How Much Extra Does High-Performance Rooflight Glazing Cost?
High-performance rooflight glazing, meaning a solar control double unit with a warm-edge spacer and argon fill over a plain clear one, usually adds a modest amount per unit rather than a large sum, often in the low hundreds of pounds on a domestic rooflight. Stepping up again to triple glazing is the bigger jump, adding several hundred to a couple of thousand pounds depending on size. What the high-performance glazing buys is a lower whole-unit U-value, summer overheating control from the solar control coating, and warmer edge glass that resists condensation. On a sunny aspect it is usually the right call at quote stage.
The glazing step is only part of the price, though, and it is worth seeing it against the whole job so you spend where it counts.
The uplift, step by step
| Step | Whole-unit U-value | Cost uplift per unit | What you get |
|---|---|---|---|
| Clear double, argon, warm-edge (baseline) | 1.3 to 1.5 | Baseline | Comfortable, high daylight |
| Solar control double | 1.2 to 1.4 | Modest, often low hundreds | Overheating control plus slightly lower U-value |
| Triple glazing | 0.7 to 1.1 | Several hundred to a couple of thousand | Lower heat loss, warmer inner glass, less downdraught |
Uplifts are indicative and depend on unit size and system. Your survey gives the exact figure for your unit.
The clear-to-solar-control step is usually the best value in the whole specification, because for a modest uplift you fix summer overheating as well as trimming the U-value, and on a sky-facing rooflight you were going to need solar control anyway. The double-to-triple step is the larger commitment and it is right less often, which is why we weigh it separately on is triple glazing worth it for a rooflight and price it on how much a triple glazed rooflight costs.
What the extra actually buys
- A lower whole-unit U-value, so less heat loss and a warmer room in winter.
- Solar control, cutting the g-value from the 0.60 to 0.72 of clear glass to roughly 0.28 to 0.38, which keeps the room usable through a hot spell without air conditioning. Covered on solar control glazing for rooflights.
- A warm-edge spacer, which raises the edge glass temperature by several degrees, exactly where condensation forms first, and improves the whole-unit figure.
- Neutral, bright light, because modern solar control keeps light transmission above 60 per cent, so you get the heat control without a tint.
Spend on the upstand before the glass upgrade. The most cost-effective pound on a rooflight is not the glazing step, it is a properly insulated upstand, because a bare timber upstand loses heat and causes mould that costs far more than the glazing uplift saved. If the budget is tight, get the junction right first, then choose the glazing with what is left. The order is set out on how you reduce heat loss through rooflights.
Deciding at quote stage
The glazing decision is easiest to make when the unit is being specified, because the coating is inside the sealed unit and cannot be added later without a new unit. At quote stage the uplift to solar control is small against the cost of retrofitting overheating control after the room turns out to bake. So on any south, west or flat rooflight, specifying solar control from the start is the honest recommendation, and the modest uplift is money well spent. On a north-facing pitch, clear glass is usually right and the uplift is not needed. The full cost picture, including the upstand and Building Control fee, is on what energy efficient rooflights cost.
How much more does high-performance rooflight glazing cost?
The step from a clear double unit to a solar control double with a warm-edge spacer is usually modest, often in the low hundreds of pounds per domestic rooflight, and it buys summer overheating control as well as a lower U-value. Triple glazing is the bigger jump, adding several hundred to a couple of thousand pounds depending on size. Your survey gives the exact uplift, and on a sky-facing rooflight the solar control step is usually the best value in the specification.
Is high-performance glazing worth paying for?
On a south, west or flat rooflight, yes, because the modest uplift to solar control fixes summer overheating, which you cannot retrofit without a new unit. On a north-facing pitch, clear glass is usually right and the uplift is not needed. Either way, if the budget is tight, get the upstand properly insulated before spending on a glazing upgrade, because the junction loses more heat and causes more damage than the glass step saves.
Get the glazing priced against your aspect
We specify the glazing from orientation and room use and put the uplift, the whole-unit U-value and the g-value on the quote, so you can see exactly what the extra buys. One fixed price, a 10-year workmanship guarantee, and installers with 25 years on rooflights.
Request a fixed quote, or start from energy efficient skylight installation.
Thinking about this job? We survey across Ipswich, Suffolk and north Essex and give you a fixed price before any work starts, with a 10-year workmanship guarantee.