The Great Home Performance Test
A villa. A new build. An energy efficient home. We put three homes to the test, measuring air tightness, air quality, humidity, and temperature. Which home will come out on top as the healthiest, most comfortable, and most economical?
The Contestants
The Old Villa
This 3-bedroom villa is draughty and expensive to heat.
1880-1890
3
140m²
Wood stove and heat pump
Roof
The New Build
This new build is warm and airtight, but could it be hiding a bigger problem?
2025
3
140m²
Heat pump
Building code minimum: Roof, walls, underfloor
The Energy Efficient Home
2024-2025
4
206m²
Heat pump, mechanical heat recovery system
R3.9: Roof, walls, underfloor
Performance Scorecard
VILLA
NEW BUILD
ENERGY EFFICIENT
Airtightness
27.94 ACH
0.39 ACH
Overnight Air Quality
Low CO²
2,750 ppm CO²
780 ppm CO²
Overnight Humidity
72%
71%
54%
Overnight Temperature
9°
15°
19°
Energy Use
High
Lower
Very low
Performance Scorecard
VILLA
Airtightness
27.94 ACH
Overnight Air Quality
Low CO²
Overnight Humidity
72%
Overnight Temperature
9°
Energy Use
High
NEW BUILD
Airtightness
5.02 ACH
Overnight Air Quality
2,750 ppm CO²
Overnight Humidity
71%
Overnight Temperature
15°
Energy Use
Lower
ENERGY EFFICIENT HOME
Airtightness
0.39 ACH
Overnight Air Quality
780 ppm CO²
Overnight Humidity
54%
Overnight Temperature
19°
Energy Use
Very low
What We're Measuring
Airtightness
Air changes per hour
How much air leaks into and out of the house through gaps and cracks.
Draughty homes feel cold and are harder to keep warm.
Overnight air quality
CO² parts per million
How much carbon dioxide builds up in a bedroom overnight.
High CO₂ can make you feel stuffy, tired or groggy when you wake.
Overnight humidity
Relative humidity (%)
How much moisture is present in the indoor air.
High humidity increases the risk of condensation, mould, and dust mites.
Overnight temperature
Degrees Celsius
How well the bedroom holds its temperature overnight with the heating off.
Cold bedrooms can increase respiratory problems and worsen asthma symptoms.
Energy use
KwH
How much it costs to heat the home during winter.
Power bills become more expensive.
The Old Villa
This 3-bedroom villa is draughty and expensive to heat. A blower door test shows us why.
The New Build
This new build is much more airtight, but are the lower heating bills coming at a cost?
The Energy Efficient Home
The finale of The Great Home Performance Test. Which home will emerge the winner?