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Current delta T is 112 Fahrenheit degrees

MartinHolladay | Posted in General Questions on

The wind is howling in northern Vermont. The outdoor air temperature is down to -40°F (see attached photo). That means the delta T is 112 degrees. Fortunately, the wood stove is keeping up.

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  1. StephenSheehy | | #1

    Wow! It's -17 here in mid coast Maine. Coldest in many years. But -40? Yikes!

    1. MartinHolladay | | #2

      Elevation is 1,800 feet. Under windy conditions, like last night, we get colder conditions than the valleys. On still nights, the cold air settles to the valleys, and they're the ones who get the record lows.

      Mount Washington, which I can see from my dining room window, was expected to have morning lows of -46 F today (but I haven't checked how low it actually got there).

      [Later edit: Mount Washington had a low this morning of -47 °F.]

  2. Expert Member
    BILL WICHERS | | #3

    That's some serious cold Martin! We saw a low of -7.1F last night. We're in a bit of a low spot and usually see colder than predicted lows (which I always find a little funny, since the local NOAA office is only about 5 miles from us if that), and we typically see lows in the -20ish range on the coldest nights. This has been a pretty mild winter until recently, but last year we saw near record lows here.

    Extra windy cold nights are a good time to run the back of your hand around window and door seals to find any leaky spots that could use some work :-)


    1. MartinHolladay | | #4

      On a night like last night, outdoor air enters the cracks around my entry door at an alarming clip. Fresh air ventilation! Time to throw another log on the fire.

      1. thierry19 | | #5

        No need for a fancy infrared camera...

      2. Expert Member
        MALCOLM TAYLOR | | #6

        I thought the discussion title was a joke!

  3. nickdefabrizio | | #7

    Wow!!! stay warmmm

    ....I heard that the wind chill on Mt Washington hit -107F (!!!)

    I tried to ski yesterday before the deepest cold hit and forgot my head covering under my helmet. I had to stop because the wind getting into the vent holes caused by head to hurt too much!!!

  4. Expert Member
    DCcontrarian | | #8

    Is that -40F or -40C?

    1. MartinHolladay | | #10

      It's a fun temperature reading when the "F" and "C" are optional...

  5. anonymoususer | | #9

    Hi, Martin. Were you also using heat pumps, or just woodstove? If heat pumps, how did they perform Fri nite and early Sat morning? Thank you

    1. MartinHolladay | | #11

      No heat pumps. Just one wood stove.

      1. anonymoususer | | #12

        Oh my goodness! If you dont mind being asked, what are your: a) sq footage and b) blower door numbers ? I’m amazed a wood stove alone could keep up that well !

        1. MartinHolladay | | #13

          No blower door numbers. It's an old hippie house that leaks like a sieve.

          As most rural Alaskans know, a wood stove can blast out enough heat on a -40 degree night to make everyone peel off their sweaters, even if you live in a leaky log cabin. Most wood stoves are oversized for the houses where they are installed.

  6. anonymoususer | | #14

    Thank you, Martin. We have a regency hampton h1150 log-burning insert. It’s installed in the fireplace of our ridge sitting chimney. It is small because our original fireplace was small and there is a lot of wood trim around. We needed to make the clearance to combustibles requirements when we bought it. Unfortunately we do not have a freestanding woodstove, which I believe would throw out a lot more BTUs . Our low this weekend was -18 Fahrenheit. We could not keep up with the log burning insert and plug-in infrared space heaters alone. So for the first time this winter we had to fire up the oil dinosaur. I am going to shut her off later today when temps get into the mid or high 30s, as predicted. Our nearest weather station is Silver Ranch airport in Jeffrey New Hampshire. Glad you and your family stayed warm. Thank you for your many interesting and super helpful posts and articles

  7. [email protected] | | #15

    That's seriously chilly! We were -22 when I got up friday morning, but -40 is amazing.
    I agree it's fun in a weird way when F or C doesn't matter.
    Stay warm!

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