It’s all too familiar that when winter comes, which seems to be getting colder every year, we instinctively reach for the heater to keep warm. With this attempt to artificially heat our homes, our energy bills sky rocket, which is now made worse with the rising cost of energy.
Auxiliary heating and cooling accounts for approximately 40% of the energy used in the average Australian home. With figures this high, wouldn’t it be nice if it were possible to have a house that requires zero auxiliary heating throughout the colder winter months, whilst still remaining warm?
Eliminating heating energy bills is not only possible, but it’s a lot easier than many people think. By implementing clever design principles, not only can you reduce your energy bills, but you can also minimise your impact on the environment and subsequently do your part for a sustainable future environment. Surely you would sleep not only warmer at night, but better, knowing that you are doing your part for our future?
WHAT? NO HEATING ENERGY BILLS?
Naturally heating your home through passive design principles isn’t a complicated process and actually requires no upfront cost, just some conscious, thought out design efforts. The idea of naturally heating your home requires the winter sun to enter the house through correctly positioned windows during the day, to enable it to heat the internal bones of the house. This heat then radiates to maintain a stable internal air temperature in the evening, counteracting the natural drop in air temperature.
SO HOW DO YOU GO ABOUT NATURALLY HEATING YOUR HOME?
To start with, a well positioned block is required. Finding the right block is the first step when considering a passive design. Ideally, you should look for a block that is elongated on an east-west axis, which gives the opportunity to elongate the buildings north face, exposing it to as much sunlight as possible.
LET THERE BE LIGHT
From here, the buildings openings should be positioned to expose them to as much sunlight during the winter months as possible. This means a larger percentage of north facing windows and greatly reduced windows in all other orientations- this is where elongating the building along the north face comes into the equation. Correctly designed shading needs to be incorporated to ensure the windows are shaded from the harsh summer sun, but the lower angled winter sun is still able to enter into the home.
Along with allowing the suns heat into the house during winter, windows also allow the trapped heat to escape- this is where correct window size and type comes into play. It’s not as simple as more north windows equal more winter heat gain and a warmer house.
The next step is to trap the heat from the suns rays, which can then be radiated into the house when the sun goes down, counteracting the natural drop in internal air temperature.
Dense thermal mass materials such as brick, stone and concrete should be utilised inside the house for flooring and walling to store the absorbed heat. The heat absorbing material can be the thermal mass itself, or it could be an additional dense, hard, dark material layer over the thermal mass. Lighter colours reflect heat whereas darker colours absorb heat, so a darker absorbing material is going to work better than a light coloured material. Once the heat is absorbed and stored, when the internal air temperature drops, the heat from the thermal mass will radiate, maintaining a stable internal temperature.
Thermal mass is a fantastic feature of the home as not only does it have a functioning purpose, but also can be used in an aesthetic manner to create a truly beautiful area. Brick, stone or concrete can be exposed in its raw element as a feature. Cleverly designed windows can also be positioned to shine light directly on to feature thermal mass walls to directly heat them.
A BLANKET FOR YOUR HOME
There is little point absorbing natural heat into your home if it’s just going to escape as the outside temperature drops.
Insulating your house is like putting a blanket over your home in the evening. High level insulation should be used throughout the home, in the roof, ceiling, walls and under the floor. This insulation traps the warm air inside the house and prevents the cool air from transferring through the external house skin into the home.
Additionally, thick curtains on all windows should be used, which should be drawn as soon as the window is no longer exposed to direct sunlight. Windows (even double glazed windows) are one of the areas where the most heat is lost in a well insulated house. These thick curtains serve the same purpose as insulation in your walls.
Ensuring the house is well sealed from air leakage and drafts is another measure that should be taken. Any escape of the internal warm air, or entering of cool air into the house over the cooler evenings, no matter how small, will have a dramatic negative impact. Additional care should be given even to the smallest items such as sealed down lights. Unsealed down lights work like a little exhaust fan, sucking the warm air as it rises into the roof space.
WHAT ELSE CAN I DO?
Zoning your house into separate living, sleeping and utility zones is a great measure that can be taken. Use doors to separate the living spaces (which are exposed to the north and naturally heated) from the sleeping and utilities zones, which are likely not exposed to the north. This means the natural heating isn’t working as hard trying to heat an entire house, but only the dedicated living zone.
Reversing ceiling fans in the winter. As warm air is less dense it rises, by reversing the fan blade rotating direction to clockwise you drawn the warm down to the space in which you are occupying.