sunfish

Would low voltage lighting do anything to help raise the temp. in a greenhouse.

Kim

Too many things to consider. Better off with a grow lamp or heater. What are you growing in San Diego? How large is your greenhouse? Location? Hydroponic? Low voltage=low current=low heat refracting from bulb and can = higher costs.

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sunfish

The greenhouse is 10x12x12 high. I am growing passiflora and bananas. Very seldom does it get below 40 . I already have the lighting and timer . If I can keep it above forty degrees I am fine. I was just wondering if I will get any heat out of the low voltage. Thanks

ewitte

Sure about that amps usually = heat and lower voltage usually means more amps.

momoese

I have a Malibu low voltage system in the backyard and they do put off some heat. The timer unit creates some heat as well.

hammer

lasr winter i used a 125 watt grow lamp it put off alot of heat.

sunfish

Well if they put off any heat , that is probably all I need. I am just trying to raise the temp. enough to keep them alive. I don't need a grow light , although that would be nice , it gets plenty warm here even in the winter for the plants to grow. Thanks for the help.

chong

Yes. For the same wattage, lower voltage means higher amps. Power = Voltage X Amperes.

Any electrical device will put out heat. A 60 Watt light bulb will give off ~205 BTUs of heat (60W X 3.413BTU/W). So, any supplemental lighting you operate will give off heat inside the "chamber". However, depending on the volume, and tightness of the structure and the insulation, that heat may be localized, unless you have a hood over the device and a fan to distribute the warm air throughout the "chamber".

Richard

Heat rises.

Tony, two winters ago when my dragon fruit were tiny I strung up some blue-colored "C" type holiday lights about 18 inches from the plants. (Initially closer - but noticed some heat scars.) These were connected to a thermostat for a household forced air heater: these are designed to come on below a user-selected temperature. I set mine for 40 F. Worked great -- of course here in San Diego the temperatures in that area would not have dropped below 33 F. I calculated that they cost less than a penny an hour to operate.

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sunfish

I was thinking of the safety factor using the low volt. versis 110 volts.

Richard

True, its a good idea for your lighting -- which will not be located in a good place for the small amount of heat you desire. I thought a string of holiday lights about a foot above the ground with a simple fuse was fairly safe for keeping the temperatures above freezing (again, in USDA zone 10).

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chong

That is a misconception. Heat flows naturally in any direction from warm to cold media. It is warm air rises above the cold air, as in Hot Air Balloons. The density of warm air is lighter than cold air, that is why it floats over the cold air. In a small enclosure with adequate insulation, the interior of the enclosure will get hot/warm regardless where the heat source is placed. In larger enclosures, with adequate insulation, sufficient to prevent the transmission of heat output of the source to the outside, the chamber will get hot/warm, regardless of the heat source placement.

bencelest

Why not put a string of Christmas lights around your bananas or plants that you want to protect? It's cheap and easy to take off. And that's what I do year after year to my delicate plants meaning plants that are still small. Once the plants are established or growned for 3 years or above, they are on their own.
I use 100 strings of clear Christmas lights the small kind not the medium base and I can protect about 3 3 gallon pots. I don't worry too much about safety because I believe that they are approved for outside use. I don't even use fuse or protective device because I believe they are safe to use. I just plugged them in to a timer and to an extension chord depending what time I want them on and off.
Low voltage won't give you the heat that you want because like Chong said Watts or power = current x voltage and in an alternating current such as we are using times the power factor. PW of incandescent lamps are 1. And watts is heat. So the more watts the more heat it will give off. At low voltage you need to increase the amperes to give off more heat and that's bad. You need much bigger wire to carry the current you need for warmth. That will shoot your expenses high. And 1/10th of an ampere can kill a person depending the right circumstance.

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sunfish

I am sure the best thing I could do is make sure the greenhouse is sealed. That is alot of calking to do, maybe someday I will do that. For now I am hoping all the jugs of water I have inside and a little help from the lighting will do the trick. Thanks

sunfish

Ok Christmas lights it is.

Kim

And the answere is.....YES. There are some great ideas in this thread. Keep us posted on your progress.

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bencelest

Tony:
I might add that don't buy the LED kinds. They don't give any heat at all.
I bought mine at Sears right after Christmas. For a 100 strings for 75 cents. They were 75% off so I bought a bunch so that if a string don't light I just throw them away.
And you are in San Diego. If you have a nice sealed area and water jugs are all you need. Try a trial run. Buy 1 string. Plug it in and put your hand close to the light. If you can feel the heat generated then that's the one you want. If you buy the medium base lights they will cook your plants. And you won't be able to put your hand close to the light because it is so hot.

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r3tic

If you have room, put a some rain barrels full of water in the green house. Water is a great heat sink, gets warmed in the day lets off heat all night.

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rv

Lighting is a very inefficient way to provide heat.
There are ceramic bulbs that fit in a standard light socket that produce infa-red heat, not those red bulbs that you see keeping meat warm at a buffet.
These are non light emitting and have been used in Europe for decades and can be found here through any place that carries reptile supplies.
They are available in several different wattage choices and you can put a rheostat inline to raise or lower the output.
They aren't cheap but they last a long time.
I've had them last as long as 5 years of almost continuous use.

bencelest

rheostat, ceramic bulbs and availability plus your gas looking for it =$$$$ and
To me anything that exceeds my budget is a no-no.
So I go the cheapest way. And the most practical. You can spread your Christmas lights a long distance to protect more plants for your money.
"Lighting is a very inefficient way to provide heat." I question the inefficiency of lighting versus the expense by other means. How many times you use them anyways in a year? 3 or 4 times at most?

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