Garage insulation may seem optional, when other more obvious home improvements vie for limited dollars. But with rising fuel costs, it’s a good idea to take a close look at all the ways it could make good sense, and good cents, to insulate all or part of the garage.

This is particularly true for the attached garage. Insulation of common walls shared by the garage and the main living space is obviously of great importance. This includes the ceiling of the garage if there is living space above. All too often, there is great heat loss or gain through these walls, because the air in the garage can rise or fall to temperatures that are even more extreme than those outside. It is therefore almost more important to insulate the walls between the garage and the house as it is to insulate the house’s exterior walls.

Other reasons to insulate these walls include sound proofing, especially if the garage is ever used as a workshop. Perhaps the garage will someday provide a safe place to set up a generator for times when the power goes out. By opening the garage door wide and placing the generator in a safe position, adequate ventilation can be arranged, and the sound barrier between garage and home would be much appreciated by occupants of the house. Maybe the garage will someday serve as a practice room for the budding rock musician in your family, young or old. Or maybe it’s where you will lock the barking dog.

Proper insulation between the house and garage also serves a safety function, making it less likely that fire or fumes will spread between the two spaces.

A thorough evaluation of the insulation or lack of insulation in such walls should include careful examination to see if there are any holes between living and garage spaces, and whether the spaces around the doors are airtight.

Next, consider the reasons to insulate the exterior garage walls, including the roof, if there is no living space above. Insulating these exterior walls makes the temperatures inside the garage less extreme. This adds to the effectiveness of the insulation barrier between the house and garage and it also keeps the contents of the garage in a better temperature range.

Now, let’s consider the unattached garage. If you live in a cold climate and store your car in the garage, good insulation means your car will not be as exposed to the kinds of temperatures that can make it difficult to start in the morning. Conversely, if you keep your car in the garage in a hot climate, good insulation will mean your car will not have to endure such extreme temperatures. Nor will you, when you enter it.

If you use your unattached garage for storage or as a work area, the effect of insulation on your comfort and on the items you store will be beneficial. And if you heat or cool the garage for these purposes, then your energy bills will be that much less with good insulation.

It may be tempting to consider DIY spray insulation, especially if you decide to insulate only a small area. Keep in mind how quick and easy expanding foam insulation can be, especially if you already have finished walls in the garage, or if you will be insulating the ceiling. It’s definitely worth talking with a spray foam insulation contractor when you consider all your options for how to best complete your garage insulation project.

Insulation in the roof and walls is clearly beneficial for its ability to reduce heating and cooling losses and costs. The savings achieved by reducing heat transfer by conduction justifies the cost of adequate insulation.

But don’t forget that convection is another source of heat transfer when air moves between two spaces. Minimizing or controlling losses via convection is desirable but requires more consideration. Adequate outside air is necessary for breathing, and sufficient air transfer is required to ventilate other gases and odors from interior spaces.

Most homes are so leaky that there is plenty of opportunity for air to intrude and be enough for the occupants. However, as structures become more air-tight and interior materials become more synthetic, there is the possibility that the indoor air quality is compromised.

Controlling infiltration of outside air is important. Not only is uncontrolled air infiltration wasteful of energy it can also carry outside pollutants such as fumes and dust. Inadequate exhaust of indoor pollutants can cause allergies, respiratory distress and ’sick building syndrome’.

Expanding foam insulation applied to walls and roof voids fills small spaces and gaps that allow air to flow between the interior of a home and the outside environment. Eliminating these gaps prevents air convection from carrying heat between the interior and exterior of a home, which results in lowering the expense of heating or cooling a space.

Minimizing air from entering from the outside into the house means that expanding foam insulation can improve the quality of air inside your house. With proper permeable filters and especially electrostatic filters installed with your air-handler, circulating inside air can be controlled and cleaned of allergens, particulates and pollutants within a building’s interior. By using expanding foam insulation to reduce infiltration of outside contaminates, the inside air is a higher quality. This may be an even more important consideration if a resident suffers from allergies or respiratory conditions.

A more sophisticated installation that is used in commercial buildings and may be justifiable in homes is the use of an ‘economizer’ air handling system. By using an arrangement of ducts and dampers in an ‘H’ pattern outside air and exhaust air can be controlled to allow recirculation and proper ventilation. Depending on the sensible heat and latent heat outside, controllers move the dampers to allow the desired air flow in and out of the building space, which maintains adequate fresh air and takes advantage of the energy of the exterior for cooling or heating. This is especially effective for ‘air-tight’ structures and locations where day and night time temperatures and humidity vary significantly.

Expanding foam insulation is extremely useful to address multiple issues of conduction and convection. Whether it is maintaining the temperature of a home, controlling air infiltration, soundproofing a space, and minimizing energy consumption, almost everyone will enjoy the benefits of expanding foam insulation.