Passive House Principles - What does this means for you?
There are 5 passive house principles which form the base for Passive House Design. They are Airtightness, Quality insulation, Quality Windows, No Thermal Bridging and Heat Recovery Ventilation.
While there are many posts and blogs about what this means in building science and performance terms, I wanted to explain what this means for you and your experience of living in a Passive House. None of these principles act alone, they all work together to make a comfortable, healthy, energy-efficient home. So, what does this mean for you and why should you embrace these principles in the Architectural Design Brief of your newly renovated or built home.
Airtightness does what it says on the tin. This means no draughty spots and all indoor heating is contained inside your home. Result = less heat loss, lower power bills, more comfortable constant indoor temperature.
Airtightness stops moisture from moving through your construction so there is much less risk of hidden rot and mould in your home. Result = no leaky building surprises.
Airtightness stops draughts from moving through your insulation, which increases the performance of your specified insulation product. Result, your building's thermal products perform to the best of their ability and making your home cheaper to run and giving you the best return on the insulation that you have invested in.
Quality Insulation plays its part. When the right amount of insulation is balanced in the right places around your home, this can mean that hot and cold between inside and outside can be best regulated. Simply stuffing insulation in walls, floors and ceilings isn’t enough to guarantee energy efficiency. Understanding what needs to go where and how much is critical for good or high performance. Result, the performance of your home is designed and calculated, not just blindly expected.
Quality windows cost more but windows are the weakest thermal link so the design of windows, size, shape, composition, materiality, orientation, and shading impacts on interior comfort levels and energy required to achieve those. The suns energy is free, but too much or too little is costly. We are smart enough to work with the sun, not against it. Result, best return on financial investment in better windows for a warm home with low power bills.
Thermal bridging, is the secret heat escape route we can never see but can predict through calculation. Heat is like Houdini, it finds the quickest, most secretive and easiest path to reach cold. That can be from inside out or outside in, depending on the time of day and time of year. Plugging these leaks reduces unnecessary energy consumption to create a healthy comfortable home without us even lifting a finger.
Lastly Heat Recovery Ventilation. This is twofold. Airtight buildings (including modern minimum standard homes) don’t allow air changes by leaking air through the construction envelope as we don’t build or desire draughty Villas anymore. We cannot rely on opening windows to provide enough fresh air and enough air movement through our indoor spaces for a healthy home. Opening windows are great in theory, but ineffective in practice. We are the asthma capital of the world. Result, a home that is healthy to breathe in.
Ventilation also removes moisture from our indoor environments. Dry air is easier and cheaper to heat. Removing moisture stops condensation on our inside surfaces, usually evident on our windows. Mold needs warm moisture to grow, so no more weepy windows and no more interior mold. Result, healthier cleaner home.
The second aspect of Heat Recovery Ventilation is that the warmth in the building can be transferred to either the incoming or outgoing air, so we can remove the heat or transfer it to fresh air to recycle it back into our homes. This smartly uses our ventilation system to remove or recycle energy we have already used. Result = dual use of a system and lower heating or cooling power bills and a comfortable constant interior temperature.
Lastly, the cost is a common complaint or barrier to conversations about Passive House or High Performing Houses, so I am going to leave you with this. The NZBC (New Zealand Building Code) sets out minimum standards to comply with. This is the worst-performing building you can legally build. A Passive or High Performing House costs approx. 5 -10% more at construction but offers energy efficiency and so reduces the cost of operating over these worst-performing homes.
Our homes are the greatest financial investment we make in our life. Would you put your money in the worst-performing investment legally available? Or would you make sure you chose wisely and made your money work really hard for your future? Would you avoid the get-rich-quick schemes and invest in the more stable secure portfolios? Now how about the biggest investment in both your financial and physical health? How important is it for you to get your family home or property investment right? What kind of homeowner or landlord do you want to be?