When it comes to renovating you’re home the expense of insulation is always a factor. Unless homeowners opt for spray foam the two least expensive options are Cellulose Blown-In Insulation and Fiberglass Batts when it comes to residential insulation applications.
Both cellulose and fiberglass allow air to pass through and need to be paired with an air barrier. The effective R-value of fiberglass can be particularly affected by air flow. It’s true that neither insulation is an air barrier. Neither cellulose (even when dense-packed) nor fiberglass meets any technical standard for an air barrier. However, cellulose will slow air flow whereas fiberglass does not.
Cellulose and fiberglass have similar insulating values. Although cellulose does have a slightly higher R-factor, cellulose may settle over time, potentially leaving (in walls mainly) with little or no insulation. Cellulose retains its insulating value no matter the temperature while fiberglass has been shown to lose some of its insulating value as the temperature drops. In extreme temperatures, the loss of insulating value in fibreglass can be as much as 50%.
Fiberglass and cellulose have different issues with fire and flame spread. Fiberglass is spun glass; it won’t burn at any reasonable temperature. Under a direct flame, it will just melt. However, most fiberglass batts are faced with kraft paper which most certainly will burn.
Since cellulose is made from newspaper, it naturally will burn if ignited. Cellulose insulation manufacturers have responded to that concern by treating it with fire-retardant chemicals such as boric acid, ammonium sulfate, or sodium borate in the manufacturing process. These chemicals aren’t harmful to people but are very useful flame retardants. These chemicals have the additional benefit of repelling mice and other rodents.
Which is better?
The simple truth is, both, and sometimes neither when spray foam is required. In some areas, one may have an advantage over the other. This is where working with the professionals at Chase Insulation comes in:
- Attic insulation – don’t batt what can be blown in, either fiberglass or cellulose. In an attic, when you consider cost vs. benefits, it is hard to beat cellulose. There are still situations that call for fiberglass, as in if there is the potential for excessive heat. Fiberglass may also be better if there is a concern for weight, but if weight is a concern, the biggest issue is not the type of insulation being used. Sometimes fiberglass batting can be used to stabilize blown-in insulation, perhaps on steep vaulted ceilings.
- Wall insulation – The air infiltration factor gives the edge again to cellulose. The slight upcharge for dense-pack is compensated by the added energy savings and comfort, making cellulose a value.
At Chase Insulation, we have work with a variety of techniques and materials. We know what will work best for your home. Give us a call and ask us, or have your building contractor give us a call. Let us show you why Chase Insulation is the best choice for all your insulation needs in London and surrounding area.