I wanted to see if anyone has any experience with in floor radiant heating systems in greenhouses, or knows of any farms/growers utilizing it. We’re thinking of adding a hydronic system to our greenhouse before we pour the slab, but I’ve only found a few blogs and resources discussing it. We have hydromic baseboard heat in our home and love it (the coziest warmth), but obviously a relatively uninsulated greenhouse is a different beast. It seems like it might function better in some aspects than a forced air system, but also has some limitations. There are a lot of considerations.
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About a month ago I received a dump truck full of arborist waste (wood chips, leaves, twigs). Considering the amount of heat it gives off while decomposing, you might want to consider installing a non-flammable, removable floor material. If you make space beneath the floor, you could fill that space with arborist waste in the fall and let the decomposition heat your greenhouse all winter. Just a thought.
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I am on the hunt for an adequate heating element as well 
just purchased 2 different room heaters from Costco lol. rip electric bill maybe…
The voltron heater isn’t great and barely does anything except to the area directly in front.
The lasko tower fan, the same but it does say in the box that it’s only for a 150 sq ft room.
I’m thinking of getting a 300 sq ft room heater next to see if it will do anything as well.
My greenhouse is 10x20
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A heat pump ( bi-directional air conditioner) should be much more efficient than a space heater and if it doesn’t work out you can still move it to air condition a room in your house. It also doubles as a fan.
That’s especially true if you want to use your greenhouse for more than pushing plants an extra zone or extending your growing season a bit. The electric bills will pile up pretty quickly without a heat pump if you want to increase the temperature by more than a few degrees all winter.
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I have hydronic inside my house but I think it could work in a greenhouse like this:
Radiant tubing in the floor, going up to some solar water heating roof panels from Craigslist free. So far it’s pretty cheap. Then you need a single zone circulating pump which is around $100 and a basic thermostat. I think a small solar panel could power the circ pump. $300 materials?
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What are you hoping to keep the temp above vs your minimum winter temps? I’m hoping to do 50°F, but we’ll see how that shakes out in reality.
We’re breaking ground next week, hoping to get everything up before it’s truly cold.
I’m considering a walipini greenhouse to regulate temperatures both in the winter and the summer. I recommend exploring that option and investing in a geothermal system over other options.
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heat pump like a mini split? or is it another thing? I run space heater on the coldest nights and would love to cut that electric bill
You are right. I meant a mini-split.
I just learned that it’s called a heat pump when you use air to transfer heat and it’s called a mini-split when you use refrigerant to transfer heat. I believe mini-splits are more efficient.
A mini-split should reduce your electricity expenses about three times compared to a regular space heater. You can use that formula to calculate how quickly it would pay for itself. On the box it says more than triple the efficiency, but that’s in ideal conditions.
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A mini split is a heat pump but not all heat pumps are mini splits. There are air source, geothermal (open loop, closed loop, horizontal, vertical) and probably other iterations and combinations of heat pumps.
They are capable of achieving such high efficiency because the energy used to run them simply moves the heat energy of the intended system where it is needed, rather than a ‘traditional’ heating element actually using their energy to expel heat.
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Check slickdeals.net or other bargain hunting sites to look for systems. Some on sale are pretty affordable, especially when comparing what an electricity bill would be for other systems.
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That’s what I thought at first, but decided to fact-check myself before posting to make sure I don’t give the wrong info. I can’t believe somebody would just use AI to post lies on the internet. I’m shocked!
Thanks for correcting me.
It’s ok, we are here to learn and do the best we can with the information we have!
An update to add that we’re hoping to put down the radiant tubing this week and get the slab poured ASAP before the weather really turns. Depending on how things go, I’m guessing we’ll have the full structure up before gas/electric are run. It will be nice to have even an unheated structure immediately.
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