70 mm or 86 mm profile: which windows to choose in 2026 and why more and more customers are switching to warm systems.

Choosing a window profile is one of the key factors that directly affects warmth in the home, noise levels, and future heating costs. Systems with a 70 mm installation depth are still available on the market, but customers are increasingly considering more modern solutions — the 86 mm profile, designed for energy efficiency and comfort.

70 mm profile windows: a classic solution.

PVC windows with a 70 mm profile are a widely used standard that has been in use for many years. These systems allow installation of:

• glass units from 24 mm
• extended options up to 40–44 mm

They provide basic thermal insulation and are suitable for standard operating conditions. However, it is important to consider that 70 mm profile конструкции have limitations:

• thinner glass units
• typically 2 sealing contours
• lower level of airtightness

With rising heating costs and increasing energy efficiency requirements, such windows are not always the optimal solution.

86 mm profile: modern warm windows.

Window systems with a depth of 86 mm represent a higher level of comfort and thermal insulation. These windows are designed according to modern energy-saving requirements and are suitable for both apartments and private houses.

Key advantages:

• glass units up to 48 mm
  significantly reduce heat loss and improve energy efficiency
• three sealing contours
  improve airtightness and protect against drafts and moisture
• high sound insulation
  especially relevant in urban environments, particularly if windows face the road
• thermos effect
  keeps heat inside in winter and protects from overheating in summer

Why the 70 mm profile is no longer a forward-looking choice.

With current heating energy tariffs, installing windows with a 70 mm profile is increasingly becoming a compromise solution. Savings at the purchase stage may result in:

• higher heating costs
• less comfortable indoor climate
• faster obsolescence of the window

That is why, when choosing plastic windows, it is important to consider not only the price but also long-term efficiency.

Real practice: replacing old windows with 86 mm systems.

According to our company statistics, about 30% of clients approach us with the task of replacing already installed old-type windows (including 70 mm profiles) with warmer systems.

Most commonly chosen:

• 86 mm profile
• 48 mm glass unit
• 3 sealing contours

Main reasons:

• cold indoors during winter
• street noise
• overheating in summer
• desire to reduce heating costs

Conclusion: which windows to choose

If windows are considered as a long-term investment, the choice is obvious:

• 70 mm profile — a basic solution that is gradually becoming outdated
• 86 mm profile — a modern standard for energy-efficient windows

Such windows provide:

• savings on heating
• a high level of comfort
• excellent sound insulation
• a stable indoor climate all year round