How to choose windows, from glazing to frames 

Everything you need to know: We show you how to see clearly when choosing panes and frame colours

With timber left on show to the interior of wood-detail windows or AluClad, there's no compromise on long-term performance and contemporary style. Roof windows by Fakro, fakro.ie.

Building new or renovating, window choices are one of those decisions that can keep you up at night. 

The economy of PVC, the prestige and performance of AluClad, or the heritage beauty of timber? Double or triple-glazing? Whatever the framing material or where you place the opening sections, energy efficiency should be your primary concern above all things with Low-E glass, warm-edge technology and argon filled units, but of course there’s more.

U-values and G-values (solar gain) are two details you should ask your supplier about from the get go. With the right glass, the right frame and — crucially — the right installation, it’s possible to achieve up to 70% better U-values than the recommended building regulation-compliant standard. As the thermal performance of the window increases, the U (the watts of heat being lost per sq m expressed as W/sq m) is a number that goes down. Top-hung, side-hung, pivoting or sliding — know your U-values.

A darker determined grey here really trims out and frames the view. Today, dark grey or black is not, in almost every instance a fashion colour or a huge, wobbly risk. AluClad from Carlson Windows, carlson.ie.

Expect U-values for the entire window (frame and glass) of 1.3W/sq m-1.2W/sq m for good double glazing. In triple-glazing, a snug 0.8W/sq m-0.4W/sq m reaching passive standards, can be reached through meticulous construction, sealing and installation of the windows with no thermal bridging. The U-values for fixed glazing should be even lower (say 0.65 W/sq m if say the opening windows are 0.8 W/sq m).

With the increased air tightness and depth of triples, you can shut out the noise of the world stirring outside your boundary. Glazing bars set between panes, rather than physically dividing the window up, will preserve your design dreams but reduce potential heat loss.

Something that’s either rushed in a premeditated conclusion or just elbowed out of view until the specifications and schedules are being polished up, is colour — exterior and interior colour. Even where the design is done and dusted, frame colour is a curiously powerful architectural element of your window choice, whether you’re yearning for sashes, French casements or fragile slender contemporary framing.

Period colour doesn't have to be black and white. An unexpected colour to a timber or AluClad window calmed by the right traditional materials injects character and charm. Furniture by OKA.

Today, with timber and AluClad windows, you are very likely to be confronted with choices from the entire spectrum of the trade standardised RAL colour chart. This can prove overwhelming. RAL is a set European colour-matching system which defines colours for paint, coatings and plastics. You choose the magic RAL number, and this is put into your schedule and flown off to the manufacturer for composition, spray and/or brush application.

Where you have an exterior and separate interior colour choice, you have double the work to do choosing either from a limited array of colours from your supplier or (a more satisfying prospect) from the complete RAL play-sheet. Indoors, if you have wood or timber AluClad, you can stain the timber to leave the grain on show too. Check for any price loading on dual-colour choices. PVC comes in dual-colours in a limited palette at a slight premium, giving you the option (once three colours right through), of say white indoors and a more contemporary new choice outside.

Today, in new builds, the area between nine RAL whites to greyed whites, moving through the grey hymn-sheet of 36 RAL biomorphic and industrially guided greys to a choice of their five RAL blacks, is most popular with architects and homeowners. There are about 200 standard RAL colours total, and of course if you fancy a blue/green/yellow set of windows and doors — there’s nothing to stop you, assuming the exterior wall colour is calm enough to balance it all out. With a white or black interior colour, a more dramatic outdoor colour is less likely to frighten future viewers or interrupt interior decorating changes.

If you think you are ready to choose any RAL colour, only choose from a physical colour card. Don’t trust the virtual colour chart for more than a hint. The subtle nuances can be very surprising. You can buy a full RAL fan-deck online for €17.50 if you have a big project and would like it in hand to make comparisons and to choose other colour-ways and make comparison for your home. There are various finish choices in other decks too.

Window colour is a statement, and it can make your framing more or less present indoors and out, depending the colour of the surrounding wall and the aspect of the room. We have moved well beyond the universal shrug of white PVC or timber-effect toffee browns. White was popular in PVC partly because decades ago it was cheaper. Darker colours offered less UV-stability and could ultimately fade. Indoors, white was unobjectionable.

In PVC, white and wood grains have been joined by a family of creams and sages, and handsome up-to-date grey neutrals sometimes available in metallic finishes that shouldn’t upset future buyers if the windows are energy efficient and well detailed in every other way.

Today, dark grey or black is not — in almost every instance — a fashion colour or a huge, wobbly risk. Architect Dermot Bannon regularly causes teary-eyed uproar from this mesmerised clients on RTÉ’s Room To Improve as he routinely jumps to black AluClad windows and patio doors for his rural designs. On completion, the final finish says it all.

In our suburbs and towns, dark grey frames set on white walls are a crisp modern, familiar classic in new developments and one-off builds, already available in all window frame materials. Darker colours might be expected to visually pop off pale renders and stone with their European flat profile and simple aesthetic, but keep in mind that glass seen from outside generally reads as a dark void anyway the frames recede and can all but disappear. Expect any architect to have an opinion, but ask them to explain it.

Singing with the natural hues of the countryside including surrounding shadow, black and rubbed black can be calming and so soundly right with their narrow sight lines. White windows with darker exterior walls are more likely to sit out against the darkness of rooms beyond, separating them from the glass, but they hide stains like bird droppings better than black. Window reveals outside (masonry) can be painted too — so explore what’s possible with an online image search and save these prospects to a folder or mood-board app on your PC or phone.

Indoors, dark choices are a whole different story as these windows looking into the contrast of the sunlight will look even darker, and will trim out the view if you have glazing bars or casement openings. They can pick up other elements in the room, say the dark cabinetry of your kitchen for example — often fantastic. For smaller rooms, white windows, like white walls will scatter light and amplify space.

Naturally, you should explore the style of the house and the colour of extant exterior materials that cannot be changed like brick or tones of natural stone, but don’t leap to the notion that a vintage terrace, cottage or farmhouse cannot wear black timber windows. They can, and did as far back as the 1700s and up in the 1920s when black steel Crittal windows were commonplace in factories and public buildings. Black is a heritage colour. That said, white is a heritage colour. Don’t be persuaded directly into period correct colours for period-style windows, talk to your architect or designer regarding doing something more unexpected like an anthracite grey. Samples should be seen in a variety of light and colours, see see ralcolourchart.com.