Sustainability is becoming an ever more relevant and desirable factor in everything we do, including building.
Creating a new home that includes sustainable and recycled materials in its construction is great, but that’s just one part of the equation.
Once the building is complete, how sustainable will everyday living in it be?
There are many methods to make a home healthy and warm in a sustainable and energy-efficient way, and this is the goal of all high performance homes.
Here’s what you need to know about high performance homes.
While there’s no official definition or set of standards that define a high performance home, aside of course from ratings such as Passive House or Homestar, there are a few generally agreed-upon ideals or principles that a high performance home should embody.
In a sentence, you could say ‚a high performance home excels at efficiently providing a safe, healthy and comfortable environment for its occupants to live in.‘
Think of it like this: What are homes designed to do? What is their function?
Well, they have many: they provide shelter; they keep you warm; they are a space in which to live your life. A high performance home is therefore one that does exceptionally well at all the things a home is designed for and, crucially, does so without requiring a lot of energy.
High performance energy-efficient buildings are designed and constructed to be highly energy efficient, they have the potential to use up to 90% less energy than the current building stock, whilst performing the same (if not better) functions as traditional buildings.
High performance energy-efficient windows for example can reduce heat losses by more than 70% compared to existing double glazed windows.
High quality external insulation added to a wall can reduce heat losses by 90% and an efficient heat recovery system can reduce ventilation heat losses by up to 90%. This means very little additional heating/cooling will be required to maintain comfortable indoor temperatures.
Through its meticulous design and moving away from glass enclosed structures, passive homes utilize the surrounding environment to reduce GHG emissions associated with the typical home functions such as heating, cooling and lighting.
So what does this mean for the end user? The total cost of homeownership includes much more than qualifying for monthly mortgage payments, property taxes and homeowner’s insurance.
Other costs to budget for include utilities such as electricity, water and gas, which can add an additional hundreds of dollars on top of other monthly housing expenses. However, new building codes and technologies such as Passive Housing are being introduced to decrease these costs for homeowners and provide more ecologically-friendly homes.
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OUR buildings allow for heating and cooling related energy savings of up to 90% compared with typical building stock and over 75% compared with average new builds. OUR buildings are also praised for their high level of comfort. They use energy sources inside the building such solar heat entering the building as well as the body heat from the residents – making heating a lot easier
Appropriate windows with efficient insulation and a building shell consisting of good insulated exterior walls, roof and floor slab keep the heat in the house during winter – and keep it out during summer
A ventilation system consistently supplies fresh air making for superior air quality without causing any unpleasant draughts. This is e.g. a guarantee for low Radon levels and improves the health conditions.
Radon levels are measured in picocuries per liter, or pCi/L. Levels of 4 pCi/L or higher are considered hazardous. Radon levels less than 4 pCi/L still pose a risk and in many cases can be reduced, although it is difficult to reduce levels below 2 pCi/L.
R value = 5.0 W/m²K
EXPOL R value = 1.4 W/m²K or
EXPOL R value = 1.8 W/m²K
In the context of building and construction the R-value is a measure of how well a two-dimensional barrier, such as a layer of insulation, a window or a complete wall or ceiling, resists the conductive flow of heat.
R value = 4.8 W/m²K
R value = 1.59 – 2.95 W/m²K
Tape plywood or Oriented strand board (OSB) as vapour retarder
R value = 5.0 W/m²K
No internal moisture control at all
R value = 1.8 – 2.4 W/m²K
A vapor retarder is defined as a material or system that adequately retards the transmission of water vapor under specific conditions.
Tape plywood or Oriented strand board (OSB) as vapour retarder
R value = 4.8 W/m²K
No internal moisture control at all
R value = 1.8 – 2.4 W/m²K
Tape plywood or Oriented strand board (OSB) as vapour retarder
R value = 5.0 W/m²K
Tape plywood or Oriented strand board (OSB) as vapour retarder
R value = 4.8 W/m²K
No internal moisture control at all
R value = 1.8 – 3.6 W/m²K
NZBC R-Value product minimum standards (applicable to a timber-framed house*)
Assembling floor, wall & roof panel; incl. any necessary fixing (350 – 450 screws)
Between 1 – 4 days
Assembling of NZ standard subfloor between 1.5 -3 days
Assembling of NZ standard pre-nail framing between 1 – 3 days
Assembling of NZ standard pre-nail trusses or rafter between 1 – 3 days
Installing of any necessary fixing between 1 – 2 days
Total time approx 5 – 8 days
Straight away WEATHER-TIGHTNESS
Installation of NZ standard building wrap between 1.5 -3 days
Assembling of NZ standard roofing paper & lining between 2 – 5 days
It could take another 1 – 3 weeks to get WEATHER-TIGHTNESS
VERY LOW
VERY HIGH
Under clause E2: Internal Moisture of the NZ Building Code, the maximum moisture contents for timber framing at pre-line must be less than 20% for insulated buildings, (all dwellings) and less than 24% for non-insulated buildings
Vapour permeability
Vapour permeability is a material’s ability to allow a vapour (such as water vapour or, indeed any gas) to pass through it. To be more precise it is a measure of how much vapour is transmitted through a material (or compound object) under a given set of circumstances. The higher the values of the permeability of the material, the more rapidly vapour can pass through it. Vapour permeability is the rate at which vapour passes through a material.
High degree of water vapour permeability
If there should be existing moisture it can and will dry out through our wooden fibre board (thermally free bridge envelope and our FPS weather tightness system
Low degree of water vapour permeability
Existing moisture will stay in the framing and will transfer to insulation and any other nearby installed material – sequence: toxic black mould, fungus and bacteria growing
Moisture development for the average life time duration of a house
According to the standard building physics a wooden frame construction has to be 4-6 times more airtight inside as outside.
Our wooden frame construction system with internal brace by wood-based panels (usually OSB) as vapour retarder and diffusion-open outer clothing, often also designed as a diffusion-off-wood-fibre thermal insulation composite system.
NZ standard wooden frame construction system with internal plasterboard diffusion-open and NZ standard building or wrap board as vapour retarder
A person could perspire and exhale 40g of water vapour per hour when sleeping, 70g/h when seated and 90g/h when standing or doing housework.
Theoretically, if the occupants didn’t leave the dwelling, slept for seven hours, sat for ten hours and stood or did housework for seven hours each could generate 1.6 Kg of moisture purely due to metabolic moisture generation.
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Weight of water vapour (i.e. moisture) released by various domestic activities:
OUR LOW-E, HIGH PERFORMANCE BUILDING METHOD
The contributed moisture will be transported through our heat recovery ventilation system to the outside and consistently supplies fresh air for making superior healthy air quality. The highly efficient heat recovery unit allows for the heat contained in the exhaust air to be re-used.
Click to enlarge
STANDARD NZ STICK-FRAMING BUILDING METHOD
The contributed moisture will diffuse through the plasterboard and will be stop by the NZ standard building or wrap board as vapour retarder (like a crying baby) and will stay in the framing and will transfer to insulation and any other nearby installed material – sequence: toxic black mould, fungus and bacteria growing.
Click to enlarge
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