How to Turn Off a Radiator: A Complete Guide

Whether hot water or steam warms your home, this guide’s got you covered

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We know they heat our homes, but knowing how to turn off a radiator and how they work can be confusing. Some units use hot water, while others use steam, and the valves and knobs on the side might leave you fearful you’re going to turn the wrong thing off (or on). Don’t worry. Learning how to turn off a radiator or balance one is not as complex as it might seem.

If You Have a Thermostatic Valve

3 radiator valve types compared visually, including thermostatic, non-thermostatic, and lockshield
Photo 1: Gudella / iStock / Getty Images Plus / Getty Images; Photo 2: dropStock / iStock / Getty Images Plus / Getty Images; Photo 3: scaliger / iStock / Getty Images Plus / Getty Images

Thermostatic valves are designed to self-regulate the amount of hot water flowing through pipes in your home based on room temperature, meaning you shouldn’t have to adjust them often. But if you need to, you’ll find the radiator shutoff valves (or valve) on the top of your radiator. 

In most cases, you’ll be able to choose a setting between 0 and 5. To turn it off, turn the dial to 0. To turn up the heat, turn the dial one number at a time until a desired temperature is reached.

If You Have a Non-Thermostatic Valve

Three dimensional render of old-fashioned radiator
Photo: Westend61 / Getty Images

If your radiator doesn’t have a thermostat, then you have a non-thermostatic valve, which is common in older homes. You can usually adjust this by hand. Some may use a numbers system, while others may have a simple dial, located either on top or on the side of your radiator. Clockwise tightens and lowers the heat, while counterclockwise opens the valve and increases it.

Firmly tighten the valve on the side of your radiator until it doesn’t move. Then, open it slightly or as desired. This establishes a baseline with it closed completely (no heat) and allows you to add as much heat to the room as you wish.

If You Have a Lockshield Valve

Lockshield valves are sometimes found on manual radiator valves now. They control how much water can exit the radiator, which can also help you cool or heat a room. The more open it is, the cooler the room, as hot water won’t stay in the radiator as long.

Look for a valve covered with a plastic cap and tighten or loosen it as needed. Lockshield valves usually come with a key, which you’ll need to put inside the slot underneath the plastic cap.

Tips to Maintain a Radiator

A plumber inspecting a radiator
Photo: Angelov / Adobe Stock

Repairing a broken radiator costs $100 to $500 on average, so maintaining yours is a savvy way to keep cash in your pocket and keeps you from being stuck on cold winter days with no heat.

Bleed the Air

You should bleed your radiator of air annually. “Bleeding” means letting all the excess air out of your pipes. Air trapped in the pipes rises to the top of your radiator, resulting in uneven heating. The bleed valve at the top of your radiator should have a hand dial or key you can insert to remove built-up air.

Flush

Radiator coolant and other debris can decrease efficiency in your home’s hot water or steam radiator system. Having a professional flush your radiator every five years (or every three years if it’s about seven or more years old) is a good idea. 

Check for Leaks

Dripping water could lead to corrosion and expensive repairs if left untreated. Add looking for leaks to your annual checklist before turning on the heat when cold weather creeps in. 

Clean Your Steam Radiator

Homeowners can clean their steam radiator with 1 gallon of water mixed with 1 cup of vinegar. Use a sponge or cloth to wipe down the outside to prevent corrosion as it ages. Steam radiators are closed systems, so the inside doesn’t need to be cleaned.

Know Where to Use Thermostatic Valves

Never install thermostatic valve radiators in rooms where the temperature can fluctuate greatly. Moisture and heat from other appliances can wear down the radiator’s self-regulating mechanisms faster, leading to more frequent repairs. Don’t install a thermostatic valve radiator in rooms with consistently fluctuating temperatures, like bathrooms or laundry rooms. 

A heating and cooling specialist can help with your maintenance plan, or you can save money by tackling the tasks yourself (when safe to do so).

Frequently Asked Questions

Yes, it is OK to turn off some radiators, and you’ll save money on heating costs if you make it a regular habit to turn your radiators off in unused rooms that don’t need heat. That said, turn them back on when you need to heat your whole home instead of cranking up the dial on the ones you haven’t closed to compensate. The latter will result in higher heating costs and more wear and tear on your system.

Generally speaking, yes, turning one radiator off does save some money, especially if the system is a little older—so long as you’re not cranking up the dial on the ones you leave on. But some HVAC specialists argue that keeping your entire system on ensures that your boiler stays efficient. After all, it’s rated to fit your home and heats the amount of water your heating system needs. This could be the case if you have a new system. However, turning radiators off in unused rooms lowers the amount of hot water you need.

If your radiator turns on every time you turn on your hot water, your problem is likely your motorized three-port valve that’s attached to your boiler. When it malfunctions, the valve isn’t closing properly, so the water begins to flow to your radiator, thus kicking off the heat. To fix this, hire a boiler repair tech near you to replace your valve.

No, there isn’t always water in radiators. In a one-pipe system, water is constantly circulating from the boiler to the radiators and back. In a two-pipe system, water travels through two separate channels: one that goes to your radiators and one that returns back to the boiler so it can heat up again.

Over time, a radiator can leak if turned off due to the built-up air pressure, which can cause water or coolant to leak. If your radiator leaks when it’s off, turn your whole system off and bleed the radiator, then turn it back on. If it’s still leaking, you might want to have an HVAC professional look at the issue.

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