When people walk into a truly comfortable home, they often struggle to explain why it feels so good.

It’s quiet.

The temperature feels just right.

The air feels fresh — not dry, not stuffy.

There are no cold drafts, no clammy corners, no overheating rooms.

And yet, comfort in buildings isn’t magic.

It’s not luck.

And it’s certainly not about expensive finishes or oversized heating systems.

Comfort is the predictable outcome of good building physics.

At reimagined habitat, this belief underpins everything we do. Whether we’re designing a new home, a deep retrofit, or improving an existing house, the principles remain the same: when a building is designed to work with physics rather than against it, comfort, health and efficiency follow naturally.

Why Australian homes so often feel uncomfortable

Australia has some of the least energy-efficient housing in the developed world. Many homes are:

• Leaky and draughty
• Poorly insulated
• Prone to condensation and mould
• Overheated in summer and freezing in winter
• Reliant on oversized heating and cooling systems

This isn’t because Australians don’t care about comfort. It’s because our building industry has historically focused on appearance and minimum compliance, rather than performance.

When the fundamentals are wrong, no amount of air conditioning, heating or “smart tech” can truly fix the problem.

Building physics: the invisible forces shaping your home

Building physics is simply the science of how heat, air and moisture move through buildings.

These forces are always at play — whether we design for them or not.

The key questions are:

• Where does heat flow?
• How does air move?
• What happens to moisture over time?

When these forces are ignored, buildings become uncomfortable, unhealthy and expensive to run. When they’re properly understood and managed, homes become calm, stable and resilient.

This is where Passive House principles come in.

Passive House: not a style, but a performance framework

Passive House (or Passivhaus) is often misunderstood as a niche or “extreme” building approach. In reality, it’s simply a rigorous, evidence-based application of building physics.

It focuses on getting the fundamentals right:

1. Excellent insulation
2. Airtight construction
3. Thermal bridge-free design
4. High-performance windows
5. Balanced mechanical ventilation with heat recovery (HRV / MVHR)

These principles work together as a system. Miss one, and the whole building suffers.

Air leakage: the hidden comfort killer

One of the biggest issues in Australian homes is uncontrolled air leakage.

Many people assume draughts are harmless — or even “healthy”. In reality, uncontrolled air movement causes:

• Cold drafts in winter
• Hot air infiltration in summer
• Difficulty maintaining stable temperatures
• Increased energy bills
• Moisture being driven into walls and ceilings

The average Australian home can exchange the entire volume of its indoor air 15–25 times per hour. That means you’re constantly heating or cooling fresh outdoor air — whether you want to or not.

Airtightness doesn’t mean sealing a home shut.

It means controlling where air enters and exits — intentionally, not accidentally.

Humidity: comfort, health and mould are deeply connected

Humidity is one of the most overlooked aspects of comfort.

Too much moisture leads to:

• Condensation on windows and walls
• Mould growth
• Dust mites and allergens
• Respiratory issues and asthma flare-ups

Too little moisture causes:

• Dry skin and eyes
• Irritated airways
• Increased susceptibility to illness

Good building physics aims to keep indoor humidity within a healthy range — typically between 40–60%.

This cannot be achieved through opening windows alone, especially in modern, compact homes or during extreme weather.

Thermal bridges: small details, big consequences

Thermal bridges are areas where insulation is interrupted — such as slab edges, window frames, balconies or structural penetrations.

These spots become:

• Colder than surrounding surfaces
• Prone to condensation
• Ideal breeding grounds for mould

They’re often invisible until damage appears.

Passive House design pays obsessive attention to these junctions — not because it’s fussy, but because the consequences of ignoring them are very real.

Ventilation: fresh air without the energy penalty

Here’s one of the biggest myths we hear:

“If my house is airtight, won’t it be stuffy?”

The answer is no — if it’s ventilated properly.

High-performance homes use mechanical ventilation with heat recovery (HRV or MVHR). These systems:

• Continuously supply fresh, filtered air
• Extract stale, moist air from kitchens and bathrooms
• Recover heat (or coolth) from outgoing air
• Maintain stable temperatures and humidity
• Improve indoor air quality dramatically

Instead of relying on random air leaks, ventilation becomes deliberate, balanced and predictable.

This is especially important for people with asthma, allergies, chemical sensitivities or compromised immune systems.

When buildings make people sick

Poor building physics doesn’t just affect comfort — it affects health.

We regularly see links between poorly performing homes and:

• Chronic respiratory conditions
• Persistent coughs and asthma
• Fatigue and poor sleep
• Headaches and brain fog
• Anxiety linked to thermal stress

A home that is cold, damp, noisy or unstable places constant stress on the human body. Over time, that stress adds up.

Healthy homes don’t just feel better — they actively support wellbeing.

Practical ways to improve comfort and health in your home

You don’t need to build a certified Passive House to benefit from these principles. Even small, thoughtful upgrades can make a real difference.

1. Reduce air leakage

• Seal gaps around doors and windows
• Install door seals and draught excluders
• Address obvious penetrations and cracks

2. Improve insulation — properly

• Upgrade ceiling insulation first
• Ensure insulation is continuous and well installed
• Avoid compressed or poorly fitted batts

3. Address condensation early

• Improve ventilation in wet areas
• Avoid blocking airflow behind furniture
• Monitor humidity levels

4. Upgrade windows wisely

• Focus on performance, not just “double glazing”
• Look at U-values, frames and airtight installation
• Even targeted upgrades can help

5. Consider mechanical ventilation

• Especially in airtight or renovated homes
• HRV/MVHR systems can transform indoor air quality
• Decentralised units can be easily retrofitted into existing homes
• Not just for Passive House projects

6. Think in systems, not products

• Comfort comes from how elements work together
• Avoid piecemeal fixes without understanding the whole picture

Comfort is designed, not guessed

When homes are designed using sound building physics, outcomes become predictable:

• Stable indoor temperatures
• Lower energy bills
• Better air quality
• Reduced mould risk
• Improved physical and mental health

Comfort stops being something we chase — and becomes something we expect.

At reimagined habitat, we don’t believe healthy, comfortable homes should be the exception. They should be the baseline.

Because comfort isn’t a mystery.

It’s simply the result of doing the fundamentals well.