Save Money with Insulation – Which is Best?

Save Money by Insulating Your Home

But Which Type is Best?

Having said that fibreglass is the most common insulating material used in the US as it is one of the cheapest, it’s time to look at alternatives. But first, there are a couple of terms you need to know.

R value All insulation materials are rated for their performance in restricting heat transfer.  The R value is a guide to its performance as an insulator—the higher the R value, the greater the insulating effect.

Boron Boron is commonly used in insulation as a fire retardant.   Many of the fire retardants currently used are toxic and singularly non-eco-friendly.   Boron is toxic but only in very high doses, and with roof insulation, we’re not exposed to it on a regular basis.  It is mined in arid areas of the world including California – often in open pit mines.  Boron is used with most insulation including fibreglass.  Boron provides anti-pest capabilities; this is why it is so widely used, as it serves two purposes – anti-fire and anti-insect.

Now we can look at alternatives to fibreglass for home insulation.  As you know, insulation is important because it can save you money on utility bills, and reduce your energy use.

1. Denim Insulation

Denim insulation is made from – yes, you guessed it, denim!   Some is made of fabric scraps from the manufacturing process, some is recycled denim. (It takes about 500 pairs of jeans to insulate the average US house).  If you’re from San Francisco, you could decide to be patriotic  – denim jeans were pioneered there by Levi Strauss during the mid-1800’s gold rush.

Originally, this product was made from virgin cotton – and cotton isn’t particularly eco-friendly (mono-culture, heavy pesticide use, lots of water required ).  Now it’s made from jeans remnants from factories – cleaned, cut into strips and treated.  Denim that used to go to landfills, now goes into homes as insulation.  And sometimes, old jeans are recycled to make the insulation.  According to TheFreeLibrary.com, Americans purchase 450 million pairs of jeans annually which means there’s a lot of old denim around!

National Geographic did a Guinness World Record collection of old jeans, and stores such Gap periodically have collections where you can donate your old jeans – donations often go towards providing insulation for homes built after a natural disaster.

Details: Its R-value is around 3.4 to 3.7 per inch – very similar to fibreglass.  Installation is essentially the same as with fibreglass, and no special equipment is required, nor is protective clothing needed.  It comes in rolls or batts, and also in loose form so it can be used as blown insulation.   Often, the insulation is covered with a plastic vapour barrier.

Pros:   Denim insulation requires less energy to produce than many other forms of insulation and is recyclable.  According to the Science Insider, denim insulation is light, non-dense and  contains no skin or throat irritants, as well as providing superior sound dampening.  Denim insulation is resistant to mould, fungus and pests.

Cons: It’s got a 15 – 20% price premium over fibreglass.  It contains 10 percent boron.  Cotton is not necessarily the most environmentally-friendly of crops, plus jeans are bleached and dyed as part of the manufacturing process, and often packaged in plastic.

Well-known Brands: Ultra-Touch denim fibre.  (Often seen advertised with kids handling it – in direct contrast to fibreglass)

Where can I Buy it? Distributed across the United States in hardware stores, and The Green Depot sells it in its stores and online.  Worldwide, see Carhartt.com or any good hardware store.

2. Wool Insulation

People have known for thousands of years that sheep’s wool has excellent insulation qualities. Garments have been made out of wool for centuries.   Wool insulation provides an option that is natural, sustainable and renewable.

On its own, wool has a lower R-value than manufactured materials such as fibreglass.  Thus it is sometimes mixed with polyester in order to improve its R-value.

Details: Wool’s R-value is variable, depending upon what it’s mixed with, but in general it’s around 3.5.  Installation is essentially the same as with fibreglass, and no special equipment is required, nor is protective clothing needed.    It comes in insulating batts and rolls as well as ropes (ropes are primarily used between the logs in log homes).

Pros:  It can absorb up to 30-40 percent of its own weight in moisture without being wet to the touch.   Wool has a long lifespan, can be used over and over again, and is biodegradeable.   The insulation manufacturing process is eco-friendly, however ideally you would want to choose wool which was ‘grown’ and produced as close as possible to its destination to reduce its impact.  Wool is naturally flame resistant (it is self-extinguishing and doesn’t melt).  It is naturally resistant to mould.   Many people believe that wool insulation helps prevent “sick building syndrome” because it traps substances such as formaldehyde, nitrogen dioxide and sulphur dioxide emitted by other common building materials and combustion processes; however, this quite difficult to prove.  Wool is a preferred insulation option for people with asthma and allergies.  Wool has good sound insulating properties.

Cons:  Cost – wool insulation is expensive compared to other insulation types.  If the wool is mixed with polyester it may be less flame resistant than other types of insulation, however, this is offset by the addition of boron, which is used anyway as wool is subject to insect damage.  The sheep who ‘grew’ the wool may have been treated with insecticides, and chemicals are sometimes used on the fleece after shearing.

Brands:  ThermaFleece is a patented sheep’s wool insulation material for buildings, produced by Second Nature in northern England. Kontrol Premier Wool Insulation is also based in the UK.

Where Can I Buy It? Wool insulation is used more in Europe, Australia, New Zealand and Canada than it is the United States; manufacturers are, however, trying to expand their distribution to the US.

In my next blog post, I’ll look at some more insulation alternatives.

View other types of insulation: Cellulose, Polystyrene, Straw, Nanogel. Could you be at risk from Asbestos in your home?