One side firm, one side soft
There will be circumstances when a dual spring tension support element will be required to suit varying body weight. When this is the case you will have to take into account a particular set of compromises.
The first one is to realise that the mattress cannot be completely turned and rotated to enable you to keep your own ‘side of the bed’. The mattress can only be turned.
In the second instance, there will obviously be a change of tension where the set of firm springs meet the set of medium springs. There is no way that this can be alleviated by construction methods and is not really that intrusive to the sleepers.
I must point out here that despite the title of this post, it is not usually possible to have a mattress with half side using firm springs and half the mattress using Soft springs. the combinations are usually medium / firm or soft / medium. There are exceptions to this which we will touch on later.
The other alternative is to opt for a zip and link construction. This can involve having one side with a lower or higher spring count than the other. It can also be constructed with firm plus soft or any combination of spring tensions. Once again, the mattress can only be flipped not rotated without losing your sleeping side. On zip and link models, there are ways to combat this by having the zippers on each side of each individual mattress however, this method does come at a price to account for the extra labour involved. Read here for all about zip and link mattresses.
So why do we need dual spring tensions?
There are several governing factors for this arrangement and the main two are detailed below. Before you read those there is an important factor to bear in mind. In order for the manufacturer or retailer to know what tensions to use in the mattress, you have to accurately describe how different the tensions that you are asking for should be, and also the reasons why you think you require different tensions. I mention this because I wonder whether you actually need to go down this route. Read about soft / med / firm Mattresses here.
However, I find that when people do ask about differing tensions there is a fundamental reason for them doing so. The main reason is usually a large weight difference between couples making it uncomfortable/impossible to sleep together. If so, it may be that you bought the wrong mattress last time and you just need additional help in choosing the perfect mattress for you both without going to additional expense.
The second reason is usually based on what you have as a current mattress. One person may decide that this is the correct level of comfort and support, the second person may feel that for whatever reason it isn’t.
Due to the limitations described above with a dual spring tension mattress it has to be said that this combination is to be looked upon as a compromise to a single tension mattress. Obviously there is not a mattress out there that will adequately support and comfort people of significantly varying body weights, and therefore, a Dual tension spring unit or zip and link models are the only available option open to them. But, if the differences are only nominal degrees of perceived comfort it is advisable that you make the necessary tweaks to comfort yourself with the use of mattress enhancers or toppers.
There really isn’t that much more to say on this particular subject. With all low-priced mattress models out there you do not have this level of choice of differing spring tensions and it will only be an available choice within the mid to high-end range from most manufacturers.