+30 210 9734853 info@demenegas.gr

Customer Care

Frequently Asked Questions

What should I do before choosing the door and aluminum window manufacturer?

A) Select a certified manufacturer. Certified by an independent operator for the production process, not only by the company’s system provider.

B) Take care of the ‘traps’ in the offerings. It is not only the range of aluminum profiles but also the mechanisms, paints, and glass panes. The quality of the parts plays a decisive role in the lifetime of the frame.

C) Visit the manufacturer’s workshop. A look at the manufacturer’s level of organization will give you useful conclusions.

D) See real works of the manufacturer. Over one.

E) The system (aluminum series) is not related to the quality of construction. The proper operation of an aluminum window and the durability depend on many factors. Chassis-fittings-glazing-construction and fitting play a decisive role.

What do I gain if I change the old window frames with new ones?

It is now known that one of the main reasons for energy loss in buildings is the old-style window frames. New technology frames following the parameters of the building ensure the reduction of this loss in heating-cooling up to 35%, increase the sound reduction to 100% air permeability to 100% and water permeability of 100% as well.

Short example.

85sqm residence with a total glazing area of ​​15m (single glazing with U-value 5.7W / (m² * K)), year of construction 1973.

Consider a cold winter day with an outside temperature of 6 ° C and an internal temperature of 24 ° C. Temperature difference of 18 ° C. This means that the thermal losses of the house due to the old windows are 5.7 x 15 x 18 = 1.539 Watts. So if we change the old window frames with new heat-shrinkable frames with Uw 2.0 W / (m² * K) in the same house with the same temperature difference we will have the following heat losses of 2 x 15 x 18 = 540 Watts.

If we calculate the current cost for the heating needs with old windows in the period November-February and cooling in the period June-September to 0.12 € / kWh to 2000 kWh then at 12 hours we have a cost of 8.21 € which in the four months is translated at the cost of thermal losses of 985 € for 2000kWh. By replacing the old frames and making the same calculation with the same parameters the cost of thermal losses is reduced to 345.6 € / four months. So we save 639.4 € / four months simply by changing the frames!

What is the Uw coefficient in the windows?

Uw is the coefficient of thermal permeability of the aluminum frame. It shows the amount of thermal energy that transmits an enclosure from outside to the opposite. It comes from a mathematical formula taking as parameters the aluminum profiles and the glass pane. The lower the factor, the less energy is transferred.



For more information please do not hesitate to contact us. We will be happy to assist you.

Address: 17 Soufliou street, Aghios Demetrios, 173 43

Phone:+30 210 9734853

Opening Hours: 7.00 – 17.00 Monday – Friday, 7.30 – 15.00 Saturday

Rules for maintenance and proper operation


Doors should be opened and closed with care and meticulousness. Particular care must be taken when closing the window to prevent damage to an accessory or mechanism.

Clean the frames with a soft cloth and neutral cleaning fluids often, in-out. Never use acids or other strong cleaning fluids. Do not rub the frames with brushes or other engraving materials.

Aluminum frames are designed to accept and expose the rainwater through the drainage water sinks. This does not mean that they have the ability to dispense water drops on them with high pressure, such as when they are pouring water with the watering hose pressure. It is recommended to avoid this cleaning method.

The customer’s obligations are the general service of the frames every three years in order to maintain proper operation.

The company assumes the cost of service components if the replacement is notthe fault of the customer.

In all cases the cost of work is undertaken by the customer.
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