What is Passive House?
Think of snuggling up with the whanau in the warmest most comfortable home you can imagine. A passive home could be even better than that!
Passive House is a voluntary, international best practice standard, for buildings that aims to produce warmer, drier, healthier, more comfortable, energy efficient homes. Passive House principles are perfect partners for Kiwi conditions. The first passive house was certified in Germany in 1991, and in New Zealand in 2012, so it’s not a new standard, nor new to Kiwis. To see where passive houses have been built in NZ click this link https://sustainableengineering.co.nz/nz-au-certified-passive-house-projects-map/
THE FIVE PASSIVE HOUSE PRINCIPLES
Wickedly warm walls, floors and ceilings!
A Passive Home is designed and constructed to maintain a wonderfully warm 20 to 24 degrees in each and every room all winter. We also check for overheating in summer, to ensure your home won’t get warmer than 25 degrees. Insulation is used to keep warm in winter and cool in summer. As an indication*, insulation values are generally considerably higher compared with the NZ H1 acceptable solutions.
*Insulation values vary depending on climate zone.
Energy modelling optimises insulation to where it is most effective and the extra insulation helps reduce your electricity power bill significantly. You can save on average 86% of the energy needed to heat a standard home, when heating a passive house, all rooms, all the time. The uninterrupted insulation duvet around your home is called the thermal envelope.
Quiet, Condensation free, Positioned perfectly!
High performance windows are a quiet thing of beauty in their own right. A window is the weakest link in the thermal envelope of a home. Therefore, wonderfully warm windows provide the biggest bang for buck for highly healthy homes.
Double or triple glazed, located to best capture the winter sun, while avoiding the summer solstice, installed in line with your insulation layer, they are comfort controlled and condensation free. Secure, multi-locking and airtight, they can be opened often too, or not at all to keep the flies out, you choose! I prefer tilt and turn, for additional ventilation and cleaning.
Delightfully Draught free!
Draughts make you feel uncomfortable in your bones and in your wallet. A giraffe gazing over your shoulder is not relaxing! An airtight home helps direct airflow to where you need it, keeping unwanted cold damp air out. Airtightness is tested with a blower door machine and measured in air changes per hour. An average new NZ house is likely to have 5-7 uncontrolled air changes per hour.
Every eight to 12 minutes, all that expensively heated air escapes the house through cracks and crevices. A certified Passive Home is only allowed 0.6 air changes per hour!
Heat Recovery Ventilation
A ray of sunshine and a breath of fresh air!
There are three types of mechanical ventilation (https://www.abodemagazine.co.nz/home/2021/10/28/the-air-we-breathe).
Only one is good enough for a passive home, and then only the best of them.
The lungs of your passive home, Balanced Mechanical Ventilation with Heat Recovery (MVHR) takes warm, stale, stinky, moisture laden air from your kitchen, laundry and bathrooms and replaces it with the right amount of farm fresh filtered air to your living room and bedrooms. It cleverly uses a device called a heat exchanger, which extracts heat from the warm, outgoing air and uses it to heat the cool fresh incoming air, recovering at least 75% of the heat. This means that if the exiting extract air is 20 degrees and the incoming fresh air 0 degrees then the incoming air is warmed to 15 degrees for the cost of running a lightbulb!
You then only need to heat a further 5 degrees, this is partially why a passive home is so energy efficient.
The Clever Heat exchanger, find out more here...
Thermal Bridge Free
Cold corners and crevices cancelled!
A Thermal Bridge is a heat escaping superhighway. Like a rat down a drainpipe, heat will find the fastest route out, if allowed. Insulation uses still air to trap that radiant rat, but corners, connections and crevices, compromise insulation thickness. Passive homes correct these compromises to improve comfort. Keeping highly conductive elements like structural steel out of the thermal envelope, improves performance and prevents condensation that leads to mould growth.
Passive House Explained in 90 Seconds
eHaus is the only volume builder in Aotearoa that only builds high performance homes and it's a great privilege to be working in cooperation with them across the country.This animation explains very simply the what is required build a passive house, superhome or any high-performance home for that matter.
Ph: 027 348 1110