How to care for steam and hot-water radiators.

old heater

How to care for steam and hot-water radiators.

It’s important to know that you should always speak to a professional before trying to repair or maintain any old radiators found in your home.

The reason for working with a pro is that you need to know if your home has steam or hot-water radiators.

How can identify Steam from Hot-Water Radiators?

Generally speaking, the way to tell if you have steam or hot-water radiators is to look at how many pipes are coming from your radiator. If you see only one pipe, then it likely a steam radiator. If you see two pipes, then you may have a steam or hot-water system in your home. The second pipe is generally used for the cool or condensed water so it returns back to the boiler.

Photo of a home's radiator with a cat sleeping on it.
Photo by he gong on Unsplash

Care of your Home’s Radiators

Hot-Water Radiators

Professional HVAC contractors understand how hot-water radiators use convection in order to distribute heat across your home. In hot-water heating systems, that don’t have circulating pumps, water flowed using gravity and convection where hot water rose, would transfer it’s heat into your room, then the cold water would fall and flow back to the water heater.

Maintaining these systems can get complicated as there are many variables to account for like:

  • Is a circulating pump being used?
  • How many floors are there in the building?
  • What is the water pressure from the street?
  • Is there a pressure valve on the system?
  • Are there orifices installed to create resistance?

When troubleshooting it’s important to know how to balance the system. So it’s incredibly important to not troubleshoot or modify your hot-water heating system without consulting a professional who will take into account all these variables

What can I do to maintain my hot-water radiators?

You can adjust the bleeder valve.

On a hot water radiator, if it is not heating the room properly, it’s possible air may be trapped inside. To address this do the following:

  • Turn down the thermostat to reduce water flow
  • Locate the bleeder valve on the radiator
  • Hold a cup or cloth under the bleeder valve to catch water
  • Open it with a bleeder key, long-nose pliers, or screwdriver
  • Water may spit or hiss as air may come out
  • Once water flows in a steady stream, tighten the valve

Steam Radiators

Steam radiators will have either one or two pipes. Steam radiators use gravity to return the condensed steam (condensate) back to the boiler. Unlike hot-water heating systems, steam systems use much lower pressure. A professional HVAC contractors understand that if there is too much pressure, the vents won’t open and release air. This leads to steam not being able to get in or condensate, being able to return.

How can I maintain my steam radiators?

You can release air by using the valve on the side of the steam radiator.

  • Locate the air vent on the side of the steam radiator
  • Ensure the air vent has an open air hole by sticking in a piece of wire or a small needle
  • Air vents that are painted over will clog the air vent and create problems

Provide better air flow.

  • Be careful to keep proper air flow around below, and behind the radiator
  • Move furniture and other objects out of the way
  • Use aluminum or reflective insulation placed behind the radiator to direct heat into the room


Water and steam based heating systems are great ways to heat your home in the winter. In order for them to remain efficient, they need to be maintained.

Reach out if you have any questions about how to maintain your heating system.