The Science Behind Insulation

Insulation is essential to a comfortable and efficient environment. The essential point of insulation is to isolate your indoor environment from the outdoor environment. We want to control the flow of heat, energy, into and out of our workspaces as much as possible. To pull this off, we need to find the worst conductors and most obstructive blockers in history. We need to make the opposite of a radiator, a blocker.

 

Blocking the Heat

Insulation works against three basic ideas:

  • Conduction
    Heat which is passed through a surface. Consider the copper pipes used to heat a home. The heat spreads through them. If you hold a torch to one end, the pipe will be hot even feet away from the heat source. It conducts the heat.
  • Convection
    Heat which moves with the air. A typical gas or electric oven uses convection. The air is heated and circulated around the thing that is being heated.
  • Radiation
    Put down the hazmat suit. We mean heat caused by intense light. This is the sort of heat used in laser cutters. This is the heat of the sun and all its powerful infrared and ultraviolet rays. This is the kind of heat that turns a sitting car into an oven.

The most comment type of insulation is going to work against conductive heat flow. This is that fluffy material behind your walls. These insulations are rated with an R-Value, their Thermal Resistance to Conductivity. The greater the R-Value, the greater the better the insulation.

Most of this insulation if made of fiber glass. Some of it is made of mineral fibers or plant fibers. It’s even possible to get wool and cotton insulation. These materials are packed in and don’t readily give off heat to the environment. The fibers pushing against each other prevent air from readily flowing out as well, which prevents the heat from just ‘leaking away’. That is, these types of insulation work well against both Conductive Heat Loss and Convective Heat Loss.

These fiber-based insulations are all well and good, but they’re not perfect. The best way to keep the inside separate from the outside is to make sure they never touch. This is the rationale behind most insulated mugs and double-pane windows. The space between the inside and outside is filled with low-conductivity glasses or a complete vacuum. Convective and Conductive Heat don’t work when there is no contact.

This thinking forms the basis of Foam-Insulation. Foam insulation can be sprayed into a space. Inside that space, it’ll expand to fill every little gap. The foam material itself is not the essential thing: the gas inside is what does the work. The foam is essentially a solid, but it’s packed with low-density, non-conducting gas. The wall cavity with foam inside, can be made to perform almost like a vacuum. The mix between gas bubbles and solidified foam turns it into essentially an inert gas in a cage.

Reflective Insulation is less common. Many packages of fiberglass insulation will be held in foil, which helps, but doesn’t make it a great solution to radiant heat. More commonly, special foils will be installed in attics to directly combat radiant heat flowing through the roof. There are however, challenges to this type of insulation. Most significantly, it conducts electricity. Where foams and fibers are inert and even fire-retardant, radiant barriers will conduct a charge. Electrical safety must be observed to prevent fire and injury.

 

Is It Really a Big Deal?

Yep. Just look at your car or truck in the dead of winter after a snowy morning. Vehicles generally don’t have much insulation if there’s any at all. Your house would be just like the car without its insulation. A vehicle is only warm so long as its running with the heater on. Turn that heater off for more than a few minutes and it starts to change inside.

For a house or an office, insulation could potentially halve the cost of heating and cooling, depending on the local climate. For a home in sunny Miami, a house without insulation would require the AC to run non-stop. This would drive up not only electrical bills but also maintenance bills from the extensive, constant cycling required to fight mother nature. At the same time, an office in the Northeast like ours would be unbearable. It would take uncountable gallons of fuel to last the winter.

Worst of all, an uninsulated building probably wouldn’t be a comfortable building. Consider that the lack of insulation would lead to a draftier office. The air would cool all the faster. If you weren’t near a heat source, cold spots could form. During extreme weather, it would almost have to be an unbearable place to be. If it’s below zero outside, the furnace would have to be enormous to keep up against those heat losses.

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