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Winterizing a building: how to freeze proof a building when heat will be turned off:
This article explains with a step by step guide just how to winterize or freeze proof a building when the building's heating system is going to be turned off completely.
We discuss turning off water supply, draining piping and plumbing fixtures, turning off and if necessary winterizing a heating system, and other steps to avoid freeze damage or water, leaks, and mold damage to buildings that are being left in a "shut down" condition.
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.
Is the building heat going to be left "on" or "off" - the answer determines the extent of freeze-proofing needed.
If heat is to be left ON in a partially winterized building see the procedure
at: WINTERIZE - HEAT ON
If heat is to be turned OFF and the building completely winterized, see the procedure
at: WINTERIZE - HEAT OFF(continuing just below)
If you have decided to shut down the building's heating system, some steps to protect the building from freeze damage are simple (you don't worry about figuring out the thermostat set-temperature nor about finding "cold spots" where pipes may freeze).
Incidentally, don't make this common mistake: never leave a garden hose attached to your outdoor faucet in winter as water in the hose may add to the risk that the faucet will be freeze damaged. See details about outdoor faucets, hose bibbs, sillcocks
at FAUCETS, OUTDOOR HOSE BIBBS.
But other critical steps need to be performed if you are going to avoid frozen pipes and future leaks and water damage in a building to be winterized with the heat left off (such as an empty summer cabin, vacation home, or an unoccupied residence.)
Close the main building water supply valve. Check that the valve really closed fully during the process of draining the piping. Be careful: some valves that are seldom used or which are old may not close off completely. You just think you've turned off the water supply, but really your water main valve may still be slowly feeding water back into the supply piping. Details on how to find and use water shutoff valves is
at WATER SHUTOFF VALVE LOCATION, USE.
If a water pump and pressure tank are installed, turn off electrical power to the water pump. (Draining the pump and water tank are discussed below.)
Drain the building water supply piping; because most homes other than some vacation cottages are not built with piping intended to be periodically drained, there may be long horizontal pipe runs that will not easily drain out all of their water by gravity, or even some supply pipes that slope "backwards" and refuse to drain.
Use air to remove water: Some plumbers try blowing air through the piping to force out water, or they may install multiple points at which piping can be drained. Below we address some steps to check for frozen, burst piping when turning the water supply back on.
Cut pipes to remove water: Other plumbers will simply cut open any water supply pipe that may not be draining properly, figuring that it's a much smaller repair to later close that cut connection than to fix a building that has been flooded.
Use the building drain: Most buildings include a building drain valve located at or near the lowest point in the building supply piping, but "inside" the building or past the main building water supply shutoff valve.
Drain the building plumbing fixtures, tanks, faucets, such as
Winterize toilets, and remove all toilet water from bowls and toilet tanks. Some winterizing companies pour an anti-freeze mix into building toilets and traps. Some anti-freeze chemicals are toxic and should not be discharged into a septic system. See notes below about use of antifreeze in buildings.
Winterize water heaters (never turn on electricity to a drained electric water heater, nor turn on power to a gas or oil fired water heater either - it is dangerous and is likely to destroy the heater too)
Winterize well water tanks and pumps: need to be completely drained of water - a frozen burst in-building water pump adds an expensive repair later
Winterize all building faucets: after water supply has been turned off, open every faucet and leave it open - water left in a faucet can freeze and break it.
Open outdoor faucets: be sure also to remove any garden hoses on outside faucets. A garden hose left connected to its outdoor hose hook-up point (the hose bibb) can retain water that freezes and damages the outdoor hose bib (faucet) and can lead to burst piping, leaks, and building damage.
Winterize the building supply piping: above we recommended removing all water from the supply pipes, cutting pipes if necessary.
To be sure that you have not left water in a hidden corner of supply piping somewhere, if you have not done so, see our tips
at FIND & FIX WATER PIPE FREEZE-UP POINTS discussed under the "heat-on" winterization notes.
If your incoming municipal water supply piping is not well below the frost line it may be necessary to find or even install a water shutoff valve closer to the connection of your building's water piping to the municipal water main. Private water supply systems are easier to shut down but also need to be drained.
Turn off and drain the water softener or other water treatment equipment.
This article explains water softener shut-down procedure, explain why we use the water softener bypass valve, and how that can reduce the risk of freeze damaged pipes, leaks, and even indoor mold growth.
Winterize all building drains: if you have not already done so, review our tips
at DRAIN FREEZE PROTECTION which was discussed under the "heat-on" winterization notes. Further steps include removing traps and use of a non-toxic antifreeze in traps or toilets that cannot easily be removed or emptied of all water.
Empty or remove building fixture traps; see our note below about use of antifreeze.
Use of antifreeze to winterize a building: Be careful: unless the anti-freeze is specifically designed for winterizing a building it could be highly toxic (such as automobile antifreeze).
We do not recommend using toxic antifreeze to winterize a building since later you're moving that contaminant into the public sewer or into soils (and possibly ground water) around a private septic system. Only inside of closed water systems such as a heating boiler do we recommend use of anti-freeze mix in a building.
Protect well piping from freezing: If your water supply system's piping is not below the frost line your water system should include protection against well or lake water freeze-ups. But sometimes a building's water supply piping that has never frozen before will freeze when no water is run during long periods of freezing weather.
See SNIFTER & DRAIN BACK VALVES
Shut down & drain or freeze-protect the heating system when all other steps to protect the building have been completed:
Winterizing forced warm air heating systems: as long as your heating system does not use any water piping (such as a water-to-air system) you can shut off the furnace when leaving a building shut down.
Winterizing hot water heating systems: Drain the building heating boiler and heating supply piping, or install an anti-freeze mix in the heating boiler and its supply piping.
See ANTIFREEZE for BOILERS
Notify your oil heat supplier if you are turning off heat in the building, and remember to notify them again when it is turned back on.
Winterizing steam heating systems: drain the heating boiler and condensate lines and condensate pump if a pump or pumping station are used.
Winterizing electric heat or warm air furnaces: can simply be turned off.
Watch out: for all oil or gas fired heating equipment (furnaces, boilers, water heaters) wWe recommend having the heating equipment cleaned before shutting it down - a step that will avoid corrosion, clogs, and trouble when heat is later turned back on.
Reader Question: How can we test for possible foundation damage if we leave our home with heat off completely?
We built our home 15 years ago. It is a split level with concrete foundation. When we retired we stated to spend our winters in a warmer climate (we live in N. Ontario). Every winter we have left some heat on the lower level of the house keeping the temperature around 4c.
However with the increase in the cost of oil and our dwindling income buying power, we have been thinking of ways we could cut off both the hydro and the oil heater. Is there any way of us testing what effect this might have on the concrete foundations?
The foundation is covered with a layer of ceramic tiles which we later covered over with a laminate flooring.
Thank you. - C.W., northern Ontario
Our sketch (left, courtesy of Carson Dunlop Associates) shows what happens when a home is left with heat off in a freezing climate.
Reply: Tests for possible frost damage to foundations? try these local research topics
I don't know of an actual test that you can perform to predict foundation damage if the heat is left off completely in your building, since testing would require creating the actual freezing conditions and would itself risk building damage. Sketch at left, showing evidence of frost heaving is provided courtesy of Carson Dunlop Associates.
At "A Common Source of Vertical Frost Heave - Un-heated Homes" found in our article
VERTICAL MOVEMENT IN FOUNDATIONS we discuss the problem of foundation damage in un-heated homes.
Sketch (left, courtesy of Carson Dunlop Associates) shows upwards as well as horizontal frost pressure on a building and it indicates where cracks and dislocation commonly appear.
Here are some things you can check:
Where is the home located? In northern Ontario your home is not at the same level of risk as the far north, but we agree that frost damage is a real risk.
How is the home constructed? In those same extreme climates builders use a floating slab design or other methods intended to avoid differential heaving or settlement of the structure.
How deep are your foundation footings and basement or crawl space slabs? If the footings and slabs are well below the frost line (which should be the case) then frost heaving of the slab or footings should not be a significant risk.
Is there exterior foundation insulation installed? Foam foundation insulation on the building exterior increases resistance to frost damage. See BUCKLED FOUNDATIONS due to INSULATION? for a discussion of the role of foundation damage and foundation insulation on the interior side of the building foundation walls
Well drained soils and good roof drainage that keeps water well away from the building reduce these risks.
Other Steps to Reduce the Cost of Heating Left On to Avoid Frost Damage
An alternative to turning heat off in the building entirely is to continue your practice of leaving heat on at a low setting (4 C or about 40 F) but take measures to protect the building from damage (possibly allowing a slightly lower heat setting) and to reduce heating cost by finding and fixing drafts, air leaks, or by improving building insulation.
See WINTERIZE - HEAT ON PROCEDURE
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Winterizing the heating system: Is it OK to drain un-used heating zone piping, baseboards and radiators?
I have a boiler with 5 heating zones. I am living alone in a big house and do not use the rooms for 3 of the zones. I would like to know if I can drain those zones so they don't freeze and just use the 2 remaining zones for heat.
Thank you - Anon
Sure, provided your heating zones are individual piping loops, and that you have control valves at both ends of the un-used heating zones, you can drain them and leave them turned off.
At AIR BLEEDER VALVES we describe air bleed valves found on hot water heating systems. These valves, normally used to purge trapped air that can cause cold radiators or baseboards, can also be opened to make it easier to get water out of the heating system piping when the building is being drained so as to leave heat off completely.
Watch out to get all of the water out of the piping. It can be difficult to get water out of long horizontal pipe runs without blowing air through the system. For this reason some winterizing companies actually cut the heating pipes, planning to repair them when the building heat is restored. Don't forget to check for cut or burst heating pipes later when de-winterizing the building.
Question: Winterizing the heating system: Can I put antifreeze in the heating system instead of draining it?
I've read the other parts of your website as you suggested and I hope you don't mind more questions. Instead of trying to drain the heating zones I don't need, can I just put a non-toxic antifreeze in the whole boiler system? It sounds easier if it is a good solution.
Reply: use an antifreeze intended for use in heating boilers and piping
Sure, there are specific antifreeze products intended for use in hot water heating systems.
Question: Winterizing the heating system:Can I shut off the first radiators in the heating zone without losing heat in the rest of the house?
I have such a system, and only one zone. The thermostat is located in the warmest room in the house. Causing frigidity and numbness of extremities in other areas of the home. Since the location of the thermostat is also where the first radiator is in the home, can I "shut off" that baseboard radiator, and the next one, without losing heat to the rest of the home? - Jacke
Reply: It depends ... on how heating piping is arranged
Whether or not you can shut off or turn down the first two radiators or baseboards in your home to improve heat distribution depends on how the piping is arranged.
If all of the baseboards are piped in series (which is usual for single-zone hot water baseboards) then the input of each baseboard is fed directly from the outlet of the one prior. In that case you can't turn off any baseboard because 1. you have no shutoff valve installed and 2. more important, you'd be shutting off all hot water flow through the system.
If you have radiators, heating convectors, or even some baseboard installations that are piped in parallel, that means that there will be a loop of hot water heating piping that runs through the buildings and that off of that loop, individual risers and returns feed individual radiators or convectors (heating baseboard is not usually piped this way).
In this second case it would be possible to turn off an individual radiator or convector.
So part of my long answer is due to confusion on my part - you use the terms radiator, then baseboard radiator - so I'm not sure what you've got.
Let us know the details - what we learn will assist others.
Question: How to Add antifreeze for hot water heating piping
how do i add antifreeze to my boilers baseboard heating system - Gene Griswold 7/22/12
Gene, please search InspectApedia for
"Guide to Fixing an Air-Bound Hot Water Heating System - Procedure#2," and you will see an article on how a service tech uses a pony pump and fittings to place antifreeze into a hydronic heating system.
Question: emergency steps to avoid freeze damage
(Jan 28, 2014) Tracy said:
Help! NE North Carolina, 9-12" snow expected, possible power outages & probable road closures so leaving b4 we CAN'T leave..planning to drain piping but leave heat on...if I don't drain water heater & power goes, how long might it be safe b4 water in heater to freeze & should I leave wh breaker on or off? PLEASE HELP QUICKLY! I HAVE ONLY 3 HRS TIL LEAVE TIME!!!
Review the checklist at
WINTERIZE - HEAT ON PROCEDURE
the link is at the top of this article.
At a bare minimum: if you expect power to be off, turn off the building water supply.
That should minimize the extent of leakage that can occur if a supply pipe breaks.
Then on return to the home go through our De-Winterizing checklist - basically you will turn heat on and water on and check for leaks.
Question: some heat left on to avoid interior cracks
(Nov 5, 2014) Deborah Frenette said:
I wonder if it is true that in an unheated home that damage can occur to the walls and floors caused by the extreme cold? WE plan to not waste $$ on heating this year. my smart hubby has done all that is needed to protect the water supply. thank you.
Yes Deborah, in extreme cold some building materials may show signs of cracking or movement. I've seen this show up as drywall cracks and on a few occasions fine cracks in ceramic tile floors on a concrete slab. For this reason, while it is still possible and even reasonable to leave heat off completely (with proper winterizing) for modern construction and where a building is not being left for an extended period such that we are trying to eliminate heating costs completely, I prefer to keep some low heat in the building to try to keep it a bit above freezing.
(Nov 5, 2014) Deborah said:
thank you! WE are not using the building (my office, it is attached to our big house) and that is why we are turning off the heat. I will show this to my hubby. The heating bill for an empty building is getting too high. But we do not want to have to repair cracks in the walls!
You might see no cracking at all - a lot depends on the particular details of construction including materials, connectors, foundation type, basement vs slab, and importantly, water under and around the building.
If the building is more than a decade old you might have some clues by noting whether or not settlemnt or other cracking has ever occurred.
Question: antifreeze for traps and toilets vs. environmental contamination
(Jan 14, 2015) Anonymous said:
house in pa had oil burner 4 heat got wood burner heats house now also electric hot water heater new in years to come what are the steps to close oil stoker down for long extended time need all steps thank you ed
(Feb 3, 2015) Crafty said:
We have a camp that we regularly dump antifreeze into the traps and toilets because it is left unheated. I absolutely hate this, so I've been looking for a way to get around it, or at least minimize how much is needed. Would love to eliminate some traps if possible, but does anyone have a recommended non-toxic antifreeze, until I get around to finding a solution? I think I'll just buy a bunch of that to keep there. We try to use RV antifreeze as it's supposedly bio-degradable, but we've allowed people to bring their own, and they don't always comply. I hate to be dumping toxins into the ground.
Crafty there are food grade antifreeze products used in RVs and water systems. Those products should not be harmful. If you let visitors use whatever they bring we've lost control of the problem and may be killing off the septic system to boot.
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"New Electric Heat Tapes Help Prevent Fires," US Consumer Product Safety Commission (CPSC) #00936
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"Freezeproof Your House," Mike McClintock, Rodale's New Shelter, p. 30, October 1985 (approximate date)
"How to Winterize Your Pipes," Mike McClintock, Homeowners How-To Magazine, p. 59-62, Nov-Dec 1979.
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