In the average home, a quarter of the heat generated disappears via the windows. At Senator Windows we’re working very hard to bring that figure down, for the sake of the environment, your comfort and your wallet. And heat loss isn’t just through the glass, every component, from hardware to frames, can play its part. For example, there are multiple chambers inside our window and door frames, which act as a barrier which make it more difficult for the heat inside your home to be transferred to the outside. Your glazing choice also plays a huge part in energy efficiency, as does the spacer bar and the gas barrier between the panes of glass. While the emphasis is on preventing draughts and containing heat inside the house, it’s also important to remember that sunlight is a source of natural, free energy. The use of different glazing options throughout your home will ensure you get the benefit of the sun’s warmth to heat your home.

Here are some of the questions we are often asked about energy efficiency. If there’s anything else you’d like to know, please don’t hesitate to ask your local Senator Dealer.


The Senergy range of uPVC windows is designed by Senator to provide the ideal combination of energy efficiency and security. The Senergy range offers homeowners a comprehensive choice of security and glazing options to suit all kinds of homes, from traditional, to modern, from window replacements, to new-builds and extensions.

Product Profile Glazing Locking System Glass Glazing Overall U-Value Window Energy Rating Solar Gain View Certificate
Senergy 6 Chamber 70mm Double Espag security locking Float low E 28mm 1.3 A rated- A 6 0.71
Senergy Plus 6 Chamber 70mm Double Shootbolt High Security Low Iron/Low E 28mm 1.3 A rated- A+12 0.75
Senergy Premium 6 Chamber 70mm Triple Shootbolt High Security Low Iron/Low E 36mm 1.0 A rated- A+20 0.64
Senergy Elite 6 Chamber 70mm Triple Shootbolt High Security Low Iron/Low E 40mm 0.9 A rated- A+24 0.64
Tilt & Turn Plus 6 Chamber 70mm Double Multi-Point High Security Low Iron/Low E 28mm 1.3 A rated A 2 0.75
Tilt & Turn Premium 6 Chamber 70mm Triple Multi-Point High Security Low Iron/Low E 36mm 1.0 A rated A 7 0.64
Tilt & Turn Elite 6 Chamber 70mm Triple Multi-Point High Security Low Iron/Low E 40mm 1.0 A rated A+12 0.64
Vertical Slider Energy Efficient Profile Double Multi-Point High Security Low Iron/Low E 24mm 1.4 A rated- A+11 0.75

uPVC Passive and High Performance Casement Windows from Senator are crafted using the EnergyPlus90 window system. Most uPVC window systems are limited to 40mm glazing options – however EnergyPlus90 offers triple glazing as standard, in a choice of 48mm or 56mm units. There are numerous combinations of glazing available for EnergyPlus90, to suit every type of installation. Triple glazed units can incorporate laminate glass if high acoustic values are important to you.


Profile Glazing Locking system Glass Gas Glazing Overall U-value Solar Gain
Passive House Compliant Window
9 Chamber 90mm Triple Espag Security Locking 6.8 Lam/Low E Argon 56mm 0.73 0.57
High Performance Triple Glazed Windows
9 Chamber 90mm Triple Espag Security Locking Low Iron/Low E Argon 48mm 0.78 0.64
9 Chamber 90mm Triple Espag Security Locking Low Iron/Low E Plus Argon 48mm 0.71 0.39
High Performance Quadruple Glazed Windows
9 Chamber 90mm Quadruple Espag Security Locking Low Iron/Low E Plus Argon 56mm 0.64 0.31
9 Chamber 90mm Quadruple Espag Security Locking Low Iron/Low E Plus Krypton 56mm 0.53 0.31

BER, or ‘Building Energy Rating’, is the standard used to measure the thermal efficiency of your home. BER ratings are a legal requirement for any building in Ireland which is being built, bought, sold or rented but they’re simple to get. You simply contact a BER assessor who will evaluate your home and issue a BER certificate. When evaluating windows and doors, the BER rating is based on the U-value (thermal transmittance) and the G-value (solar gain). BER ratings go from ‘A’ to ‘G’. ‘A’ means lower fuel bills, a warmer home and a property that’s more attractive to potential buyers or tenants. ‘G’ means your wasting heat and therefore money. Energy efficient windows and doors are a big part of it. If you’re building a new home, talk to your architect or BER assessor. They may have specific energy requirements for the windows and doors you choose.

Energy-efficient glazing refers to the double or triple glazing used in today’s windows and doors. They differ from traditional single glazing or old double glazing because they are built with the following:
Low-emissivity glass Low-emissivity or ‘low-e’ glass, has a special coating to prevent loss of heat through glass. This coating thermally insulates doors and windows, improving your home’s energy efficiency and saving you money on heating bills. Senator offer low-e glass as standard on all products where appropriate.
Low-iron glass Low-iron extra clear float glass, is practically colourless and lacks the green tone present in other glasses. It allows very high light transmission which can reduce the need for heating during winter.
Warm edge space bar All glazing options include a warm edge spacer bar between the panes. The spacer bar is a long, rigid warm edge tube that is sealed to the glass and keeps the panes separate. The composition of the warm edge spacer bar ensures that the glazing unit is structurally sound while also helping to reduce heat loss.
Gas The gap between the panes of glass is often filled with gas, usually either air, argon or krypton. Read more about
glazing options

A window energy rating label is a recognised way of verifying your ‘U-value’ and ‘G-value’ for BER. Senator Windows products have registrations with the NSAI and BFRC.

The WER, or Window Energy Rating, indicates the energy-efficiency of your windows. The rating is established by measuring: a) the total solar heat transmittance, or the level of solar energy it allows in through the glass, this is known as the ‘G-value’; b) The ‘U-value’, which measures how well the whole window (glass and frame together), keeps heat in your home; and c) the level of air allowed in through the window seals.

Together these elements give the Rating for the whole window. A standard window size and configuration is used to ensure the rating is standard across all products. The value given to your window is given on a scale of ‘E’ to ‘A’, A-rated windows being the most energy-efficient. The WER rating system makes windows consistent with other products that have energy performance labels, such as washing machines, light bulbs and refrigerators


A ‘U-value’ indicates the level of thermal transmittance, or heat loss, you can expect from your windows and doors. It’s measured in W/m2 K, or Watts per metre squared and, put simply, the lower the U-value, the better your home is insulated. You can find U-values for each Senator product on the individual product pages. The U-values quoted refer to the whole window or door, including the glass and frame. Click here to view the U-values for a range of glass options available for the Senergy range of uPVC windows.

G-values indicate the amount of solar heat a door or window allows to enter a building. While it’s important to prevent heat loss, it’s also important to make use of as much natural, solar heat as possible. Low Iron glass helps improve G-values by allowing the maximum amount of solar heat in, without compromising insulation. G-values are expressed as a number between ‘0’ and ‘1’, with the higher G-value indicating better heat gain. View the G-values for our Senergy range of uPVC windows .

Also known as the ‘L-factor’ this is a measure of how airtight a window or door is. When tested, a good quality window or door should have zero air leakage. The lower the L-factor, the greater the air tightness and the better the assembly of the door or window. View the zero air leakage values for our Senergy range of uPVC windows.


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