Which insulation to use

So, does a higher insulation R-Value mean it's the best option for your home? No, because it boils down to the R-Value versus creating an air seal. You might hit the R-Value you want, but if it doesn't create that air seal then you still have air movement which effects the comfort and energy efficiency of your home. Safety is another important aspect about anything you put inside your home. All three of the insulation options have materials on the market that are Class One Fire Rated.

What that means is, if the materials have this rating, the insulation won't serve as a catalyst if there were a fire in your house. Lastly, I'd like to discuss the cost and maintenance together. As you can see in the chart, fiberglass is the cheapest, cellulose comes in second, and spray foam has the highest initial cost.

The reason maintenance is good to talk about when you talk about cost is because both fiberglass and cellulose must be maintained and eventually replaced over time, while spray foam is one and done, meaning it doesn't need any kind of maintenance and won't need to be replaced. Now that all of that is out of the way, let's look at your house starting at the top and head on down to the bottom.

High energy bills and the inability to maintain a constant temperature are just some of the problems you'll notice when your attic needs new or updated insulation. 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. Cellulose can be either a loose-fill or blown-in material and is primarily made of recycled newsprint or denim.

Cellulose can be a DIY project and is fairly inexpensive when it comes to insulating attics in comparison to other insulation materials. This means cold and hot air can move freely through the attic without any barriers, raising monthly energy bills.

Fiberglass is another traditional insulation material that consists of extremely fine glass fibers. Fiberglass can be installed as a DIY project and is inexpensive. The downside of fiberglass is that the fibers it is made up of can be inhaled and even embed in the skin. But even in these areas there are lots of different wall and roof construction types out there and these all have different requirements when it comes to retrofitting the best insulation for homes.

When retrofitting there will be certain insulation types that you simply can't use, such as solid insulation sheets like polystyrene sheets or foil backed PIR boards etc. The VCL restricts the amount of water vapour entering the insulation. Failure to install a VCL would allow water vapour to permeate the insulation causing interstitial condensation within the insulation, reduce its effectiveness and could potentially cause rot to timbers. The breather membrane will help reduce heat loss from wind wash where air movement over the insulation draws heat out of it , reduce draughts from uncontrolled ventilation and allow any water vapour within the structure or insulation to escape, but more about that later.

But there are, in my opinion, a lot of downsides with this form of insulation. Not lease the Volatile Organic Compounds VOCs that they give off, the fact that they do not readily absorb or release water vapour and the fact that they are chemical based, to name a few.

Traditionally, in a new build cavity wall, there would be a layer of insulation board against the inner leaf of the wall and an air void next to the outer leaf of the wall.

But if there are gaps between the sheets of insulation the thermal efficiency for the wall falls off a cliff. The principle of this was to have a gap next to the outer leaf in order to avoid any moisture that may penetrate the outer leaf from being transported across the insulation to the inner leaf which could cause penetrating damp within the home.

In an existing property with cavity walls you can't obviously remove the outer leaf to install insulation boards and maintain a gap. So the only options are to pump in insulation or insulate externally or internally. But the latter two usually aren't done due to the increased costs involved. Filling an existing cavity with insulation can raise its own issues which are explained in my article on cavity wall insulation problems below.

There are of course a few types of cavity fill insulation that are available but I'm not a fan of many of these for reasons I'll go into within the articles below.

If your existing property has solid walls then your only option is to insulate internally or externally. Whether you want to insulate a floor or an unvented low-slope roof, foam boards and rigid foam panels can get the job done.

Homeowners rely on this type of insulation—which is usually made of polyurethane, polystyrene, or polyisocyanurate—for both exterior and interior wall sheathing. Foam boards work well to insulate everything from foundation walls and basement walls to unfinished floors and ceilings. R-values typically vary between R-4 and R Best for: Attics, unfinished walls, ceilings, and floors—especially in hot climates.

Reflective or radiant barriers work differently than most types of insulation, and so its effectiveness is not measured by R-values. While standard insulation reduces heat flow in a home, reflective insulation instead reflects the heat away from the home to prevent heat gain and radiant heat transfer to cooler surfaces indoors.

The insulation is constructed using a reflective barrier like aluminum foil placed over a substrate material like kraft paper or polyethylene bubbles. Homeowners in warmer climates typically place reflective or radiant barriers in the attic between joists, rafters, and beams, since the attic is where most heat enters a home.

Installation here, too, can be done without a professional. Installation of most types of liquid foam insulation requires special equipment and certification and should only be done by experienced installers. Following installation, an approved thermal barrier equal in fire resistance to half-inch gypsum board must cover all foam materials. Also, some building codes don't recognize sprayed foam insulation as a vapor barrier, so installation might require an additional vapor retarder.

Foam insulation products and installation usually cost more than traditional batt insulation. However, foam insulation has higher R-values and forms an air barrier, which can eliminate some of the other costs and tasks associated with weatherizing a home, such as caulking, applying housewrap and vapor barrier, and taping joints. When building a new home, this type of insulation can also help reduce construction time and the number of specialized contractors, which saves money.

Structural insulated panels SIPs are prefabricated insulated structural elements for use in building walls, ceilings, floors, and roofs. When installed properly, SIPs also result in a more airtight dwelling, which makes a house energy efficient, quieter, and more comfortable. SIPs not only have high R-values but also high strength-to-weight ratios. A SIP typically consists of 4- to 8-inch-thick foam board insulation sandwiched between two sheets of oriented strand board OSB or other structural facing materials.

Manufacturers can usually customize the exterior and interior sheathing materials to meet customer requirements. The facing is glued to the foam core, and the panel is then either pressed or placed in a vacuum to bond the sheathing and core together. SIPs can be produced in various sizes or dimensions. Some manufacturers make panels as large as 8 by 24 feet, which require a crane to erect.

The quality of SIP manufacturing is very important to the long life and performance of the product. The panels must be glued, pressed, and cured properly to ensure that they don't delaminate.

The panels also must have smooth surfaces and square edges to prevent gaps from occurring when they're connected at the job site. Before purchasing SIPs, ask manufacturers about their quality control and testing procedures and read and compare warranties carefully.

SIPs are available with different insulating materials, usually polystyrene or polyisocyanurate foam. SIPs are made in a factory and shipped to job sites. Builders then connect them together to construct a house. For an experienced builder, a SIPs home goes up much more quickly than other homes, which saves time and money without compromising quality. These savings can help offset the usually higher cost of SIPs.

Many SIP manufacturers also offer "panelized housing kits. Fire safety is a concern, but when the interior of the SIP is covered with a fire-rated material, such as gypsum board, it protects the facing and foam long enough to give building occupants a chance to escape.

As in any house, insects and rodents can be a problem. In a few cases, insects and rodents have tunneled throughout the SIPs, and some manufacturers have issued guidelines for preventing these problems, including:.

Boric acid-treated insulation panels are also available. These panels deter insects, but are relatively harmless to humans and pets. Because it can be very airtight, a well-built SIP structure may require controlled fresh-air ventilation for safety, health, and performance, and to meet many building codes. A well-designed, installed, and properly operated mechanical ventilation system can also help prevent indoor moisture problems, which is important for achieving the energy-saving benefits of a SIP structure.

Installing Insulation. When hiring a professional certified installer: Obtain written cost estimates from several contractors for the R-value you need, and don't be surprised if quoted prices for a given R-value installation vary by more than a factor of two.

Ask contractors about their experience in installing the product you are considering. Types of Insulation. Type Material Where Applicable Installation Methods Advantages Blanket: batts and rolls Fiberglass Mineral rock or slag wool Plastic fibers Natural fibers Unfinished walls, including foundation walls Floors and ceilings Fitted between studs, joists, and beams.

Concrete block insulation and insulating concrete blocks Foam board, to be placed on outside of wall usually new construction or inside of wall existing homes : Some manufacturers incorporate foam beads or air into the concrete mix to increase R-values Unfinished walls, including foundation walls New construction or major renovations Walls insulating concrete blocks Require specialized skills Insulating concrete blocks are sometimes stacked without mortar dry-stacked and surface bonded.

Insulating cores increases wall R-value. Exterior applications: must be covered with weatherproof facing. High insulating value for relatively little thickness. Can block thermal short circuits when installed continuously over frames or joists. Insulating concrete forms ICFs Foam boards or foam blocks Unfinished walls, including foundation walls for new construction Installed as part of the building structure.

Cores in the blocks are typically filled with concrete to create the structural component of the wall. Insulation is literally built into the home's walls, creating high thermal resistance. Loose-fill and blown-in Cellulose Fiberglass Mineral rock or slag wool Enclosed existing wall or open new wall cavities Unfinished attic floors Other hard-to-reach places Blown into place using special equipment and, although not recommended, sometimes poured in.

Good for adding insulation to existing finished areas, irregularly shaped areas, and around obstructions. Reflective system Foil-faced kraft paper, plastic film, polyethylene bubbles, or cardboard Unfinished walls, ceilings, and floors Foils, films, or papers fitted between wood-frame studs, joists, rafters, and beams.

Suitable for framing at standard spacing. Bubble-form suitable if framing is irregular or if obstructions are present. Most effective at preventing downward heat flow, effectiveness depends on spacing and number of foils. Rigid fibrous or fiber insulation Fiberglass Mineral rock or slag wool Ducts in unconditioned spaces Other places requiring insulation that can withstand high temperatures HVAC contractors fabricate the insulation into ducts either at their shops or at the job sites.