Start by Understanding How Your Old House Breathes

Period homes were designed to manage moisture, not to trap heat. Solid brick walls, lime plaster and suspended timber floors all absorb and release water vapour, and if you block that process with the wrong materials you get condensation, damp patches and eventually rotten timbers. That is why the first rule of improving energy efficiency in a Victorian terrace or Georgian cottage is to work with the building rather than against it. Cement renders, plastic paints and foam injected into old wall cavities usually cost far more to put right than they ever save on bills.

The reassuring part is that the cheapest measures — draught-proofing, secondary glazing, a proper loft top-up and sensible heating controls — are also the ones that respect the fabric of the house. You can make a real difference to your bills for a few hundred pounds, without touching the things that make a period property special.

Draught-Proofing: The Best Value Job in any Old House

Air leaking through gaps and voids often accounts for a surprisingly large share of heat loss in older homes, and it is the cheapest thing to fix. Work around the house on a windy day with a lit incense stick or a damp hand and you will soon find the culprits.

• Chimneys: an open flue is a permanent hole in your ceiling. Fit a chimney balloon or a sheep's wool draught excluder in unused fireplaces, but keep one flue ventilated if the chimney is in use or if damp is a concern.
• Sash windows: brush seals or silicone draught strips on the staff beads, plus a foam strip in the meeting rail, make a noticeable difference. Avoid sealing sashes shut completely; they are your summer ventilation.
• Floorboards: draughts rise between boards on suspended timber floors. Paper-backed wool or foam strips pushed between the joists from below work well if you have a cellar or crawl space.
• Skirting boards and joist ends: a bead of flexible mastic where the skirting meets the floor stops cold air tracking in from the wall cavity.
• Doors: letterbox brushes, keyhole covers, a draught excluder on the bottom of the door and a close-fitting threshold strip will do more than you would expect.

Budget roughly £100–£300 in materials and a weekend of your time for a typical two- or three-bedroom terrace. It is the single best return on effort in the whole house.

Windows: Secondary Glazing Beats Replacement for Most Budgets

Replacing original sash windows with double glazing is expensive, often needs consent in a conservation area or on a listed building, and can change the character of a façade for good. Secondary glazing — an additional pane fitted inside the reveal, either as sliding panels or a discreet magnetic acrylic sheet — cuts noise, condensation and heat loss for a fraction of the cost. Expect around £150–£400 per window for professionally made units, or considerably less for DIY acrylic or shrink-fit film kits on less prominent windows.

Pair this with heavy curtains lined with a thermal interlining, hung on a track that overlaps the window reveal, and traditional shutters where they exist. Closing curtains at dusk is one of those habits that quietly trims a few percent off the heating bill every winter.

Insulate Where You Can Without Damaging the Building

Loft insulation remains the most cost-effective upgrade available to period homeowners, and most old lofts were either never insulated properly or had a thin layer laid decades ago. Topping up to 270mm of mineral wool is a straightforward DIY job, though you must keep the eaves ventilated and avoid blocking air paths along the rafters. Do not insulate directly beneath a slate or tile roof without a breather membrane designed for the job — trapping moisture against old timbers is a false economy.

For solid walls, internal insulation is possible but rarely cheap, and it must be breathable, using wood fibre or lime-based boards rather than foil-backed plasterboard. If your budget is tight, prioritise the loft, the floors over unheated spaces, and any exposed hot water cylinder, which should have a jacket at least 80mm thick.

Heating Controls and Getting More From Your Boiler

Old houses are usually heated by a single thermostat in the hallway, which means bedrooms and reception rooms are guessing games. Fitting thermostatic radiator valves to every radiator, balancing the system, and setting the boiler flow temperature to around 60–65°C for a condensing boiler can cut gas use noticeably without any loss of comfort.

• Smart thermostats with zoning let you heat only the rooms you use, and they learn how long your house takes to warm up — useful in a property with thick walls and high ceilings.
• Radiator reflector panels, a few pounds each, push heat back into the room instead of into an external wall.
• Programmable TRVs on individual radiators are a cheaper alternative to full smart zoning and work well in a room-by-room regime.

A Sensible Order of Work

Tackle draughts first, then loft insulation, then windows, then controls — in that order, because it is the cheapest and least disruptive sequence. Reassess after each stage: an old house that has been draught-proofed and insulated often needs a smaller boiler setting, not a bigger one. Keep ventilation in mind throughout, especially in kitchens and bathrooms, since a period home that cannot breathe will find another way to tell you about it.