Yawnder Reviews · Original product research, current model not tested firsthand
Our verdict
For someone comparing 10-inch all-foam mattresses at Costco, Serene Foam II deserves consideration for its Medium and Firm options and listed adjustable-base compatibility. This is a specifications-based buying guide, not a hands-on Yawnder test or measured performance score.
Current status and value
How to use this review
This is a research-based buying overview of Costco’s Comfort Tech Serene Foam II, not a hands-on test of this specific model. Yawnder has not published model-specific measurements or a score for it.
Comfort Tech Serene Foam II at a glance
| Feature | Manufacturer or retailer listing |
|---|---|
| Type | 10-inch foam mattress |
| Firmness | Medium and Firm options |
| Adjustable base | Listed as compatible by Costco; check your specific base |
| Queen size | 59.5 × 79.5 × 10 inches, listed weight 65 lb |
| Testing status | No current model-specific Yawnder hands-on score |
- Construction: 10-inch foam mattress; Costco lists CertiPUR-US certified foam.
- Firmness: Costco lists Medium and Firm options. Confirm the option and size selected before ordering; availability can vary.
- Adjustable base: Costco lists the mattress as compatible with adjustable beds.
- Queen dimensions: Costco lists 59.5 by 79.5 by 10 inches and 65 pounds. Check dimensions for the size you choose.
- Purchase: Costco lists it online only, with parcel delivery. Price, availability and delivery options can vary.
Specifications can change. Check the current Costco listing for your selected size and firmness. Comfort Tech sells other mattresses with similar Serene names, so do not assume their layer specifications apply to this model.
Choosing Medium or Firm
Medium is the more accommodating starting point if you prefer a balance of cushioning and support. Firm is worth considering if you prefer a less yielding surface. Firmness is subjective: body weight, sleep position and personal preference affect how either option feels. The available information does not establish how this model performs for pressure relief, cooling or edge support.
If you sleep with a partner, compare your preferences before choosing. If you need especially sturdy edges for sitting or easy entry and exit, check whether the retailer’s return terms give you enough confidence to evaluate the mattress at home.
Foundation, delivery and returns
The mattress is listed as adjustable-base compatible, but check the manufacturer's support and foundation requirements before placing it on an existing frame. Measure the frame and consider the 10-inch height alongside your sheets and bed height.
Check the final checkout page for shipping, availability and any removal services. Costco’s satisfaction guarantee is subject to its terms and exceptions; verify the current mattress return process with Costco before purchasing. Do not assume a separate 365-night trial or that removal is included everywhere.
What CertiPUR-US means
CertiPUR-US certification applies to qualifying polyurethane foam and its program standards. It does not mean the entire mattress is organic or emissions-free. Ask the seller for the specific certification and warranty details if these matter to your decision.
Who should consider or skip Serene Foam II?
It may be worth comparing if you want a 10-inch foam mattress and prefer shopping through Costco. Compare the delivered price, firmness, foundation requirements and return terms with alternatives. Shoppers looking for spring-like bounce, a taller mattress or independently measured edge support may want to compare other models as well.
Frequently asked questions
Is it available in more than one firmness? Costco lists Medium and Firm; selection can depend on availability.
Can it be used on an adjustable base? Costco lists it as compatible with adjustable beds. Verify your base and foundation requirements.
Has Yawnder tested this exact mattress? No model-specific test results or standardized score are available on this page.
Bottom line
Compare Medium and Firm based on your preferred feel, then verify the exact Costco listing, foundation requirements and retailer return terms. Our review does not assign a measured score to a model we have not tested.
Yawnder scoring framework
When complete data is available we score pressure relief, spinal alignment, cooling, motion transfer, edge support, responsiveness, durability and off-gassing.
Compare this mattress against 142 tested mattresses
Sort all 142 mattresses we have tested by pressure relief, support, cooling, motion isolation, edge support, price, trial and warranty, then filter by how you actually sleep. Of those, 84 hold a complete standardized record and 41 a partial standardized record.