During the depths of winter, when the temperatures drop and the winds start howling, you really begin to feel the importance of having the highest quality insulation in your house. Sure, good insulation is important throughout the year for maintaining energy efficiency, but the cold and wind affect homes differently than hot weather does, exploiting the weaknesses of lower quality or poorly installed materials.

In the summertime, the heat causes a house’s insulation and construction materials to expand, which can actually tighten any gaps that might exist due to age or wear. In the wintertime, however, the cruel irony is that the colder it gets, the worse your house becomes at protecting you from the cold. Falling temperatures have the exact opposite effect on building materials: It shrinks the house and insulation, causing them to pull away from each other. This widens all of those gaps that weren’t such a problem in the summer.

The wind further exploits these structural deficiencies. Wind has a way of finding all of the chinks in a house’s armor, and pushes the cold in through all of the points where the house’s insulation has failed. The combination of widened gaps and harsh winds create an exponential drop in insulation effectiveness, making it exceptionally difficult to keep temperatures evenly regulated. As a result, heating bills are driven through the roof.

Some insulation materials are more vulnerable to the effects of cold and wind than others are. Fiberglass is one of the most common materials used in American homes, due to its initial cost effectiveness. However, fiberglass and the also-popular cellulose can end up wasting any money saved in the initial installation thanks to their decreased energy efficiency. The problem with both fiberglass and cellulose is that they dramatically lose effectiveness with imperfect installation – and they’re basically impossible to install perfectly. In fact, it’s estimated that the insulation gaps in an average fiberglass-insulated home add up to the size of a basketball.

Most housing experts agree that closed-cell polyurethane spray foam, or spray foam insulation, is the most effective material for keeping out winter weather. Polyurethane foam has an estimated R-Value of over 6, where fiberglass and cellulose materials only measure between 3 and 4 R/inch. As a matter of fact, these numbers assume that the fiberglass and cellulose were installed perfectly, and do not account for the real world effects of cold, wind, and human error. Spray foam is also much easier to install, so it functions to its highest capacity. During installation, the foam expands to fill all gaps, which eliminates the potential for faulty craftsmanship. It also minimizes the debilitating effects of harsh temperatures and conditions.

R-Values are a good starting point when measuring insulations, but the true effectiveness of a material is how it stands up during the most difficult real world conditions. Falling temperatures and wind-chill factors can turn homes that are great at keeping their cool in the summer into drafty money pits that are difficult to regulate in the winter. Make sure you use only the best insulation materials and installers when building or repairing your home. The environment, your wallet, and everyone that lives in your home will benefit.