Memory Foam Mattress Buying Guide
What is visco foam?
Also known as "memory foam." Originally developed by NASA, this temperature sensitive, slow recovery urethane foam that conform to the body and distributes pressure according to body heat and weight. Not all memory foams are created equal, but come in come in a variety of thicknesses, densities, and different levels of softness and firmness. Visco foam may be used as the primary construction material, or as a component of the comfort system of an innerspring mattress.
Is all memory foam the same?
As with all things, there are differences in the qualify of visco foams. Different manufacturers will use varying resiliencies and densities which will impact the springiness, durability and firmness of the foam.
How is memory foam rated?
There are four different factors that contribute to the quality of foams, including visco. These measurements can vary slightly between foam batches, even from the same manufacturer.
- Weight: The weight of the foam is measured by the amount of chemicals used in making it. The more chemicals, the higher the density. This measure does not indicate the hardness of the mattress. Generally, ratings can be labeled "3-budget", 4-good" and "5-premium". But don't get caught up in labels. What feels good to you is all that matters.
- Indentation Load Deflection (ILD):
is a measurement of foam firmness. Firmness is independent of foam density, although it is often thought that higher density foams are firmer. It is possible to have high density foams that are soft – or low density foams that are firm, depending on the ILD specification. ILD specification relates to comfort. It is a measurement of the surface feel of the foam. ILD is measured by indenting (compressing) a foam sample 25 percent of its original height. The amount of force (in pounds) required to indent the foam is its 25 percent ILD measurement. The more force required, the firmer the foam. Flexible foam ILD measurements range from 10 pounds (supersoft) to about 80 pounds (very firm).
- Resilience: This is the measure of the foam's springiness as determined by measuring the rebound of a steel ball dropped from the height of 36". In general, the higher the resiliency rating, the more durable the foam will be over time.
- Tensile: This is a measurement of how much a foam can be stretch, and isn't really relevant when visco is used in a mattress.
How do I know if a memory foam is right for me?
Like any mattress, what feels comfortable to you is going to be unique and the best way to decide is to try it for yourself. Given that memory foam mattresses are generally among the most expensive, you want to be sure you try it before you buy. Even if a retailer offers a 90 day trial period, you may have some expenses tied to return the bed if you don't like it. The Better Sleep Council recommends taking a "SLEEP Test":
S elect the mattress
L ie down in your sleep position.
E valuate the level of comfort and support
E ducate yourself about each selection
P artners should try each mattress together
Take your time and don't be embarrassed. You don't think twice about test driving a car, and you shouldn't think twice about "SLEEP Testing" a mattress. Lie down on the mattress for several minutes in your normal sleeping position and assess how well it provides support and how comfortable it is for you. The only way to tell if a mattress is right for you is to lie down on it.
Why wouldn't everyone want a memory foam bed?
Aside from the fact that these are among the more expensive beds, not everyone is comfortable with a bed that conforms so closely to their body. Typical complaints about these beds include being too hot or being difficult to move in once the mattress warms up and conforms to your body. If you're concerned about it being too hot, look for a bed with ventilated visco in the top layer. You can avoid the "sink hole" feeling by selecting a bed that has no more than 3" of visco foam on the top layer. During your SLEEP test, take the time to settle in, rollover and shift positions--after all, we average over 50 position changes per night so try more than just one. One popular alternative is too look for an innerspring mattress that uses visco, latex or a combination in it's construction. You'll get most of the same benefits, without the drawbacks.
I heard memory foam smells. Why is that?
Memory foam can smell when it first comes out of the bag if it was bagged while still warm. It's not toxic, but it may be irritating if you have a sensitivity to smell. The best thing to do is leave the bedding off for a few hours and let it air. The smell should dissipate within a week or two. If not, check with your retailer.
Do I need a foundation or box spring with a foam mattress?
A quality memory foam mattress should feel the same whether you put it on a box spring or a cement floor. If you have a good box spring, you can reuse it, however, if you put your new mattress on a worn out box spring, both will eventually sag and you could void your warranty. If you're using a bed with slats, make sure they are in good shape and can hold the extra weight of the foam mattress.