Dealing With Cold Weather in Climate Zone 3
The temperature hit a record low of 5 degrees in Georgia, but we don’t need to bring our car batteries inside
We had some serious cold weather down here in Georgia recently, and although it didn’t come close to Martin Holladay’s recent experiences in Vermont, the low temperatures were a bit of a shock and caused a lot of problems.
As the cold wave settled in, I was amused by a radio interview with a local plumber who said that the freezing wasn’t the problem, rather it was when everything thawed the pipes started leaking. He wrapped up by saying that he was going to have a very busy weekend and he was going to make a lot of money.
My plumbing survived
Having just reoccupied my almost finished renovation, I was a bit concerned about how it would fare in the deep freeze.
My house has an unconditioned and unvented crawl space with spray foam insulation on the underside of the first floor. I initially insulated the floor about eight years ago when the crawl space regularly filled up with water and sealing it was not feasible. As part of the renovation, I elected to retain the insulated floor rather than insulate the crawl space walls and remove floor insulation.
I use a dehumidifier in the summer, and as part of the renovation I was able to fill up the low spots so the area is now dry. I recently had all the plumbing pipes insulated with spay foam, a simpler process than installing separate pipe insulation.
I never checked the temperature in the crawl space during our cold spell, but no pipes froze, nor did my outside tankless water heater have any problems, so I think I’m safe for the next half century or so.
My single-glazed windows iced up
The house still has several single-glazed windows, and about half the walls remain uninsulated. That's normally not much of a problem in this moderate climate, but 5 degrees sure doesn’t seem moderate (unless of course you live in Vermont).
I had installed cellular blinds on most of the windows just before moving back in, and while I realize they have insulative properties, they were primarily intended for privacy. I was somewhat amused to learn just how well they insulate. When I woke up on the first freezing morning, I opened them to see a fairly thick layer of ice on the inside of all the single-glazed windows. I had never seen even condensation on these windows in the past, so the ice was a bit of a surprise.
Part of the renovation project included comprehensive air sealing of the addition, and as much of the existing house as possible. (I have not done a blower-door testTest used to determine a home’s airtightness: a powerful fan is mounted in an exterior door opening and used to pressurize or depressurize the house. By measuring the force needed to maintain a certain pressure difference, a measure of the home’s airtightness can be determined. Operating the blower door also exaggerates air leakage and permits a weatherization contractor to find and seal those leakage areas. to compare the before and after numbers yet, but will report on that when it's done). I surmise that the improved air sealing is retaining a fair amount of moisture inside the house (rather than letting it leak out through exfiltrationAirflow outward through a wall or building envelope; the opposite of infiltration. as is common in the winter), keeping the relative humidity fairly high for the winter.
So, I had the very cold windows that created opportunities for condensation on the inside, and, the insulating blinds kept the space between them and windows below freezing, leading to the lovely layer of ice. I had not planned on installing storm windows, but now I am reconsidering that decision.
The house itself was never uncomfortable, although I tend to keep the temperature low. My minisplits did a great job of keeping it toasty, somehow, almost magically finding enough heat in the frigid outdoor air.
I do notice that the uninsulated walls tend to be a bit of a heat sinkWhere heat is dumped by an air conditioner or by a heat pump used in cooling mode; usually the outdoor air or ground. See air-source heat pump and ground-source heat pump. in very cold weather, as the plaster slowly acclimates to the wall cavity temperature. I chose not to insulate these walls as it would have required stripping interior plaster or exterior siding, neither of which would have any reasonable payback period. Sweatshirts and slippers are a much better investment for the few cold days we get here.
Southern winters are pretty short
So after single digits last week, I had the doors open yesterday when it was in the 60s and sunny. I feel fortunate that I made it through the cold snap with no frozen pipes, and the ice on the windows didn't last long or cause any damage.
Having just moved back in a few days before, I was able to be there as the house got a good workout and fared quite well. I feel like I will be pretty comfortable for the foreseeable future.
With the exception of a few minor details, the interior is complete. The exterior carpentry is finished and ready for paint. Last on the list is a new driveway and landscaping. I'm hoping to have everything wrapped up in another month or two, depending on the weather.
I’m still working on some hot water distribution issues, and will write about them when I figure everything out.
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- Carl Seville
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