critical cactusSpa Depot Thermo-Float Hot Tub Blanket is our top choice for the Best Hot Tub Thermal Blanket because its heavy-duty 16-mil construction provides superior insulation and durability compared to thinner alternatives.
These thermal blankets serve as a critical secondary layer of protection, floating directly on the water surface to minimize evaporation and heat loss. By trapping warmth, they reduce the workload on your spa heater and help maintain consistent temperatures, especially during colder months or when the main hard cover is removed for frequent use.
Selecting the right blanket requires balancing material thickness, ease of trimming, and long-term resilience against spa chemicals. We evaluate these covers based on their ability to create an effective thermal barrier while remaining easy to handle and maintain for the average spa owner.
If you are looking to optimize your spa's efficiency, pairing a thermal blanket with the Best Hot Tub Heaters can help maintain your desired temperature with less energy consumption.
10 Best Hot Tub Thermal Blanket in 2026 Honest Reviews
Quick Comparison
| Product | Best For | Key Strength | Score |
|---|---|---|---|
| Spa Depot Thermo-Float Hot Tub Blanket | Best Overall | 16-mil heavy-duty thickness for improved durability. | 4.9 |
| MADHOLLY Square Hot Tub Thermal Blanket | Thick 16-Mil Heat Retention | 16 MIL thickness offers enhanced heat preservation and durability. | 4.7 |
| Angooni Hot Tub Thermal Blanket | Durable Floating Bubble Design | 16-mil thickness provides superior insulation compared to standard covers. | 4.3 |
| BigXwell Square Hot Tub Thermal Blanket | Heavy-Duty Energy Efficient Pick | 16Mil thickness provides effective thermal insulation. | 4.3 |
| Spatender Floating Thermal Spa Blanket | Durable Closed-Cell Foam Insulation | Reduces heat loss by effectively blocking water evaporation. | 4.8 |
| TOPZEA Hot Tub Spa Thermal Blanket | Easy-Trim Custom Fit | 16 mil thickness provides superior heat retention compared to thinner 8-12 mil alternatives. | 4.5 |
| Gekufa Winter Hot Tub Bubble Blanket | Cold-Weather Performance | 16-mil thick PE material provides excellent durability and heat retention. | 4.3 |
| Mosenpol Hot Tub Bubble Thermal Blanket | Reliable Evaporation Control | Thousands of bubbles for effective heat retention and solar energy absorption. | 4.3 |
| Kakolvan Round Hot Tub Thermal Blanket | Best for Circular Spas | 16-mil thickness provides superior insulation compared to standard 8-12 mil covers. | 4.6 |
| BigXwell Rectangle Hot Tub Thermal Blanket | Versatile Shape Compatibility | 12-mil thickness provides enhanced heat retention compared to thinner alternatives. | 4.3 |
How We Chose
When evaluating the best hot tub thermal blanket, we focus on material density and practical usability. An effective cover must provide a robust barrier against heat loss while remaining flexible enough for daily use. We prioritize models that offer significant thickness to ensure longevity and consistent energy efficiency across diverse spa environments.
- Material thickness measured in mils to ensure adequate insulation and tear resistance.
- Ease of customization for various spa shapes and sizes through trimming.
- Evaporation reduction capabilities to maintain water levels and chemical balance.
- Durability of bubble or foam construction against chemical exposure and UV degradation.
- Compatibility with existing hard covers for winter-ready heat retention.
1 Spa Depot Thermo-Float Hot Tub Blanket — Professional-Grade 16-Mil Insulation
Maintaining water temperature and minimizing energy consumption are primary challenges for spa owners, particularly in cooler environments. The Spa Depot Thermo-Float Hot Tub Blanket addresses these concerns by utilizing a 16-mil thick film design that acts as a thermal barrier on the water's surface.
This floating cover is engineered to reduce evaporation heat loss by up to 95%, which helps in retaining water temperature and lowering the workload on your spa heater. By sitting directly on the water, it also serves as a protective layer that keeps the underside of your primary hard cover dry, preventing the common issue of water absorption and heavy, saturated insulation.
Designed for versatility, the Spa Depot Thermo-Float Hot Tub Blanket features a generous 7' x 7' (84" x 84") footprint. The material is trim-to-fit, allowing users to customize the shape to match the specific contours of their spa shell. Its heavy-duty construction is intended to provide a longer service life compared to thinner, standard-grade alternatives.
While the cover provides significant insulation benefits, it is intended to be used in conjunction with a rigid spa cover rather than as a standalone security or safety barrier. Its lightweight, 4.4-pound build makes it easy to remove and store when the spa is in use, offering a practical solution for daily heat retention.
Best for: Owners looking to improve heat retention and protect their primary spa cover from moisture saturation.
Skip if: Users who require a rigid, locking safety cover or those with spa dimensions exceeding 84 inches by 84 inches.
- 16-mil heavy-duty thickness for improved durability.
- Reduces evaporation heat loss by up to 95%.
- Trim-to-fit design accommodates various spa shapes.
- Protects primary cover from water absorption.
- Not a safety cover and must be used with a rigid hard cover.
- Requires manual trimming for non-square spa layouts.
2 MADHOLLY Square Hot Tub Thermal Blanket — Thick 16-Mil Heat Retention
Maintaining water temperature and minimizing maintenance are essential for maximizing the enjoyment of your spa. The MADHOLLY 7×7FT Square 16Mil Heavy-Duty Spa Hot Tub Cover is engineered to address these needs through its 16 MIL thickness, which provides superior heat retention compared to standard 8-12 mil alternatives. By placing this blanket directly on the water surface, you can significantly reduce heat loss and evaporation.
Designed for versatility, this bubble solar blanket is built to be trim to fit, allowing users to customize the size for irregular tub shapes by marking and cutting the material as needed. The design features a bubble-side down orientation, which helps prevent dust accumulation and reduces condensation on your primary hot tub cover. When not in use, the material is straightforward to clean and maintain.
Beyond temperature regulation, this cover serves as a practical tool for efficiency. It is capable of preventing up to 95% of water evaporation loss, which helps conserve water and chemicals over time. By absorbing solar energy, it can also assist in maintaining water temperature, potentially reducing the energy required for your heater to reach desired levels.
To ensure optimal performance, the manufacturer recommends laying the cover flat with heavy objects for a few hours upon arrival to remove any creases from folding. This simple preparation step ensures the blanket sits flush against the water, providing the intended insulation and protection for your hot tub.
Best for: Owners of square hot tubs looking for a durable, customizable thermal barrier to reduce heat loss and evaporation.
Skip if: Users with non-square hot tubs who are unwilling to manually trim the material to fit their specific dimensions.
- 16 MIL thickness offers enhanced heat preservation and durability.
- Trim to fit design accommodates various square and irregular tub configurations.
- Prevents up to 95% of water evaporation loss.
- Helps shorten heating time by retaining water temperature.
- Requires manual trimming for non-standard or irregular spa shapes.
- Creases from folding may require flattening before initial use.
3 Angooni Hot Tub Thermal Blanket — Durable Floating Bubble Design
Maintaining water temperature in a spa or pool often involves battling constant evaporation and heat loss. The Angooni 7'x7' Hot Tub Thermal Blanket addresses this by providing a physical barrier that floats directly on the water surface, designed to lock in heat and significantly reduce energy consumption.
Engineered with a 16-mil thickness, this thermal blanket offers a more robust construction than standard 8-12 mil alternatives. This increased density provides superior insulation and improved tear resistance, while the integrated air bubbles are built to resist bursting, extending the functional lifespan of the cover during regular use.
Usability is a primary focus of the design, allowing users to trim the blanket to fit specific dimensions using standard scissors. This makes it suitable for various water features, including square spas, in-ground hot tubs, and stock tank pools. For optimal performance, the manufacturer recommends placing the bubble side down against the water.
Beyond heat retention, the blanket serves as a protective layer that blocks debris like leaves and dust, which helps keep the water cleaner and reduces the workload on filtration systems. While it is a consumable product with an expected lifespan of one to two seasons, it acts as an effective supplement to a standard hard cover, particularly in colder climates where heat retention is critical.
Best for: Owners of 7×7 square hot tubs or stock tank pools looking to minimize heat loss and reduce evaporation.
Skip if: Users seeking a permanent, multi-year solution, as this is a consumable cover designed for periodic replacement.
- 16-mil thickness provides superior insulation compared to standard covers.
- Trim-to-fit design allows for a custom fit on various square water features.
- Reduces evaporation by up to 95%, helping to maintain water temperature.
- Acts as a protective barrier against debris and condensation.
- Consumable nature requires replacement every 1-2 seasons.
- Requires manual trimming for a precise fit.
4 BigXwell Square Hot Tub Thermal Blanket — Heavy-Duty Energy Efficient Pick
Maintaining water temperature in a spa often leads to significant energy loss, but the BigXwell Square Hot Tub Thermal Blanket addresses this by creating an insulating barrier directly on the water's surface. Designed specifically for square hot tubs, this 16Mil thick cover acts as a thermal shield to minimize heat dissipation and reduce the workload on your spa heater.
Beyond its primary function of heat retention, this cover is engineered to cut evaporation by 95%, which helps maintain water levels and chemical balance over time. The 7x7ft dimensions provide a substantial footprint, and the material is designed to be easily trimmed, allowing for a precise, custom fit that ensures an airtight seal against the spa shell.
The BigXwell Square Hot Tub Thermal Blanket is built for seasonal use, featuring a robust construction that stands up to the demands of outdoor environments. By effectively blocking debris from entering the water, it also simplifies maintenance routines, keeping the spa cleaner between uses while simultaneously lowering energy costs associated with frequent reheating.
For homeowners looking to optimize their backyard oasis, this thermal blanket offers a practical solution to improve energy efficiency. Its straightforward design focuses on performance, ensuring that your spa remains invitingly warm even during colder months without requiring complex installation or specialized tools.
Best for: Homeowners who want to improve the energy efficiency of their square hot tub and reduce daily heat loss through evaporation.
Skip if: Users with non-square spas or those who require a rigid, locking safety cover, as this thermal blanket is designed for insulation and evaporation control rather than structural security.
- 16Mil thickness provides effective thermal insulation.
- Cuts evaporation by 95% to maintain water and chemical levels.
- Easy to trim for a custom, airtight fit on square spas.
- Blocks debris from entering the water.
- Not a structural safety cover for preventing unauthorized access.
5 Spatender Floating Thermal Spa Blanket — Durable Closed-Cell Foam Insulation
Maintaining water temperature in a spa often leads to significant energy expenses due to constant evaporation. The Spatender Floating Thermal Spa Blanket addresses this by providing a physical barrier that traps heat at the surface level, effectively minimizing the energy required to keep your water warm.
Constructed from 3/8" thick Thermaltech high-density closed-cell foam, this blanket is designed to float directly on the water. This material choice serves a dual purpose: it acts as an insulating layer to reduce heat loss and functions as a protective shield for your expensive hard cover. By preventing evaporation, it limits the accumulation of harsh chemical gases that can deteriorate the underside of hard covers and headrests over time.
The Spatender Floating Thermal Spa Blanket offers a versatile, user-friendly design that can be customized to fit most hot tubs. Because it is made of flexible foam, you can simply place it over your filled tub and trim it with scissors for a precise fit. This makes it a practical solution for both summer and winter use, providing a clean surface that keeps debris out of the water while looking more streamlined than a bulky hard cover during warmer months.
Choosing this thermal blanket is a straightforward way to protect your spa investment and reduce monthly heating costs. Its durable construction is built to withstand varying weather conditions, ensuring it remains an effective insulator throughout the seasons.
Best for: Owners looking to reduce energy costs and protect their hard spa cover from chemical-induced deterioration.
Skip if: Users who require a rigid, locking safety cover for child or pet protection, as this floating foam blanket does not provide structural security.
- Reduces heat loss by effectively blocking water evaporation.
- Protects hard covers from chemical gas damage.
- Customizable fit allows for easy trimming with scissors.
- Durable 3/8" high-density Thermaltech foam construction.
- Not a safety cover and does not provide structural protection for children or pets.
6 TOPZEA Hot Tub Spa Thermal Blanket — Easy-Trim Custom Fit
Maintaining water temperature and minimizing energy consumption are primary challenges for spa owners, and the TOPZEA Hot Tub Spa Thermal Blanket addresses these through a specialized 16 mil thick PE construction. By floating directly on the water's surface, this cover acts as a physical barrier that helps retain heat and significantly shortens heating times, allowing for more efficient operation of your spa's heating system.
The TOPZEA Hot Tub Spa Thermal Blanket is designed with a bubble-wrap-style surface that excels at heat retention and minimizing evaporation. This design is particularly effective for outdoor installations, as it helps keep the water warm during cooler nights and prevents debris from entering the spa. When placed with the bubble side facing down against the water, the material creates an insulating layer that reduces heat loss and condensation.
Measuring 7 feet by 7 feet, this square cover provides a versatile solution for various hot tub shapes and sizes. The material is engineered to be easily trimmed with standard scissors, allowing users to achieve a custom fit for inflatable spas, traditional hot tubs, or even small pools. Its durable, well-made PE composition is designed to resist tearing while remaining lightweight enough for easy daily placement and removal.
Beyond its primary thermal benefits, this blanket serves as a practical maintenance tool. By covering the water surface, it effectively blocks leaves and wind-blown debris, keeping the spa cleaner between uses. This combination of heat management and debris protection makes it a functional addition for both indoor and outdoor spa environments.
Best for: Owners of 7×7 foot or smaller hot tubs looking to reduce energy costs and minimize water evaporation through an easy-to-trim, floating thermal barrier.
Skip if: You require a rigid, locking safety cover, as this floating bubble blanket does not provide structural protection or child-safety features.
- 16 mil thickness provides superior heat retention compared to thinner 8-12 mil alternatives.
- Easily trimmable PE material allows for a custom fit on various spa shapes and sizes.
- Reduces evaporation and heat loss, leading to more efficient heating cycles.
- Keeps spa cleaner by acting as a protective barrier against leaves and debris.
- Manual handling required for every use as it is a floating cover rather than a hinged hard top.
- Not a safety device and cannot support weight or prevent unauthorized access.
7 Gekufa Winter Hot Tub Bubble Blanket — Cold-Weather Performance
Maintaining water temperature during colder months requires an effective barrier against heat loss and evaporation. The Gekufa Winter Hot Tub Bubble Blanket utilizes a 16-mil thick PE material designed specifically to provide thermal insulation for spas and hot tubs, helping to retain warmth overnight and reduce overall energy consumption.
This heavy-duty floating cover serves a dual purpose by acting as a solar collector during daylight hours to assist in heating the water while simultaneously minimizing water evaporation by up to 95%. Its robust construction is engineered to be resistant to cracking, fading, and deformation, ensuring it remains functional even when exposed to snow or frost during winter seasons.
Versatility is a core feature of this blanket, as the material is designed to be cut at will to fit specific spa or hot tub dimensions. Whether you are covering a standard square unit or a custom-shaped pool, the material can be trimmed to size. Beyond thermal regulation, it also acts as a protective layer to keep debris, leaves, and dirt out of the water when the tub is not in use.
The Gekufa Winter Hot Tub Bubble Blanket offers a practical solution for those looking to extend their spa usage into the autumn and winter months. By focusing on heat retention and durability, it provides a straightforward method to manage heating costs and water maintenance throughout the year.
Best for: Owners of square hot tubs or spas seeking a durable, cut-to-fit thermal cover to reduce heat loss and energy costs during cold weather.
Skip if: Users who require a rigid, locking safety cover for child or pet protection, as this is a lightweight floating thermal blanket.
- 16-mil thick PE material provides excellent durability and heat retention.
- Customizable size allows the user to cut the blanket to fit specific dimensions.
- Reduces water evaporation by up to 95% to help preserve water levels.
- All-season design resists cracking and fading in cold weather conditions.
- Manual trimming required for non-standard or smaller tub shapes.
- Floating design does not provide structural safety or locking security.
8 Mosenpol Hot Tub Bubble Thermal Blanket — Reliable Evaporation Control
Maintaining water temperature and minimizing maintenance are primary goals for spa owners, and the Mosenpol Hot Tub Bubble Thermal Blanket addresses these needs through a design focused on heat retention. By utilizing thousands of air-filled bubbles, this cover acts as an insulating layer that helps capture solar warmth and slows down heat loss, which can reduce the frequency of heater cycles and potentially lower energy costs.
The Mosenpol Hot Tub Bubble Thermal Blanket is constructed from durable PE material designed to withstand outdoor conditions, resisting common issues like stretching and tearing. Measuring 7 by 7 feet, it is sized to fit most standard square hot tubs, though it offers the flexibility to be trimmed to accommodate irregular shapes or custom spa dimensions.
Usability is straightforward, requiring the user to place the bubble side directly against the water surface. This specific orientation is essential for the cover to function as intended for both solar absorption and evaporation control. By creating a barrier over the water, the blanket also helps reduce condensation buildup on the primary spa cover, which can extend the lifespan of the main enclosure.
While this thermal blanket provides a practical barrier, users should note that it is a lightweight accessory intended to supplement, not replace, a rigid locking spa cover. It serves as an effective tool for energy efficiency and water conservation, provided it is maintained and positioned correctly during periods of inactivity.
Best for: Owners of square hot tubs looking to improve heat retention and reduce water evaporation through a simple, trimmable insulation layer.
Skip if: Buyers seeking a heavy-duty, locking security cover, as this bubble blanket is a lightweight thermal accessory and does not provide structural safety or child-proofing.
- Thousands of bubbles for effective heat retention and solar energy absorption.
- Customizable fit allows for easy trimming to match irregular spa shapes.
- Reduces water evaporation and minimizes condensation on the main spa cover.
- Durable PE construction designed to resist outdoor wear and tear.
- Not a security cover and cannot replace a rigid, locking spa lid.
- Requires manual placement and removal before each use.
9 Kakolvan Round Hot Tub Thermal Blanket — Best for Circular Spas
Maintaining water temperature in a spa often leads to significant energy consumption, but the Kakolvan Round Hot Tub Thermal Blanket addresses this by utilizing a specialized bubble-layer design. This 16-mil thick cover floats directly on the water surface, acting as a barrier that minimizes heat loss and reduces water evaporation by up to 95%.
Beyond its primary insulating function, the Kakolvan Round Hot Tub Thermal Blanket serves as a protective shield against debris. The design features a bubble-side-down configuration, which is essential for maximizing heat retention and preventing dust or contaminants from entering the water. The smooth top side helps reduce condensation and prevents freezing along the edges during colder conditions.
Constructed from durable material, this 16-mil cover offers greater thickness than standard 8-12 mil alternatives, providing increased toughness while remaining lightweight and flexible for easy storage. The unit is designed to be versatile, fitting most 1-4 person inflatable or traditional hot tubs. For owners with irregular spa shapes, the material can be trimmed to size after marking the required dimensions.
Proper application requires accurate measurement of the spa's inner diameter to ensure a snug fit. By effectively trapping solar heat and reducing the workload on internal heaters, this cover can decrease heating times by approximately 30%, offering a practical solution for managing utility costs while keeping the spa ready for use.
Best for: Owners of circular hot tubs or spas looking to reduce heating costs and minimize water evaporation through passive thermal insulation.
Skip if: Users with non-circular or irregularly shaped spas who are not comfortable trimming the material to fit their specific dimensions.
- 16-mil thickness provides superior insulation compared to standard 8-12 mil covers.
- Reduces water evaporation by up to 95%, helping to keep the spa clean and reducing the need for water refills.
- Energy-efficient design can reduce heating time by 30% by retaining warmth.
- Easy to trim to fit specific tub shapes and sizes.
- Requires manual trimming for non-standard or irregular spa shapes.
- Must be measured accurately to ensure the cover fits the inner diameter of the tub correctly.
10 BigXwell Rectangle Hot Tub Thermal Blanket — Versatile Shape Compatibility
Maintaining water temperature and minimizing maintenance are common challenges for spa owners, and the BigXwell Spa and Hot Tub Solar Pool Cover addresses these through a 12-mil thick thermal design. This blanket utilizes thousands of integrated thermal bubbles to effectively trap heat, reducing the energy required to keep water at a comfortable temperature.
Beyond heat retention, this 1200Series (6X6 FT) cover serves as a barrier against water loss. By covering the surface, it prevents up to 95% of water evaporation, which helps manage both water levels and the associated costs of heating. The material is designed for outdoor exposure, offering durability against harsh weather conditions while remaining lightweight enough for simple installation and removal.
The BigXwell Rectangle Hot Tub Thermal Blanket features a versatile trim-to-fit construction. Because it is made from durable PE material, users can easily resize the 6×6 foot sheet using standard scissors to match the specific geometry of their inground or above-ground spa. This flexibility ensures it can accommodate various tub shapes beyond its original rectangular dimensions.
This thermal blanket provides a practical, low-maintenance solution for daily spa use. Its primary function is to simplify the management of water temperature and cleanliness by acting as a protective layer that is easy to handle, store, and customize.
Best for: Owners of rectangular or custom-shaped hot tubs looking for a durable, customizable cover to improve heat retention and reduce water evaporation.
Skip if: Users requiring a rigid, locking safety cover for child or pet protection, as this is a lightweight thermal blanket without structural locking mechanisms.
- 12-mil thickness provides enhanced heat retention compared to thinner alternatives.
- Trim-to-fit design allows for customization to fit various spa shapes.
- Reduces water evaporation by up to 95%.
- Lightweight material ensures easy daily handling and removal.
- No locking mechanism for security or child safety.
- Requires manual trimming for non-rectangular installations.
Best Hot Tub Thermal Blanket Buying Guide
Understanding Material Thickness
The thickness of a thermal blanket, measured in mils, is the primary indicator of its insulating performance. A 16-mil blanket is significantly more durable and effective at trapping heat than standard 8-12 mil options, offering better resistance to the harsh chemical environment of a hot tub.
While thicker materials are more robust, they can be slightly heavier to handle. However, the trade-off is a longer service life and better protection for your primary spa cover, as the blanket prevents moisture from reaching the underside of the hard cover.
Customization and Fit
Most thermal blankets arrive in standard square dimensions, such as 7×7 feet. Because hot tubs vary in shape and corner radius, the ability to trim the material with standard scissors is essential for a clean, professional fit.
When trimming, it is often best to lay the blanket over the water first, mark the desired shape, and cut slightly inside the line to ensure it floats freely without bunching against the spa walls.
Bubble vs. Foam Insulation
Bubble-style blankets are the most common choice, utilizing air pockets to create a thermal break between the water and the air. These are lightweight, easy to store, and highly effective at absorbing solar energy if the spa is located outdoors.
Closed-cell foam blankets offer a different approach, providing a denser, more solid layer of insulation. These are often preferred for their durability and lack of bubbles that could potentially burst over time, though they may be bulkier to fold and store.
Maintenance and Longevity
Thermal blankets are considered consumable items. Even high-quality 16-mil covers will eventually degrade due to constant exposure to heat and sanitizing chemicals. Rinsing the blanket periodically with fresh water can help extend its life by removing chemical buildup.
Proper storage when the tub is in use is also vital. Avoid leaving the blanket in direct sunlight for extended periods when it is not on the water, as this can accelerate the breakdown of the plastic or foam materials.
Winter Performance
In colder climates, a thermal blanket is most effective when used in conjunction with your existing hard cover. The blanket acts as a vapor barrier, preventing steam from condensing on the underside of the hard cover, which helps prevent water absorption and prolongs the life of the cover's internal foam core.
During winter, ensure the blanket is fully submerged or floating flat to maximize the air-gap insulation. This dual-layer approach is the most efficient way to maintain water temperature during freezing temperatures.
Frequently Asked Questions
Which side of the bubble blanket faces the water?
Always place the bubble side down against the water surface. The smooth side should face up to minimize debris collection and improve the blanket's overall durability.
Can I use a thermal blanket on an inflatable hot tub?
Yes, thermal blankets are highly effective for inflatable spas, which often have less insulation than permanent acrylic models. Trimming the blanket to fit the specific diameter or shape of your inflatable tub is straightforward.
How much energy will I save with a thermal blanket?
While exact savings depend on your climate and usage, a thermal blanket can reduce heat loss through evaporation by up to 95%. This significantly lowers the frequency at which your heater needs to cycle on.
Do I need to remove the blanket every time I use the spa?
Yes, the blanket must be removed before entering the hot tub. Most users find it easy to fold or roll the blanket aside, as it is lightweight and designed for quick removal.
How often should I replace my hot tub thermal blanket?
Most thermal blankets last for one to two seasons depending on chemical usage and exposure. Signs that it is time for a replacement include brittle material, peeling bubbles, or significant tearing.
Conclusion: Our Top Pick
Our top pick is Spa Depot Thermo-Float Hot Tub Blanket. Investing in a high-quality thermal blanket is a practical way to enhance your spa's efficiency and protect your primary cover from moisture damage. By choosing a 16-mil option, you ensure a better balance of insulation and durability for your specific setup.
Whether you have a square or round spa, the ability to trim these blankets allows for a customized fit that maximizes heat retention. Regular maintenance and proper placement will help you enjoy warmer water and lower energy bills throughout the year.