Windows typically occupy about 15 to 20 percent of the surface area of the walls. Windows not only add aesthetic looks and often a very important aspect of a home, but also a very significant component of home heating and cooling costs. Windows lose more heat per square meter of area in winter and gain more heat in summer than any other surface in the home if not energy efficient.

1. LIFE CYCLE COST ANALYSIS BETWEEN DOUBLE
GLAZED AND TRIPLE GLAZED WINDOW TO
PROPOSED STUDENT HOUSE
BUKAR ALI KIME
17500831

2. ABSTRACT
• Windows typically occupy about 15 to 20 percent of the surface area of the walls.
Windows not only add aesthetic looks and often a very important aspect of a
home, but also a very significant component of home heating and cooling costs.
Windows lose more heat per square meter of area in winter and gain more heat
in summer than any other surface in the home if not energy efficient.

3. INTRODUCTION
• An average home loses up to 25% -
30% of its heating and cooling energy
around windows and doors. If you have
inefficient windows installed in your
building, you also have rising energy
costs because of the energy that you
will used for the heating and cooling of
the house. An energy efficient home is
a comfortable home, as it is one that is
easier to heat or cool.

4. DOUBLE GLAZED WINDOW
• Double-glazed windows have two panes of
glass fitted into a window frame. An inert gas
like argon is filled between the two panes to
increase insulation. Double glazed glass is
perfect for weather conditions, especially where
there are scorching summers and moderate
winters. The double window panes not only
provide relief from extreme temperatures
outside, but also insulate your space from the
noise outside. They are also very hard to break
through and therefore provide you with ample
security against intruders.

5. HOW DOUBLE GLAZED WINDOW WORKS
• A single pane of glass provides very poor insulation because
glass is a good conductor of heat. So much of the heat in your
room literally goes out the window. Install double glazing and
you have a layer of air or argon gas trapped between two panes
of glass. Because air or argon gas is a poor conductor of heat,
much less heat is lost through the window. If the inside of one
sheet has Low E coating, even less heat is lost because the
coating reflects heat back into the room. A house with double
glazed window operates just like fibreglass batts and woollen
clothing. It traps a layer of air or argon gas between two panes.
Air or argon gas is a very poor conductor of heat, so the trapped
layer sets up a blanket of protection between cold air on one
side and warm on the other. Glass itself is a very good
conductor. So in a home without double glazed window, heat is
going straight out of the window. As shown in the figure 4.
Argon gas is an inter gas.

6. TRIPLE GLAZED WINDOW
• Triple-glazed windows, as the name suggests,
have three panes of glass fitted into a frame.
The three sheets of glass have two air gaps
filled with argon.
• These window offer 28% - 30% (approximate)
more insulation than double-glazed window. It
also decreases thermal transfer by 75% - 80%
making it the most energy-efficient option
around. It also mitigates noise. Therefore,
triple-glazed windows perform all the functions
of double-glazed windows, but with more
effectiveness. They are just marginally more
expensive.

7. HOW TRIPLE GLAZED WINDOW WORKS
• Windows has many uses such as
allowing light into a building,
enable us to see outside from the
home and, at the same time,
keeping the inclement weather out.
All this be achieved by a window
with a single pane of glass, triple
glazed units provide the more
insulation against the loss of heat,
wind, rain and reduce noise levels
from outside the home.

8. METHODOLOGY
This research focuses on the following two questions:
• The energetic performance of window types (does double glazed or triple glazed
window reduce required heating and cooling energy?)
• Life Cycle Cost analysis of the two types (is it financially beneficial and feasible to
invest in triple glazed or double glazed window?)
The energetic performance is measured using computer analysis software (EnergyPlus),
which also gives us our usage cost. Using life cycle analysis data, a comparison is made
concerning the environmental costs of the product itself, and a quick cost comparison
shows the financial benefits and drawbacks between the two products and the payback
period of the two different window types.

9. CASE STUDY
• The case study of this experiment is setup for a proposed student house for Eastern
Mediterranean University Located Famagusta North Cyprus. The house is 350 meters
square with openings on each side. It consists of 6 bedrooms 3 livings and a study
room where by must to the living space are oriented to face the south side for passive
solar energy gain during winter, and this can also reduce the heating load as well.

10. TESTED GLAZING TYPES
• There are many type of available glass that can be compared are chosen for this
research. For this research, five type were tested, all commonly used products in
building industry, and standardized for energy-plus calculation (energy calculation
software or simulators). A single plate glass type is used as a reference, and for each
double and triple glazing unit a high performance variant is added. “UGlass” is the
insulation value, and “Trans” is the transmission value. The once with “HR” means
glazing with Low-E Coating in the middle of the glaze.

11. ENERGY CALCULATION
• The graph in figure 6 above shows
the total energy usages of the
various glazing types and for the
30% and 90% south glazing houses,
as well as the models with increased
wall insulation. It's immediately clear
that there are large benefits to using
double glazing types and beyond. It's
also clear that the double HR glass
outperforms the normal triple glazed
unit.

12. CO2 GENERATION AND SOLAR GAIN
• From figure 7 above, it shows that the left side of the figure shows the
gas usage versus CO2 emissions. We can see that they are related, but
that CO2 emissions are not decreasing by as much as the gas usage of
the entire house. This is due to other forms of energy use within the
house such as electricity and water. This means that only a limited
amount of CO2 reductions can be affected by glazing types.
• On the right of figure 7 we can see a large difference in solar gains
between the different glazing types due to the difference in
transmission values. Glass with a higher transmission value admits
more light and heat from the sun. In winter this has a direct effect on
gas usage, and the effect is in the same order of magnitude as the gas
usage itself. This explains why the double HR glass outperforms the
normal triple glazing types, despite the higher insulation value of the
triple glass types, because the double HR glass allows more solar
energy to enter the house, which will help in heating the building
interior during the winter time of the year. Which will also drastically
reduce the use of gas itself.

13. COST
When you start investing for double glazing or triple glazed windows, you'll find the
following aspect affecting the cost of the window:
• The material the window frames are made from
• The window style
• The type of glazing used
• The size of your installation
Source: Leroy Merlin Company (https://www.leroymerlin.com.cy/)

14. COST SAVINGS
• All houses lose energy through their windows. It is a natural thing. But double
glazing or triple glazing keeps your home warmer or cooler as well as reducing
your energy bills. The costs and savings will be different for every home,
depending on its size and the quality of the glazing types. It is expected that on a
standard house, you can save approximately 200-250 euros per year with double
glazing and 200-280 euros per year with triple glazing.

15. SCENARIO
S/n
o
Cost Double Glazed
Window
Triple Glazed
Window
1. Investment Cost 350 x 12 = 4200
euros
460 x 12 = 5520
euros
2. Implementation
cost
7 x 20 = 140 euros 10 x 20 = 200 euros
3. Maintenance cost 3 euros/year 5 euros/year
4. Electricity bill
saving
200 euros/year 200 euros/year
5. Life span 20 years 20 years
Following a simplified version of the proposed case
study models, I am comparing the implementation
costs with the benefits gained during the life span
of the product. The double glazed and triple glazed
(HR) products are shown for a period of 20 years.
For the proposed student house with south glazing
(12 glass opening of 2.1 x 1.2m). We are using a
value of 350euro for double glazed window and
460euro for triple glazing with an interest rate of
6%.