Windows grant, BER and glazing glossary
Plain-English definitions of the 15 technical, BER Advisory Report and SEAI grant terms you will see when preparing for new windows and doors.
Free, no obligation. One registered contractor prices it, not five.
- 15terms defined A to Z
- Below 2.3target HLI
- €4,000detached windows grant
- €800per external door
A to Z of windows grant, HLI and glazing terms
Air-to-Water Heat Pump Readiness
The fabric standard a home must reach—specifically a Heat Loss Indicator at or below 2.0 W/K·m² (or up to 2.3 W/K·m² with compensating existing fabric)—so a low-temperature heat pump can run efficiently.
Airtightness Tape & Foaming
Flexible vapour-variable membranes and low-expansion polyurethane foam applied around the perimeter junction between a new window frame and the structural masonry reveal to stop cold air infiltration.
BER Advisory Report
The companion document generated alongside every official Building Energy Rating certificate that records the dwelling's current Heat Loss Indicator and sets out the specific fabric upgrades needed to reach a Good or Very Good rating.
Declaration of Works
The formal sign-off form completed by the SEAI-registered contractor and BER assessor after installation, confirming that all upgraded units meet scheme technical specifications before grant payment is released.
Double Glazing (Low-E)
A two-pane sealed unit featuring a microscopic metal-oxide coating on the inner pane and argon gas fill, usually achieving whole-window U-values between 1.2 and 1.4 W/m²K.
Fixed Higher Grant Rate
An increased SEAI grant amount for attic and cavity wall insulation available to qualifying lower-income households and social welfare recipients under the Individual Energy Upgrade scheme.
Heat Loss Indicator (HLI)
The metric on a Building Energy Rating (BER) report measuring heat lost per square metre of floor area per degree of temperature difference (W/K·m²). A rating of Good or Very Good (typically under 2.3 W/K·m²) is required to qualify for the standalone SEAI windows and doors grant.
Individual Energy Upgrade Grant
Formerly known as the Better Energy Homes scheme, this SEAI pathway lets homeowners apply for and manage single fabric grants—such as attic insulation, wall insulation, or windows and doors—one step at a time.
One Stop Shop (OSS)
An SEAI-registered project management provider that handles an entire whole-home retrofit, deducts grants upfront from the invoice, and bundles windows and doors alongside insulation and heat pump works.
Solar Value Factor (g-value)
A measure from 0 to 1 indicating how much solar heat energy passes through glazing into the room. South- and west-facing windows often balance a low U-value with a moderate g-value to capture free winter solar gain.
Thermal Bridging at Reveals
Heat loss occurring where an uninsulated window frame meets the masonry wall jamb, sill, or lintel. Proper frame positioning and insulated reveal boards prevent damp spots and mould around new glazing.
Trickle Vent
A controllable background ventilation slot integrated into a window head or frame to maintain indoor air quality and comply with Part F of the Irish Building Regulations when older draughty frames are replaced.
Triple Glazing
A sealed insulated glass unit made with three panes of low-emissivity glass separated by argon- or krypton-filled cavities and warm-edge spacer bars, typically achieving whole-window U-values of 0.8 to 1.0 W/m²K.
Warm-Edge Spacer Bar
An insulating composite or thermally improved strip separating glass panes around the perimeter of a sealed unit, reducing edge condensation and thermal bridging compared with older aluminium spacers.
Window U-value (Uw)
The overall rate of heat transfer through an entire window unit including glass, frame, and spacer bar, measured in W/m²K. Lower figures mean less heat escapes; SEAI-funded replacements require high-performance double or triple glazing.
Is your home ready for the windows grant?
Four quick taps. You see where your home stands, what has to come first and every grant on the way. Your number is only asked for at the end, if you want a price.
A semi-D with the attic done and cavity walls never filled: 1 step first, the €1,300 cavity grant, then €3,000 for the windows and up to €1,600 for two doors.
How this is worked out
SEAI's windows and doors grant needs a Good or Very Good Heat Loss Indicator on the BER Advisory Report after the work, which SEAI says an HLI below 2.3 meets. Attic and wall insulation rated Good or Very Good on your report means you meet the standard. The grants are SEAI's fixed amounts for your home type, and the doors grant is shown for two doors. The check is a guide: a BER assessor and SEAI decide.
Questions people ask
Can I apply for the windows grant and the external doors grant at the same time?
Yes. Under the SEAI Individual Energy Upgrade scheme, a qualifying home with a Good or Very Good Heat Loss Indicator on its BER Advisory Report can claim the full window replacement grant (€1,500 to €4,000 by house type) plus €800 per new external door up to two doors (€1,600 maximum) in the same application.
Do I have to replace every single window in the house to get the SEAI grant?
Under SEAI technical rules for the windows grant, all existing single-glazed or older poorly performing windows in the heated envelope of the dwelling must be brought up to the required U-value standard so the building fabric performs as a complete thermal envelope.
Does the SEAI grant cover replacing a sliding patio door or French doors?
Glazed patio, sliding, and French doors are generally classified under the glazing/window package or counted toward the external door allowance depending on the glass-to-frame ratio and how the BER assessor and registered contractor record the openings on the Declaration of Works.
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Where you stand, what comes first and every grant on the way. Then, if you want, one SEAI-registered contractor who covers your county rings with a price.