The best time of year to double glaze.

The demand curve is completely predictable.

Nobody thinks about their windows in November. Then Melbourne delivers its first 4°C morning sometime in early June, everyone wakes up to streaming condensation and a cold room, and the entire industry's phones ring in the same week. It happens every single year and it is the single biggest thing standing between you and a sensible price.

What that surge does is queue, not price. Standard argon Low-E IGU manufacture runs about six weeks in the quiet months and stretches to nine or eleven from mid-June. Add a week for measure-to-quote and three to five days of install on a 16-20 opening house, and the June caller who wants it "before winter" is realistically looking at late August - by which point the worst of it is behind them and they have paid peak-season rates to arrive late.

Book in February, warm in May.

Work the calendar backwards. Measure and quote in February. Order in early March. IGUs land mid to late April. Install across a week in late April or early May, in weather that is settled enough to have a wall open for four hours without drama. You are sealed up and insulated before the first serious cold snap, and you get the entire benefit in that season instead of catching the tail of it.

There is a second reason autumn is the right call, and it is about measurement rather than comfort. Much of the flat southern half of the City of Casey - Cranbourne, Hampton Park, Lynbrook, Lyndhurst - sits on highly reactive clay classed H1 or H2 under AS 2870. Those soils swell through winter and shrink through summer, and frames move with them by a few millimetres. Measuring in late summer or early autumn catches openings closer to their mid-range dimension than measuring at either extreme does. It is a small thing that shows up as fewer packing shims and tighter reveals.

The season-by-season honest read.

• February to May - best. Settled weather, short queue, benefit lands immediately. Book the measure in Jan or Feb.
• June to August - worst for queue, fine for work. We install right through winter. You will just wait longer and negotiate less. Sealant cure slows below about 10°C and rain stops open-wall work outright, so expect the odd reschedule.
• September to November - quietly excellent. The queue has cleared, we have gaps to fill, and this is where you have genuine negotiating room. The catch is you are eight months from feeling the thermal benefit, which is why almost nobody books it.
• December to January - awkward. Factories shut for two to three weeks over the break and everyone is away. Good time to get quoted, poor time to expect glass.

When is the best time of year to install double glazing in Melbourne?

Late summer through autumn, roughly February to May, is the sweet spot. The weather is settled enough that an open wall for four hours is not a problem, lead times have come off their winter peak, and the work lands before the cold arrives so you get the benefit in the first season rather than waiting a year for it. The genuinely wrong time is June and July, when everyone in Melbourne simultaneously decides their windows are the problem and factory lead times blow out from six weeks to eleven.

Can double-glazed windows be installed in winter?

Yes, and we install through winter every year. Each opening is out for two to four hours, not days, and we work one room at a time with the rest of the house closed off. The only genuine winter constraints are silicone and sealant cure times, which slow noticeably below about 10 degrees, and rain, which stops work on an open wall entirely. Expect the odd rescheduled day between June and August. The real winter cost is not comfort, it is the queue.

How far ahead should I book to have double glazing done before winter?

Work backwards from May and give yourself sixteen weeks. Measure to quote is about a week, IGU manufacture is six to eight weeks for a standard argon Low-E unit and longer for uPVC or anything non-standard, and install on a 16-20 opening house takes three to five days. Book the measure in January or February and you are comfortably installed by autumn. Ring us in June wanting it done before the cold and we will be honest with you: you are looking at August, and you have paid peak-season prices to get there.

Does the weather affect how well double glazing gets installed?

It affects the sealants more than anything else. Neutral-cure silicone wants 5 to 40 degrees and moderate humidity to skin and cure properly, so a 41-degree February afternoon on a west wall is as unhelpful as a 6-degree July morning. Both are workable with the right product and sequencing, both are slower. Wind matters too, because handling a 2.1-metre IGU that weighs 45 kilos in a gusty southerly is a safety call, not a preference. We simply stop when it is not safe.

Is double glazing cheaper at certain times of year?

Modestly, and not in the way the advertising implies. Spring and early summer are the quiet stretch and that is when you have real negotiating room, particularly on a whole-house job where we are filling a gap in the schedule. The difference across a 16-opening retrofit is realistically 5 to 10 percent, not the half-price fantasies you see advertised in June. The VEU rebate of $2,500-$4,500 on a typical whole-house job dwarfs any seasonal discount, and it does not care what month it is.