Solar Tube Options

Sometimes our homes are a little lacking in the light department.solar tube

Even if there are lots of windows, if your property is overlooked at all, or faces the ‘wrong way’, you might find yourself craving that natural light.

You may need to light

  • Bathrooms,
  • Walk in Robes
  • Corridors
  • Pantries
  • Toilets

That’s where Solar Tubes come in handy.

By allowing bright natural light to pour into your home, these economic fittings add a stylish new dimension to your space.

 

Room Sizes

Domestic units come in two sizes:

A smaller size suitable for rooms 3m x 3m

A larger unit suitable for rooms up to 5m x 5m.

For larger spaces you can use multiple fittings, or go for a commercial unit.

The units come in a wide range of prices from a simple unit with a flexible light duct, through solid duct models, to top of the range models which incorporate LED lighting.

 

Ceiling Diffusers

Because they have a range of ceiling diffusers they fit perfectly with all styles of interior – from modern contemporary to more traditional older-style properties.

 

 

 

Energy Through The Windows

Ever wondered how much actual benefit you get from the sun shining in?

How The Sun’s Energy Warms Your Home.

Basically when the suns energy (which includes both visible and invisible energy such as Infra Red and Ultra Violet [UV] radiation) hits your window three things happen to the energy:

  • Reflection – Plain glass will reflect around 8% of the total energy.
  • Absorption – 5mm plain glass (the minimum thickness for most domestic windows) will absorb around 12% of the total energy. (Typically around 1/3rd of the energy that is initially absorbed is re-radiated to the inside of your house)
  • Transmission –  The remaining energy, 82% of total energy for 5mm glass will be transmitted into your home.This is known as the RAT Equation

    Solar Heat Gain Co-Efficient (SHGC)

    Rather than have to keep working through the RAT Equation the glass industry has come up with a Solar Heat Gain Co-Efficient which makes calculations easier.

    Values of the SHGC range from 0.82 (5mm float glass) to around 0.15 (double glazing with reflective coatings.

    There is more information including SHGC values for a wide range of glazing types at www.nationalglass.com.au

    To find the amount of energy coming in through a North facing window you multiply the radiation from the sun by the SHGC.

    Winter Example Calculation

    For a sunny winters day in Melbourne that the average angle of the sun on the window will be around 20 degrees, so around 800 watts of energy will be  falling on each square metre of glass.

    The Solar Heat Gain = 8oo watts/m2  x  SHGC 0.82  =  652 watts/m2

    Assuming that on that sunny winters day the outside temperature is 10 degrees and the internal temperature is 22

    Heat loss through the window = 12 degrees x ‘u’ value of 5.8 = 70 watts/m2

    Net heating benefit of the window =  652 – 70 =  582 watts / m2.

    Summer Evening Example

    For a summer evening in Melbourne  the average angle of the sun on a window facing the sun will be around 10 degrees, so around 900 watts of energy will be  falling on each square metre of glass.

    The Solar Heat Gain = 900 watts/m2  x  SHGC 0.82  =  738 watts/m2

    Assuming that on that summer evening the outside temperature is 35 degrees and the internal temperature, with air conditioning, is 22

    Heat gain through the window = 13 degrees x ‘u’ value of 5.8 = 75 watts/m2

    Net heating gain of the window =  738 + 75 =  813 watts / m2. (no wonder the air conditioning is working hard!)

For more see Sustainability

 

Big Window – Fail

I have previously talked about Good Orientation and Window Size in this Blog.

It’s not as though this sort of information is secret knowledge. . . . . I would have thought all architects would be aware of the importance of these sort of issues.

So I wonder why this custom designed,  suburban house in Melbourne has this huge South facing window.

Here is why I think it’s a fail:

  • Minimal privacy.
  • Massive heat loss in winter meaning huge heating bills, or a house like a fridge.
  • No solar benefit in the winter.
  • Considerable heat gain in summer due to the poor insulation value of glazing.

Just in case you thought the purpose of the window was to take in a magnificent aspect . . . . . here is the view!

 

 

For more Unusual House Photos, Wins, and Fails, have a look at: What the………………….?

 

Window Abbreviations

When you are looking at builders plans it can be hard to understand what all the abbreviations mean!

Here are some common window Abbreviations /Acronyms:

AL – Aluminium (also Alum)
AW – Awning Window
CG – Clear Glass
CLR.OPG – Clear Opening
CR – Curtain Rod
DG – Double Glazing
DH – Double Hung
FG – Fixed Glazing
FO – Finished Opening
FR – Frame
FRG – Fire Resistant Glazing
FS – Fire Shutter
GB – Glass Block (also GL BLK or GLB)
GP – Glazed Partition
HSW– Horizontal Sliding Window
IS – Insect Screen
LVR– Louvre
MUL – Mullion
OB – Obscured (e.g Frosted also OG -Obscured Glass)
OPG– Opening (also OW – Opening Window)
PG – Plate Glass
PW – Pivot Window
RS – Roller Shutter
SD – Sliding Door
SGS– Silicone Glazing Sealant
SH – Side Hung
SW – Sliding Window
tr – Transom
UPVC– Unplasticised PVC
VP – Vertical Pivot
VS – Vertical Sliding
WERS– Window Energy Rating System
WF – Wood Frame
WG – Wired Glass
WS – Window Sill (or Cill)
WW – Window Wall

If you have seen an acronym you don’t understand, then let me know, and I will try to give you an answer.

See Jargon for more posts

 

Skylights

Thinking about putting some skylights in the roof?

Planning one of those rooms with a glazed roof panel?

You really need to think very carefully before you go ahead!

Summer

In summer the heat gain and glare can be enormous causing major overheating. A typical North facing 900mm x 900mm sky light can put 3kw of heat an hour into your room between 9.00am and 3pm.

Sky lights are difficult to shade effectivly, although putting them on a South facing roof can help. Don’t forget though in most of Australia the sun is almost directly overhead in summer.

Winter

As heat naturally rises in a room high level windows can lose 30% more heat than a typical  window in a wall. Even with double glazing you will be loosing far more heat than would be the case for an insulated ceiling. With the sun at a low angle you will also get minimal heating benefit on sunny winter days.

Generally

If you feel there is no alternative keep the skylight as small as possible (see Australian Standard AS4285 Skylights for sizing guidelines), or use daylight tubes.

A better solution is Daylight Tubes

 

Daylight Tubes

Solatube

If you have a gloomy smaller room (for example bathroom, WIR, or hallway) consider a daylight tube. They are a more energy efficient alternative to conventional skylights or having to keep putting the lights on.

Daylight tubes have three parts:

  • Roof mounted clear, hemispherical dome
  • Connecting  smooth highly reflective tube/duct
  • Ceiling level diffuser

As they require a smaller area of roof glazing than a traditional skylight, heat gain in summer and heat loss in winter is significantly reduced.

 

Selection and Installation

Smooth shiny tubes. will deliver more light than corrugated flexible tubes.

Although the advertising show the ducts bent into all sorts of shapes in practice the straighter the tube the better the light.

Although you can buy DIY kits working on a house roof is risky. If you are not confident it may be better to pay for it to be installed.

Make sure the ceiling insulation is replaced tightly around the tube

The Risk Of Too Much Security

As I visit lots of houses I often wonder if some houses have too much security.

I see lots of houses with roller shutters or even steel gratings over the windows like these.

Quite often when I ring the bell the owner seems to spend ages unlocking the various locks and bolt on the front door.

Yes they are keeping people out . . . . . but what happens if there is a fire in the house?

In a typical year around 70 People die in Home fires in Australia.

So before you put more security in your house . . . .Think about how you would get out in a fire!

Here are some thoughts about making sure you keep safe:

  • Although I typically have two locks on my doors I only lock the deadbolt when I am going out.
  • If you do want to lock the deadbolt while you are inside always leave a set of keys where it is easily accessible in an emergency.
  • Think about how you would escape through the window if you couldn’t get to the door. I would be able to smash a window and get out . . . But would shutters or bars lock you in, with the flames!

 

See : Doors and Glazing for more posts

 

 

Upstairs Windows

 

Have you got visions of being able to look out of your upstairs bedroom windows like this lady.

Not anymore if you are building a new house. New laws to protect children falling out of windows have come into force.

Since 1 May 2013, the Building Code of Australia (BCA) requires “protection for openable windows in new homes where the floor below the window is more than 2m above the surface beneath” (i.e. 2-storey homes).

The protection is either a device to restrict the window opening, or a  screen, so a 125mm diameter sphere (representing the size of a young child’s head) cannot pass through. The device or screen must also be able to withstand an outward  horizontal force of 250 N.

 

The picture is called “By the open window” painted by Konstantin Makovsky.

 

For more about windows see : Glazing

Roller Shutters – Fail

Sorry if you like them……….. but I just don’t get roller shutters!

To me they just say someone has got it wrong.

You have a house built with nice big windows and then you install shutters.

Either the orientation is wrong,….or if its a security measure you bought in the wrong neighbourhood!

As far as security goes good Double Glazing can provide similar security, similar insulation, and lets the light in!

And as for houses like the one below which has shutters on upper floor, South facing, windows what are they worried about?

 

For more Unusual Houses and Fails see What the………………….?

 

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