We were advised by a dealer RV technician to winterize our water lines while driving in cold weather. The claim is that windchill would freeze the water lines while driving. When I review a windchill chart driving at 50 mph in 40 degrees F the windchill is 26 F. It sounds like every time we travel we will need to winterize water lines. —Tim Connors
Answer (from Mark Polk, RV Education 101)
What I recall from my research, the ambient temperature is the ambient temperature and cannot be changed by the effects of windchill.
For example, if the ambient temperature is 40 degrees with a windchill of 30 degrees, and there was warm water (70 degrees) sitting in the water lines of the RV, the water in the plumbing system would cool down to 40 degrees faster because of the windchill, but it would not go below the ambient temperature.
But, if the possibility exists that temperatures could drop and stay below freezing at some point while getting to your destination, it will freeze.
Wind chill formula was developed by the army to measure wind effects on exposed skin. Cover that exposed skin and wind chill goes away. -20 is still – 20 not colder.
windchill is only applicable to organics such as your skin, your pets, etc. it has zero effect on “stuff”.
Rich, after reading many (if not most) of the comments on the issue, yours is the most succinct. Thanks
Ok, I understand the concern, but it would highly doubtful the waterlines would freeze going down the road. If you are or have been using the rv, the furnace has run, keeping you warm, your dash heater is on, and if necessary, you can run the furnace while going down the road too, most modern RVs are built with some heated air ducted into the basement to keep plumbing from freezing. Most travel is 300 miles or less, and you make stops to eat or personal business. It might happen in Alaska in winter.
Sometimes I think RV’s are designed to be stored and operated at seventy degrees year round.
Larry got it right (first reply).
Wind Chill does not apply to inanimate objects. It only applies to body temperature!
Wind (or airflow) can accelerate the time it takes objects to reach the ambient temperature but not lower or raise the ambient temp. Same thing applies to heating an area. Thats why we use blowers or fans.
Wind chill takes into account the evaporation of water. Plumbing lines don’t have water on the outside, so there is no evaporation.
There is wind, however, which will ‘push’ the coldness into places where you have the water pipes more quickly than still air. If the temperature is above freezing, then that’s OK, but when the temperature drops below that, pipes will freeze more quickly.
Exactly What Larry said, I can’t believe anyone had to question it.
What happened did many people skip science class while in school?
Now, Butch, not all people grew up/live(d) in Ohio like you and me. Some people down south have not had to consider wind chill, so they are not intimately familiar with it. Do you know to check your shoes for scorpions when you are camping in Arizona, for instance? Not something many of us ever think about. Or, you flatlanders coming to Colorado (I left Ohio when I was 13) and wanting to hike. There is less oxygen here, but many flatlanders don’t think about it, as they have always had plenty of oxygen where they have recreated.
Cut others some slack. We don’t all have the same experience or background.
I solved 90% of those problems in 1985 when I migrated south from the Chicago area to Alabama. Never looked back, and glad y’all enjoy that weather and stayed there. Lol
Not sure you are correct. Every single engine airplane pilot knows of carburetor icing caused from fast moving air entering the carburetor so we have to add carb heat to prevent freezing. I don’t think it is likely in an RV unless the water line is exposed directly to the wind. Thanks for the great article.
It’s the humidity in the air that freezes.
Not the same thing as wind chill. In the antique boating and car world carburetor icing can happen on an 80* day. If the carb is not being heated by the engine it can ice up and stop working. Let it thaw for a few minutes and continue on your way.
Carburetor icing on gasoline powered piston aircraft occurs because of the heat energy required to evaporate the gasoline entering the air stream in the carburetor.
The venturi effect.
Tom: I think maybe you should go back to ground school. (I hold a commercial instrument and ground instructor tickets!)
About 5 years ago we were driving south to north towing a TT, mid-October. We left late morning it was 68 degrees and by 2:00 pm we hit a freak cold front coming down out of the north (good ol’ Colorado!)…By 3:00 it hit 29 degrees and snowing! At one point had to slow it down to 30mph as the snow was starting to stick. Reached home an hour later and still snowing. Climbed under the TT to check the low point lines and they were frozen solid! But the lines INSIDE the trailer were fine and water was flowing from fresh water tank. Thawed out the low point lines with a heat lamp for about an hour, plus turned on the heater in the trailer and everything was fine, no damage to the the lines. My point being, exposed lines froze, lines within the trailer were ok. So that’s MY experience, wind chill? Maybe.
29 degrees is below freezing. Wind may have aided the below freezing air to enter the trailer but did not cause the freezing.
As Jerry Clower once said he’d like to get his hands on the guy that came up with wind chill factor. He said his Momma lived 60 years before the wind chill was invented and the last 20 years of her life she’s been freezing every winter because of the weather man giving the wind chill temperatures. Lol
I believe if the vehicle is moving, the inverter/charger is active, it put out loads of heat in the process of charging batteries and inverting 12DC to 120VAC to run Refer and other AC items. That heat will offset the Windchill/cold temps outside. If not plugged in, or the furnace is used to keep it warm once parked, then you might a problem. In fact, it would have to be in the mid-high 20’s to freeze the water lines if in storage for at least one whole night or for at least 3-5 hours, a dip down and then right back up won’t do it. Time is the answer.
I think you meant if the vehicle is not moving, or you have some load on the inverter while driving like a residential fridge. While driving, the heat from the engine dissipates pretty quickly, and the dash heater doesn’t reach the house plumbing. We run our furnace in sub-freezing weather while driving.
I guess if moisture such as fog or rain was introduced into the wind a refrigeration effect could be produced due to evaporation. Still, I doubt it would make a significant difference to RV plumbing. We have towed our fifthwheel long days (10 to 12 hours) in temperatures in the 20’s F without any problems. We drove the long days in anticipation of arriving at our warm spot in Death Valley in February. I suppose weather below 20 F requires winterization measures. Just my experience.
And the magic words in this article are “…could drop and STAY BELOW
No, windchill can’t take the temperature below ambient, but it can accelerate heat removal from any object.
Wind chill is a formula based on temp and wind speed on EXPOSED skin. If you cover that skin with hat or gloves etc. It is no longer is exposed and only temperature is considered. I for one an tired of hearing about wind chill.
Agreed! If it is cold out, I more than likely am not going to expose my skin and have the God given intelligence to put on jacket, gloves hat and whatever else I think is prudent.
Same goes for the so called heat index in the summer time…when it’s hot, it’s hot.
Hi, Thomas. Sorry you’re tired of hearing about wind chill, but I think this is the first time we’ve discussed this topic regarding it possibly affecting water lines when driving. I thought it was interesting, especially since I hadn’t heard about it in this context before. (No, I didn’t post that article.) Have a great day. 🙂 —Diane at RVtravel.com
I would venture to say that Thomas is, like myself, tired of the term being applied by the weather announcers as if it were actually something to be concerned with. It is a concern if you are standing in it or working in it with the temperature below freezing, as that would affect a human’s comfort and well-being over time in those conditions.
The article is informative for clearing the air of wind chill with regard to inanimate objects. I thought it was a very good answer to an overused and misunderstood term.
Ask any TV weather guesser and they will tell you wind chill only affects bare skin feels like. Its only a mind over matter situation, if you don’t mind it doesn’t matter. Lol
Very good information….For me the weather people use windchill to dramatize so we go ooooo and whow then give graphics to back up what has been said…….if cold out put some clothing on…….simple…
From Wikipedia: Wind–chill or windchill (popularly wind chill factor) is the lowering of body temperature due to the passing-flow of lower-temperature air. Wind chill numbers are always lower than the air temperature for values where the formula is valid. It does not apply to inanimate objects like your water lines.