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Community and Q&A

Unheated Home Dangers?

Stephen Edge | Posted in General Questions on

In general, what can happen if I leave my home unheated in the winter? Sounds like the green thing to do at first blush… Zone 6. Lots of passive solar windows on the south side of all three floors: Walk out basement, main floor, and attic floor.

The house is well insulated, vented, and dehumidified. Soils are well drained. Basement has 2in of xps on the outside below grade.

Pex lines will be blown out dry before summer shut down.

Thanks, Steve

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  1. User avatar GBA Editor
    Martin Holladay | | #1

    Everything will probably be OK, as long as your remember:

    1. Drain all your plumbing traps, or replace the fluid in the traps (including toilet traps) with windshield washer fluid. Empty your toilet tanks before you do this.

    2. Remove all products that will be damaged by freezing, including cans of latex paint, drywall compound, Elmer's glue, canned food, etc.

  2. Keith Gustafson | | #2

    When you allow the temp in a building to drop through the dewpoint repeatedly, things get damp, things rust, things can [sometimes] mold. I would suggest freeze proofing but setting a thermostat at 40 degrees Would use very little energy in the described house and would keep it nicer.

  3. Garth Sproule 7B | | #3

    Good advice, but even at 40°, there could still be a lot of frost and condensation on the interior of the glass. A dehumidifier that would work at that temp would be nice insurance...if there is such a unit.

  4. Stephen Edge | | #4

    What is a safe temp to avoid the rust and mold? 50d? I always wondered why I see so many rusty wood stoves..

  5. User avatar GBA Editor
    Martin Holladay | | #5

    If the indoor temperature and the outdoor temperature are the same, then there's no reason to believe that indoor surfaces are at risk of condensation problems. Problems occur when a cold spell is followed by the sudden arrival of warm, humid weather; under those circumstances, the warm humid air may contact cold surfaces. These conditions, while possible, are rare enough that most homeowners don't have to worry about them.

    Tens of thousands of seasonal homes are left unheated every winter without problems.

  6. Malcolm Taylor | | #6

    Those lucky enough to have spent their summers at a cottage will remember the rituals of closing it up. Most involved the contents - packing linens, curtains, mattresses and pillows in bags so that they didn't acquire that distinctive mildewy smell - but also applying a coating of Vaseline to the wood stove and chimney to avoid rust. One vulnerable part of a house to dramatic changes in temperature and humidity is wood flooring. Perhaps why so many cottages featured loosely laid rustic boards.

  7. Stephen Edge | | #7

    That's right Malcom.... I do recall the smell when we returned to our summer camp every spring. And of course I just bought 1,000 sqf of 2 1/4 oak flooring. There will be no heat in it this year for sure because I don't have the funds. I may forgo insulating the roof rafters for now to help keep the temp the same. There's a bunch of south facing pella solar gain glazing that will surely swing the temps every day.

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