Radiant barriers are installed in homes -- usually in attics -- primarily to reduce summer heat gain and reduce cooling costs. The barriers consist of a highly reflective material that reflects radiant heat rather than absorbing it. They don't, however, reduce heat conduction like thermal insulation materials.
Simply put, the biggest possible problem with any kind of radiant barrier is dust. To understand why dust creates issues for all kinds of radiant barriers, it's important to understand how they work: Radiation transfers heat directly outward from an energy source.
Because radiant barriers prevent the movement and retention of heat within a home, they are huge energy savers. If installed and working properly, a radiant barrier greatly reduces a homeowner's use of the home's cooling system. This ultimately cuts down cooling costs.
This type of insulation is most effective in warmer climates, but can also be used for comfort and energy savings in cold weather. The radiant-barrier insulation is attached to roof rafters, floor joists, and wall studs to reduce radiant heat flow, mostly from the outside in, but also from the inside out.
As long as homeowners or certified attic specialists install them appropriately, radiant barriers last anywhere from 80 to 100 years.
Then, the heat transfer method switches from radiant heat to conductive heat to move through the attic insulation and into your home. This is why you need both types of insulation. Traditional attic insulation and radiant barrier work together and each do their part.
With Wi-Fi signals, unless the radiant barrier is between you and the router, there is unlikely to be any impact.
Ideally, after you install a radiant barrier the air temperature inside the attic should probably be within 10 to 15 degrees of ambient temperature.
When the paint is installed correctly, it will reflect about 75% of the radiant heat and can be a very good product. Getting good results with radiant barrier paint assumes a couple of things: The rafters are being sprayed completely (this usually costs more when you get an estimate).
This is because an air gap provides an additional layer of insulation that helps to prevent heat from passing through the barrier and into the living space. If you are installing a radiant barrier, it's recommended to leave an air gap of at least 25mm (1 inch) between the barrier and the surface it's installed on.
Installing a radiant barrier costs $1,700 on average, but often ranges between $710 and $2,840 depending on whether your pro uses a foil or spray on type.
In simpler terms, a radiant barrier decreases the sun's heat that penetrates your home and is not very good at transferring heat but excellent at deflecting it. On the other hand, you cannot do away with blown-in insulation. Insulation seals your attic from pollens, allergens, mold spores, and other threats.
Another alternative to radiant barrier foil are the various types of foam insulation. What is foam insulation? Foam insulation most commonly comes in two forms: rigid and spray.
Aluminum covered radiant barrier products (like Original AtticFoil™) are pretty difficult to start burning, but once they flash (catch fire) the polyethylene scrim inside will continue to burn at a relatively slow rate.
Installation Summary:
Use a stick (1/4" furring strip with nail in the end works well) to help push the barrier into the tight spaces of your attic. Continue covering the attic floor by overlapping each section of radiant barrier already rolled out by 2" inches.
Moisture problems, air leaks, inadequate attic ventilation, dust accumulation, compatibility issues with existing insulation, and condensation are some of the common challenges associated with radiant barriers.
Some studies show that radiant barriers can reduce cooling costs 5% to 10% when used in a warm, sunny climate. The reduced heat gain may even allow for a smaller air conditioning system. In cool climates, however, it's usually more cost-effective to install more thermal insulation than to add a radiant barrier.
Spray-in foam is more expensive on its face. But before you brush it off, consider the long-term cost savings from better energy efficiency. With that in mind, spray-in foam wins out over radiant barrier insulation. If you want immediate cost savings or you're on a budget, get radiant barrier sheathing.
Note excessive heat – if it's 90 degrees outside, the attic temperature shouldn't be more than 110 degrees. More often than not, attic temperatures will be in excess of 125 degrees on a 90 degree day. This will overwork your air conditioning equipment, run up your utility bill and shorten the life of your roof.
In cold climates, the preferred installation method is laying radiant barrier foil over the insulation on the attic floor to keep heat in during the cold months and to help block heat in hotter months. This type of installation is easier than the conventional staple-up method, but it also has some precautions.
Generally speaking, vapor barriers are considered an essential moisture-blocking tool for climates that experience significant levels of humidity. For that reason, building codes in more humid locations will often require them, in which case you might not have much say about whether to install one or not.
Radiant barriers are designed to be durable. A professionally installed radiant barrier typically lasts for several decades. Its lifespan often matches that of the roof it sits beneath. Yet, various factors can influence this longevity.
It has specifically been suggested that the use of radiant barriers in roof structures can 'attract lightning' and further, a structure with a radiant barrier system will be more likely to be struck by lightning than an identical structure without it.
What is the R-value of your radiant barrier? Radiant barrier on its own has NO R-value; R-value is attributed to materials slowing conductive heat. AtticFoil™ works to block radiant heat (97%) coming in to the attic by stapling it to the rafters, but it has no R-value.