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Insulation

If you are looking for insulation or if you are wondering whether you need more insulation the following information may be helpful.

 

Insulation is only half the story of keeping warm though. Insulation by itself does not generate warmth. If you want a warm, healthy home at an affordable cost, you will also need efficient heating.

 



Checklist of an unhealthy home

So how do you know whether your home is a healthy home? There are a few indicators that could be a sign of an unhealthy home:

 

  • High power bills
  • Very low fuel bills: You need to heat your home to a certain standard to keep warm and healthy.
  • Heater not heating properly: You may lose the heat faster than your heater can generate it due to a lack of insulation or your heater may not be sized correctly for the room.
  • Cold floors: You may not have (enough) underfloor insulation.
  • Dampness, condensation, mould in cupboards and on walls: Cold air can hold less water vapour causing condensation on walls and windows encouraging mould growth.
  • Continuous colds and flus: Cold homes are associated with an increased incidence of colds and flues. 

 

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How does insulation work?

Insulation works by trapping still air. It is this still air that keeps the heat in not the actual insulation material. This is why compacted insulation is not effective. Insulation may get compacted by water damage, dampness, compression (eg when store boxes on top of it) or simply because it settles over time.

 

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What are R-values and thermal bridges?

How well insulation works is indicated in the R-value. The higher the R-value the less heat escapes through the insulation. There is a difference between a product R-value and installed R-value, the latter incorporating the way the product is installed.

 

Thermal bridges are material in the house through which heat can easily escape. Examples are (some) aluminium window frames and ceiling joists.

 

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What does the Building Code say about insulation?

Since 1977 the Building Code incorporates national standards for insulation with local insulation requirements for new homes in Christchurch already in place before that time. The first insulation standard was considerably lower than today's standard and was the same for the whole of New Zealand. Since the standards were introduced, they have been upgraded several times and different standard for the different climatological areas of the country now exist.

 

The Building Code for insulation was last updated in October 2008.The current required R-Values in Canterbury are:

  • Ceiling insulation: R3.3
  • Underfloor insulation: R1.3 

 

The Building Code only applies to new homes and there is no requirement for existing homes to retrofit them with insulation. However, to access the ENERGYWISETM subsidies for insulation and heating your home needs to be insulated up to the Building Code standards. The current Building Code is a good guideline when retrofitting an exiting home.

 

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What is the difference between an un-insulated and under-insulated home?

Your home is un-insulated if there is no ceiling, floor or wall insulation whatsoever.

 

 
Above is photo of a house without underfloor insulation. 

 

Houses built during or after the 1970's are commonly built on a concrete slab and don't require (and cannot be fitted with) underfloor insulation. Some kinds of ceilings cannot be insulated because of the design of the building. These include ceilings with a very low-pitched roof, skillion roofs, flat roofs and cathedral ceilings. 

Your house is under-insulated if you have some insulation but it does not meet the current Building Code standards for insulation. An under-insulated house will be cold and expensive to heat. A house can be under-insulated for a number of reasons:

  • Insulation has been installed some time ago

Ceiling insulation will settle and thin over a period of 15-20 years, significantly reducing its effectiveness. It is the trapped still air in the insulation material which does the actual insulation not the material itself so when insulation sags with age the effectiveness becomes less and less.

 

  • Gaps and partial insulations

Gaps in the insulation reduce its effectiveness. Like a bucket of water with a hole in it loses water slowly but surely, insulation with gaps will lose valuable heat.

 

Gaps in insulation occur where it was not installed properly or by tradespeople who have done work in the roof or under the floor and have not returned insulation properly. Some homes have only ever had insulation installed over the lounge. Where roof leaks have occurred, the insulation may have compacted reducing its effectiveness.

 

There should be gaps around hot surfaces such as downlights and flues, for fire safety reasons. Like with all materials, insulation should be kept away from hot surfaces. The gaps, although necessary, reduce the effective of your insulation and Community Energy Action recommends replacing downlights. Find out more...

 

  • Poor quality or illegal installation

Sometimes a house didn't get a sufficient amount of insulation when it was first installed. Community Energy Action has come across many instances where insulation hasn't been installed properly or less insulation than required by the Building Code at the time was installed.

 

Registered providers for ENERGYWISETM subsidies are audited by EECA, giving you the best guarantee insulation is installed properly.

 

  • Insulation was installed before the current Building Code update (October 2008)

If your house was insulated prior to the latest changes to existing Building Code standards for insulation, you are likely not having enough insulation to keep your home warm at an affordable cost.

 

Signs of an under-insulated house

The easiest way to find out if your home is under-insulated is by requested a free and obligation-free assessment and quote from Community Energy Action. The Community Energy Action assessor will come to your home and inspect your insulation.

 

Signs of an under-insulated house include:

  • Uneven coverage, with existing insulation piled up in the corners and thin in other places
  • Exposed rafters and ceiling infrastructure in the roof space
  • The level of insulation is lower than the height of your rafters (joists)
  • Dirty lines forming on your ceiling: This happens when the warm air in your room rises and is able to escape through the ceiling lining because it is not insulated. This air escapes and leaves fine dust particles on your ceiling. The lines are the ceiling joists which provide a bit more insulation than your ceiling lining - the warm air doesn't escape through the joists.

 

Caption: the left side of the ceiling has insulation, but the right side has no insulation, showing accumulated dust where heat has escaped leaving behind the dust.

 

What can you do about an under-insulated house?

Existing insulation in the ceiling does not need to be removed. An extra layer of new insulation can simply be installed on top of the existing layer. Depending on the condition and the thickness of the existing layer, costs may be reduced as only a thinner layer is necessary to comply with the current Building Code.

 

Foil as underfloor insulation will need to be removed. There is no subsidy for underfloor insulation available for homes with foil underfloor insulation in good condition. However, loose and ripped foil underfloor insulation will qualify for the subsidy.

 

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Why is underfloor insulation important?

As heat rises, more heat in an uninsulated home disappears into the ceiling space than through the floor, walls or windows. With 30-35% of the heat being lost through the ceiling and only 12-14% through the floor, many people concentrate on ceilings only.

 

However, insulating underneath a house can have a significant impact on your comfort level. This is because you will feel cold when you come into contact with cold surfaces such as a cold floor surface and you need to maximise the warmth as close to your body as possible (including your feet). Underfloor insulation helps to do this. The ENERGYWISETM subsidies require both ceiling and underfloor insulation to be installed where possible to be eligible for the subsidies.

 

A warm floor is especially important for people with poor circulation or people who spend a lot of time sitting, for children who live closer to the floor and for babies who often lie on the floor for safety reasons and who cannot keep themselves warm as well as adults.

 

Damp proofing

Damp air is harder to heat than cold air. This is because part of the energy from your heater is used to turn water into water vapour. This is why damp proofing wet soils underneath can also benefit the warmth and energy efficiency of a house.

 

Carpet

Carpet alone has very little insulation value Carpet (R0.2-R0.35). This is because carpet usually does not contain any trapped air. If you want to make your floors feel warmer, it will be more effective to install good underfloor insulation than to lay carpet.

 

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Insulation and your safety

Like most materials, insulation should be kept away from hot surfaces such as downlights and flues for fire safety reasons.

 

More about downlights

When installing insulation yourself, be careful with (underfloor) insulation that requires stapling to joists. There have been accidents with DIY installers who have stapled through live wires. Community Energy Action only uses trained installers.

 

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A healthy home for you

If you think you may need more insulation give Community Energy Action a call or make an appointment online.

 

Even if you think you cannot afford insulation, do not hesitate to give us a call. Community Energy Action is committed to keeping the community warm. We try to help as many people as we can regardless of income. Surpluses from our ‘regular' ENERGYWISETM subsidised insulation installations together with financial support from our sponsors and funders enable us to help many people through our charitable programmes.

 

Insulation is only half the story of keeping warm. Having heating is just as important. The ENERGYWISETM programme provides subsidies for heating as well.

 

More about heating your home...

 

More about (dis)advantages of different heating systems...

 

More about costs of different heating systems...

 

More about oher home energy issues...

 

If you have any more questions about insulation in your home, contact our Advice Service.

 

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