Primal Bound

Old ways to keep your house warm without turning up the heat

October 20, 2026

It is half past four on a January afternoon and the light is going. You are in the living room in a cardigan, your hands are cold, and this winter's heating bill is on the side table. Your hand goes to the thermostat. Two more degrees would feel good, and they would cost money. Your great-grandparents had no thermostat at all. Many had one fire, thin windows and winters as cold as yours. How did they keep warm?

They heated the people and one room

A British government report, the UK Housing Energy Fact File, says few homes had central heating in 1970. Reports of the study put the average winter home at 13.7 °C then (about 57 °F), against 17.7 °C more recently. The report's authors, Cambridge Architectural Research, estimate from modelling that homes have warmed by about four degrees since 1970. It is an estimate, not a thermometer reading.

So people made warmth another way: heavy curtains, a cloth snake along the door, one warm room, and warmth worn on the body instead of blown into the air. One rule before the list. Everything here is cheap and safe: no open flames, no fuel-burning heaters, nothing that gives off fumes.

The curtains

Researchers at Glasgow Caledonian University tested traditional sash windows for Historic Scotland. Historic Environment Scotland reports that timber shutters cut the heat lost through the window by 51%, and heavy, lined curtains by 14%. Another write-up of the laboratory tests gives the same two numbers, while some other write-ups give a bigger curtain figure. We use the smaller one.

That is heat through one window, not your whole bill. At the University of Salford, Richard Fitton's team tested curtains in a full-size Victorian house built inside a climate chamber (Fitton, Swan, Hughes and Benjaber, 2017, Energy Efficiency). Their estimate: drawing the curtains during the heating hours cuts a typical year's energy use by about 2%. Small, but it costs nothing and takes ten seconds at dusk.

The draft

Great-grandmother sewed a tube of cloth, stuffed it with sawdust and laid it along the bottom of the door. The government's Energy Star program says sealing air leaks and adding insulation can save up to 10% on annual energy bills. That figure is for the whole job done properly. A rolled towel at one door is the smallest piece of it.

One warning, from local councils' gas-safety advice. Do not block ventilators or airbricks, and do not block or cover outside flues or chimneys. Any room with a gas or fuel-burning appliance must stay ventilated. Those openings are there on purpose.

One warm room, but warm

In a house with one fire, the family lived where the fire was. You can copy the shape of that without copying the cold. The modern rule is stricter than the old practice, though. The NHS says that, if you can, you should heat the rooms you regularly use to at least 18 °C (about 64 °F). The UK Health Security Agency, quoted by Devon County Council, adds that this is particularly important if you are over 65 or have a health condition. The 1970 average was colder than that.

Warm the body, not the air

Wool indoors, a shawl, thick socks, a blanket over the knees. The same UKHSA advice says several layers of clothing keep you warmer than one thicker layer. Does warming only the body work in a cold room? Someone measured it.

The test

In a study published in 2013, Wilmer Pasut, Edward Arens and colleagues at UC Berkeley tested an office chair that warms the person sitting in it (HVAC&R Research, 19(5)). Thirty college students sat in it for 150 tests of about 1.75 hours each, in a climate-controlled test room. The coldest room was 16 °C (about 61 °F). The students set the heat themselves. The researchers reported that the chair provided thermal comfort under all the conditions tested. At 16 °C it drew 27 watts on average. Berkeley notes that conventional space heaters operate at up to 1,500 watts.

The limits: young students, not people in their seventies; a lab, not a living room; short sessions. One small set of tests, so hold it loosely. It is no reason to let a room drop below the 18 °C above.

What that looks like on a bill

The Energy Information Administration puts the average US home electricity price in 2026 at 18.2 cents per kilowatt-hour. This is our own sum, not the study's, and your price will differ. A space heater at full power for a four-hour evening uses 6 kWh, about $1.09. The chair at 27 watts for four hours uses about 0.11 kWh, about two cents.

The fix

What the numbers support is small and cheap. It will not halve your bill.

  1. At dusk, draw your heaviest curtains. The estimate is about 2% of a year's energy.
  2. Lay a rolled towel along the bottom of an outside door, never over a vent or flue.
  3. Close the doors of rooms nobody is using, and keep the room you sit in at the 18 °C the NHS gives.
  4. Wear layers, wool socks and a blanket on your knees, so you warm the person instead of the air.

This reports what was measured. It is not medical advice, and whether it changes your winter is yours to find out.

Sources

  1. UK Housing Energy Fact File (DECC), as reported in Energy in Demand and Cambridge Architectural Research
  2. Glasgow Caledonian University for Historic Scotland, via Historic Environment Scotland and Bruce Clark, buildingconservation.com
  3. Fitton, Swan, Hughes and Benjaber (2017), Energy Efficiency 10(6). doi; University of Salford summary
  4. Energy Star, Seal and Insulate
  5. NHS, Keep warm, keep well; UKHSA advice via Devon County Council
  6. Pasut, Zhang, Arens et al. (2013), Effect of a heated and cooled office chair on thermal comfort, HVAC&R Research. IIR; UC Berkeley News
  7. EIA Short-Term Energy Outlook, October 2026

Film version, with the sources on screen: Old Ways to Keep Your House Warm Without Turning Up the Heat (7:18).