Engineers explain why some homes feel colder despite identical heating settings

Harriet Pemberton • April 28, 2026 03:37

Two homes, two identical thermostats set to 20 °C.

In the first lounge, you could happily pad about without socks, and a mug of tea cools at its own leisurely pace on the coffee table. In the second, hands linger near the radiator, blankets are hauled up to shoulders, and someone insists-again-that the boiler must have packed up.

The display shows the same number. The monthly costs look much the same. The kit on the wall isn’t wildly different. Yet one room feels genuinely cosy, while the other has that odd, sharp chill-like the warmth never quite reaches your skin.

Heating engineers will tell you it isn’t mood or mystery. It’s everyday physics, doing what it always does. Once you notice it, it’s hard to ignore.

Why 20 °C doesn’t always feel like 20 °C

Ask most heating engineers and you’ll get the same blunt answer: the thermostat only tells part of the story. What you experience as “warmth” is a blend of:

the air temperature,
the temperature of the surrounding surfaces (walls, windows, floors),
and the movement of air (draughts and convection currents) across your skin.

So two rooms can both read 20 °C and still feel miles apart, because the building fabric-walls, glazing and floors-quietly decides how quickly your body loses heat.

When the surfaces around you are cold, your body effectively “notices” that cold and sheds warmth more quickly. Your skin reacts before your brain has even processed the little number on the programmable panel.

That’s why some houses feel like a warm embrace, and others feel like sitting beside a fridge that’s only just been switched off.

Engineers have a term for the surface side of comfort: mean radiant temperature. It sounds niche, but it’s simply a way of describing how warm the surfaces around you are.

Picture a winter evening beside a large single-glazed window. The air in the room might be 21 °C, but the glass itself can sit closer to 5–8 °C. Your body then radiates heat towards that cold pane-like an unwilling little human radiator.

Building-physics researchers often use thermal camera images to make the point in a way you can’t argue with: bright orange streaks where pipes run, and deep blue blocks where heat escapes through loft gaps or around sockets. One study looking at older UK housing stock reported that, in some properties, up to 35% of heat loss came from uncontrolled draughts rather than the walls themselves.

In day-to-day terms, that can mean you’re paying good money to heat the street, while your feet stay cold on that “wood-effect” laminate.

When the room’s surfaces are chilly, your body is constantly swapping heat with them. You can feel cold even when the air is technically “warm enough”. Add a hidden gap under the front door, or leaky downlights in the ceiling, and moving air starts stripping heat from your skin as well.

Engineers see this contrast constantly: two houses that look almost identical on paper, yet one has ageing single glazing, uninsulated loft edges and a suspended timber floor with gaps; the other has decent double glazing, tighter doors and heavy curtains. Same thermostat setting-completely different lived experience.

The hidden culprits in UK homes: draughts, cold surfaces and habits

From an engineering perspective, warm air behaves predictably: it rises, gathers near the ceiling, and escapes through any route it can find. Cold air stays low and slips in through the smallest openings. That’s why one of the biggest “warmth upgrades” often isn’t a new boiler at all-it’s draught-proofing so the wind stops living rent-free under doors and along skirting boards.

Thermal comfort specialists often begin with a simple walk-through:

Where does your hair move?
Where do your ankles feel a faint stream of air?
Where does a candle flame wobble?

Those barely noticeable air movements can make you feel colder than a full 1 °C change on the thermostat.

In a 1930s house in Leeds, an engineer stood in the hallway holding a smoking incense stick near the letterbox. The smoke shot sideways. The owner assumed the place was “just naturally cold”. In practice, the hallway was acting like a chimney turned horizontal-pushing warm air out and drawing cold air in.

She set the thermostat to 21 °C most evenings, yet her toes were always numb and her son wore a hoodie indoors. The bills were unpleasant, but comfort never arrived. A cheap brush draught excluder on the letterbox, a foam seal around the front door, and a thick rug over the bare floor changed things immediately.

Nothing about the boiler changed. What changed was airflow-and how quickly bodies in that space were losing heat to both moving air and cold surrounding surfaces. The thermostat stayed put, but she described the room as feeling about 2 °C warmer.

When engineers explain why “the same temperature” doesn’t feel the same, they usually return to three technical drivers:

Cold surfaces: thin walls, older windows, uninsulated floors and exposed external corners can radiate cold towards you. Your body responds by constricting blood vessels, which can make you feel tense and chilly.
Air movement: even a slow draught of around 0.5 m/s can reduce perceived temperature by several degrees. Your brain doesn’t care about the displayed number; it reacts to how fast heat is being pulled from your skin.
Humidity: drier air can feel cooler at the same temperature because moisture on your skin evaporates more readily. In many leaky, under-insulated homes, air ends up both draughty and dry-so 20 °C can feel more like 17 °C even when controls insist everything is fine.

A quick extra check engineers use: measurable comfort, not just the dial

One useful step-rarely mentioned in everyday thermostat talk-is to measure surface temperatures. A basic infrared thermometer (or a home energy audit with thermal imaging) can reveal whether the real culprit is a 7 °C window reveal, a cold patch on an external corner, or a badly insulated floor zone. It turns “this room feels wrong” into a specific list of fixes.

Comfort also depends on ventilation done properly

It’s tempting to block every gap, but good engineers also think about controlled ventilation. If you seal draughts while keeping purposeful airflow (for example via trickle vents used sensibly, or correctly timed extractor fans), you can reduce heat loss without encouraging condensation and mould-especially in bedrooms and bathrooms.

What heating engineers actually do to make a home feel warmer (without turning it up)

Ask an experienced heating engineer how to improve comfort without simply cranking the thermostat, and they rarely start with kilowatts. They talk about gaps, curtains, floors, furniture placement and timing. A common approach is to choose one room you use most and build a “comfort bubble” there first.

A practical rule-of-thumb is to work in layers:

Stop the wind (draught-proofing).
Take the edge off cold surfaces (rugs, thick curtains, lined blinds).
Even out heat delivery (bleeding and balancing radiators, then running lower temperatures for longer).

This doesn’t just change the number you see-it changes the way your body exchanges heat with the space.

Engineers will also point out simple airflow mistakes, like radiators smothered by sofas, where warm air can’t circulate to the people who actually need it.

On a wet Tuesday in Birmingham, a heating surveyor visited a modern flat the owner described as “cursed”. The thermostat read 20.5 °C, yet visitors kept their coats on. The main radiator sat hidden behind a huge corner sofa; curtains stopped just above a cold aluminium window frame; and the bathroom extractor ran most of the day due to a faulty timer.

The fixes were plain:

pull the sofa about 15 cm away from the wall and fit a small foil reflector behind the radiator;
correct the timer so the extractor wasn’t continuously dragging warm air out;
hang a heavy, lined curtain that covered both the window and the frame.

No smart-home wizardry. No glamorous upgrades. Yet the flat felt calmer and less “edgily cold”, as the owner put it. The next week, he lowered the thermostat by 1 °C and didn’t notice-until the gas bill arrived slightly reduced.

Engineers also see the same behavioural patterns on repeat: people turn the thermostat up hard for short bursts, then let the house cool right down; radiators contain air or sludge so heat is patchy; curtains are flimsy; floors are bare; windows are left on the latch all day “for a bit of fresh air”.

Let’s be honest: almost nobody sticks to perfect routines every day, but engineers often recommend something closer to steady, gentle background warmth in the colder months. That way, walls, furniture and floors become a slow, even heat store instead of cold sponges that need reheating every evening.

One energy consultant put it like this:

“People assume comfort is a number on the thermostat. It isn’t. It’s how your body feels in the room: air temperature, surface temperature, draughts, humidity, clothing, even whether you’re sat by the window or in the middle of the room. The dial comes last, not first.”

Turning that into something you can actually use, specialists typically suggest:

Seal the obvious draughts first (letterboxes, keyholes, gaps under doors, around pipe penetrations).
Warm the surfaces you “see”: heavy curtains, rugs on cold floors, furniture pulled slightly away from icy external walls.
Bleed and balance radiators so they heat evenly, then run the system for longer at a lower temperature.
Use trickle vents and short, sharp airing (5–10 minutes) instead of leaving windows ajar all day.
Create one main “cosy zone” and optimise that space before attempting to heat every corner.

Why this matters more than ever for comfort, bills and EPC reality

On paper, two properties can appear almost identical: same EPC band, same boiler model, same thermostat brand. In real life, one household sits in T-shirts in January while complaining about costs; another wears three layers and still feels the cold gnawing at their shoulders.

Most people know the feeling of stepping into a friend’s home and relaxing within seconds-while their own place never quite manages the same ease. It isn’t just décor or scented candles. It’s the quiet background decisions of how the building retains heat, where draughts slip in, and whether warm air can move as intended.

The engineers I spoke to rarely promise “perfect comfort”. They talk about compromises, quick wins and “warm enough” in an era of rising energy prices and ageing housing stock. They know nobody is tracking humidity nightly or wandering around with incense every weekend. But they also know one focused afternoon spent spotting gaps, tackling cold surfaces and getting radiators behaving properly can feel like installing a new heating system.

If you’ve ever stared at the thermostat in mild disbelief-wondering why your toes are still freezing at 20 °C-you’re not imagining it. Your body reads the whole story of your home, not just the headline number. And once you start seeing where the warmth actually goes, small improvements can become oddly addictive.

Key points at a glance

Key point	Detail	Why it matters to you
Perceived temperature	A mix of air temperature, surface temperature and draughts-not just the thermostat	Explains why a room can feel cold at 20 °C
Draught-proofing	Seal leaks under doors, around windows and where pipes pass through	Improves comfort without increasing energy use
Warmer surfaces	Thick curtains, rugs, furniture slightly away from cold walls	Makes a room feel cosier with simple, visible changes

FAQ

Why does my house feel colder than my friend’s at the same thermostat setting?
Your body responds to the walls, windows, floors and draughts-not only the air. If your surfaces are colder, or the air moves more, you lose heat faster and feel chilled sooner.
Is it worth lowering the thermostat and improving insulation instead?
Yes, over the medium term. Reducing air leaks and warming surfaces makes every degree work harder. In some homes you can drop the setpoint by 1–2 °C without losing comfort.
Do thick curtains really make a difference?
Yes-particularly at night. They form a barrier in front of cold glass and reduce heat exchange between your body and the window, making the room more pleasant.
Why do my feet stay cold even when the room feels warm?
Poorly insulated floors and cold air pooling at floor level cool your feet quickly. A decent rug or better underfloor insulation can make a noticeable difference.
Is it better to heat the house all day or in short bursts?
For comfort, longer, gentler heating stabilises walls and furniture. Short, intense cycles allow surfaces to become cold again, which increases the sensation of chill.