Before spending money on insulation, sort out draughts. Seal around doors and windows, block off unused chimneys and remove downlights that are not rated 'close abutted' (downlights with air gaps around them).

But remember you will still need to air or ventilate the house to prevent damp accumulating and to maintain air quality. Even on the coldest nights you will need some fresh air in the house. There is a fine line between draughts and ventilation.

You may be eligible for a grant or interest subsidy (see below) to fund insulation improvements.

Are you going to install insulation yourself?

Here are some things to consider before you buy and install insulation:

• The first step is to check your current insulation: is there any? What state is it in?
• Check what the R values are for your climate zone (see Building Code requirements).
• Make sure all leaks (roof and pipes) are repaired so the new insulation doesn't get wet. Damp insulation is less effective.
• Have an electrician check you can safely cover electrical wiring that can't be placed outside the insulation.
• If you have recessed downlights that are not closed abutted (CA) rated, replace them to eliminate the air gaps. CA rated recessed light fittings are now available that allow insulation to touch them. If you're not replacing the downlights, check to see how big a gap in the insulation is needed around each light fitting to prevent over-heating.
• Choose a product that is independently accredited and complies with the standard AS/NZS 4859.1: 2002. Compliance with this standard is mandatory under the Building Code. A compliance statement must be on the label of the insulation.
• Wear a dustmask, goggles, gloves, long sleeved shirt and closed footwear when installing fibre insulation products.

The quality of installation is of paramount importance. Even small gaps will undermine the performance of the insulation. A comprehensive easy-to-use guide on installing insulation is available as a free download from www.energywise.govt.nz

Need some expert advice?

If you are unsure about how best to insulate your house, consider paying for a home energy rating. For background information see www.energywise.govt.nz.

You will receive an independent assessment of the energy performance of your home including how well the building's design, construction and orientation enables it to maintain a comfortable indoor temperature, and how efficient the indoor heating and water heating are. You will get recommendations for the most cost-effective ways to improve the house's energy efficiency and reduce your energy costs.

For a list of qualified home energy rating assessors go to the Association of Building Sustainability Assessors website.

Grants and interest subsidies

The Energy Efficiency Conservation Authority (EECA) offers grants and interest subsidies through its Energywise residential programmes. These are available to fund improvements to insulation and other energy efficiency measures for homes. Only ceilings and underfloor insulation projects are eligible.

There are 3 different funding options available:

For households on low incomes, to be eligible for funding:

• Your property must have been built before 2000.
• You must be eligible for a community services card. The home grants programme targets households on low incomes.
• In some areas people with health problems such as asthma and other respiratory illnesses are given priority because of the significant health benefits insulation provides.

For households or landlords earning less than $100,000 a year, to be eligible for funding:

• Your property must have been built before 2000.
• You must earn, before tax, less than $100,000 a year (one or two earners) or less than $140,000 a year (three or more earners).

If you are a landlord with low income tenants, there is also funding available through the nationwide rental project. To be eligible for funding:

• The property must have been built before 2000.
• The tenant named on the tenancy agreement must be eligible for a community services card.

Check www.energywise.govt.nz for terms and conditions or call 0800 749 782.