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.

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

Adding 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 COIL & 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.

Pipe heating cables to avoid frozen pipes (at right in the photo above) are discussed

at HEAT TAPES to AVOID FROZEN PIPES

Roof heating cables for ice dam protection (at left in the photo above) 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

Adding 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.

• 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

...

---

---

ADVERTISEMENT

---

---

Reader Q&A - also see RECOMMENDED ARTICLES & FAQs

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.

Question: what about using heat tape on sewer pipes - our mobile home sewer line keeps freezing

You don't say anything regarding using heat tape on sewer pipes. We have an annual problem with a mobile home sewer line freezing. The line connects a toilet, shower and tub so when it freezes it is a mess. - Anon. 9/19/11

Reply:

Anon, you can add a heat tape on a sewer line provided the tape you choose is connected and secured to the sewer line the way the manufacturer instructs. Make sure that the bottom of the waste pipe is in contact with the heat tape, and provided the heat tape manufacturer permits, insulate the line as well. The combination of a proper heat tape and sewer line insulation is usually enough to stop freeze-up but here are some additional tips for mobile home waste line freeze problems:

• Watch out: some heating tapes cannot safely be used on drain pipes, possibly because of a concern for heat damage to the piping. Details are in the article above at HEAT TAPES to AVOID FROZEN PIPES
• Because the waste line typically has a vertical segment between the floor of the mobile home and the ground and because that segment is exposed to cold air in the crawl space beneath the home you will want to insulate it. But in termite prone areas the risk is that your insulation provides an insect path from the soil up into the floor of the home. Ask your local pest company for advice about protecting this area from insects or perhaps construct a surrounding (openable for inspection and repair) partition wall that uses termite shields.
• Watch out for dripping faucets and running toilets. A drain line does not normally contain standing water but when routed through freezing spaces and when there is a small rivulet of water in the drain due to a slow leak indoors such as a drip or running toilet, that water can freeze and accumulate until the line becomes blocked, frozen solid, and burst.

Question: what kind of heating tapes can be used on PVC plumbing drains?

I have a PVC drain line for my water softener that goes outside. When it got very cold two winters ago, the drain line froze and it backed up into house. The drain line lays on the ground. I went to a local store to look for heat tape and they specifically stated not to use on drain lines. Is there some type of tape I could use that would be safe, and how should it be installed? - Don Corbett 9/30/11

Reply:

Don:

A concern with heat tapes on plastic piping is that it may damage the pipes. And if your water softener drain is simply draining onto the ground surface, that is an improper and illegal disposition of wastewater in just about every jurisdiction. Unfortunately the proper fix is costly: reroute drainage to a drywell or other approved drainage destination.

If you use drain piping of sufficient diameter and proper slope, even exposed to cold temperatures the drainage will generally not freeze up in normal use. More help on avoiding freezing piping is at WINTERIZE A BUILDING.

Heating tapes and cables can be installed on PVC supply and drain piping provided you choose the right kind of heating tape or cable and that you follow the manufacturer's instructions. Details are in the article above at HEAT TAPES to AVOID FROZEN PIPES.

Question: is it OK for the water line to run atop a concrete slab or should it be under ground?

In a mobile home in N.E. should the water supply line be placed on top of the concrete slap for 30 feet or more. Would that be up to code? Should the line from the street be 4 feet under ground to within 6 feet of the hot water heater? - Lee Broad 1/23/12

Reply:

Lee, if you are describing a water line atop the rat slab beneath a mobile home, there are a couple of hazards including freezing and also movement-caused abrasion and leakage. If the line is supported off of the slab by blocks and insulated you may be OK, else you'll need to add frost protection as well. Heating cables (see advice above in this article) are readily available in lengths up to 60 ft. so you won't have trouble finding one long enough. Don't buy one longer than you need and be sure it is connected according to the manufacturer's instructions.

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. - See more at: https://InspectAPedia.com/plumbing/Pipe_Heat_Add_Points.php#sthash.Nk3hbfK8.dpuf.

Question: tips on how to use a circulating pump to prevent water from freezing

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

Reply:

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

...

Continue reading  at HEAT TAPES to AVOID FROZEN PIPES or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

Recommended Articles

• ANTIFREEZE for BOILERS
• DRAIN a WATER HEATER TANK
• FAUCETS, OUTDOOR HOSE BIBBS
• FREEZING FORCE of ICE
• FROZEN PIPE THAW-OUT
• GREYWATER FREEZE PROTECTION
• PIPE FREEZE PROTECTION - home
  • DRAIN FREEZE PROTECTION
  • HEAT SOURCES to AVOID FROZEN PIPES
  • HEAT TAPES to AVOID FROZEN PIPES
  • HEAT TAPES on OIL TANK PIPING
  • HEAT TAPE HAZARD ON OIL TANK
  • INSULATION to AVOID FROZEN PIPES
  • PIPE FREEZE-BURST PATTERNS
  • PIPE FREEZE-UP POINTS
  • PIPE INSULATION CHOICES, MATERIALS, TYPES
  • WELL SNIFTER & DRAIN BACK VALVES
• WINTERIZE A BUILDING - home

Suggested citation for this web page

HEAT SOURCES to AVOID FROZEN PIPES at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

Or see this

INDEX to RELATED ARTICLES: ARTICLE INDEX to BUILDING FREEZE PROTECTION

Or use the SEARCH BOX found below to Ask a Question or Search InspectApedia

Ask a Question or Search InspectApedia

Try the search box just below, or if you prefer, post a question or comment in the Comments box below and we will respond promptly.

Note: appearance of your Comment below may be delayed: if your comment contains an image, photograph, web link, or text that looks to the software as if it might be a web link, your posting will appear after it has been approved by a moderator. Apologies for the delay.

Only one image can be added per comment but you can post as many comments, and therefore images, as you like.
You will not receive a notification when a response to your question has been posted.
Please bookmark this page to make it easy for you to check back for our response.
Our Comment Box is provided by Countable Web Productions countable.ca

Citations & References

In addition to any citations in the article above, a full list is available on request.

---

ADVERTISEMENT

---