PLEASE NOTE: THIS SECTION IS UNDER CONSTRUCTION.

CEILING INSULATION

Ceiling insulation is usually the easiest way to start insulating your house. It is estimated that around 30% of existing houses in New Zealand don't have ceiling insulation. Note: if there is already some insulation in your roof space, adding more insulation will not reduce your heat loss proportionatly, as once the original insulation is added, the main areas of further heat loss will be the walls, windows and floor. Read more from a housing research study by the Energy Management programme at the University of Otago.

WALL INSULATION
Walls usually account for the largest areas in the building fabric. Insulating the walls will have a major impact in reducing energy requirements to keep your house warm in winter. Click here to estimate your losses through walls. In this section, explore your options, learn about characteristics, and link to suppliers.

UNDERFLOOR INSULATION
Suspended wooden floors are very typical in New Zealand houses. If there is enough access in the basement, floors should be insulated. There are basically two options: reflective insulation and bulk insulation. Adding insulation will not only reduce heat losses but usually will also reduce draughts.

Wool ›

Wool comes in batts, blankets or loose fill. It is made of spun sheep's wool.

Fiberglass ›

Fiberglass is made of melted glass spun and waste fiberglass. It is the most common insulation material used in NZ. Usually used as batts to insulate walls. Also available as blankets/batts for insulating ceilings.

Description	Specification	Rvalue	Cost (NZ$/m2)
	blanket	1.2	6.5
	blanket	1.3	5.7
	batts/banklets	1.8	8.4
	batts	2.2	10.2
	blanket	2.3	13.1
	batts	2.6	12.5
	batts	2.7	10.1
	batts	3.2	12.7
	batts	3.6	14.7
	batts	4.0	17.2
	batts	4.6	25.7
	blanket w foil (underfloor)	1.3	14.9
		1.5	10.6
		2	13.5

Cellulose fibre ›

Commonly known as macerated paper, very common in NZ during the '70s & '80s. This is the cheapest option to insulate the attic space. But it can settle and if wet it looses performance.

A type of loose-fill insulation made from recycled wood fiber, primarily waste newspaper and cardboard. The wood fiber, which is composed of cellulose, is shredded and pulverized into small, fibrous particles that pack tightly into closed building cavities, inhibiting airflow. This provides a thermal resistance of R-3.6 to R-3.8 per inch. Manufacturers add chemicals to the cellulose to make it insect and fire resistant. The major disadvantage of cellulose is that it absorbs more water than fiberglass or mineral wool. This can become a problem if water leaks from the outdoors since cellulose wicks water into itself and stores it. Too much water can also wash away the fire retardant.

Description	Specification	Rvalue	Cost (NZ$/m2)
	Loose fill	2.25	6.7
		2.6	7.0
		3.2	9.0
	Average	1	2.7

Polyester Fiber Blankets ›

Polyester blankets are made from polyester threads spun and are very commonly used to insulate attic spaces as they are easy to install covering all the ceiling space and providing a very good, fast and easy way to reduce losses through the ceiling. Available in blankets and batts.

Description	Specification	Rvalue	Cost (NZ$/m2)
	Roll/blanket	1.3	6.0
		1.8	8.12
		2.2	9.0
		2.4	11.8
		2.5	9.0
		2.6	12.8
		3.2	14.9

Polyurethane/Polyscocyanurate Board and Foam ›

This material made of non renewable resources provides very low conductivity properties together with high levels of durability. It comes as as boare and foam. It has high levels of embodied energy and environmental impact.

*AIRFOAM™ is nontoxic, does not create a fire hazard, and is hydrophobic, (repels water)(from airfoam) –

* Rigid Polyurethane Spray Foam (PSF) retains virtually all its original insulating power when its surface is protected from air(from plasticraft)

Expanded Polystyrene Sheets ›

Commonly known as EPS, comes in semi rigid boards made of Polystyrene beads. It can be found as pre clad panels, easy to install.

A type of insulation that is molded or expanded to produce coarse, closed cells containing air. The rigid cellular structure provides thermal and acoustical insulation, strength with low weight, and coverage with few heat loss paths. Expanded polystyrene (EPS) is often used to insulate the interior of masonry basement walls. Unlike the other common form of polystyrene, extruded polystyrene, EPS is not made using chlorofluorocarbons (CFCs), which are harmful to the environment. In the case of EPS, the expansion agent is pentane. Like all plastics, EPS foam is recyclable. Since EPS foam does not biodegrade, it is benign to the environment and provides a stable fill material similar to earth, rock or concrete. This allows for safe landfill reclamation for parks, schools, ball fields, golf courses, and other public or greenbelt utilization. Our goal, however, should be to limit materials from getting to the landfill through source reduction, aggressive recycling, and other environmentally sound waste management programs. EPS foam products whether used for insulation or packaging are lightweight, versatile, sanitary, energy efficient, and most of all cost effective. The manufacture of EPS foam uses less energy than that used in the manufacture of paper based alternatives. According to The Midwest Research Institute study on special packaging applications, the total energy requirements to make plastic containers (including both processing and materials energy) were lower than or equal to the energy consumed to make competing materials.

Description	Specification	Rvalue	Cost (NZ$/m2)
	sheets	1.2	12.0
		1.4	9.5
		1.5	14.0
		1.9	17.5

Extruded Polystyrene Foam ›

This insulation is known as styrofoam (XPS). It is easy to install as it comes in Rigid boards with very low thermal conductivity providing high levels of insulation. *also known as: aka. Blue foam, Green foam, Styrofoam, Styrodur, Roofmate. Although heavier and more expensive than EPS, extruded foams provide a cut surface that is very smooth and can be vacuum bagged.

A type of insulation material with fine, closed cells, containing a mixture of air and refrigerant gas. Popularly known by its Dow trademark Styrofoam, it has a high R-value, good moisture resistance, and high structural strength compared to other rigid insulation materials. Both extruded polystyrene and the other common type of polystyrene foam, expanded polystyrene (EPS), are used extensively as thermal insulation in industrial, commercial, and residential construction. Most food service applications including meat trays, egg cartons, hamburger clam shells, foam plates, and trays are extruded polystyrene, although disposable coffee cups are made of expanded polystyrene. Environmentally-damaging chlorofluorocarbons (CFCs) are used in the manufacture of extruded polystyrene, however the expansion agent for EPS material is pentane.

Rockwool ›

Made of melted volcanic rock spun, this material comes in batts, blankets or loose fill (as granules), also wired matt and pipe sections at varying densities.

Aluminium Foil ›

Aluminium foil is commonly used to insulate suspended timber framed floors in NZ. It requires an air gap between the floor and the foil to reflect the heat escaping from inside. It can loose performance if dust settles in the surface reflecting heat. Available in roles and also with enclosed air cavities between layers of foil. Requires a sealed air space of at least 25 mm. between foil and solid surface to provide full insulation.

Reflective insulation systems are fabricated from aluminum foils with a variety of backings, such as kraft paper, plastic film, polyethylene bubbles, or cardboard. The resistance to heat flow depends on the heat flow direction. Reflective insulation is most effective at reducing downward heat flow.

Composite insulation (bulk + reflective) ›

WINDOW INSULATION

Windows have very poor thermal performance. Even a double glazed window will perform worst than an uninsulated wall. Try not to oversize window areas and provide them with thick curtains with pelmets for night time or explore your other options: window film, acrylic sheets are also available to retrofit and reduce losses in cold months. Double glazed aluminium window frames should be thermally broken to reduce very high losses which occur through these type of frames.

Double Glazing ›

Cost reference: indicative only (Rer: Rawlinsons book) * Prices includes material supply, delivery(+other margins), fixings (nails-screws-glue), labour to install, others. For more accurate prices contact your local supplier/manufacturers.

A type of window having two layers (panes or glazing) of glass separated by an air space. Each layer of glass and surrounding air space reradiates and traps some of the heat that passes through thereby increasing the window's resistance to heat loss (see R-value). In factory-made double glazing units, the air between the glass sheets is thoroughly dried and the space is sealed airtight, eliminating possible condensation and providing superior insulating properties.

Other ways of improving windows efficiency ›