You can save money
by changing
the windows
In Finland, many houses still have the
original 30 or 40-year-old, or even older,
windows. Significant amounts of energy and
money are wasted due to the old windows.
The situation before window renovation:
• Old two-pane windows in poor condition with a U-value of over 2.5 W/m2K
and the calculated E-value, i.e., the energy consumption value of the windows,
approximately 275 kWh/m2.
• Direct electric heating
• Electricity price approx. €0.11/kWh
Detached house 125 m2
• Window area approx. 15%
• The new windows are Lammin
WattEco 200 windows, and the Motiva
energy window classification is based
on the VTT test report VTT-S-04085-15,
U-value 0.62 W/m2K and E=36.
• Energy class A++
Detached house 200 m2
• Window area approx. 15%
• The new windows are Lammin
WattEco 200 windows, and the Motiva
energy window classification is based
on the VTT test report VTT-S-04085-15,
U-value 0.62 W/m2K and E=36.
• Energy class A++
Here are some sound reduction values (dB) typical
for the Lammin windows with standard glazing:
The sound reduction capabilities of windows
can, on a case by case basis, be improved by
changing the distance between the window’s
glass elements as well as the air gaps.
Annual consumption difference
per window area:
275 - 36 = 239 kWh/m2
125 m2 x 15 % / 100 % = 18.75 m2
239 kWh/m2 x 18.75 m2 = 4,481 kWh
4,481 kWh x €0.11 kWh = €493
Annual consumption difference
per window area:
275 - 36 = 239 kWh/m2
200 m2 x 15 % / 100 % = 30.00 m2
239 kWh/m2 x 30.00 m2 = 7,170 kWh
7,170 kWh x €0.11 kWh = €789
When evaluated with the current
average price of electricity,
the heating energy consumption
may decrease by up to
When evaluated with the current
average price of electricity,
the heating energy consumption
may decrease by up to
Rw dB Rw+C dB Rw+Ctr dB
MEKA 35 - 42 32 - 40 28 - 37
MSEA 44 - 48 42 - 47 37 - 45
Eco Watt 44 - 50 43 - 49 41 - 47
ENERGY SAVING
POTENTIAL
SOUND REDUCTION OF WINDOWS
The sound reduction index according to Standard SFS-EN ISO 717-1:
• Rw medium frequency generic noise
• Rw + Ctr low and medium frequency noise, usually from urban traffic
• Rw + C medium and high frequency generic noise, typically from air as well as fast vehicle and rail traffic.
€500 a year
€800 a year