Thermal insulation



All properties and business lose heat through their windows. But energy-efficient secondary glazing from NLSG keeps your home warmer as well as reducing your energy bills. Explore the real benefits of thermal insulated high quality secondary glazing





Benefits of secondary glazing for thermal insulation



Reduces heat loss

Minimises draughts

Increases the rating on an EPC (Energy Performance Certificate)

Improves comfort

Reduces energy bills

Reduces air infiltration

Assist with BREEAM ratings

Meets heritage guidelines







Secondary Glazing Products


Find out more information about the different types of secondary glazing we can provide





Secondary glazing noise and sound insulation properties



Secondary glazing noise and sound insulation properties



Secondary glazing noise and sound insulation properties

NLSG Energy Efficiency


Our Energy Efficiency range of secondary glazing is often the best choice when coming to choice a secondary glazing product.

Correctly specified and installed, our secondary glazing can achieve thermal insulation for windows with a better rating than the Building Regulations requirements.

It is also the product of choice for traditional buildings and properties, Listed Buildings & Conservation Areas, maintaining their appearance, character, integrity & value.


Key thermal points


  • designed for maximum energy efficiency
  • very effective against heat loss through the windows
  • extremely discreet for glass & glazing insulation
  • the best all-round single glazing insulation available
  • environmentally friendly and saves energy
  • much more economical than replacement double glazing




Optimum thermal performance U-Values



U-Vaules thermal properties secondary glazing


Standard Thermal Insulation Performance


Assuming an average single glazed primary window, using secondary glazing with 6mm Low E glass, we can achieve thermal efficiency U values for windows of 1.5W/m²K - compared to the standard for commercial replacement windows of 1.8W/m²K


Excellent Thermal Insulation Performance


Assuming a single glazed primary window, using a secondary window with a combination of 6mm Low E glass and argon-filled sealed units our secondary glazing systems can achieve thermal efficiency U values for windows of between 1.2 and 1.0 W/m²K




Secondary Glazing Installation & After Sales Service


Installation dates are agreed well in advance by phone. We usually start early on the day of fitting! the fixing system is concealed we use a wide range of matching finishing trims to ensure a neat, sympathetic, discreet finished job



After installation you will receive:


  • Product demonstration from our installer
  • Comprehensive, no-quibble guarantee
  • Full set of maintenance instructions
  • Locally based after-sales service