Technical
Information

Warm Home - Cold Day

Heat naturally flows from areas of higher temperature to lower temperature. That’s the reason your hot coffee gets colder as it loses heat. Your home behaves in exactly the same way. 

The amount of heat lost from a home is dependent upon the difference between the indoor and outdoor temperatures. The warmer your home or the colder the outside temperature, the more heat energy is lost. No surprises there, as we all know it takes more heat to keep our homes at a higher internal temperature particularly in the colder winter months. 

Heat travels by a combination of convection, conduction and radiation and it is practically impossible to actually stop heat moving. However bulk insulation products are very effective at drastically slowing heat movement. An insulated coffee cup achieves the same thing keeping your coffee hotter for longer.

By slowing the amount of heat loss, your home is able to retain more heat energy for longer - and all other things being equal - the internal temperature of your home will increase. In reality home owners usually change their lifestyle after their home is insulated by turning down the heater, lighting the fire later or not at all or keeping more doors open so more of their home is at a comfortable temperature. 

A fully insulated home enjoys generally warmer temperatures without that morning chilly feeling and the home warms up considerably faster when a heat source is used or sunshine enters through glazing. The home will maintain its temperature for longer after the heat source is turned off and because the internal air temperature is warmer the relative humidity is lower so the home feels drier. Insulated walls have less condensation so mould is less likely to grow.

Where do I to begin insulating?

Big is bad when it comes to heat loss :

The amount of heat that is lost from a structure is dependent upon the area of the surface. So, a larger surface area, like your ceiling, looses more heat than a smaller surface area, like your walls, if all things are equal.

A "typical" older 100 square meter home has 100 square meters of ceiling and 100 square meters of floor. It also has approximately 81 square meters of exterior wall and about 27 square meters of windows/doors. 

Warm surfaces loose more heat than cooler ones

The ability of ceilings, walls and floors to resist heat flow is fairly similar and quite low but because warm air rises and cool air sinks ceilings tend to be a lot warmer than floors. Walls and windows have a temperature somewhere in between - warmer towards the ceiling and cooler towards the floor.

Insulate ceilings first:

Because ceilings are the largest and warmest surface area in your home they loose the greatest amount of heat.  When you also consider that it's relatively easy and inexpensive to insulate your ceiling, insulating your ceiling to the current standard has to be the priority.

There are many open ceiling options including DIY if your roof space has good access.  Insulmax^® is a good option for tight roof spaces where access is difficult or skillion roofs with no access. Insulmax^® ceiling insulation performs well because it fills all available gaps, so there are no voids or joins. Placing conventional segment insulation between joists and other timbers means that approximately 15% of the ceiling is not insulated because heat is able to flow and escape through the uncovered timbers. Covering open ceiling timbers is the preferred option by placing conventional segment insulation in a "cross hatch" pattern or alternatively Insulmax^® ceiling insulation naturally covers all roof timbers.  

Insulate floors second if you can:

Your floor area has the same area as your ceiling but, because cold air sinks, floors are generally colder than ceilings and walls which means they loose considerably less heat than ceilings or walls. Floor coverings such as carpet and underlay also reduce heat loss through floors. Floors feel cold because that is where the cold air collects and no amount of underfloor insulation will change that.  However because floors are relatively easy and inexpensive to insulate they should be insulated. However the improvement will not be as drastic as insulating ceilings and walls.

Insulate your walls after insulating your ceiling:

Walls represent a relatively high surface area, at a mid point temperature and lose less heat than ceilings and more than floors. Walls should be insulated as soon as possible after ceilings. If your interior wall linings are in very poor condition and require replacement, adding conventional segment insulation during renovation is an ideal opportunity. An application to your local council for a building consent or exemption will be required for all forms of exterior wall insulation.

Insulmax^® retrofit wall insulation is certified to be installed in all types of homes through all common claddings or interior linings and is a good option to avoid time consuming and expensive renovations. The resulting insulation rating is at least equal to conventional segment products and in most cases achieve a higher rating.

The value of wall insulation

Every building material or structure has an R value, which is a measure of how well the material or structure allows heat to flow through it. A woolly jumper would would have a high R value and an aluminium saucepan would have a very low R value. 

Roughly speaking, if the R value can be doubled, the amount of heat lost goes down by about half. "So what does this have to do with making my home warmer and insulating my walls?"

Insulating your walls with Insulmax^® dramatically increases their insulation rating and so dramatically decreases the amount of heat lost, in the same way that wearing a woolly jumper keeps you warmer. The jumper or Insulmax^® insulation is simply reducing the amount of heat being lost.

We pay for heating and most of that heat escapes from uninisulated parts of our home. If your home has ceiling and underfloor insulation, the uninsulated walls are loosing the largest amount of heat.

By insulating your weatherboard walls with Insulmax^®, heat loss though the wall structure will be reduced by around 86%* - so for every $100 of heating that escapes through the walls of your home Insulmax^® would reduce that amount to just $14 !  

The heat loss though the walls of brick homes would be reduced by about 89%* and so reduce the $100 heating lost through the walls to a mere $11!

You'll experience the value of wall insulation for years to come, through reduced heating bills and a warmer, drier, more comfortable home.

Additional benefits include:

• Reduced internal relative humidity
• Substantially reduced condensation on walls, preventing mold growth (particularly in bedrooms, behind drawers etc.)
• Decreased health issues
• A quieter home, as Insulmax^® reduces sound transfer from external noise.

*Technical 

Insulation ratings are derived from Design Navigator, a leading New Zealand industry resource in the theoretical calculation of building variables.

Framing assumed to be 100mm x 50mm framing and 450mm centres with nogs at 800mm centres. 

Weatherboard  walls -  exterior rusticated weather board. Interior 10mm plaster baord insulated with the addition of R2.8 Insulmax^®

Whole wall structure uninsulated R value      R0.32

Whole wall structure when insulated             R2.3 

Heat flow/loss reduction approximately 86%*

Brick walls (masonry veneer) - exterior 90mm clay brick. Interior 10mm plasterboard insulated with the addition of R4.2 Insulmax^®

Whole wall structure uninsulated R value      R0.30

Whole wall structure when insulated             R2.8

Heat flow/loss reduction approximately 89%*

Walls or windows?

All homes should enjoy the benefits of insulated walls AND double glazing but installing wall insulation should be considered first. Here’s why. 

For every $100 spent on heating that escapes through windows and walls:

Uninsulated walls lose $64, which reduces to a mere $9 when insulated with Insulmax^®...  

Compared with...               

Timber framed single glazed windows lose $36, which reduces to $27 when replaced with aluminium framed double glazed units. 

Let us explain… 

Heat is able to move across all types of material and structures at different speeds and the larger the surface area the more heat is lost.

A typical 100 square metre home has about 81 square metres of exterior wall and about 27 square metres of windows and doors - so about three times more external wall area than windows.

While an area of glass loses ≅50% more heat than the same area of uninsulated wall (all things being equal), when you consider that your home has about 3x more wall area than window area, the total heat loss from walls is significantly more than from windows. 

We pay for heating and most of that heat escapes from uninsulated parts of our home. If your home has ceiling and underfloor insulation, the uninsulated walls and glazing are losing the largest amount of heat.

Consider a typical weatherboard home. For every $100 spent on heating that escapes through walls and windows, approximately $36 is lost through timber framed single glazed windows, compared to approximately $64 lost through uninsulated walls.

When you Insulmax^® your walls, you're adding at least 100mm depth of high performing thermal insulation to the wall structure. This dramatically reduces heat loss - by approximately 86% - making a substantial  improvement to a large surface area of your home.

However in the real world, insulating walls with Insulmax^® dramatically reduces heat loss by approximately 86% making a large improvement to a relatively large surface area of your home. This is because at least 100mm of high performing thermal insulation can be added to the wall structure.

Compare this with the typical option of replacing single glazed timber framed windows with double glazed aluminium framed windows. This adds about 6-10mm of air and 4mm of glass. This change results in about a 25% reduction of heat loss

The benefit of insulating walls with Insulmax^® is far greater than replacing windows with double glazed units. Low E, argon, uPVC or timber frames all increase the efficiency of double glazing but give relatively marginal improvement because the basic process of double glazing can only add about 4mm of glass and 6-10 mm of air. 

The cost of insulating exterior walls with Insulmax^® is far less than the cost of double glazing your home and has a greater benefit. The cost benefit of double glazing is recognised in NZ Building Standards as wall insulation became mandatory in new builds from 1978 compared to double glazing which became mandatory in new builds 20 years later in 2008.

Technical Data

Every building material or structure has an R value which is a measure of how well the material or structure allows heat to flow through it. A woolly jumper would have a high R value and an aluminium saucepan would have a very low R value. Roughly speaking if the R value can be doubled the amount of heat flowing and being lost will be reduced by half.

Insulation ratings are derived from Design Navigator, a leading New Zealand industry resource in the calculation of building variables. Insulation ratings of windows are sourced from The New Zealand Window Energy Efficiency Rating System

Weatherboard walls

Framing assumed to be 100mm x 50mm framing and 450mm centres with nogs at 800mm centres and exterior rusticated weatherboard. Interior 10mm plasterboard insulated with the addition of R2.8 Insulmax^®.

Whole wall structure uninsulated                  R0.32

Whole wall structure when insulated             R2.3

Heat flow/loss reduction approximately 86%*

Windows

Timber frame single glazed window          R0.19

Aluminium frame double glazed window   R0.26

Heat flow/ loss reduction approximately 25%*

Note: the insulation rating of double glazed windows is lower than the insulation rating of an uninsulated wall structure meaning that once double glazed, windows are still losing more heat than the same area of uninsulated wall