Crawl space heater (C) Daniel Friedman Where & How to Add Heat to Prevent Frozen Pipes
     

  • HEAT SOURCES to AVOID FROZEN PIPES - CONTENTS: How to Add Heat, Heat Tapes, or simply increase building warm air circulation to prevent frozen pipes. Should we add insulation in spots where water pipes are likely to freeze? - How to winterize pipes: frost protection for plumbing systems
  • POST a QUESTION or READ FAQs about how to protect buildings from freeze damage: prevent frozen pipes, frost heaves, cracking due to freezing, and prevent water and mold damage that follows frozen, burst pipes.
  • REFERENCES

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Freeze-protection for buildings: this article explains where, why, and how to add heat at cold problem spots to avoid freezing pipes. We discuss the safe use of heat tapes in buildings and warn about unsafe heating tapes and fire hazards.

The articles at this website will answer most questions about freeze protection for piping and other building plumbing and heating system components: how to winterize a building to avoid frozen pipes, and how to thaw frozen water supply & drain piping, wells, & water tanks.

We discuss various methods to give each spot in danger of freezing its own heat source. For example simple passive heating may be sufficient to avoid freezing in some locations: in kitchens and bathrooms we may leave open vanity cabinet doors to permit warmer building air to reach pipes in those areas.

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How & Where to Add an Active Heat Source Heat to Protect Plumbing Pipes or Components from Freezing

Crawl space heater (C) Daniel FriedmanAdding heat to protect plumbing in un-heated areas such as crawl spaces: you may add heat either by installing a short section of heating baseboard, an extra opening cut in a warm air supply duct running through a crawl area, a small thermostatically-controlled electric heater set to operate only at low temperatures, or in small but cold areas, a simple light bulb may provide enough heat to prevent freezing.

Check these auxiliary heaters frequently to assure that the heat source is still working; be sure to respect fire safety when installing any heat source.

Adding small point-sources of extra heat in a building to protect from freezing is likely to be more economical than running the central heating system to a higher temperature just to warm up a cold corner or two.

Particularly if the thermostat set-back temperature results in the heating system turning on less often, adding point source heating may be needed.

We can add heat to protect plumbing and heating piping using any of the methods listed below and described in detail in this article:

  • Increase the flow of warm building air from the heated space into the cold corner or spot at risk of freezing by cutting one or more openings that let air circulate into the cold spot. In some bathrooms or kitchens we may simply leave the cabinet doors open to let room air reach sink plumbing.
  • Add a point-source of heat such as a tiny low-temperature-on electric heater, a short section of hot water heating baseboard, or by cutting an extra opening to let warm air blow out of a warm air supply duct into the cold area.

    Notice that the convector heater suspended from the crawl space ceiling (photo at left) has nothing combustible too close to the heater? Make sure that your added heat source does not create a fire risk.

    We discuss adding heat to un-heated or chilly areas using fan convector units in more detail
    at FAN CONVECTOR HEATERS - HYDRONIC COILS
  • Use heat tapes on piping in areas which are difficult to heat.

    Watch out: buy the correct kind of heating tape or cable. Shown at left is a roof heating cable intended for outdoor use. While the braided metal heat tape or cable at below right in the photo below is really appealing and can be made to any length needed, this is not the right stuff. The braided metal cable heat tape and its connectors are intended for use only indoors in a dry location and are designed to prevent pipes from freezing.

Types of heating tapes & cables for roof ice dam prevention and pipe freeze protection (C) Daniel Friedman

Roof heating cables for ice dam protection are discussed
at HEAT TAPES & CABLES for ROOF ICE DAMS

  • Use a light bulb as a heat source. Keep light bulbs at least two feet from any combustibles. Even a light bulb can start a fire if it's too close to combustibles.
  • Add insulation on piping to protect it from freezing
  • Change heating system controls to continuously circulate the water inside of heating baseboards or radiators even when the boiler is not itself heating the water.
  • Leave water faucets open to a drip or very slow trickle: this is an emergency procedure that you may need to use if your building loses heat. Normally it's not a great idea to leave water running as we are wasting water, risking frozen drain lines, and if a septic system is installed, we risk flooding the septic system.

    Watch out: while some experts advise leaving faucets open or dripping to avoid freezing pipes, this advice is risky if the building drains are exposed to freezing. In many areas the building main drain exits above the frost line and can be exposed to very cold conditions.

    During normal plumbing use the surge of wastewater down the drain makes it past this cold spot without freezing. A trickle of water can be cooled enough to freeze in the bottom of cold sections of drain piping; ice will build until eventually the drain is blocked (which can cause a sewer backup in occupied buildings). Eventually enough ice pressure may form to break the drain line.
    See FREEZING FORCE of ICE

Increase warm air flow: Another way we've added heat to problem areas where pipes freeze is to simply make one or more openings to permit warm air to circulate from the building into the cold area.

After finding freezing water pipes entering a bathroom located over a kitchen in a home with warm air heat, we cut an opening in the kitchen ceiling and installed a heating register there to make the hole look nice. Warm air rising from the kitchen proved sufficient to prevent a future freeze-up of the pipes in that location.

In any cold area where you are adding heat to avoid freezing pipes, the amount of heat you need to add will be reduced a lot if the cold area itself is insulated. Fiberglass insulation is fine for most building locations, but to reduce the risk of mold growth, we prefer to use solid foam insulation in areas like crawl spaces that are exposed to dampness.

How to Add Passive Heat Flow to Protect Plumbing Components from Freezing

Air register added to stop freezing pipes (C) Daniel FriedmanAdding heat to protect plumbing in un-heated areas such as crawl spaces: you may add heat either by installing a short section of heating baseboard, an extra opening cut in a warm air supply duct running through a crawl area, a small thermostatically-controlled electric heater set to operate only at low temperatures, or in small but cold areas, a simple light bulb may provide enough heat to prevent freezing.

Check these auxiliary heaters frequently to assure that the heat source is still working; be sure to respect fire safety when installing any heat source.

Adding small point-sources of extra heat in a building to protect from freezing is likely to be more economical than running the central heating system to a higher temperature just to warm up a cold corner or two. Particularly if the thermostat set-back temperature results in the heating system turning on less often, adding point source heating may be needed.

Our photo (above left) shows how we stopped freezing pipes under the second floor of a home.

On the first floor we cut an opening into a pipe chase through which both supply and drain piping rose upwards to the floor above. Just allowing air to enter the pipe chase by natural convection stopped the freeze-up problem we had experienced in the bathroom above this location. The orange arrow indicates the direction of warm air flow by convection.

The red arrow in our photo (above left) shows a cover we constructed to hide hot and cold water supply pipes that we had moved out of the wall cavity and into the building interior stop freezing. Moving those pipes to the inside of the wall and keeping the pipe cover an inch off of the floor permitted enough warm air to enter the covered space that the horizontal pipe run never froze again.

Air register prevents frozen pipes (C) Daniel Friedman
  • Increase warm air flow to freeze-protect piping in cold spots: Another way we've added heat to problem areas where pipes freeze is to simply make one or more openings to permit warm air to circulate from the building into the cold area.

After finding freezing water pipes entering a bathroom located over a kitchen in a home with warm air heat, we cut an opening in the kitchen ceiling and installed a heating register there to make the hole look nice. Warm air rising from the kitchen proved sufficient to prevent a future freeze-up of the pipes in that location.

In any cold area where you are adding heat to avoid freezing pipes, the amount of heat you need to add will be reduced a lot if the cold area itself is insulated.

Fiberglass insulation is fine for most building locations, but to reduce the risk of mold growth, we prefer to use solid foam insulation in areas like crawl spaces that are exposed to dampness.


How to use a circulating pump to prevent water from freezing

Reader comment: Vincent 1/21/13: Great suggestions - good article!

Beside insulating pipes from cold weather, or trying to use heat tape, a very effective way of protecting pipes from freezing is to introduce a circulating pump into the water system. By installing a circulation system, the water from the 'hot' side of the system gets sent to the 'cold' water line. This greatly reduces the possibility of water pipes freezing because the water temperature never reaches the critical freezing point.

The best circulation system on the market that I've seen is available at http://avoidfrozenpipes.com/ It is the only circulating pump I've seen that doesn't need electricity to run. It can be installed anywhere in the water system, and save hundreds if not thousands of dollars in home repairs if frozen pipes burst from water expansion.

That's my two cents; I hope it helps! - Vincent 1/21/2013

This comment was originally posted at HEAT TAPES to AVOID FROZEN PIPES

Reply:

Thanks so much Vincent. We welcome content critique & suggestions for InspectApedia articles. Working together we are smarter than any individual. - Daniel

Reader Question: what is the best way to heat a well pit?

what is the best way to heat a well pit - Jim, 10/18/2012

Reply:

Jim:

A well pit is intended to protect its contents, well head, piping, possibly even a water tank and pump from freezing by its depth below ground. If you have to add heat then the pit was perhaps not properly constructed, not deep enough, or left uncovered.

That griping done, you could consider adding a small electric heater;

We have also used a simple light bulb in a small, closed well pit. The risk of course is that electricity fails or the bulb burns out.

That's why I think a small oil-filled electric heater is probably more safe. Be sure that ALL electrical components in a well pit are protected from water, including the occasional well pit flood. More suggestions for adding heat and cutting drafts that would help freeze-proof a well pit are in the article above.

 

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Or see INSULATION to AVOID FROZEN PIPES

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