Installing insulation

To get the best benefits from your insulation, it is essential for it to be installed correctly. Poor installation - such as small gaps, folds or tucked-in areas - can reduce your insulation's performance significantly.

Insulation must also be installed properly for safety reasons - for example, having the right clearances around downlights, chimneys and flues means that heat from these sources does not create a hazard.

EECA recommends getting your insulation installed by a professional to ensure it is done correctly and safely. But if you are considering doing it yourself, here are some things you need to know ((please bear in mind EECA cannot cover every situation that may arise).

Tips for safe, good-quality insulation installation

Follow the Standard for installing insulation and manufacturer's instructions

Standards New Zealand has produced a national Standard on how to install insulation in residential buildings. It provides comprehensive guidance on the best and safest ways to install insulation to ensure that it works as efficiently as possible.

Download Standard NZS 4246:2006 Energy efficiency - Installing insulation in residential buildings.

Also follow the manufacturer's instructions for the specific insulation product you're using.

Fit your insulation properly

Insulation that's not fitted properly will not perform as well as it should. Ensure there are no gaps between insulation pieces, and that there are no tucks or folds. Use off-cuts to fill any small gaps.

Make sure your ceiling space is dry

Before you install any insulation in your ceiling, check that it's dry (i.e. there are no leaks) and free of contaminants and mould. Remove any existing insulation that is damp.

Follow safety practices

There are a range of safety considerations when installing insulation, and it is very important to follow safe work practices when installing insulation products, especially with underfloor or ceiling insulation. Some of the safety considerations are outlined below, but for more comprehensive information it's worth reading through the safety instructions in Appendix B of the insulation installation (above).

Ceiling insulation - safe installation around heat sources

Insulation must have the correct gaps around heat sources - like recessed down lights, chimneys, flues or extractor fans - for fire safety reasons.

Downlights

If you've got recessed downlights you need to consider both safety and effectiveness when it comes to insulation.

Because the downlights can get very hot, there must be a 150 mm safety gap between the insulation and most downlights. Though you can insulate right up to (but not over) some downlights with special fittings, unless you know for sure you should always leave the 150 mm gap.

Downlights reduce the effectiveness of your insulation significantly. The required safety gap for downlights is essential, but it leaves you with holes in your insulation and that means a lot more of your home's heat is lost through the gaps.

These are your options when it comes to safe installation of insulation with downlights:

• The simple option - keep your existing downlight fittings and leave the required safety gap. Leave a gap of 150 mm between your existing downlight fittings and your insulation, and never place insulation over the top of the light or any transformers. This will ensure the rising heat from the downlights is not a fire hazard. Once installed, you should also check your ceiling insulation occasionally to be sure it hasn't slumped towards your downlights.

• The better option - replace standard downlight fittings with fittings that don't require a safety gap - these can have insulation fitted right up to them (but not over the top). There are a few different options on the market so ask your supplier or manufacturer for more information. If you are not sure of the type you need, check with a registered electrician.

• The best option - replace standard downlights with non-downlight fittings. Even with a good downlight, you will still lose heat through the ceiling of your house. The best solution is to remove recessed downlights - or don't put them in in the first place. Taking out downlights make sense especially if you are renovating anyway.

Find out more about choosing efficient lighting.

Chimneys and flues

Chimneys and flues can also get very hot. Leave a gap of 50 mm between the outer face of a brick or concrete chimney and the insulation, or a 150 mm gap for metal chimneys and flues.

Extractor fans

Insulation can get trapped in unducted extractor fans, causing the motor to overheat. Leave a gap of 150 mm between unducted extractor fans and insulation.

Safety gaps for loose-fill insulation

If you have loose-fill insulation in your ceiling space, install rigid open-ended collars around downlight fittings, chimneys, flues and unducted extractor fans to maintain the required safety gaps. Contact a loose-fill insulation supply and installation company about sourcing and installing these collars.

Underfloor insulation - special care with electrics

There are some important electrical safety considerations when checking or installing underfloor insulation.

Avoid stapling insulation near electric cables

When stapling underfloor insulation, be sure to avoid stapling near or through electrical cables - doing so could result in a serious or fatal electric shock.  An accidentally stapled cable, even if it went undetected during installation, can also create a fire risk. Foil insulation is a good electrical conductor, so take special care when installing this type of insulation.

Care when replacing existing underfloor foil insulation

Existing foil insulation that's fixed with staples can unknowingly be live (even if it was installed a long time ago) if an electrical cable was accidentally stapled during installation. Turning off the mains won't necessarily solve the problem. If you're replacing underfloor foil, the safest thing to do is get a registered electrician to check whether the foil is live before you touch it.

For more detailed information electrical safety when installing underfloor insulation, consult Appendix B of the New Zealand Standard NZS4246:2006 and the Energy Safety website.

Polystyrene insulation

If in direct contact with electricity cables, polystyrene insulation can cause the coating on the cables to harden and crack, creating a fire or electrical safety risk. To avoid this, polystyrene insulation must not get into direct contact with any PVC coated cables. They should be separated using self-adhesive paper, polyethylene or polypropylene tape between the PVC and polystyrene, or by installing the cables through conduits.

Getting professional advice

Getting professional advice can help you get the right insulation solution for you, installed properly and safely.

• Consult a builder or visit a hardware shop that sells insulation products
• Use our supplier and partners directory
• Get a professional report of your home's insulation requirements with a Home Energy Rating.

 More information

• Another useful guide to installing insulation is the Department of Building and Housing's Guide to Smarter Insulation.
• The Energy Safety website has general information on working safely around electrical wiring.
• The New Zealand Building Code specifies minimum mandatory insulation standards for new houses. Check with the Department of Building and Housing website for changes to the Building Code.