Choosing Frames & Glass

We all know windows and doors make a big difference to a home. If not we would only need holes in the walls. When you think about it, it is not light and ventilation that we need first from windows. It is protection. Let’s have a brief look at what windows can do for us. Hopefully this will help you make really good choices that will give you great satisfaction for decades to come. To make it easier we will group the main features.

LIGHT

1m

view east at 5pm

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view west at 5pm

Lighting needs vary for different rooms and different times of day. A good starting point is to consider when you are most likely to need natural light in any particular room. Bedrooms, for example, are usually occupied at night, for a short time in the mornings and for longer periods in mid and late afternoons. This leads us to the question of which way a window is facing. If your bedroom window faces east it will have afternoon shade when you most need the light . If natural light is important to you, choose a slightly larger window. On the other side of the house, western bedrooms can be extremely bright in the afternoons . For west facing bedrooms light will rarely be a problem, but overheating may be! Provided other needs are met western windows should be smaller.

North is the sunniest side of the house. In Victoria north facing windows offer more than other windows because they usually get more light and gain the most from the suns free energy in cooler months. (Skilful design and placement of north facing glass is a big key to successful home plans. This subject is addressed under  ‘Services – Design’).

VENTILATION

The Australian building code requires all living spaces to be properly ventilated. This is reflected in every building plan that is approved (the required area is usually 5% of floor area that must be included as opening window sash). This is sometimes true, however many make the mistake of thinking; ‘bigger is better’ and therefore opting for much bigger windows and opening parts. It surprises them to discover that this is a mistake. The results of this mistake included excessive heat and cold, especially in west facing windows. There are some tricks to know that will allow you to have great natural ventilation when desired and to satisfy the other vital aspects of a really good and efficient design.

Have you ever found yourself sitting in a hot stationary car? Winding one window down helps give you some fresh air. Winding down a second window on the opposite side of the car usually works much better because air can enter one side and exit the other creating a natural flow. This is called cross ventilation. In homes it can work even better, especially double story homes, because you can open a high window and a low window at the same time to take advantage of the natural tendency of the hot air in the top of a room to flow out drawing cooler air in down below. This will set up positive air-flow even on calm days. Why is this a good thing? Great design gives you better control of your home environment. It means that your home will be able to give you even more free heating and free cooling days each year. Doing this is a win for you and a win for the planet.

APPEARANCE

Appearance is important. It is a personal thing. Glass looks great. It can make or break a room too! We see a lot of sleek clean expanses of glass. Very often they look good but make the rooms inside too cold, too bright or too hot depending upon the aspect they hold, the time of day and time of year. For appearance the frame type you choose is relatively minor provided the window frames are in good condition. The colour is important.

Using a frame colour that contrasts to that of the home will draw attention to the window frames themselves unless the colour matches well with other parts of the home like roof and gutters. Colour tones that blend in with the walls help show off the home as a whole. The overall impression of a home will vary from one person to another, so why not design to windows to impress yourself first? How impressed you are with the look of your home and its windows will depend a lot on how well you understand what they are doing for you and your family. Impressing ‘The Jones’ should only be your main concern if your name is Jones.

For those who already understand good design viewing a house is similar to viewing people; a bikini clad beach-girl and large expanses of exposed glass may look good in winter, but they can look silly at the same time. If you are still in the design phase we can help you.

INSULATION VALUE

Heat loss from standard single glazed windows can be as high a 40% in cold conditions. Keeping the home warm would mean turning up the heat to compensate. With the heat turned up and much of it being lost through the glass, rooms are not warmed evenly. Living spaces closest to the glass and heating will feel less comfortable.  With fan forced heating systems there will be a draught and some noise as well. With curtains and blinds drawn, natural light and view is lost.

Insulating your windows and glazed doors with double glazing has the effect of making rooms more comfortable, less draughty, quieter and cheaper to run in winter and summer.

The frame type you choose is less important than your choice between single or double glazing because the glass itself is the larger part.  The frame type should be considered alongside questions of looks, functional efficiency, durability and up-keep. These days, all window frame materials are now achieving high insulation values. Aluminium windows are now available with thermally broken frames. These frames have an inner and an outer part that is separated by an insulating section made from PVC to give excellent insulation performance.

Special glass coatings designed to reduce heat loss in winter and heat gain in summer can be very useful.

FREE HEATING

Well designed windows can get you a lot of free heat in cooler months. Double glazing will help you keep it. The same well designed windows can exclude summer heat giving you the best of both worlds. Northern aspect windows and glazed doors are particularly important for this. When combined with day-time living spaces in your home it will be possible to capture a lot of free winter home heating directly from the sun and enjoy the sunshine at the same time. The higher sun angles in summer allow well designed homes to exclude unwanted heat.

PRIVACY

For windows that you require to have a view and privacy this can be achieved by use of reflective or tinted glass that offers a clear view from inside whilst giving you privacy.

NOISE INSULATION

Any single glazed window will reduce noise transmission when it is closed. Double glazing upsets the passage of sound even more . It reduces most common noises like traffic noise and voices to about half of what you would normally expect to hear through single glass. (In the case of secondary glazing is is usually possible to reduce noise even further because designs can be optimized for noise reduction. See Products – Secondary glazing)

MAINTENANCE & DURABILITY

For weather-exposed windows and doors maintenance can be important. Aluminium frames, being strong and virtually maintenance free in any weather, have a natural advantage over most other frames. The life-expectancy of aluminium frames has not really been tested and may run to centuries or longer. This may be a longer time frame than we are worried about, but it cannot be a bad thing when combined with the knowledge that maintenance will only be occasional cleaning and possible replacement of locks or hinges.

Having said how good Aluminium frames are, it is fair to mention that wooden frames made from good quality timbers are rigid, durable attractive and offer excellent insulation. With good weather protection most windows frames will last a long time.

FIRE RESISTANCE

Window and door frames are usually the front line in fire defence and vulnerability. In fire-prone areas the use of metallic screens externally can reduce fire danger by diffusing heat and stopping embers.

SECURITY

Security is enhanced by the use of strong frames and toughened glass. Both can make unwanted entry to your home more difficult. A window that has been snibbed from inside is effectively secure from outside unless someone breaks the glass. A key-locked window can prevent children or others climbing or falling out. It may also prevent them from leaving in a fire emergency! It is wise to have a good security and fire plan that is known to all household members.

FUNCTIONALITY

Protection is the number one job of any window after light and ventilation. To protect really well a window must be able to seal effectively to stop draughts, dust, insects and heat passing through. Aluminium frames are ideal. Machine perfect, the hinged models have fitted rubber sealing tapes similar to the car doors (usually two or three) that compress when the windows sash is closed giving a tight seal. The brushes on sliding models are also efficient. Rigid frames that do not warp or flex, built-in seals and ease of use are advantages.

SUMMARY

Windows and glazed doors are a very important to how well a home protects you. In terms of heat and noise efficiency double glazing is far better than single glazing. Those who have it are unlikely to go back to single glazing. All window frame materials types have advantages. Windows and doors made with aluminium frames or wooden frames of Australian Kiln Dried Hardwood or Western Red Cedar are very good.3

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