Last year when we moved into our older house, there was no way to vent our basement dryer outside. Dh bought an indoor vent. It's small, very inexpensive and has a resevoir that holds about a cup of water. This container collects all the lint. During the winter months it heated the basement for a short time and increased the humidity level quite a bit. During the summer there was so much moisture in the air that mold began to grow on everything. Great for a greenhouse. (we use unscented dryer sheets)

I'm not sure if the dryer would be sufficient to heat a greenhouse since the heat is so temporary and the critical hours are just before dawn. You might find yourself on a cold January morning, doing laundry at 4am.

Hi Diana, the only saftey concern I can think of is if you have a gas dryer you'll be filling your Gh with carbon monoxide.

I'd suggest that you stay away from flexiduct type products and use rigid metal ducts, for a short run the cost would be minimally higher.

Robert

Plants will not take too kindly to having 'the edge taken off' the freezing weather in 45 or 60 minutes spurts. It would be very hard on a plant to go from being in a safe temperature to plummeted back again to something too cold. Not a good idea, practically speaking.

On the other hand, suppose you used Penny's indoor vent set-up, but outside? Then the heat would go into the water, not the air, and the heating up and cooling off would be much more gradual.

In addition, when the warm air hits the inside walls of the greenhouse, the outside colder temps would crystallize the moist air causing a nice "icy" sheen on the inside. I dont know, would that cause havoc on any plants?

The dryer vent thru metal pipe to the outside would supply a very small amount of heat.

I wouldn't vent it to the inside without a water type filter and then that's iffy. Sometime when you have a few min. set up a high instensity light against a dark background and obsverve the dust particles. I wouldn't want that on my plants.

My dryer vent goes directly into my greenhouse, which has a common wall with the utility area. Most of the lint is caught by the dryer vent system, and most of the rest is caught by a screen in the greenhouse which needs periodic cleaning.

This setup is not specifically for the purpose of heating the greenhouse, only because I hated to waste the heat and there is no easy way to vent it to the outside. The greenhouse is about 20 x 24'and the venting has never caused a problem. The heat received from the dryer only supplements the regular heater.

Is it possible for you to enclose the space between the house and the greenhouse walls? Or, better yet, add that space to the greenhouse. You lose so much heat having two outside walls instead of one common wall. I don't know how big your greenhouse is or what the orientation is in relation to your house. Or, for that matter, what you use the greenhouse for and if it is in use the whole year. These factors would certainly make a difference. Regarding the dryer sheets, they have never been a problem. However, it may be because I always use a small piece of one instead of a whole sheet.

I hope this info helps.

Before we moved here we lived in a house that had a back porch built on. Where the screen would have been I put up plastic and we had a screen door also. We put our dryer (gas) out there and I put alot of my house plants and water plants out there and it keep them warm enough and they did great. We would put a load in the dryer before going to bed and let them dry and it would be so humid out there. Good luck, try it. Eletta

I guess it would depend on your climate and how great the up and down temperature flux would be as Dorie had mentioned. What about routing the pipe through some sort of "heat sink" (like a tub of water or rock/sand) to absorb the heat, and then venting the moist air outside afterwards? Many sunrooms/greenhouses recommend large heat-retaining masses for passive heating.

I had one of those water dryer setups unbelievable mess in garage. Used to be car port boxed in as garage
last owner didn't reroute venting. I sent it across ceiling to outside. no noticable heat in garage exhaust
quickly exits. rigid pipe yet to be installed. 30 feet flexible metal.

you might check out what a normal heating sys cost. might be affordable if u do it yourself, and you might not need to use the dryer idea if u can find an easier way. check out lowes hardware for books on this. if not....go for it!

Someone mentioned to me that he was planning on using strings of Christmas lights to heat his small greenhouse. Not the little fairy lights, but the larger bulbs (older-fashioned kind). This sounded like quite a good idea to me, but I haven't tried it.

Sue

I posted this same question in one of the other forums.
My only concern is that all my pretty Plumerias would smell like "DOWNEY"! and they would all be soft and cuddley!

T2

HAVE YOU ALSO SEEN BINDA COLEBROOK'S "WINTER GARDENING IN THE MARITIME PACIFIC NW" OR ELLIOT COLEMAN'S "FOUR SEASONS HARVEST" IN YOUR LOCAL LIBRARY? THEY MIGHT HAVE MORE IDEAS ON HEATING YOUR GREENHOUSE. IN PORTLAND, OREGON, A MORE IMPORTANT QUESTION IN YOUR GREENHOUSE AREA IS "HOW MUCH DAYLIGHT DO YOU GET IN THE WINTER"? GOOD GARDENING TO YOU,K.

My dryer is vented to a 6x8 freestanding greenhouse.
The automatic vent on the greenhouse roof opens almost immediately when the dryer is on at any setting.
I keep the dryer at the lowest heat setting to prolong the time that greenhouse is heated.
The greenhouse gets to about 85 degrees and very moist when the dryer is running.

I have found that the most important part of heating a greenhouse through the winter is the maintaining of an even temperature. My greenhouse, about 10 x 20, is attached to the house on one side, so we have left the basement window on that side open in the winter. My husband installed radiant heat in the greenhouse floor; and I use a plastic bubble wrap type insulation in the winter months on the glass. Even with all these helpers, a small propane gas heater is needed during the coldest months. If you want anything to grow or flower during winter, an even temperature is a must.

I agree with the even temp. idea. You would be wasting money to run the dryer all night long when the heat is needed. If this were just a supplement to another heat source, I don't see any harm done. I certainly wouldn't consider it as a primary heat source.

yes use it for supplemental heating. Nothing wrong with that. Nothing at all. The bit of, what was it, lint or fine particles in the air.... no bigg deal at all.

I agree with unclechico, about using the dryer to supply heat to a heat sync. I have not tried it yet, but my idea was to build a greenhouse that attaches to the house on the south side, and paint the wall black and use black stones in the floor to get radiant heat from the sun. I wanted to take the dryer vent and route it through several metal pipes that are buried in the rock and then have them vent to the outside on the other side of the greenhouse. I would use a couple of 3 inch pipes off of the 4 inch exhaust, and several 2 inch pipes off of the 3 inch pipes to avoid any back pressure to the dryer. I am hoping to harness the dryer heat to just help heat the rocks to give off a slow radiant heat at night. I would be interested in hearing if anyone has attempted this particular method and how it went.