A cold house on a winter morning is never a good start to the day. Before you panic or book the first callout you can find, it's worth running through the usual suspects: most heating faults come down to a handful of causes, and several of them you can check yourself in minutes.

This guide walks through the most common reasons your heating stops working, what you can safely try first, and when it's time to bring in a professional.

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Common reasons your heating isn't working

Before diving into fixes, it helps to know what you're dealing with. Your heating may have stopped because of:

• A boiler that needs resetting

• A power supply problem

• Thermostat or smart control issues

• Incorrect timer settings

• Low boiler pressure

• A general boiler malfunction

• Radiator problems (cold spots, stuck valves, sludge)

• An airlock in the system

• A frozen condensate pipe

• An ageing boiler nearing the end of its life

Some of these are quick DIY fixes. Others need a Gas Safe heating engineer; especially anything involving gas, error codes, or a boiler that won't reset.

If you smell gas at any point, stop what you're doing and call the National Gas Emergency Service on 0800 111 999 straight away.

1. Reset your boiler

The simplest fix is often the right one. Turn your boiler off and on again, or use the reset button on the front panel; check your manual if you're not sure which one it is.

Because gas central heating relies on electricity to run its controls and ignition, boilers are prone to the same minor glitches as any other electronic appliance. A reset clears most of these instantly.

2. Check for power supply problems

No power means no heating, so rule this out early. Check whether there's a power cut in your area, then check your fuse box and circuit breakers: a tripped switch is a common and easy fix.

If the power supply checks out and you still have no heating, it's time to call a boiler engineer.

3. Check your thermostat, including smart controls

Start with the batteries, then check the temperature setting. If your thermostat is set below room temperature, your boiler has no reason to fire up.

Try setting it to 18-21°C or higher to trigger the boiler into action.

If you've got a smart thermostat like Hive, Nest, or tado, check the app before touching anything physical.

These systems cause a surprising number of false "boiler is broken" alarms: the schedule, override settings, or a lost connection to the receiver can all stop your heating firing even though the boiler itself is fine.

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4. Check your boiler timer

If your timer is set incorrectly, your heating simply won't come on when you expect it to.

Remember to adjust every clock in the house, including the boiler timer, when the clocks change. A worn-out or faulty timer can also drift out of sync over time, so if the times keep slipping, the timer itself may need replacing.

5. Rule out low boiler pressure

Low boiler pressure is one of the most common causes of a heating breakdown, and one of the easiest to fix yourself.

Your pressure gauge should read between 1 and 1.5 bar. If it's reading lower, locate the filling loop (usually a braided hose beneath the boiler) and slowly open the valves to let mains water back into the system, watching the gauge as you go. Close the valves once you hit around 1.2 bar, then reset the boiler.

If you're topping up the pressure regularly, that points to a leak somewhere in the system rather than a one-off drop; see the water leaks section below.

6. Look for boiler malfunctions

Pressure isn't the only thing that can go wrong with a boiler. Other common issues include:

• Error codes. Check the display panel and your manual: some codes point to a fix you can do yourself, others need an engineer

• A loose heating element. A humming noise often points to this

• A blown pilot light. Check your manual for relighting instructions, but call a Gas Safe engineer if it keeps going out

• A stuck diverter valve. On combi boilers over 8-10 years old especially, a diverter valve failure is one of the more common causes of hot water with no heating (or vice versa)

A Gas Safe engineer is the right person for any fault beyond a simple reset. Find out how to locate a qualified boiler repair engineer.

7. Check your radiators

Radiator problems can leave you with a working boiler but a cold house. Common causes include:

• Cold spots, especially at the top. This usually means trapped air: bleeding the radiator often solves it

• A stuck Thermostatic Radiator Valve (TRV). Gently turn the valve to check it isn't jammed shut

• A worn circulating pump. If the pump can't push water through the system properly, a professional fix is the safest route

• Sludge or debris build-up. This restricts water flow to the radiator over time

Younger radiators are usually worth flushing out. Older ones may be more cost-effective to replace; see how much it costs to remove and replace a radiator for a guide to pricing.

8. Rule out an airlock

Trapped air in your pipes or radiators is a common and often overlooked cause of heating failure. Look out for gurgling sounds, patchy cold radiators, or a system that's switched on but producing no heat at all.

Bleeding the radiators or flushing the system usually clears an airlock. If it doesn't, find a qualified tradesperson to take a closer look.

9. Check for a frozen condensate pipe

In cold UK winters, a frozen condensate pipe is a classic cause of a boiler that simply won't fire up.

Even a small amount of frozen water can block the pipe entirely. Thaw it gently using warm (never boiling) water poured over the affected section, and your heating should come back on once the ice clears.

10. Consider the age of your boiler

Most boilers last 10-15 years. If yours is creeping towards that age and you're noticing higher energy bills, strange noises, or repeat breakdowns, it may be nearing the end of its working life rather than suffering a one-off fault.

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Other possible causes if you're still stuck

If none of the above fits, a few less common culprits are worth ruling out:

Blocked or dirty filters

Clogged filters restrict airflow and hurt your system's energy efficiency. Many are simple enough to clean or replace yourself.

Faulty zone valves

Zone valves control which parts of your home get heated. When one sticks or fails, you'll typically notice inconsistent heating: some rooms warm, others stone cold.

A failing expansion vessel

The expansion vessel absorbs the extra pressure created as water heats up. When it fails, pressure can swing unpredictably and trigger repeated lockouts even after you've topped up the system.

Water leaks in the system

If your boiler keeps losing pressure no matter how often you top it up, a leak somewhere in the system is the likely cause. Check around the boiler and visible pipework for damp patches or drips, and call a heating engineer if you can't find the source yourself.

Depending on the cause, you might need a heating engineer for a boiler fault, a plumber for radiators and pipework, an electrician for power supply issues, or a smart thermostat installer if your controls are the culprit, Checkatrade can match you with the right one for the job.

How to prevent heating problems in future

Prevention beats a cold house every time. A few simple habits go a long way:

• Book annual servicing with a professional, ideally before winter sets in

• Bleed your radiators regularly and check pressure every few months

• Keep an eye on your smart thermostat app for missed schedules or connection drops

• Insulate exposed pipework, especially anything running through a loft or garage, to reduce the risk of freezing

Need reassurance? All tradespeople pass up to 12 checks before joining, and we keep checking after.

Checklist before you call an engineer

Quick checks before you book a callout

• Check the boiler pressure gauge

• Check thermostat settings and batteries

• Check the smart thermostat app and schedule

• Check the boiler timer and clock settings

• Check for a tripped circuit breaker

• Bleed radiators with cold spots

• Check for a frozen condensate pipe

• Note any error codes on the display

How to find the right tradesperson

If your heating fault is beyond a DIY fix, look for a Gas Safe registered engineer for anything boiler-related, or a plumber for radiator and pipework issues.

Checking reviews and past job history helps you choose someone with the right experience for your specific system.

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