Passive House
What is Passive House?
Passive House is a building science-backed design approach that optimizes energy performance to deliver an exceptionally healthy, comfortable, durable, and resilient home. It started as homes but has expanded across many building types. The building science and built results haven’t changed, but the format has expanded. Here at Sted, we’re focused on creating homes that meet these rigorous standards.
Exceptional, Continuous Insulation and High-Performance Windows & Doors
Code-minimum is the worst home that is legally allowed, so that’s a terrible bar to boast about achieving. We want to put a nice, thick sweater and rain coat around your home to keep the heat (and water) out when it’s hot and keep the heat in when it’s cold. This is achieved not only by installing a lot of insulation, but the installation must be exceptional. When you put on your winter coat, you don’t stuff the coat in between your ribs, you put it around your body - we want to do the same with insulation.
Windows and doors have an oversized effect on our buildings and unfortunately the majority of folks ignore that. You wouldn’t leave your front door open in the dead of winter, but that’s exactly how code-minimum windows and doors perform.
No Thermal Bridges
Thermal bridges are weak spots in the building enclosure that have a significantly lower insulative value. Discomfort, mold potential, heat loss/gain. They’re energy thieves and therefore must be eliminated!
Airtight
The home should be sealed up and without leaks. Houses do not have lungs, but humans do, so we want to control where the fresh air comes into the home. In a passive house, air leaks are eliminated so we’re not bringing unfiltered, unconditioned air in wherever a hole exists. Air leaks are paths for dust, pests, noise, and moisture. The way many homes are built today, the materials have less drying potential. They’re much more susceptible to mold and damage as a result.
Continuous Fresh, Filtered Air
Fresh air is something everybody needs and desires. With cooking appliances, gas-fired equipment, materials produced with glues and finishes, many homes have poor, or fair at best, air quality. Poor air quality can cause headaches, drowsiness, poor sleep, irritability, inability to focus, etc.
The outdoor air isn’t always perfect. It’s dirty, hot/cold, humid/dry. So we need to bring in filtered, fresh air. Providing this via a fresh air machine (ERV), we can have perfect air piped into your home all of the time.
Passive House Principles
Passive House can be broken down into five main guiding principles.
Exceptional, Continuous Insulation
High-Performance Windows and Doors.
Free from Thermal Bridges
Airtight Envelope
Continuous, Fresh, Filtered Air
During design, we may get into the weeds and talk about the control layers. There are four main layers, and they must be continuous for your home to be high-performance. In order of importance:
Water Control Layer - this layer manages bulk water (droplets) and keep it out and away. Water intrusion can lead to rot and mold. This is the raincoat.
Air Control Layer - this layer is responsible for air sealing to keep out dust, pollen, bugs, noise, smoke, and moisture. Think of this like a wind breaker.
Vapor Control Layer - this layer manages the water vapor to control the risks of mold. This layer is like a moisture-wicking shirt.
Thermal Control Layer - this layer is responsible for managing the flow of heat in/out of the house. Think of this layer like a winter coat.
Results, delivered.
Comfortable
No matter the weather conditions outside (hot, cold, windy, rainy, etc), the indoor spaces are always comfortable. There are no cold/warm parts of the house, and all of the surface temperatures are even throughout the house.
Healthy
A passive house is free from dust, bugs, and pests; engineered to avoid moisture issues that lead to mold, mildew, and funky smells. The house comes equipped with a fresh air machine so you always have fresh, filtered air. This doesn’t mean you can’t open the windows, but it means you don’t need to open them to get fresh air. The air inside a passive house is cleaner than outdoor air.
Durable
Minimizing maintenance is not only a way to save on operational costs, but it lowers the risks of water damage which can lead to rot and mold.
Resilient
Your house at a basic level is just a shelter. During extreme weather events, you want your home to be able to weather the storm. In the event of a power outage, your home should be able to keep you safe and comfortable. During wildfire events, you can still provide your home with fresh, filtered air. With a substantially reduced energy need, passive house buildings are much easier to be net zero energy.