Europeans have generally always kept their homes warm and dry, cognisant of the need to keep inhabitants healthy, yet here in New Zealand, particularly prior to World War II, very few homes had any kind of insulation installed and coal fires were a common but inefficient, pollution-producing form of heat; releasing green-house gasses and fine particles into the atmosphere. This is something we’re all very aware of now, but it wasn’t widely considered back then.
Of course, being stoic Kiwis, our parents and grandparents simply donned another layer of clothing and got on with things — while around 40 per cent of the heat in their homes escaped through the ceiling. As a result of this, health problems caused by the resultant mould and mildew, which is fuelled by human breath, steam from cooking and bathing in colder temperatures, meets cold air and condenses, causing respiratory illnesses.
Eventually, around the 1940s, it became better-known that many of these issues could be alleviated once insulation was installed but, the fact that suitable materials had to be imported — at considerable cost — from overseas, meant that their use was largely confined to the properties of well-off people.
By the early 1970s, the process of insulating new dwellings in order to keep heat from escaping during winter was not only more widely understood and accepted but was actively promoted by local and central government. Midway through that decade, an interest-free loan programme was implemented to enable home-owners to insulate, thereby making their homes much healthier.
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Television advertisements at the time featured a creature called “sneaky heat”, who had a habit of slipping out of the house when nobody was watching, and since there was only one channel at the time, everybody quickly became aware of the pink fibreglass insulation that was being promoted.
Eventually, in 1977, insulation became mandatory in new houses and over the past 40 years, minimum levels have gradually been raised. These days, under the Building Act 2004, all new-builds must have a certain level of thermal resistance (R-value), which is determined by their location. As you might expect, the amount of insulation required in Dunedin or Invercargill is greater than for properties in Auckland or Northland.
In 2015, then-Minister of Building and Construction, Nick Smith, announced that by July 1, 2019, all rental properties must be fitted with under-floor and ceiling insulation and that landlords will be ordered to specify what level they have provided.
The minimum will be the 1978 standard for already-insulated dwellings, while properties that haven’t had any insulation up until now must meet current standards for new builds.
With the valuable role of insulation now widely acknowledged and understood, many New Zealand home owners are retrofitting their older properties with ceiling and underfloor insulation. Unfortunately, it’s very tricky to retro-fit insulation into wall cavities although it is possible if you’re prepared to replace wall linings.
Luckily, there are other ways of improving the insulation quality in an existing property, such as double-glazing, which will reduce heat loss through windows. It can be retro-fitted reasonably easily — at a price — but it will change the appearance of your windows and they will become heavier, which means hinges might need to be replaced.
Thermal films, which are stuck on to the glass have some effect but they’re nowhere near as effective as double-glazing. Heavy thermal-backed curtains are another important form of insulation and can play a significant part in keeping thermal radiation from the day inside and minimising heat loss as long as you remember to pull them closed at dusk in winter.
While the value of insulation cannot be overstated, it can be expensive, and EECA Energywise offers support to members of the community who live in homes built before 2008, and have special needs in terms of age or physical health.
Insulation options
If you’re considering putting insulation into an existing house or a new one, there are many different types available.
Fibreglass:
Made from recycled glass, this works well at containing heat and is a reasonably priced option. It’s clean, sustainable and easy to install. You are advised to avoid inhaling any dust while putting it in place and excessive contact with skin is also inadvisable.
Wool:
This Kiwi product operates in two ways: retaining heat in winter, and keeping things cool in summer. It usually needs added preservatives, such as polyester or resin to achieve optimum effectiveness and its “R” value is lower than that of fibreglass.
Polystyrene:
A man-made material formulated using a liquid petrochemical, polystyrene provides good insulation but because it comes in blocks, it’s essential to cut it accurately in order to fit into ceiling, wall or underfloor spaces. If the cut isn’t perfect, energy escape can occur and it must have fire retardant added because it’s flammable.
Rock Wool:
Its name is intriguing and the method used to produce it is fascinating. Natural rocks and minerals are heated to 1600C in a furnace, then spun in a way that imitates the making of candyfloss. The finished product has excellent thermal and acoustic properties.
Reflective foil:
This is most-suited for under-floor insulation that’s being installed retrospectively. With the risk of electrocution it can be dangerous and must be cut perfectly to size. EECA isn’t a fan of this material because of this.
Polyester:
Made as a by-product of the petrochemical industry, it’s made from plastic bags and bottles in a process wherein it’s bound by means of very high heat. Effective at keeping a dwelling warm and dry, it resists moisture, fire, mould and vermin.
Paper-based insulation:
Cellulosic insulation is made from paper and the resultant mix needs to be blown into place. When it’s being manufactured, fire and pest retardants are included in the mix and in terms of sustainability it gets good marks, as long as New Zealand wood and paper materials are used.
- New Zealand Herald
