Do you still need a fan or exhaust fan in the greenhouse if you have windows that open and sliding doors with screens?

Guest · Post by **Guest** » Sat Dec 10, 2022 4:20 pm

Random question, do you still need a fan or exhaust fan in the greenhouse if you have windows that open and sliding doors with screens? Hoping to start building ours this spring and starting to think about design!

We live on an escarpment so it’s really windy up here most of the time, lots of airflow. The greenhouse would have big sliding doors with screens facing the west where the wind usually barrels through our property and sliding windows with screens and in the south and east for air to exit.

Rhonda · Post by **Rhonda** » Sat Dec 10, 2022 4:20 pm

I just built a greenhouse out of salvaged materials. 8 x 10. Windows open on all sides. I have no fans. I use it to extend the growing season and will test it this spring to grow early spring greens and starts. I don't plan to use it during the heat of the summer. No floor, I plant in the ground. Zone 5 Maine. Still harvesting spinach, arugula and salad greens in December. But we're having mild temps for this time of year. So, it depends on your zone and what you plan on using it for.

Keith · Post by **Keith** » Sat Dec 10, 2022 4:20 pm

My 16 x 32 greenhouse gets to 145 in the summer with all vents and windows open. I built a cooling wall and installed a 125000 cfm exhaust fan. Hard to keep greenhouses cool in the summer without a good exhaust fan and maybe shade cloth.

Steve · Post by **Steve** » Sat Dec 10, 2022 4:21 pm

Yes. To prevent disease and the moving air helps plant stems grow stronger.

Glen · Post by **Glen** » Sat Dec 10, 2022 4:21 pm

Yes. Active ventiltilation is key. Keeping a gh cool is far more difficult than keeping it warm, at least that's my experience with a solar shed design in zone 4 with long snowy winters.

Karen · Post by **Karen** » Sat Dec 10, 2022 4:21 pm

We are in OK, zone 7b. A fan is a must. Even in winter it can get near a 100 inside the greenhouse. And spring and summer is really hot in there. Need air circulation even with the windows and doors open. I have had to open 2 windows and door window this week as it was in the upper 80s inside. Fans also help mimic wind and help strengthen the stems of the plants.

Dale · Post by **Dale** » Sat Dec 10, 2022 4:21 pm

I’m with the others that advocate for continuous air circulation, 24/7, it doesn’t take a lot but keep the air moving.

Martin · Post by **Martin** » Sat Dec 10, 2022 4:21 pm

If your building on a slope then use that to orientate your direction. Then have doors at one end and large opening doors or windows at the other end and make use of the natural habit of hot air to rise, it'll move through the house and still maintain a reasonable heat in the middle.

Christine · Post by **Christine** » Sat Dec 10, 2022 4:22 pm

Yes, the roof vents and door didn’t move the hot air out enough. The automatic temp exhaust vent made all the difference in the world.

Batman · Post by **Batman** » Sat Dec 31, 2022 11:24 am