Ultra Series · fiberglass · wood clad
Ultra Series: fiberglass, for dark colours and Valley heat.
Fiberglass barely moves when it gets hot, which is why it holds a dark exterior colour on a west wall and spans openings vinyl struggles with.
Fiberglass, and why heat is the whole argument
Every frame material expands when it gets hot. The question is how much, and whether that movement matters where you live.
Fiberglass expands very little — close to the rate glass itself expands, which is not a coincidence, since it is made from glass fibres. Vinyl moves considerably more. On a 105° roofline in Chatsworth in August, a large vinyl frame in a dark colour is working against itself all afternoon, and over years that shows up as sashes that bind and seals that give up early.
That is the case for Ultra Series, and it is a narrower case than the brochure implies. On a shaded north elevation, in a standard-sized opening, in white, vinyl is fine and cheaper. Ultra earns its money in three specific places.
Dark exterior colours
A dark frame absorbs far more heat than a white one. This is the single most common reason we specify fiberglass: a homeowner wants black or bronze windows on a west or south elevation, and in vinyl that combination is asking for trouble. Ultra Series is painted fiberglass, and it holds a dark colour on a hot wall without the frame moving enough to matter.
Large openings
Fiberglass is stronger than vinyl, so the frame can be slimmer for the same span, or the span can be longer for the same frame. Where a vinyl unit would need a bulky section or a post through the middle of your view, Ultra often does not.
The wood-clad option
Ultra Series is also available with a real wood interior — fiberglass outside taking the weather, timber inside taking the stain or paint. It is the answer for a period interior where a white plastic frame would look wrong from the sofa, and for owners who want the exterior maintenance-free without giving up wood indoors. It costs meaningfully more than standard Ultra and it is a special order rather than something standing on the showroom floor.
What it costs you
More than vinyl, straightforwardly. There is no configuration where Ultra Series is the budget answer, and we will not pretend the energy difference pays for it — the performance gap between a good vinyl window and a good fiberglass one is smaller than the price gap. You are buying longevity in heat, a dark colour that stays flat, and slimmer sightlines. If none of those apply to your job, buy Style Line and spend the difference on more windows.
The catalog
Configurations, finishes and the wood-clad interiors: Milgard Ultra Series (PDF, 1.8 MB). The rest of the range is on our Milgard series page, and we are an authorized Milgard dealer in Canoga Park.
The ones people actually call about
Questions homeowners ask
Is fiberglass really better than vinyl?
At resisting heat movement, yes, clearly. At insulating, the gap is much smaller than the price gap — both use the same glass packages, and glass is where most of the performance lives. Buy fiberglass for a dark colour on a hot wall, for a large opening, or for a house you intend to keep. Buy vinyl otherwise.
Can I get black windows in vinyl instead?
You can, and on a shaded elevation it is fine. On a west or south wall in the Valley we will push back, because a dark vinyl frame absorbs a lot of heat and vinyl moves more than fiberglass when it gets hot. If you want dark frames on a sunny elevation, this is the line to use.
What is Ultra Wood Clad?
The same fiberglass exterior with a real wood interior — weather-proof outside, stainable timber inside. It suits period interiors where a white frame would look wrong from indoors. It is a special order and it costs considerably more than standard Ultra Series.
Does Ultra Series come as a retrofit?
Yes, though fiberglass is more often specified on full-frame replacements, where the slimmer frame and larger span capability actually get used. A retrofit installs inside your existing frame and costs you about an inch of glass in each direction, which works against the reason you chose it.
Is fiberglass worth it for a house I am selling?
Probably not. The buyer sees "new dual-pane windows" either way, and the difference between vinyl and fiberglass rarely shows up in the price. It is worth it for a house you are staying in, on the elevations that actually take sun.
Free, in your home, no fee
Find out what it costs
We measure, price every opening separately, and leave the written quote with you. Whether you call us back is up to you.