Hi SleepyPanda18.
Sorry to hear about his current mattress sag and rolling in the center which is especially of concern for a stomach sleeper.
Heritage is a premium/luxury design but that does not mean that it will be a good match for you. Like with every other mattress purchase you’d need to ensure that this mattress is what you need in terms of PPP (Posture and alignment, Pressure Relief, and Personal Preferences)
This mattress has microcoils (smaller and softer springs) as the comfort layer which have a different response curve (more linear) than foam (which has a more banana-shaped response curve) and they work well for those who prefer their feel and resilience or whose testing shows that they do better with this type of response vs foam. They can work well but you’d want to test it to see if you like the feel.
You are approaching higher BMI ranges and with both you and your girlfriend sleeping on our stomach I’d be concerned about the level of firmness and type of mattress that best fits both of you. The (19") Heritage in plush you listed could present some issues for your stomach sleeping which being too plush may lead to spinal misalignment through hyperextension in a swayback position that can cause back issues. You may wish to review the guidelines in this Sleep Positions Article [url] [url=https://forum.mattressunderground.com/t/ultimate-dream-mattress-firmness-level]Post #2 here has some generic guidelines for different body types and sleeping positions ,
the first part of post #2 here also has more information about couples that have a larger weight differential and
Their hybrid is available only in stores so if you are close to one you can certainly go and check it out. If you go and try it I’d definitely try their firm version for comparison with their soft.
I could not quite read the text from the photo you posted but managed to find their specs for both versions.
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• 1" Joma Wool -2 x .5" layers sustainably sourced Joma Wool
• 2.25" Microcoil Triple layer- 2 x .75" Firm gauge, plus .75" medium gauge Comfort
• 1.5" Talalay latex transition foam
• 8" Pocket coils
• 2" High Density foam base
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• 2.25" Premium Tufted top
• 2" quadruple layer Joma Wool (.5" x 4)
• 2.5" Microcoil layer- (2 x .75" Firm gauge, plus .75" medium gauge) Triple Ascension
• 1.5" soft Talalay latex foam comfort layer
• 1.5" firm Talalay latex transition layer
• 8" Pocket coils
• 1.5" High-Density foam base
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Before rushing into any of the “cooling tech” promises I’d read a bit more about the many variables that can affect the sleeping temperature of a mattress or sleeping system in post #2 here that can help you choose the types of materials and components that are most likely to keep you in a comfortable temperature range. In very general terms … there are many materials that are naturally temperature regulating. Materials, layers, and components of a sleeping system that are closer to your skin will have a bigger effect on airflow, moisture transport, and temperature regulation than materials, layers, and components that are further away from your skin and softer mattresses or foam toppers will tend to be more “insulating” and for some people can sleep warmer than firmer versions of the same material.
This mattress has the following configuration
(13") Saatva Latex Hybrid Mattress
• 1.5" quilted cover
• 1/2’’ New Zealand wool comfort layer
• 3" 5-zone natural latex (ILD 22-23)
• 8" Pocket coil
• ½" Organic Eco-Loft Pad
Comfort level Medium to Firm
The 1.5" quilted cover will affect the most how hot or cold you’d be sleeping. Typically there is some type of polyurethane in the quilting which is not the most temperature regulating material.
This mattress would be better for you than the Heritage, but still, it is impossible for me to predict if it would " " as there are too many interrelated variables including personal ones.
This is one of the most common questions on the forum (ie. which mattress type or firmness level would be better for me?) and there is some fairly extensive general information in the mattresses section of the site (particularly in the sections about sleeping style, preferences, and statistics along with putting the layers togethertips and tricks here and the page on ) that can give you some general concepts, guidelines, and insights about the effects of different body types, sleeping styles, and mattress designs for different people but this is only generic and not specific to any particular person and may be more complex than you really need to know.
For comparison listed below is the construction of your current mattress that is still in the trial period.
(14") Sealy Hybrid Premium Silver Chill Mattress
• (?) Chill cover
• 2" memory foam layer 3.5 lb/ft3 Chill immersion
• 1.5" Gel comfort sense foam
• 1" polyurethane foam
• 8" pocket coils with HD duraflex foam edge support
Comfort level: 2 options medium(plush) and Firm
Once you have a chance to read through the links above and reorient yourself let us know if you have additional questions
Phoenix