Two all-foam mattresses, two very different cooling stories. The Sweetnight CoolNest Memory Foam Mattress is built around a layered cooling system with a CoolNest cover and PCMflux high-resilience foam, offered in 12, 14 and 16 inch thicknesses. The Casper Original Mattress leads with Casper Signature Foam for airflow, premium memory foam for pressure relief and Zoned Support with three ergonomic zones. Both are all-foam designs certified by CertiPUR-US, and both target sleepers who want contouring without coils. Look elsewhere if you prefer spring support; the Saatva Classic is the innerspring alternative.
A strong alternative
Saatva Classican innerspring option if you want more than foam
- 365-night home trial
- Free white-glove delivery and old-mattress removal
- Lifetime warranty
- Dual-coil design with over 1,000 recycled carbon steel coils in full size and up
Which mattress should you choose between Sweetnight CoolNest and Casper Original?
The Sweetnight CoolNest wins for hot sleepers who want a cooling-focused all-foam mattress at a lower entry price, while the Casper Original suits sleepers who prioritize zoned spinal support and a proven, widely reviewed foam feel. The CoolNest centers its identity on temperature, with a CoolNest system the brand says feels up to 8 degrees cooler, a 3D weaving cover and gel-infused memory foam. The Casper Original centers its identity on structure: breathable polyurethane foam on top, zoned memory foam in the middle and a durable polyurethane base, all at an 11 inch height across every size.
Who is each mattress for?
The Sweetnight CoolNest is for sleepers who run hot and want a foam mattress that treats temperature as a core feature rather than a bonus. It comes in three thicknesses, 12 inch, 14 inch and 16 inch, so you can choose how much cushioning and cooling structure you want. The brand positions it as the best solution for hot sleepers, and its 5-zone ergonomic support design with 9 comfort bars targets full-body pressure relief. It is also HSA/FSA eligible, which matters for buyers using tax-advantaged health spending accounts.
The Casper Original is for sleepers who want a single, well-defined foam construction with zoned support built into the middle layer. Its Zoned Support system uses three ergonomic zones to provide support and spinal alignment, and its premium memory foam conforms to the body to absorb pressure. It comes in six sizes from Twin to California King, all at 11 inches tall, which keeps the feel consistent regardless of size. It is the mattress that started the brand, and its public review profile is substantial: an overall rating of 4.4 out of 5 from 17,942 reviews.
Side sleepers who need pressure-point contouring should look at our best memory foam mattresses for more all-foam options in this category.
How do the two mattresses compare on paper?
| Feature | Sweetnight CoolNest | Casper Original |
|---|---|---|
| Construction | All-foam, layered cooling system | All-foam, three layers |
| Height | 12, 14 or 16 inches depending on thickness chosen | 11 inches |
| Sizes | Twin, Full, Queen, King, CLK | Twin, Twin XL, Full, Queen, King, California King |
| Trial | 100-night trial | 100 days (referenced in a customer review) |
| Warranty | 10-year warranty | – |
| Shipping | Free U.S. shipping, in-stock orders ship in 1 to 2 business days | Fast delivery noted in customer reviews |
| Certifications | CertiPUR-US foam, STANDARD 100 by OEKO-TEX fabric | CertiPUR-US certified polyurethane foams |
How do they feel and support the body?
Both mattresses are all-foam designs, so both deliver a body-cradling feel rather than a floating-on-top feel. The Sweetnight CoolNest layers a 3D weaving cover, PCMflux high-resilience foam, gel-infused memory foam, ocean memory foam, transition comfort foam and a 5-zone support foam with 9 comfort bars. That stack is designed for full-body pressure relief with a zoned approach under the body. The Casper Original uses a simpler three-layer build: a top layer of breathable polyurethane foam, a second layer of zoned memory foam and a durable polyurethane base. Its Zoned Support system divides the mattress into three ergonomic zones for support and spinal alignment.
The practical difference is in how each brand frames support. Sweetnight emphasizes zones and comfort bars for pressure relief across the whole body. Casper emphasizes three-zone spinal alignment with memory foam that conforms and absorbs pressure. Neither brand publishes a firmness number on these pages, so a firmness comparison would be guesswork.
Which one sleeps cooler?
The Sweetnight CoolNest makes cooling its headline. The brand states the CoolNest system feels up to 8 degrees cooler, with the CoolNest cover and PCMflux high-resilience foam working together for all-night cooling and sweat-free sleep. The 3D airflow structure design and breathable comfort layer add to the airflow story, and the 16 inch model is labeled ultimate cooling and support. The Casper Original addresses temperature more modestly: Casper Signature Foam increases airflow, and the top layer of breathable polyurethane foam supports that. If sleeping cool is your main concern, the CoolNest is built for that need, and you can compare more options in our best cooling mattresses selection.
See the Saatva Classic price in your size →
What do materials and certifications tell you?
Both mattresses use CertiPUR-US certified foams, which means the polyurethane foams are made without ozone-depleting chemicals and phthalates regulated by the Consumer Product Safety Commission, and tested for low VOC emissions for indoor air quality. The Sweetnight CoolNest adds an OEKO-TEX STANDARD 100 certification for its fabric, covering the cover that sits against your skin. The Casper Original’s certification statement covers all its polyurethane foams with the same low VOC testing threshold of less than 0.5 parts per million. If certified organic materials are a priority for you, our best organic mattresses guide covers that category.
How do trial, warranty and shipping compare?
The Sweetnight CoolNest carries a 100-night trial, free U.S. shipping and a 10-year warranty, with in-stock orders shipping in 1 to 2 business days. The Casper Original’s product page does not state a trial length or warranty in the material available here; a customer review references a 100-day return period, and other reviews describe fast delivery. For a foam mattress with a stated trial and warranty on the product page itself, the CoolNest gives you that information up front. Buyers who want a longer trial and white-glove setup can consider the Saatva Classic alternative above, which carries a 365-night home trial and free delivery with in-room setup.
What is the price difference?
The Casper page also notes the Original Mattress is excluded from all sitewide sales and promotional offers. Check the current price on each brand’s site before deciding. For shoppers whose budget shapes the decision more than features, our best hybrid mattresses list includes options across a wider price range.
Who should NOT buy which mattress?
Skip the Sweetnight CoolNest if you need a Twin XL size, as the sizes listed are Twin, Full, Queen, King and CLK. Also skip it if you want a firm, on-top-of-the-mattress feel, since both brands describe foam constructions that cradle rather than resist. Skip the Casper Original if cooling is your primary concern, since its temperature story is limited to airflow-focused foam rather than a dedicated cooling system. Skip the Casper if you want a mattress height above 11 inches or a stated warranty on the product page. Neither mattress is a coil option, so sleepers who prefer spring support should look at innerspring or hybrid designs instead.
What is our strong alternative if neither fits?
The Saatva Classic is an innerspring mattress with a 3 inch Euro pillow top, a dual-coil design of over 1,000 recycled carbon steel coils in full size and up, and patented Lumbar Zone technology for spinal alignment. It comes in three comfort levels: Plush Soft at 3 out of 10, Luxury Firm at 5 to 7 out of 10 and Firm at 8 out of 10, so you can match firmness to your sleep position rather than accept one feel. It is available in two heights, 11.5 and 14.5 inches, and carries a 365-night home trial, free white-glove delivery with in-room setup and old mattress removal, and a lifetime warranty. It is chiropractor approved and endorsed by the American Chiropractic Association. Read the full details in our Saatva Classic review.
World Sleep Almanac score: 8.4/10. The score is an editorial rating based on these criteria: cooling features stated by the brand (9/10 for the CoolNest’s layered cooling system, 7/10 for the Casper’s airflow foam), support design (8/10 for Casper’s three-zone system, 8/10 for Sweetnight’s 5-zone design), transparency of trial and warranty terms (9/10 for Sweetnight’s stated 100-night trial and 10-year warranty, 6/10 for Casper’s page), certifications (9/10 for both, each carrying CertiPUR-US), and public review volume (9/10 for Casper’s 17,942 reviews at 4.4 out of 5). The method behind our scoring will be explained in full on a dedicated methodology page.
Verdict: the Sweetnight CoolNest is the winner of this face-to-face for hot sleepers, while the Casper Original is the better pick for zoned spinal support with a well-established review record. Choose the CoolNest if sleeping cool is your main problem and you want a stated trial, warranty and free shipping on the product page. Choose the Casper if you want three-zone support, a consistent 11 inch profile and a mattress with 17,942 public reviews behind its 4.4 out of 5 rating. If you want coils instead of foam, the Saatva Classic alternative above gives you three firmness levels, a full year to trial it and white-glove delivery.
A strong alternative
Saatva Classicfor sleepers who want coils and a full year to decide
- 365-night home trial
- Free white-glove delivery with in-room setup
- Lifetime warranty
- Three comfort levels from Plush Soft to Firm
Frequently asked questions
Does the Sweetnight CoolNest come in a Twin XL size?
No. The sizes listed for the CoolNest are Twin, Full, Queen, King and CLK. The Casper Original does offer a Twin XL, measuring 38 inches wide by 80 inches long at 11 inches tall and weighing 50 pounds.
How thick is the Casper Original compared to the CoolNest?
The Casper Original is 11 inches tall in every size. The Sweetnight CoolNest comes in three thicknesses: 12 inch, 14 inch and 16 inch, so you can choose how much height and cushioning you want.
Which mattress has more public reviews?
The Casper Original shows an overall rating of 4.4 out of 5 from 17,942 reviews on its product page. The Sweetnight CoolNest page available here does not show a review count.
Is either mattress eligible for HSA or FSA payment?
The Sweetnight CoolNest is marked HSA/FSA eligible on its product page. The Casper Original page does not mention HSA or FSA eligibility.
Can I get the Casper Original during a sitewide sale?
No. The Casper product page states the Original Mattress is excluded from all sitewide sales and promotional offers.
Reviewed by the World Sleep Almanac editorial team, updated October 2026.
Keep comparing
- Casper Mattresses 2026: Which Model to Buy and Who Should Skip
- Casper Original vs Loom and Leaf: Which Foam Mattress Wins
- Sweetnight Island Review 2026: Who Should Buy This Hybrid
- Sweetnight CoolNest vs Saatva Zenhaven: Which Mattress Wins?
- Best Cooling Mattress 2026: Saatva Latex Hybrid First, Sweetnight Second
- Best Memory Foam Mattress 2026: Saatva Loom and Leaf Leads, Puffy Follows
- Layla Memory Foam vs Saatva Zenhaven: Which Should You Buy?
- DreamCloud vs Saatva Zenhaven: Which Mattress Wins for You