The heating behaviour landlords notice too late

The first winter after you buy a few let properties, you start to learn the rhythms you can’t see on a viewing day. Predictable heating behaviour is one of them: the small, repeatable patterns tenants fall into when the house feels hard to keep warm. It matters because those patterns quietly decide your mould risk, your boiler call-outs, and whether a “minor” issue becomes a dispute by February.

I’ve watched landlords fix the obvious things-new thermostat, bigger radiator, fresh paint-then still get the same messages: the bedroom is freezing, the bathroom smells damp, the windows run with water every morning. It’s rarely because tenants are careless. It’s because they’re trying to make a cold, expensive building feel liveable with the tools they have.

The pattern: heat the person, not the home

When heating costs sting, people stop thinking in rooms and start thinking in zones. They’ll warm the sofa, not the sitting room. They’ll heat for an hour, not a morning. They’ll shut one door, open another window, and hope it balances out.

It looks like this in real life: one electric heater blasting in the lounge, bedroom radiators off, and a towel rail that never quite dries anything. The house feels “fine” when someone is in it, then drops cold as soon as they leave for work. By evening, the cold has soaked into walls and soft furnishings, and the quick blast of heat can’t shift the damp.

Landlords often notice the end result-condensation and a musty smell-without spotting the behaviour that’s feeding it.

Why landlords spot it too late

Because the paperwork looks reassuring. The EPC is “acceptable”. The boiler service is up to date. The tenants didn’t complain for months, so surely it was fine.

But predictable heating behaviour is delayed feedback. The first few weeks of short, sharp heating cycles don’t cause drama. Then the weather turns, washing can’t dry, bathrooms stay steamy, and the coldest corners become little climate zones of their own.

By the time you see it, it’s wearing a disguise:

• “Black spots behind the wardrobe”
• “Paint bubbling by the window”
• “A sour smell in the second bedroom”
• “The extractor is useless” (sometimes true, sometimes a symptom)

At that point, everyone feels blamed. Tenants feel accused of “not ventilating properly”. Landlords feel like they’re paying for someone else’s lifestyle. The building is just doing what buildings do when heat and moisture aren’t managed steadily.

The three behaviours that predict the next problem

1) The on/off heating sprint

A lot of households run the heating like a kettle: on hard, off fast. It’s logical when you’re watching the meter.

The trouble is that cold surfaces invite condensation. When warm, moist air hits a cold wall, it doesn’t matter that the room felt warm for an hour-water still drops out of the air and settles where airflow is weakest.

A steady, lower background temperature often prevents more moisture than a daily “blast”. That’s not a moral statement. It’s building physics.

2) The closed-door “heat hoarding” plan

People close off rooms to save money. Again: sensible. But if a bedroom goes unheated with the door shut, it becomes the cold sink for the whole flat’s moisture.

Then the classic message arrives: “We don’t even use that room and it’s the one with mould.” Exactly.

Watch for clues on inspection: one room noticeably colder, windows shut tight, and a wardrobe hard up against an external wall. That combination is a mould starter kit.

3) The window war: either sealed or wide open

Tenants tend to swing between extremes: never opening windows because it “lets the heat out”, or opening them wide because the air feels heavy.

Neither is wrong. Both are incomplete. What works best in typical UK stock is short, repeat ventilation (especially after showers and cooking) plus enough background warmth to stop surfaces dropping to dew point.

If the property lacks decent extraction, tenants compensate with windows. If the property is draughty, they stop opening them at all. Either way, the behaviour is predictable once you understand what the home is asking them to do.

A landlord’s “early warning” checklist (before mould shows up)

You don’t need to become the heating police. You just need to notice the signals early, when fixes are still small.

• Ask one neutral question: “How do you usually run the heating-steady, timed, or as needed?”
  
• Check the cold corners: behind wardrobes, in box rooms, around bay windows, and on north-facing walls.
• Look at drying habits: if there’s no tumble dryer space and no working extractor, laundry will end up on radiators.
• Notice the ventilation tools: trickle vents open, bathroom fan effective, kitchen hood actually ducted.
• Confirm the controls are usable: a modern thermostat doesn’t help if nobody understands it, or it’s hidden in a cupboard.

If tenants feel they can answer honestly without being punished, you’ll learn more in two minutes than you will from a dozen “please ventilate” emails.

The fix isn’t one gadget-it’s a simpler routine the home can support

Most tenants aren’t refusing to heat properly. They’re trying to keep costs down while staying comfortable. Your job, as a landlord, is to make the “good pattern” the easiest pattern.

That usually means:

• Controls that make sense: clear timer settings, a thermostat that reads properly, thermostatic radiator valves that aren’t stuck.
• Ventilation that works quietly: strong bathroom extraction with overrun, kitchen extraction that vents outside where possible.
• Small layout changes: wardrobes off external walls, a gap for airflow, door undercuts where needed.
• A target that isn’t extreme: a modest background heat rather than dramatic peaks and cold troughs.

And yes, sometimes it’s insulation, glazing, or a chronic cold bridge that needs real investment. But you’ll only diagnose that correctly once you’ve understood the human pattern happening inside the building.

“People don’t create damp by existing. Damp happens when the building can’t cope with normal life on the budget and controls it’s been given.”

A quick landlord note you can actually send (without starting a fight)

Keep it short, practical, and non-judgemental. Something like:

• Aim for a steady low background rather than short blasts if you can.
• After showers/cooking, run the fan and crack a window for 10 minutes.
• Keep furniture a few centimetres off external walls.
• If any room is always cold, tell me early-it’s easier to fix before winter sets in.

The magic is not the content. It’s the tone: we’re on the same side, solving the house together.

What you’ll notice first	What it usually means	What to do early
Condensation every morning	Surfaces too cold / ventilation too weak	Check fans, trickle vents, heating schedule
One room “always damp”	Unheated room acting as moisture sink	Encourage background heat, improve airflow
Musty smell after laundry	Drying indoors without extraction	Provide drying options, upgrade ventilation

FAQ:

• Isn’t mould just tenants not opening windows? Sometimes ventilation habits play a role, but predictable heating behaviour is often a response to high bills, awkward controls, or weak extraction. Treat it as a system issue first.
• Should I tell tenants to leave the heating on all day? Not necessarily. The goal is avoiding big temperature swings and cold surfaces. A modest, well-timed background heat can be enough, depending on the property.
• What’s the quickest upgrade that actually helps? Effective bathroom extraction with overrun and clear heating controls tend to reduce condensation fast, because they support the routines tenants can realistically follow.
• How do I raise this without sounding accusatory? Ask neutral questions about comfort and costs, share a simple routine, and frame it as protecting the home together-not “rules” for living.
• When is it a building defect, not behaviour? If mould persists despite reasonable heating/ventilation, or it’s concentrated on specific cold spots, suspect insulation gaps, cold bridging, leaks, or inadequate ventilation design.