Heat transfer by conduction and convection works by particles colliding and transferring energy, as there are no particles in a vacuum heat transfer can only occur by radiation. This is because radiation involves electromagnetic waves, not particles, and is therefore able to transmit heat across a vacuum.

All these waves propagate in vacuum with the same speed c, the speed of light. The speed of light in air (at standard temperature and pressure) is very close to the speed of light in vacuum (the refractive index of air, n, is 1.0002926, meaning that the speed of electromagnetic waves in air is c/n ≈ c).

Unlike conduction and convection, radiation does not need matter to transfer heat. Energy is radiated from the sun, through the vacuum of space at the speed of light. The ground soaks up the energy from the sun’s radiation, and this causes it to give off heat, too.

Space is an almost perfect vacuum, full of cosmic voids. And in short, gravity is to blame. By definition, a vacuum is devoid of matter. Space is almost an absolute vacuum, not because of suction but because it’s nearly empty.

Insulating materials Most insulation is used to prevent the conduction of heat. In some cases radiation is a factor. A good insulator is obviously a poor conductor. Less dense materials are better insulators.

Go even further to reduce solar heat gain by applying reflective, heat-control window film to any windows in the hot room (or, if you choose, throughout the entire house). Made up of multiple UV-blocking layers, insulating window films limit the extent to which the sun’s rays can drive up the temperature indoors.

Compared to fiberglass insulation, any of the above options would be safer than insulating your home with tiny glass shards dipped in formaldehyde. However, the safest option of all is cellulose.

Non-Toxic Mineral Wool Brands Rockwool (formerly Roxul) is the most common and accessible mineral wool insulation. They have a newer version called AFB, that does not contain formaldehyde. The binder is an undisclosed polymer (a plastic, likely acrylic), it also contains mineral oil.

The best types of home attic insulation are open cell spray foam, fiberglass, and cellulose.

• Cellulose is the oldest insulation material used for not only the attic but other areas of the home as well.
• Fiberglass is another traditional insulation material that consists of extremely fine glass fibers.

There are three types of natural insulation: Animal-based insulators: sheep wool, feathers and more. Plant-based insulators: hemp, cotton, cellulose, wood fibre, cork and more. Mineral-based insulators: clay, pearlite and vermiculite.

Natural insulation materials, such as hemp, flax and wool, have been the most interesting products for low carbon construction, becoming widely recognised for their sustainability.

The most common insulation materials are fiberglass, cellulose and foam. Home insulation types include any of the above materials in the form of loose-fill, batts, rolls, foam board, spray foam and radiant barriers.

It is the air pockets that do the insulating more than anything else, reducing conduction and convection. It has an R value of 0.65-0.7 which is better than cardboard, wool, fiberglass, straw bales, wood, bricks and glass.

Because aluminum foil reflects light, it can be used for insulation, especially in areas that need to be guarded against heat. When it is used with other materials, it can be used to warm an area, too. Aluminum foil can keep things like wires or pipes insulated, as it traps air when it is wrapped around an object.

Glass is used as an insulator because it has atoms that have electrons that are closely connected with each other. And because of this property, it does not allow electrons to freely roam around and be shared by nearby atoms thus preventing the flow of electrical current in other materials.

The research lab behind the creation of see-through wood has developed a new type of material that could be used as a cheaper, stronger and more environmentally friendly insulator. They’re calling it nanowood and it insulates better than Styrofoam and silica aerogels.

Polystyrene and plastic foam are both used as insulators as they have small air bubbles trapped inside them. This makes them very good insulators because heat energy can’t flow through them. This stops the movement of air in the space between the two layers of glass and reduces heat loss from the window.