What should I do if my radiators are not heating?

What this symptom usually points to

Cold radiators tell you the boiler system is not delivering hot water where it needs to go. That is different from a boiler that will not fire at all: with this symptom, the problem is often in circulation, pressure, trapped air, or a specific room or zone valve rather than total boiler failure. Homeowners often notice the thermostat is calling for heat and the house stays chilly, but the issue is really that the radiators never get fully hot.

What you can tell from the way the radiators feel

The pattern matters. If every radiator in the house is cold, low system pressure or a circulation problem is more likely than a single bad radiator. If only one radiator is cold, a stuck valve or air pocket is common. If the radiator is warm at the bottom but cool at the top, trapped air is a strong clue. If one room or one whole zone is cold while the rest of the house heats normally, the issue is often a zone valve, circulator, or flow restriction in that branch.

When weak airflow, noise, ice, or water show up with cold radiators

Radiator systems do not rely on supply-air airflow the way a furnace does, so homeowners sometimes describe the house as having weak airflow simply because it never feels warm enough. Gurgling or rushing-water sounds often go with air in the lines. Water around a radiator can mean a leaking valve, vent, or union, and that can lower pressure enough to keep radiators from heating. Ice on heating pipes is less common indoors, but if exposed pipes in crawl spaces, basements, or exterior walls have frozen, that can stop circulation to the affected radiators.

What a technician usually checks on a service visit

A boiler technician will usually verify the thermostat call, check boiler temperature and pressure, confirm whether the circulator is running, inspect zone valves, and compare temperatures on supply and return piping. They may test whether individual radiator valves are opening, look for air in high points of the system, and inspect for leaks that caused pressure loss. On older systems, they may also look for sludge, partially blocked piping, or improper balancing that keeps far radiators from getting enough flow.

What affects repair cost

Cost depends heavily on where the problem is. Bleeding air and correcting pressure are usually at the lower end of boiler repair pricing, while replacing a circulator pump, zone valve head, or radiator valve costs more because of parts and labor. Typical 2025-2026 US repair ranges are roughly $150-$350 for simple service such as venting and repressurizing, $250-$700 for many valve-related repairs, and about $500-$1,200 for circulator pump replacement, with higher totals possible on older multi-zone systems or when draining and refilling the loop is required.

Because radiators that do not heat can leave rooms much colder than the rest of the house, it is smart to schedule service soon, especially in freezing weather or if only bedrooms, nurseries, bathrooms, or exterior-wall rooms are affected. A referral platform like HVAC Rescue can help you request boiler repair from an independent contractor, but final diagnosis, timing, and pricing depend on the company that takes the job.