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Using Radiant Barriers

Radiant barrier is a type of heat insulation that looks like a shiny foil sheet. It is often used during construction workUsing Radiant Barriers to reflect heat but can also be installed in the attic of a house to prevent radiation as it works well in closed and narrow spaces.

The attic is the top covering of a house. In hot weather, the attic gets extremely hot and passes the heat to the house. The temperature of the attic and of the house, however, can be controlled by installing radiant barriers sheet. Heat waves flow from hotter region to the cooler region. The radiant barriers work as an obstacle creating it difficult for heat waves to pass through it and enter the house through the roof.  The radiant barriers require airspace in front of them to work.  They may become heat conductor if placed in-between the two pieces of siding. Besides, any dust accumulated on the barrier sheet may reduce its ability to reflect heat.


Insulation Options for an Efficient House Plan

When putting together plans for a home, attention must be given to every detail. While your focus might be on making sure you have enough closet space or that your garage has enough space to include a small workshop for your hobbies, there is more you need to plan for than just what you can see. What you can’t see behind the walls is important as well. You need to plan for insulation.

According to U.S. Department of Energy statistics, homeowners can cut their energy costs as much as 20% when their homes are properly insulated. Where you reside in the country plays a big part in what type and how much insulation you’ll need for your home. For instance, take a typical home design. If that home was built in Arizona, it is going to have different insulation needs than the same home built in Delaware because the climate in each place is unique to that particular environment.

With differences in house styles and plans, as well as the varying degrees of climate throughout the country, special attention needs to be paid to your choice of insulation for the house during the planning stages. There is no single option available to you. Knowing the differences and choosing the right one can save you money on your heating and cooling costs.

Let’s first take a look at the considerations for choosing home insulation. Depending on where you live in the United States, you’ll have to consider the R value for your walls, floors, ceilings, basement and crawl spaces. The higher the R value, the better the material used as insulation can impede air from flowing through the walls or cavity the insulation is in.

Living in the desert heat of Arizona or a similar climate, you’ll need a high R value to keep the heat out of your house and keep cooling costs down in the summer months. Living in the mountains of Wyoming you’ll also want extra insulation with a high R value to keep the heat in your house in the winter. In milder climates, or where the temperature doesn’t fluctuate to the extremes, a lower R value can be used.

Different types of roof designs can also change the amount of insulation needed for a home and will need to be planned for in the early design stages. For instance, if the home has an attic, thick batt insulation can be used to obtain the correct R value needed to reach building codes to heat or cool the house effectively. You don’t need to consider the thickness of the roofing studs because there is plenty of room for the insulation to sit in the attic space.

However, if you have a room that is full of glass windows or has cathedral ceilings, you’ll need to either put in wider roofing studs that will accommodate the thickness of batt insulation you’ll need to come up to building code, or you’ll need to choose another insulation option that will give you the same R value of the smaller roofing stud. This is particularly important in homes with cathedral ceilings and Cape Cod style homes where there is a sloped ceiling on the second floor.

Loft Insulation Guide

Things you need to know when insulating your loft

Attic insulation has become a necessity now days, especially bearing in mind that lofts are often transformed into dwelling, residential places where some basic living conditions must be fulfilled in order of enabling normal and enjoyable residence. One of the primary concerns is maintaining a constant temperature that is preventing the cold air from penetrating in during the winter and hot air during the summer, which can only make your loft unbearable to stay in. The most common solution is proper insulation that can not only protect your loft from undesired external temperature effects, but also make a significant impact and contribute to the overall energy efficiency of your home. This is why there are some things you need to know when insulating your attic and we provide some of the answers right here.

Basics and precautions

Before choosing and installing proper attic insulation, there are some things to consider and some precautions that must be taken into account. First off all, you must understand some potential problems that could occur in this type of insulation and some basic ways to prevent and overcome such problems. It is important to try to avoid thermal bypass that can occur at the eaves, then to avoid placing heavy objects on top that can crush air pockets between the fibers and reduce overall insulation effectiveness. Another great problem when insulating your attic is condensation, which could be avoided by proper ventilation across the roof, usually from eaves to eaves. Finally, it is very important to prevent air leakage from the rooms below, traveling through some ceiling penetrations (like wiring or light fixtures).

Loft insulation types

Blanket insulation

One of them is using batt or blanket insulation, which includes the use of mineral fiber, that is rock, glass or sheep wool fiber insulation, which is the most commonly used material. The basic advantage of this loft insulation type is that it is basically a DIY job and is particularly suitable for accessible spaces insulation. On the other hand, make sure to take the previously mentioned precautions, since some materials can cause skin irritations and bear in mind that these insulation materials can be to bulky and not always suitable for insulating small and tight places. Before installing insulation, make sure that the loft space is cleared up and that all the wiring is previously taken care of. After measuring the floor space length, this insulation material is laid between the joist, starting from the eves to the center of the loft, when the material is cut and pushed down the joists edges. The process is then repeated from the opposite side again to the center of the loft. Another layer can be placed across and over the joists so the overall insulation reaches the recommended depth of 270 mm. If you need to adjust the length of the insulation material, use scissors to cut it into right size and avoid any stretching or tearing which could damage the material and affect its thermal performance. Also remember to properly insulate the loft hatch as well by fixing a piece of insulation material on the top of the hatch.

Sheet or board insulation

Another way to insulate your loft is by using sheet or board insulation which includes the use of rigid boards in insulation, such as PIR, phenolic or polystyrene boards, cut to the right sizes. Their basic advantage is that the use of available wood boards is a more eco-friendly solution, they are especially applicable in loft conversions and have substantial performance, but can be more expensive than the alternatives. This type of material is placed between the roof rafters, but always leaving some space between insulation and roof tiles in order of providing needed ventilation and thus avoiding condensation.

Thermodynamics and Reflective Insulation

Reflective insulation inhibits heat transfer by thermal radiation. It does not necessarily protect against heat transfer by conduction or convection. Why do you need to know about this insulation? It could mean thousands of dollars saved over the years for heating/cooling, in what you choose for not only roofing materials, but more importantly, what is placed between the roofing and building framing. Bear with me here.

In today’s science lesson…

All materials emit (give off) energy by thermal radiation as a result of their temperature. The amount of energy radiated depends on the surface temperature and a property called the emissivity or the emittance. Emissivity is expressed as a number between zero and one at a given wavelength. The higher the emissivity, the greater the emitted radiation at a given wavelength. A related material property is the reflectivity or the reflectance. This is a measure of how much energy is reflected by a material at a given wavelength. The reflectivity is also expressed as a number between zero and one (or a percentage between 0 and 100%). At a given wavelength and angle of incidence the emissivity and reflectivity values add up to 1 by Kirchhoff’s law.

For those of us who never studied thermodynamics (most of us), Kirchoff did it for us over 150 years ago. While he appears to have been a pretty smart guy, most of his work will go over the heads of us average folks. The important thing to remember is – a good absorber is a good emitter (if something gains heat readily it also gives it off readily) and a good reflector is a poor absorber.

Reflective insulation materials must have low emissivity (usually 0.1 or less) at the wavelengths at which they are expected to function. For typical building materials, the wavelengths are in the mid- and long- infrared spectrum.

It may or may not exhibit high visual reflectivity. This is because while reflectivity and emissivity must add up to unity at a given wavelength, reflectivity at one set of wavelengths (visible) and emissivity at a different set of wavelengths (thermal) do not necessarily add up to unity. However, it is possible to create visibly dark colored surfaces with low thermal emissivity.

To perform properly, reflective insulation needs to face open space (like air or a vacuum) through which there would otherwise be radiation.

Moving forward in time from Kirchoff…

In the 1920’s patents were filed on reflective surfaces being used as building insulation. Recent improvements in technology had then allowed low emissivity aluminum foil to be commercially viable. Over the next 30 years, millions of square feet of reflective insulation were installed in the US alone. Notable examples include projects at MIT, Princeton, and homes such as Frank Sinatra’s house.