Caring For Our Planet: Part 2 - Passive House and Energy Efficiency

This post is Part 2 of a Multi-Part series about creating a more sustainable future. Topics covered in the series are:

  • Sustainable and eco-friendly building options
  • Toxicity in your home and how to reduce it as you build
  • Recycling and reducing waste, both in the building industry and in our personal lives
  • Energy efficiency in your home
  • Living off the grid and more in alignment with our natural environment

This post will touch upon Passive House concepts, the importance of ventilation and heat exchange, and why your windows and doors are one of the most important features of creating a house that saves you money throughout the lifetime of the house.

Firstly, what is all this Passive House business about anyway?

There's a lot of people and companies chucking the term "passive house" around at the moment, seems to be a bit of a buzz word in the industry, just like "eco" (is that eco for ecology or eco for economy?). In any case, here are a few salient points to highlight what constitutes a Passive House, versus a code-minimum compliant house:

  • Passive houses can be any design, size, orientation, or aesthetic, and has no set rules on what building materials should be used in order to achieve PH standards.
  • The idea is to create a home that is healthy, dry, warm when it needs to be warm and cool when it needs to be cool (that is, the internal environment is 100% controlled by the occupants, rather than by the temperatures outside or whatever heating source is available inside), and that costs less in energy and money to run optimally, throughout the entire life of the house.
In NZ, “affordable” housing is achieved by reducing the capital cost of building a home, without considering the ongoing operational energy costs of living in the home.
— Glen Murdoch,
  • Passive houses do not have to cost an arm and a leg. The principles are to reduce energy loss through clever insulation and heat recovery ventilation systems, which can be expensive if you want them to be, and can be affordable if you're on a budget. The point is, a code-minimum house will never save you any money in the long run, even if your upfront costs are less.
  • Passive homes are genuinely more sustainable in nature, as they are built to withstand or adjust during extreme changes in external environment - think weather and global warming or cooling, think available energy sources and the policies that govern those resources, and of course the economy and the rising prices of electricity, gas, oil and fossil fuels in general. With solar systems running your whole house, or at least part of it, and a home whose internal temperature adjusts only marginally, year round, with few, if any continuous costs for upkeep, it means maintaining your home and lifestyle looks very different to what's currently the norm in New Zealand.
  • Park Homes NZ Ltd, we love incorporating as many Passive House elements as standard in all our homes, no matter how basic or ballistic you go in your design :-) 

GLAZING, Insulation, heating & cooling:


We've already covered in a previous post, why we use UPVC windows and doors as a standard feature in all of our Park Homes. One of the other features we recommend to improve the insulation of these windows is having Low E (emissive) Glass. I could explain this to you in my own words, but this little analogy from Vitro Glazings seems to do just the trick:

"Low-e glass has a microscopically thin, transparent coating—it is much thinner than a human hair—that reflects long-wave infrared energy (or heat). To use a simple analogy, low-e glass works the same way as a thermos. A thermos has a silver lining, which reflects the temperature of the drink it contains. The temperature is maintained because of the constant reflection that occurs, as well as the insulating benefits that the air space provides between the inner and outer shells of the thermos, similar to an insulating glass unit. Since low-e glass is comprised of extremely thin layers of silver or other low emissivity materials, the same theory applies. The silver low-e coating reflects the interior temperatures back inside, keeping the room warm or cold."

Ahh, gotta love a good analogy.

Whilst low e glass isn't totally essential in your home, it's certainly one of those invisible things that makes for a much warmer home in winter, or a much cooler one in summer.

general Insulation

Park Homes are constructed using Structurally Insulated Panels (SIPs), which means their structural frame and their insulation are all in one piece and, once fixed together to form the shell of the house, become very strong and perfectly air and water tight. The R-Values of a standard Park Home is already higher than what the building code calls for, thus already much more insulated, and because the EPS core is what forms the insulation, rather than bats, there are no air gaps that form over time (for example, as the bats sink), thus the integrity of your insulation is not compromised with the passage of time. 

I've already talked in more depth about SIPs in Part 1 of this series, or you can download our info pack to find out more about the materials we use in construction of our Park Homes.

Heating & cooling

Whilst I won't go to deeply into this at this point, I will say that one of the major factors that makes a Passive House truly efficient, is the heat recovery ventilation system. That is the pumping heart of the house.

To have a system that brings in fresh air and pre-heats it by the outgoing air, keeps air circulating to reduce condensation in winter, and also means that you're not having to pay excessive amounts  to warm up that air again, as it's done automatically. 

In addition, solar furnaces are free to run and can heat or cool your home (if done correctly), and they're inexpensive to construct. We'll have one of these operational in our next show home, so come check it out once built :-)

Watch out for Part 3 in the series, Living Off the Grid and Loving the Land.