Got Hydronic Heat? Here's How to Winterize It

By Lisa A. Koosis

November 02, 2025

When the temperature drops, frozen tubes, burst pipes and pressure drops in your radiant heating system can leave you cold — literally. Learn how to winterize hydronic heat to keep the warm air flowing so your home and family stay comfortable all season long.

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What Is Hydronic Heat, and How Do I Know If I Have It?

Hydronic systems heat your home using hot water pumped through a network of tubes. As the liquid circulates through your house, it heats nearby surfaces, such as walls, baseboards and floors. Once heated, these materials radiate warmth outward into the home.

If you aren't sure what type of heat your home uses, here are a few telltale signs that you have a hydronic heating system:

Radiators: Water-based systems often use radiators to disperse heat, so baseboard radiators are a strong indicator of hydronic heat.
Boilers: If you have a boiler rather than a furnace, you probably have hydronic heat. These units are commonly installed in basements, garages or utility rooms.
Lack of air vents and ducts: Hydronic systems don't use forced air to distribute heat, so homes warmed this way often don't have vents or air ducts.
A separate cooling unit: Hydronic systems don't cool your home, so a separate cooling unit could indicate hydronic heat.
No blowing air: Hydronic systems are quiet since they don't require forced air. If your home is warm but no air is blowing, you probably have hydronics.
No hot or cold spots: Hydronics heats a home evenly, so you won't find areas that are too hot or too cold.
Heated towel racks: Heated towel racks are common accessories for hydronic heating systems. If your towel rack has a nearby electrical switch, it may be designed to heat your towels using hydronics.

Do You Need to Winterize Hydronic Heating Systems?

You typically need to prepare hydronic heat for winter. These systems use water or other liquids for power, so cold weather can impact their performance. Clogs and fuel problems can lead to a loss of heat, or worse, pipes can freeze, particularly if they're located in outside walls or unheated basements and garages. If they burst, they can cause serious water damage.

Fortunately, regular maintenance and hydronic system winter care can keep everything in good working order so you enjoy consistent heat even on the coldest days.

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Step by Step, Including the Tools and Materials Needed, How Do You Winterize a Hydronic Heating System?

To winterize radiant heat, you'll need:

Digital moisture meter
Insulation (e.g., foam sticks or sleeves or fiberglass pipe wraps)
Tape measure
Duct tape or cable ties
Gloves (if handling fiberglass)
Scissors or other cutting tool
Headlamp or work light

Once you have the tools and materials, hydronic heating winterization involves a few simple steps:

Inspect your boiler and pipes. Inspect the visible elements of your system for mold, mildew and cracks, and check for obvious leaks. Make sure exterior pipes or those in areas prone to freezing are well-insulated.
Insulate exposed pipes. You'll need to insulate any uninsulated pipes you find. Measure the length of the pipes to determine what size insulation you'll need. Start at the boiler and pay special attention to the first 3 feet of pipe leading to and exiting the unit. Cut the insulation to the correct length and then place it, securing it with tape, wire or a cable tie after every foot or two. If you opt for fiberglass insulation, wear gloves and long sleeves to protect yourself from fibers.
Check for moisture throughout your home. Use a digital moisture meter, available at most hardware stores, to detect moisture that's not visible to the naked eye. If you find moisture in odd places, it could signal a leak in the tubing network of your hydronic system.
Have your boiler serviced. Regular professional boiler service is essential, but you should also call a technician before cold weather hits to diagnose and fix any potential problems.

Hydronic Heating System Maintenance

Winter care for your hydronic system is vital, but year-round preventive maintenance can forestall many unnecessary problems. Turn your heating system on periodically, even in warmer months, to help maintain pressure and keep water flowing properly. Additionally, if you're going on vacation during cold-weather months, leave your boiler on. Otherwise, you risk burst pipes.

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