Many of us have suffered in a hot house or a cold house and now, there are designs for passive houses. Nick Radford and April Sampson-Kelly explore the ways to make existing homes more liveable and sustainable.
True Cost of a New Liveable Home
The way that we build today, in this privileged society, uses a high level of manufacturing. It’s really quite hard to achieve what we would call genuinely sustainable. There’s a cost – environmentally and financially. It’s difficult to wear the cost of building at the moment. The building industry is no longer about shelter. It’s driven by capitalism.
When we’re starting with our housing stock that is not well designed, not well built for passive solar, what can we do about that?
Nick reminds us, this system we have is not the one we must have. In a lot of European countries renters have much more security. They have very long leases that are really hard to break as a landlord. And it is worth upgrading the performance of your rental because you know it’s going to pay for itself.
Goldilocks
What’s the goldilocks recipe for a liveable home? We can get a good picture of climate sensible building from many traditional cultures. In cold climates are usually squat and they’re often rounded to reduce the effects of wind and for the ease of construction. And they have minimal airflow and high insulation. Whereas homes in the tropics are often elevated to shade the area below. They are tall and narrow. They have high ventilation and high airflow. The steep roof also helps to shed water. They have low insulation and low thermal mass. On the other hand, homes in the deserts traditionally are squat they have high thermal mass, often have a flat roof. So, you can sleep on it at night. And they have small windows to reduce the sun’s heat rays.
Keys to the modern climate responsible, liveable home
A liveable home needs to be warm, not too hot, not too cold, dry, light, a good amount of light to work with clean air and secure. It’s nice to feel cool in summer and warm in winter. This can be achieved without fossil fuels. To be cool we need to shade the area, be insulated from the sun’s rays and have air movement. That can be created by the shape of the building or by devices like fans. And we can use something called a heat sink. That is a block of thermal mass to absorb some of the heat.
With passive solar, the occupants actively modify the building throughout the seasons. Whereas in the passivehaus standard, the house design and materials respond.
How do we create warmth?
How do we make a space warm and liveable? We can use energy from nature but actually our bodies create a lot of warmth. So, if you are cold right now the fastest way to get warm is to insulate your body. Put some more clothing on. Also. we can reduce the amount of air movement. Because, we know when air moves it cools down. And we can insulate the building so the warmth is not lost. The buildings need to stay water tight. By being watertight we have more control over the temperature.
Insulation, thermal bridges and thermal mass
There are many creatures in this world that use insulation – like the bear in a cave, and the fur on its skin and the sheep with its wool. But when we look at the elephant – it uses its ears to cool down. It fans those gigantic ears to cool its body. But if it was in the snow then it would benefit from insulation on those ears because they would be very cold. The ears are like thermal bridges they move the heat from the elephant’s body out into the air. So, if you have a doorway or a window that has wood a wooden lintel right through from the inside to the outside that is a thermal bridge. When we cover the thermal bridge we’re reducing the heat loss or the heat transfer from outside.
Thermal mass is usually a bulky material like mud boulders. Or even water tanks, a brick floor or a wall can act as a thermal mass. In many ways it’s the opposite to insulation because insulation is usually light and airy using the trapped air to block the transfer of heat. However, wood can act as a thermal mass. But it can also act as insulation. Some homes, especially underground homes and cave homes, don’t need much thermal mass because the cave or the soil around it is the thermal mass. And we see evidence of ancient underground housing as well as many modern underground houses use the constant temperature of the earth.
Use Natural Energy for Liveable Spaces
One of the most important aspects of building a design is its orientation – the way it greets the sun. Thousands of years ago, Socrates noticed that when the homes are facing the sun the light can penetrate into the home. And if there’s a portico on the front that stops the hot summer sun from coming into the home. But in winter the sun can still get through underneath the portico or the porch. These were gracious, liveable homes.
Socrates suggested that we elevate this sunny side and lowered the sunless side to block out winter winds. It allows the sun to come in in winter but not in summer because it has shade control on the sunny side and not many windows if any on the sunless side. But it also has thermal mass on the floor to absorb some of the energy during the day and release it at night in winter.
Frank Lloyd Wright used the same principles but it incorporated a berm on the back of the home. In front was a large section of glass and overhanging is the roof it comes out sufficiently so it blocks the sun in summer.
Earth ships are very similar. Here I am in an earth ship in Taos New Mexico, United States and it is in the middle of winter. You can see some snow on the ground there was no heating for this house. And you can see the sun is coming through onto a small dividing wall which is a thermal mass dividing the area between the kitchen and the living room. And you can also see (a little bit further to the right and a little bit screened for privacy, I imagine), is a large thermal mass in the bathroom.
Socrates work became the start of solar passive design thinking, yet thousands of years later, modern buildings depend upon fossil fuels.
PassiveHaus sits tight and regulates
The passive housing standard doesn’t rely on sunlight but you can have the same treatment on the sunny side. You can have your windows. But they tend to have triple or double glazing on all the windows. Because the whole Passivhaus standard requires that it is super insulated, the thermal bridges are covered. And so, there’s very little chance of any exchange of energy – warmth from the inside to the out or vice versa. The colder your climate the more that passive housing suits. It’s useful also in a warmer climate that’s subject to heat waves.
The passive house is about really super heavy insulation and the ability to shut the building completely off the outside world. And then really carefully regulate the airflow – the temperature movement across the wall. So, we’re probably going to need more and more houses that are resistant to heat waves. I like that it measures the actual built performance because in Australia we’ve got this big gap between the theoretical performance and the stars that are awarded to a design compared to the the actual built performance. And it is quite hard to measure whether the house really stands up to the standard. And passive houses is very clear on what the standards are and how you measure them.
More liveable
There are a couple more things that make homes feel liveable. Being secure includes being fire safe and there is a standard for this. We need to determine if the building honestly meets the standard. Or make plans to escape. And chemical safety is a factor especially if the homes are surrounded by pollution or have lead paint or a long history of chemical use. For pest control in the building construction phase we can choose to use physical barriers like a termite mesh instead of chemicals. But this is tricky to retrofit on established buildings.
Liveable Spaces For Climate Security
Homes are more liveable when they provide other functions such as harvesting water, generating electricity, supporting indoor production by having sufficient natural light. And some buildings have really good outdoor spaces where we can work they provide windbreak, frost protection, some reflected light, some shade and of course the runoff water.
To design for the variation of the seasons and for climate change use the angles of the sun to set up shade. Add thermal mass or phase change materials within the home. Add insulation, especially between the roof and the ceiling in that cavity. Block thermal bridges such as window and door frames. Adjust the air flow. An increase in ventilation will be cooling. Whereas, when we block off rooms – divide the rooms – it makes them snug and warm. In summary, liveable buildings are warm. They’re not too hot and they’re not too cold. They’re dry. They have good natural light. They are safe and secure. And I hope this has given you lots of ideas on how to improve your home.