type that resembles bubble-wrap, known as a bubble solar cover. Fortunately, they are more durable than bubble-wrap!
The bubbles on solar covers are often round-shaped. However, other shapes –such as diamond– are also marketed as providing unique heating characteristics.
Typical solar covers are constructed of vinyl, polyethylene or polypropylene along with addition of UV-protective chemicals.
Vinyl is typically limited to covers that won’t be taken on/off as frequently, as they are more heavy-duty and difficult to move around.
Solar covers come in a range of thicknesses with the most common ones being offered in 8 mil, 12 mil and 16 mil. A mil is equivalent to one-thousandth of an inch (or 0.0254 mm).
Solar rings (also known as lily pads) are most commonly seen in the circle shape –however, they do come in other shapes, such as squares. For the purpose of our comparison, we’ll continue with the ‘solar ring’ phrasing.
Solar rings often have two layers of UV resistant vinyl. The lower layer is typically dark colored to absorb heat from the sun and heat the water. The upper layer is clear to trap insulating air which retains heat in the pool.
A common ring size is 5 feet, but other options are available as well.
It’s recommended that you aim to cover about 70-80% of the pool’s surface with solar rings. For standard 5’ rings you can use this chart to help determine how many you need for your pool.
Outer edges of the rings often require some inflation before use. Improper inflation may prevent them from laying flat on the surface.
Many solar rings have magnets around the edges to allow them to connect to each other.
Some solar rings are also designed with water anchors intended to prevent them from blowing away. This anchor is a channel that allows water to enter in order to keep the solar ring more weighted down.
Pool Enemy #1: Evaporation
Both solar rings and solar covers share a common purpose: To reduce evaporation.
Evaporation can account for 50-70% of your pool’s heat loss. Anytime your pool is left uncovered will result in some amount of evaporation.
When cool nights occur, it’s not uncommon for a pool that was in the mid 80s during the day to drop down into the 70s overnight. Much of this temperature reduction is due to evaporation.
Pool coverings are recommended for all pool owners as these will reduce the evaporation rate.
For those that have a traditional pool heater, you probably know how expensive the utility bills can get. Heating a pool without using a covering is similar to running your home’s furnace or A/C with the windows wide open –it’s going to cost you!
Several factors work together to determine the evaporation rate of your pool.
- Surface Area: The larger the surface, the more evaporation will occur.
- Pool Temperature: The higher the pool’s water temperature, the more evaporation will occur.
- Air Temperature and Humidity: Higher air temperature and lower humidity will result in increased evaporation.
- Wind Speed: Higher wind speed will cause more evaporation.
Aside from dropping your pool temperature, evaporation also has other consequences.
Up to 1/4” evaporation rate per day is fairly typical for pool owners. While 1/4” may not sound like a lot, it could actually be 100 or more gallons leaving your pool each day, depending on the size of your pool!
While the cost of water due to evaporation won’t typically amount to more than a few dollars each month, the process of adding water regularly can be a burden.
If the water level is not monitored regularly and gets too low, you could risk pump damage.
Frequently adding water can also require more effort in keeping the pool chemistry in balance.
Most importantly, conservation of water is crucial in drought-stricken areas. Any evaporation that can be prevented in the pool will provide that much more water for more important matters.
Prior to the recent skyrocketing of costs, the average residential pool owner was spending $400 per swim season for chemicals.
Direct sunlight on a pool can break down chlorine, requiring more frequent addition of the sanitizer in order to remain effective.
Evaporation can allow up to 70% of your pool’s chemicals to escape. This means that evaporation could be responsible for upwards of $280 in chemical costs for the average pool owner.
The Matchup: Solar Rings vs Solar Cover
Now that we understand the basics of solar covers and solar rings, it’s time to determine which is the best for you! We’ll look at a number of key categories to aid in this process.
The single greatest benefit of using a traditional solar cover is its effectiveness at reducing evaporation. Using a properly fit cover can reduce up to 95% of evaporation.
Solar rings generally can provide up to 50% reduction in evaporation, but will vary based on how much of the pool’s surface is covered by them –often 75% coverage is recommended. Even if the pool is completely covered with rings, there are typically gaps between them which allows for some evaporation.
Winner: Solar Cover
Heating the Pool
Using a solar cover can provide an increase in water temperature of 10 – 15°F compared to an uncovered pool. This is largely due to the cover’s ability to reduce evaporation along with harnessing the sun’s energy.
If you’re trying to use the sun to provide additional heat, it’s recommended that you use a translucent cover. This will allow sunlight to reach the water for better heating.
While the typical blue-tinted bubble cover will allow heating from the sunlight, a clear cover allows for slightly better heating.
Solar rings do not cover as much surface as a traditional cover which will allow more heating loss. However, the gaps have some benefit in that they allow direct heating from the sun into the water –this can be more efficient than the sun having to go through a cover.
Overall, when factoring both heat gain and heat loss, the cover will provide more heating capability due to better evaporation reduction than solar rings.
Winner: Solar Cover
Safety around the pool should be the #1 priority for everyone.
Whether using solar rings, a solar cover, or nothing at all, it is important to keep the pool area secured when not in use.
Solar covers can give the illusion of being a solid surface –so much, that animals and young children may think they can walk on top of it. Walking on the surface poses a significant hazard for anyone, as it could cause entrapment and drowning.
On the flipside, solar rings allow visibility of water around the edges that may deter someone from trying to walk on it. Even if someone tries walking onto a solar ring, the rings will give way without causing entrapment.
Winner: Solar Rings
Reducing Water Consumption
This category goes hand-in-hand with evaporation. The higher the evaporation rate, the more frequently you’ll need to add water.
Reducing the addition of water will provide an easier time maintaining the chemistry of the pool, and will also keep it warmer.
A solar cover can reduce the amount of water being added to the pool by 50%. For a 600 square foot pool with 1/4″ daily evaporation, this could save you upwards of 1,500 gallons a month of makeup water compared to not using a cover.
Solar rings can help reduce the amount of makeup water by about 25% compared to not using any rings. For a 600 square foot pool with 1/4″ daily evaporation, this could equate to about 750 gallons saved each month.
Winner: Solar Cover
Reducing Chemical Loss
Chemical loss can be caused by a combination of evaporation along with sunlight breaking down the chemicals.
A solar cover can help eliminate 60% of chemical loss. For large pools, this could equate to chemical savings of several hundred dollars each swim season.
Solar rings will provide some relief in chemical loss –usually around 30% or so. This could still amount to a sizeable cost savings in chemicals.
Winner: Solar Cover
Heating Cost Reduction
If you have a gas or electric heater, heating costs can be significantly reduced when using a solar cover or solar rings.
Regular use of a solar cover can help reduce heating costs by 70%. Solar rings can reduce heating costs by about 35%.
Based on data from the U.S. Department of Energy, it costs about $3,200 on average to keep a pool in New York at 82°F all season long using a gas heater without a pool cover. By using a cover, the cost could be reduced to about $550 for the entire swim season –this is a savings of over $2,500!
Using the same New York pool example, solar rings could reduce heating costs to around $1,100. This still provides a significant savings of about $2,000 in heating costs!
Winner: Solar Cover
Keeping Debris Out of Pool
Minimizing dirt, debris and bugs will help keep your pool cleaner and easier to maintain proper chemical balance.
A traditional solar cover typically sits atop nearly the entire surface of the pool. This means that dirt and debris will often stay on the cover rather than fall into the water.
If you take care when removing the cover from the pool, most of the dirt will remain on the cover rather than falling into the pool.
Solar rings can capture some dirt and debris. However, due to lesser coverage of the pool surface more of it is likely to end up in the water.
Winner: Solar Cover
Algae Peace of Mind
Warmer water temperatures will promote algae growth without appropriate chemical balance in the pool.
If experiencing algae troubles, you may need to double-check that you’re running your pump long enough. The pump is key to keeping proper circulation and filtration of the water.
Solar covers generally provide more combined heating than solar rings. This can make a pool using a solar cover more susceptible to algae growth than one with solar rings.
Solar covers may also be more likely to create an out-of-sight / out-of-mind scenario when it comes to pool water. It’s not uncommon for a cover to be left on for an extended period of time to then find algae growth when finally removed.
If using a solar cover, it’s recommended that you periodically remove the cover during the daytime. This will provide you opportunity for surfaces to be brushed and a visual lookover of water health.
Solar rings often allow enough visibility to spot growth in the water that can be dealt with quicker.
Winner: Solar Rings
Ease of Use
Both solar rings and a solar cover are only effective if they are actually being used. Particularly when nights are cool, diligent use of them is necessary in keeping the pool warm.
One of the biggest gripes when it comes to solar covers is the hassle of taking it on and off. Sometimes wrangling the cover can become enough of a nuisance where owners will decide it’s not worth their effort to put it on.
Fortunately, solar reels can help provide a more manageable way to handle the cover. The reels can be manual or automatic and simply just require cranking of a handle.
For custom shaped pools, it may not be practical to keep a solar cover in a single piece. Cutting the cover and using multiple reels may be necessary.
Conversely, solar rings are easy to toss into the pool without any additional equipment needed –can’t get any easier than that!
Winner: Solar Rings
While wind is a huge factor in evaporation for uncovered pools, it can also cause issues when using solar covers and solar rings.
Properly fit solar covers won’t be affected much by the wind, as the covers won’t have much room to drift around in the pool.
Undersized covers could be pushed by the wind towards one end of the pool, and may be more susceptible to bunching up –this will reduce the covers effectiveness.
Solar rings have had reputation for being tossed around a bit more in the wind. Their light weight can even allow for gusty winds to lift them out of the pool.
Fortunately, water anchors are designed into some rings that helps keep them grounded better. These anchors are an important consideration if your pool is in a windy area.
Winner: Solar Cover
When not in use, you won’t want a solar cover or solar rings to be occupying your lounge area around the pool. Storage is a key consideration.
A solar cover can be stored pretty easily when using a reel. For an in-ground pool, a reel can be rolled away from the pool against the house or fence to keep away from the pool festivities.
For an above ground pool, hooks can be installed on the side of the pool to hold the cover when the pool is being used.
While solar rings can simply be stacked on top of each other, this could result in quite a large pile depending on how many rings there are. Add a breezy day into the mix, and the pile could quickly become disheveled around the pool. A dedicated and protected area for the solar rings may improve their storability.
Whether using a solar cover or solar rings, it’s important that they are stored in a shaded area or covered in order to prevent UV degradation.
Neither should be stored on an abrasive surface, such as landscaping material or mulch in order to prevent punctures.
Winner: Solar Cover (when using a reel)
When planning to purchase solar rings or a solar cover, it’s best to think of them as a consumable that will need to be replaced after a period of time. You’ll know it’s time to replace when small plastic fragments start appearing in the water.
Manufacturers of solar rings and solar covers often market their warranties with 5 or more years –don’t get your hopes up though! These warranties often do not signify typical lifespan of the products.
Many times these warranties only cover manufacturing defects (e.g., seams splitting) which are rare in occurrence. Most of the warranties do not cover normal wear such as the bubbles gradually falling apart, a very common occurrence towards the end of useful life.
Warranties aside, the longevity of a solar cover or solar rings will depend on several factors.
Thickness of Material
In general, the thicker the material the stronger they will be. Strength can often correlate to durability and longevity.
Solar covers are often offered in multiple thicknesses. A minimum thickness of 8 mil is advised with many preferring at least 12 mil.
Solar rings are often marketed as being constructed of two thick layers without choice of thickness.
Type of Material
Polyethylene is a common material for solar covers. It is flexible and lightweight, allowing for ease of use when applying or removing the cover. It’s most common for covers that will be applied frequently.
Vinyl is another type of material offered, and is generally more durable than polyethylene. However, vinyl covers are heavier and can be more challenging to handle due to its thickness.
Many solar rings indicate uses of two vinyl layers for optimal strength and durability. While solar rings may be constructed of heavier material than most covers, their inflatable section can be susceptible to punctures and leakage.
Solar covers and solar rings will be routinely sitting on the surface of the pool. Longevity of these solar products can be affected by the pool’s water chemistry.
If pH is too low or chlorine levels are too high, these could expedite degradation of the cover or rings.
It’s important that after shocking the pool, these products remain off the water for at least a few hours. Subjecting the covers to high concentration of sanitants can cause damage.
Washing the covers and rings is recommended before winterizing them in order to remove the chemicals.
As the names imply, solar rings and solar covers will see their share of sunlight when in use.
While these products typically have UV-resistant chemicals embedded within their material, the sunlight will take its toll on them.
UV in conjunction with chemical exposure will make them more brittle and susceptible to shedding in the pool.
Keeping them in the shade or covered when not in use is recommended in order to increase their longevity.
In general, it’s a good mindset to plan on only getting a couple years out of either solar rings or a solar cover –neither has a distinct advantage here. Even some of the thick covers (16 mil) may only last the same duration as a thinner cover (8 mil).
With diligent care you may be able to garner a longer lifespan from them, but it’s not a guarantee (and likely not warrantied).
Pool supply prices have rapidly increased in recent years, in which solar covers and solar rings are not immune.
It’s now typical to spend $150 or more for an 8 mil cover on a standard 18 x 36 pool. Thicker solar covers can run upwards of $200 – $300 for this size pool.
Standard 5 foot rings cost anywhere from $25 – $35 per ring. For an 18 x 36 pool, 13 rings are recommended to gain 70% coverage –this could cost $300 – $500.
Ultimately, the cost of either a solar cover or solar rings will vary based on the size of the pool.
Given that neither a solar cover or solar rings tend to last longer than one another, the solar cover will often be the cheapest –although, keep in mind the cost of a solar reel!
Winner: Solar Cover
Solar Rings vs Solar Cover – Final Verdict
There’s no doubt that solar covers provide better overall performance than solar rings. A solar cover will shield nearly the entire surface of the pool, which provides more effective heat retention than solar rings.
However, maybe you have concerns about safety aspects of a cover –such as pets or kids being entrapped. Or maybe a solar cover is more hassle than you’d like to deal with. In either case, solar rings are a worthwhile alternative.
If the high cost of solar rings is a concern, it may be worth looking into a DIY solution that is less expensive. There are also cheap DIY solar covers that will be tons cheaper than either of these options.
Regardless of which solution you choose, you should probably prepare to replace them every couple years –any additional time you can squeeze out of them is a bonus!
Ultimately, the use of either a solar cover or solar rings will provide a huge benefit to your pool when compared to not using a cover at all.
But, there can be only one winner here: Solar Cover.
The solar cover has stood the test of time as the best way to prevent evaporation and keep the pool warm –all while still being cheaper than solar rings.
Husband and father of three (actually, four if you include the pool). I’m an avid DIY-er and weekend warrior that enjoys taking up new projects around the house to help us maximize leisure right at home. I enjoy researching and sharing various tips, tricks and knowledge to help others make their home an oasis.