Advanced Options / Customise Spec
*Price guide only. Minimum charge area applies (0.3m²). Shapes and steps are estimated. Final price confirmed upon technical survey or order review.
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Double Glazed Sealed Units Price Calculator
Use our instant calculator to estimate the cost of replacement double glazing units. Whether you need standard float glass or high-performance Planitherm Low-E glass with argon gas filling, our tool provides a fast, transparent guide price for UK homeowners and tradespeople.
How seal unit pricing works
Prices are calculated based on the total square metreage of the unit. However, like most UK glass manufacturers, we apply a minimum billable area (typically 0.3m²) per unit. This means very small units (like fanlights or cat flap panels) cost the same as a standard small window due to the manufacturing setup time involved.
Understanding your glass options
- Low-E (Softcoat/Planitherm): Essential for modern building regulations (u-values). Reflects heat back into the room.
- Toughened Safety Glass: Required by law for doors and windows within 800mm of the floor (EN 12150). It shatters safely if broken.
- Warm Edge Spacer: A thermal plastic spacer bar that replaces traditional aluminium, reducing condensation and heat loss around the window edge.
- Obscure/Patterned: For bathrooms or privacy.
Frequently Asked Questions
How do I measure my replacement unit?
Measure the visible glass width and height. If the unit is still in the frame, you typically need to add approximately 20-30mm to the visible size to account for the beading depth (where the glass sits inside the frame). For accurate results, we recommend removing a single bead to see exactly where the glass ends.
Does the price include VAT?
You can toggle the calculator to show prices either excluding or including VAT at the current UK rate of 20%. The "Grand Total" in your basket will clearly state the tax status.
What is the lead time for made-to-measure units?
Standard delivery is typically 5-7 working days. We offer an "Express" option for urgent replacements, which may incur a surcharge as shown in the calculator settings.
Why is there mist or condensation inside my window?
Condensation inside the two panes of glass means the hermetic seal has failed (a "blown unit"), allowing moisture to enter. This cannot be repaired; the entire sealed unit must be replaced. Our calculator gives you the price for this replacement unit.
What overall thickness do I need?
The overall thickness is the sum of: Inner Glass + Spacer Bar + Outer Glass. For example, standard float glass is 4mm. If you have a 20mm spacer, the total is 4mm + 20mm + 4mm = 28mm overall. You must match your existing thickness for the unit to fit back into the beading.
Do you supply shaped or stepped units?
Yes. You can select "Shaped" or "Stepped" in the extras menu to get an estimated add-on cost. However, for complex shapes (raked tops, arches) or specific cut-outs (vents, cat flaps), we require a physical template or technical drawing for a precise quote.