How to choose your joinery
The questions our clients ask most often before ordering and after fitting – with short answers.
PVC or aluminium
PVC
PVC is a very good heat insulator: its profiles are close to timber in this respect and hardly ever mist up, but unlike timber they need no special upkeep. The windows keep out cold, noise and dust, and washing the glass and frame regularly is enough to keep them looking good for years.
The more chambers a profile has, the better it insulates – and the more it costs. Where the profile comes from is the first thing that ensures a long life for the window: serious makers control quality from the raw material to the finished profile.
Rigid PVC is a flame-retardant material (class B1 under DIN 4102) – it does not keep burning once the outside source of fire is removed.
Aluminium
Aluminium does not oxidise, keeps its strength and practically does not age. It does conduct heat well, though, so for the exterior glazing of a home or office in our climate it is best to use profiles with a thermal break – plastic inserts that divide the profile into an inner and an outer part. The width of the thermal break matters for the result.
“Cold” aluminium, without a thermal break, costs less and suits partition walls and other interior structures.
Replacing the joinery is only one of the steps towards a well-insulated building. Windows account for 20–30% of the heat lost, depending on the type of glazing.
Glazing units
A glazing unit is two or more panes of glass with a hermetically sealed air gap between them. The standard thicknesses are 24, 28, 32, 36 and 40 mm.
Heat insulation depends on the number and type of panes. As a rough guide, condensation may appear on the glass:
| Glazing unit | Condensation at |
|---|---|
| Double | −7 to −9 °C |
| Triple, same thickness | −16 to −19 °C |
| Double with low-emissivity glass | none even at −27 °C |
Do not save on the glass
The glazing unit takes up almost the whole area of the window, the frame only a small part. Saving on the profile system is therefore a better compromise than saving on the glazing. Choose the best glass you can afford, so that your investment really pays off.
Sound insulation, too, depends more on the glazing than on the frame material: on the thickness of the panes, on whether the two panes are equally thick, and on the number of gaskets.
Types of glass
- Float
- The most common glass today – perfectly smooth and free of optical distortion.
- Low-emissivity
- Has a coating that reflects the heat from your heating back into the room while letting light through freely. The unit is filled with gas – argon, krypton or xenon. An alternative to triple glazing, but it does not solve a damp problem in the room.
- Toughened
- Stronger under impact and sudden temperature changes. When broken, it crumbles into small pieces without sharp edges.
- Laminated
- Two or more sheets of glass bonded with resin or film. It holds together when broken, protects against break-ins and vandalism, insulates sound very well and blocks ultraviolet rays.
- Solar control
- Tinted through the glass or given a reflective coating.
- Wired
- With a metal mesh – fire and impact resistant. When broken, the mesh holds it in place and stops fire from spreading.
Hardware
Hardware is the set of parts and mechanisms that hold the opening sashes and decide how they open. Good hardware presses the sash evenly all the way round, which improves heat and sound insulation, and keeps the window working without trouble for years.
We work with German Siegenia-Aubi hardware, adjustable in every direction. Siegenia was founded in 1914 in the town of Siegen, specialises in hardware for windows and doors and has been on the Bulgarian market since 1994. Besides the classic side-hung and tilt-and-turn openings it offers less usual solutions too.
Hardware makes up 10–20% of the cost of a finished window.
What sets Siegenia apart
- The hinges have bushes that prevent metal rubbing on metal, and carry up to 130 kg.
- The fixing holes pass through the steel reinforcement of the profile.
- The mechanism lets the sash open on both a horizontal and a vertical axis.
- Visible parts have decorative caps in different colours.
- All mechanisms have a two-layer anti-corrosion coating.
- Depending on the locking parts, security classes WK 1 and WK 2 are reached – protection against break-in attempts by force, levers and tools.
Why condensation forms
Cooking, washing and bathing raise the humidity of the air at home; house plants add to it as well. Air can hold only a certain amount of moisture, and that amount depends on its temperature. When the moisture goes past saturation point, condensation forms on cool surfaces, in corners and wherever the air does not circulate.
The indoor climate is healthy at a relative humidity of 35–50%. So air the rooms regularly to stop moisture building up.
How to clean your joinery
Aluminium and PVC joinery has a coating that protects it from scratches, and it is easy to clean as long as that coating is not damaged. Make sure the products you use do not eat into this protective layer.
There are cleaners made specially for joinery – most good shops sell them. Clean the hardware regularly as well: built-up dust damages hinges, locks and handles.
Tell us the sizes and we will work out the price
The width and height of each opening are enough, plus whether you prefer PVC or aluminium. Together we will decide which option suits your home, office, shop or hotel best.