Exhaust fan in 6x8 HFGH

12 years ago

Hello everyone,

I built a 6x8 HFGH this summer and now I want to get it ready for the cooler weather. After reading a few posts, it seems necessary to install an exhaust fan. Does anyone have any suggestions or would like to share their ideas?

I see HF sells an exhaust fan. Has anyone put it in their 6x8?

Comments (5)

  • imqtpi
    12 years ago

    If you're referring to the HF Solar Fan - I have one. It's OK, but it doesn't move enough air for the size of the GH. My GH calculates out to 292 CF [b/c we raised it 12"] and the fan only moves 251 CFM. I've since screened one panel (on the north side) and added a box fan and an El-Cheapo Cool-Air humidifier (and it seems to be working out well, so far!)

    I'd started a thread earlier (that kinda fizzled), but there's a link - from there - to my GH site that shows how we installed the Solar Fan. Thread link below...



    Here is a link that might be useful: Ad'Vent'ures in Ventilation

  • mudhouse_gw
    12 years ago

    And (hope you donÂt mind Nancy) hereÂs a link to another really good thread by imqtpi, about installing the solar fan in her HFGH. I was helped a lot by some posts in here about what kind of cooling you can expect based on how quickly the air is exchanged.
    hfgh-hf solar fan installation.

    IÂve just installed an electric exhaust fan in my HF 10x12. ItÂs a 16" three-speed that I ordered from ACF Greenhouses ($169 plus shipping.) For my GH, at the top speed it should be capable of exchanging the air twice per minute. So far IÂm happy with it, although I wish it was a bit quieter (I guess that just goes with the territory.)

    Also, hereÂs a link to a fan calculator on the same website that I found helpful: Greenhouse Fan CFM Calculator.

    IÂll be putting up a thread soon with some pics of how we installed the exhaust fan. It was really very easy.

  • agardenstateof_mind
    12 years ago

    A vent fan may well be needed in Zone 8 and 9 winters, but I think it's merely an option in a NJ winter, especially in your zone 6. The roof vents should be sufficient; I trust you have an auto vent opener? And if you have a newer greenhouse, it will have two roof vents, as opposed to the single vent in my 3-year-old HFGH.

    What is important, though, is a small fan to keep air circulating inside the greenhouse, 24/7. I have a little clip-on 7" diameter from Charlie's and am quite satisfied with it.

    I would concentrate on insulation, thermal mass, backup heating plan and such and track the conditions through the winter before cutting up my greenhouse to install a vent fan.

  • taylor810
    Original Author
    12 years ago

    Thanks for all of the suggestions. I do have two roof vents, I only put a automatic opener on one of them. I think for this winter, I will wait to cut a hole to install a exhaust fan. I'll pick up a small fan. I do have a temp/hydro sensor in the greenhouse for my weather station to monitor the conditions.

  • imqtpi
    12 years ago

    FWIW: I did update my Solar Fan Page (today, even!). I've linked it below. Scroll down about 2/3 if you'd already "endured" the original ;-)

    I'm *very* happy, so far, with the "arrangement!" We're having really wacky weather right now: Warm, sunny days [mid- to upper-80's] and pretty-darned-cold nights [40's - which is mighty chilly for us Wimpy Californians!] - especially since it's only October!

    Normally Mother Nature doesn't crank-down the thermostat until Nov 1 - dammit! We're *supposed* to be having our NICEST summer weather right about now!!!

    Anyway, the GH has been "mostly closed up" full-time now (the screened panel is covered w/a poly panel), so the only "outlet" is where the Solar Fan is. I've got the solar fan + box fan + humidifier running (all are rigged up thermostatically). Daytime temps *can* hit 90*+. Nighttime temps have been dipping in the mid- to upper-40's (Brrrr!).

    I have since added my "turn-it-on-when-it-drops-below-42*" thermostat, and an A/C heater. Heater hasn't come on yet, but it's ready...

    Anyway, I "got brave" and put some plants in there a week or so, ago. Haven't had any fatalities so far (and am "guardedly optimistic!")...

    Taylor: If you're nervous about cutting holes in any of the panels (I know *I* was) - you might consider doing what we did: Install the fan in the panel above the door. You can buy a hunk of Acrylic @ Home Depot for appx $15 and use that to replace the twin-wall polycarbonate "triangle." Just make sure you put Skilsaw Lubricant on the blade before you saw a hole in it (you'll save yourself from having to buy another sheet of acrylic!!!)


    Here is a link that might be useful: 2007 Greenhouse Fan

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