Most kitchens have at least one outside wall which needs to be insulated. In many kitchen the standard has always been to use fiberglass batts, which give a R15 insulation value (the higher the R the better). Naturally, this is an imperfect solution, but it is cheap and easy to install.
A much better option is to use expanding foam which not only offers a better R value, but it also fills all of those little cracks that let heat and cold in. Foam insulation comes in two varieties, open and closed cell. Closed cell is the more expensive, and is the best option for external walls. It is imperative to have this done by a professional who knows what he or she is doing. Closed cell foam must be sprayed in layers. Otherwise, it won’t cure properly and it can be hazardous. Each inch of closed foam has an R value of 7. This kitchen will have 3″ of foam, or an R21 value which is well above the building code requirement of R15. See photos below.