Don’t change the character of your period home with the inclusion of modern frame materials and ratios. Do everything you can to live with, and eventually renovate these crucial historic elements. Picture: iStock

With the evenings already whittling down to darkness, it’s time to put your house in good order and to improve its energy efficiency as far as possible. 

This starts with the external envelope — and in particular with those windows which can release up to 20% of your heat store to the great outdoors through rattling glazing, convection and gaps, and cold-bridging around the frame.

If your windows are elderly, period pieces, or even vintage single-glazed varieties, there are proven, age-worn hacks to improve their snug performance or to just blanket them up against draughts.

Before I start, a side-note: Ripping out sashes and original casement windows and replacing them with contemporary forms and window ratios, has steadily torn the soul out of old houses and heritage terraces all over Ireland. 

One home in a street falls, and soon the whole row is blinded-out with crisp, but inappropriate replacements. Do everything you can to live with, and eventually renovate these crucial historic elements, or replace them with the original forms appropriate to the architecture of the building. 

Even the rippled old glass in an old window is well worth conserving.

For opening windows that are not hopelessly warped out of true, foam strip insulation, V-seals and brush seals (cut to size) can handle most operating styles, including sashes. Compression seals are fantastic for a DIY job on defective, operating sashes, cheap to replace, and worth even one or two winter’s work. 

Start with something like B&Q’s Diall White Self-Adhesive Draught Seal, a good all-rounder for a variety of window and door problems. Every window is different, and you may be insulating not only the glazed areas by odd, leery places where the frame meets the wall or sills with silicone caulk (gun).

We won’t create a truly modern “warm” window from a multi-paned old dear just tailoring them out with stick-down insulation around beading, but we can cut down the insidious leaks. 

Caulking with putty or cord along pane edges can be carried out inside and out if you’re truly handy. Amazon carries Duck Rope Caulk, which is rubber based and easy to handle (from around €12 plus postage). 

Expect to completely replace putty every few years as aged, softwood windows inevitably flex in the atmosphere. Clear nail polish can fill tiny holes if you’re completely stuck.

Speaking of sticking, are the sashes actually closing properly? Try running a thick pale, candle down the frame edge to give it some slip, pushing it firmly home.

Curtains and even the right blinds can act as a layering vest and geansaí. The caveat is that they will be drawn to make any impact. 

Interline your curtains, and drape the curtains right to the floor with a few centimetres to spare. Cap them off with a pelmet, or keep them as tight to the top of the window recess as possible. 

Inexpensive blackout lining and curtains offer good heat, light and sound retention from the outdoors, but the cheaper varieties have a reputation for off-gassing. Stick them out in the garage for a couple of weeks after they come out of sealed plastic packages.

Something like a heavy-weight chenille will add valuable tog-weight to curtains, qualities that can be enhanced by adding Velcro strips to the wall around the verticals of the reveal to virtually “zip” the reveal closed by night. 

With a bottom opening sash, try using a fabric draught snake, on the base and centre rail — filled with dry beans or sand and pushed into the gap to snuff out the breeze. 

Self-install thermal blinds feature 3D pockets of pleats and honeycombs in soft, fabric styles and an aluminum thermal skin that directly reflect unwanted solar gain away from the window in summer (a common annoyance with single glazing). 

Choose a light diffusing blind, and leave them down with the curtains open by day. From €40 a window. Try blinds-2go.ie.

Window film, a take on low-e coatings, comes in two forms. The first is applied directly to the glass and is generally used in commercial situations for solar gain problems and to depress the U values of large areas of glazing economically. 

The second is a domestic product, a sort of second skin for single-glazed or failing double-glazed windows that stretches over the frame rather than sucking onto the glass.

Exitex is the most popular brand here in Ireland and comes in 1.8 sq m, 4.5 sq m, and 9 sq m. The Exitex film is fixed with a dedicated double-sided tape (included), and then warmed with a hair dryer to stretch it tight over the entire reveal. 

You can also use the film on French doors, it just won’t attach well to rough or raw wood. Obviously, this is a last resort, as it’s toast once you open your windows. 

At the end of the winter, it has to be ripped down and replaced come the following autumn. If you’re really freezing your behind off, and the curtains are hiding one-third of the window opening – chances are you won’t care.

Ensure you clean both the window and frame very well before starting to ensure any film adheres well and that you don’t box in filthy glass you’ll have to look at until April 2023. Priced from €5.95 (per window) at purchase.ie.

If you can’t afford commercial film, bubble wrap, the type with the big bubbles can be taped onto the window — not pretty, but surprisingly effective in a pinch.

Long-term, all but invisible thermal brushes can be routed into sash windows, into the frame on the bottom of the lower sash, on the top of the upper sash, on the rail where the parts meet, and on the sides of the window. 

This should only be carried out by a specialist installer as a next step up when your budget allows, such as Conserve a Sash, Kilgarvan, Co Kerry, or Repair Sash Windows in Dublin.

Introducing double-glazed panes into very old original frames is expensive in even the most robust of old sashes and casements. This is largely because of the elegant skinny rebates holding the individual panes, which demands specialist glazed units, a highly skilled set of hands, and a full window renovation.

Custom-made, secondary glazing is a less costly, less invasive solution, basically installing a second window frame set in one or two large panes, that operates on hinges to open and close over the inside face of the original sash or casement.

Secondary glazing is worth consideration where you have a house firmly on the “Minister’s List” and the method of choice for large swathes of the commercial palaces of Georgian Cork and Dublin. 

Look up the meticulous work of Timeless Sash Windows timeslesssashwindows.ie for inspiration. 

It’s possible to install inexpensive, secondary windows as fixed, seasonal panels of Perspex, that just slot into place over compression tubes when the season turns. Not nailed home, they can be safely whipped out if the window is needed as a means of escape.

Whenever you seal up any windows, remember that they may have been operating hourly uncontrolled but largely healthy air exchanges — what we cheerfully term draughts. 

Ensure your home is properly ventilated – keeping wall vents and trickle vents open and ensuring there’s no soil or other debris piled up against the grilles outdoors. 

Keep an eye out for changes to condensation levels and ensure you fit a CO alarm to warn you and yours if the atmosphere is becoming dangerously stale.

Read MoreHow to choose heating and energy systems to fit tiny homes

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