What frugal thing did you do today?

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My continuing search for a better attic fan timer.

Post by dratkinson »

After a few false starts, I may have found a better attic fan timer.

My house has a large whole-house attic fan, no AC (summer utility bills ~$60/mo: electricity+NG).
--The attic fan keeps the house cool enough during the day, if I take maximum advantage of the cool overnight air to cool-soak the home.
--The attic fan running as long as possible becomes more important when we have >95°F days (~2weeks/yr). The coolest overnight air is 3:00-7:00AM. After that the day quickly heats up. So it's important that the fan runs overnight and shuts off at 7:00AM. I am not an early bird, so need a reliable attic fan timer to control it for me.

Iterations of attic fan timers.

--My house came with a mechanical (windup spring) attic fan timer, which worked intermittently: most times shutting off when expected, but sometimes not ...meaning the attic fan continued to run, pulling in warming morning air, heating the house when I awoke (a few times because of the heat). I assumed it was getting old and needed to be replaced.

A handy feature of a mechanical timer is it should shut off at the correct time, so I don't need to worry about a power outage causing timer to forget setting/shut-off late/begin heating the house in the morning.

--I tried a new mechanical timer, thinking the original timer was just old. No joy. It tested okay on the bench top, but never worked correctly after installed. It seemed to be more lightly made than the old timer and the electrical box is so tightly packed (wires in back) so the new timer may have been slightly twisted, so its internal mechanism was binding enough to not finish the cycle, so continued to run, so began heating the house.

Example of new mechanical countdown timer (returned): https://www.homedepot.com/p/Master-Flow ... /100097793

--To handle the timer binding problem, I tried a simple electronic countdown timer: you set a fixed run time (1-2-4-8 hours).

It worked okay, the binding problem was gone. But for a 7:00AM shut off, you must start the timer at 11:00PM. If you forget/miss start time (earlier or later) then you miss some of the coolest overnight air, or fan shuts OFF too late.

The thing that made me finally realize how suboptimal a solution it was, was when I had to set permanent alarms (PC, smartphone, clock radio) to remind me to start attic fan at 11:00PM. Which only worked if you're home at the time.

Example of simple electronic countdown timer (now in my parts drawer): https://www.homedepot.com/p/QuietCool-8 ... /206047411

--What I need is an electronic timer with adjustable STOP time memory, which I can start manually, at any time, when I remember to do so.

Found some complex electronic timers that can be set to adjust for: latitude, sunrise/set, daylight savings time, vary START/STOP times by ±15mins ...handy if you are controlling outside lights for changing day length, or varying inside lights to give the impression of activity ...but overkill for my need.

Eventually found/installed a simple electronic START/STOP timer with memory.

Example of simple electronic START/STOP timer with memory (currently installed): https://www.homedepot.com/p/myTouchSmar ... /301063575

Features of this last timer.
--Can set 2x START times, 2x STOP times: all four can be separately enabled/disabled. (I only need one enabled STOP time.)
--It accepts manual ON/OFF to override active automatic START/STOP time.
--The little gray square at the side of each button is an LED that turns bright blue when that feature (ON/OFF, START/STOP) is enabled.
--It has a backup for (set) clock/START/STOP times, so remembers during a power outage.

After installation, did a successful 12hour power outage test (circuit breaker OFF) of all features: enough to simulate an overnight outage/resume.
--LCD display showed current time during outage, indicating battery backup. Clock lost 4mins while on battery. Set START/STOP times were retained.
--All buttons worked (changed clock/START/STOP times, enable/disable features). Without power, no blue LEDs indicate enabled features, instead:
While on battery power:
START/STOP time buttons toggle: enabled feature shows set time, disabled feature shows clock time.
ON/OFF buttons do not toggle: the last button pressed sets ON/OFF feature.

Good enough.

The instructions don't say which backup battery technology is used. So I assume worst case: (non-replaceable) NiCd battery, meaning backup feature will fail in ~5yrs. After that I don't know what to expect.
--Best case. It would be acceptable if battery fails and all settings default to OFF/DISABLED. So it would fail-safe, like a dumb countdown timer, but with a programmable STOP time when power is ON. I could live with that, since we don’t often lose power overnight during the cooling season.
--Worst case. Anything defaulting attic fan to ON when unwanted, then I'd have to replace the timer.

I won't know which case is correct for ~5yrs. But since the other features seem to be well thought-out and can function/be queried on battery power, I’m hopeful of the best case.

So for now, so far, so good: no more setting alarms, no need to be home at 11:00PM. It makes my life easier to know I can just press the ON button before bed (after I open windows, hence I don’t want the fan to start automatically), and not worry about the attic fan missing the coolest overnight air, or shutting off too soon/late. Sweet.

Military discount.
--Learned Home Depot offers a 10% military discount. Discount is tied to our home phone number (entered at checkout). Don’t remember signing up for it. Don’t know how HD and big brother share this information, but I’ll take it.
--A friend says Lowes has same discount.

Edit. Learning more about how the timer works ...this solution gets better.
Last edited by dratkinson on Thu Jul 11, 2024 1:16 am, edited 3 times in total.
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Re: What frugal thing did you do today?

Post by WoostaGal »

Congratulations, dratkinson, for persevering on your attic fan timer.

Today I replaced the cutting blade on my mower. The existing blade was not in good enough shape to sharpen. I had hit a rock with the mower and my mower sounded ill every time I used it after that. After replacing the blade, my mower is happy again. 8-)
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Re: What frugal thing did you do today?

Post by yankees60 »

Doom&Gloom wrote: Sat Jul 06, 2024 7:05 pm Cut my own grass (as usual).

That'll teach it to grow around here!
Above provided by: Vinny, who always says: "I only regret that I have but one lap to give to my cats." AND "I'm a more-is-more person."
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Re: What frugal thing did you do today?

Post by yankees60 »

YoungHopper wrote: Tue Jul 09, 2024 9:40 am I just got a second job that's right next to my main job.

Saving on gas and time!
Quite industrious, also!
Above provided by: Vinny, who always says: "I only regret that I have but one lap to give to my cats." AND "I'm a more-is-more person."
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Re: What frugal thing did you do today?

Post by A440 »

Installed a GFCI outlet and crawl space dehumidifier as the final step in encapsulating the crawl space. Also installed a PVC pipe to drain the condensate from the dehumidifier pump.
The relative humidity in the space went from 84% to 55% in under 24 hours.
I don't know what the future holds, but I know who holds my future.
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Re: What frugal thing did you do today?

Post by IowaFarmWife »

This past week I sold an old 2002 Honda CRV and our trailer camper, neither of which were being used much at all. I pocketed about $6500 from the sales and in the future, I no longer have to pay insurance and taxes on either vehicle, saving about $600 per year. Win/win!
"A nickel ain't worth a dime anymore." Yogi Berra's financial wisdom.
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