If your plants are growing in a small room, it might makes a difference. It just add a few degrees. I don’t know what your plants requirements are. My shop are 90% led’s. I don’t see any needs for anything more. My shop is part of the whole house heating/air system.

I think you need to consider wattage which should be printed on the bulb. 40W bulb will ultimately add 40W of heat...but different bulbs will produce different lumens of light. And cost of 'producing' the wattage is different according to bulbs used.

I have some notes, but not enough to answer your q. Example: In colder climate, you need about 2500W to heat room that is 215sq.feet that is properly insulated. I do not know temps that were considered...And if not insulated, that heat could be lost fast.

I can tell that small room in my basement, where I keep about half of my plants (11.5x12.5'; no window) and has 1 heat vent, gets little warmer than bigger, uninsulated areas of basement with just few bulbs for illumination. It has mixture of lights: many CFL bulbs, few T5 and one T5HO. BUT that is basement, room is part of it, insulated, and heated. (I just checked temps using temperature reader/ gun: uninsulated part of the basement, but bigger, is almost 1*C cooler than plant room, with all lights on)

I have smaller, uninsulated space (above grade, not basement) where I keep dormant plants during winter, but they should not freeze. When cold outside, it gets below freezing too. I have a thermocube that goes on at 0*C (32*F) and off at about 3*C (37.5*F), and planning to use it to plug small infrared heater. You can get thermocubes in different settings. Right now, that room is 11.7*C (53*F), with outside temps reported at 6*C (43*F). I am sure it would be cooler in there if it was windy.

I don't know if this rambling helps...

Rina, in all of that rambling, I actually learned something. lol I just ordered a Thermocube! Looks like something I could use and never heard of before. I love it!!! I have been looking for a way to shut down my space heater so that it goes on only at 38 degrees..Thank you!

I just need bulbs that will create heat for me and sav even more. I wonder if they cell CFL long tube T8 or T12 bulbs? I could use those!

The porch is insulated and not a very large space and it could stay pretty warm if I could find these. Please, anyone if you know about these bulbs, let me know. Thanks in advance.

Bob, thank you. Yeah, on the porch there is no heat source at all. Not like my 4 seasons porch that gets heat from my home into there.

I assume that using 'space heaters' are much more expensive than running a few lights.

Mike

If you want heat, incadescent bulbs or halogen bulbs produce more heat, but are not very efficient. I do not think you can have both in same bulb, lol.

Here is a comparison of bulbs for light/heat output:

Perhaps using space heater would be best; and using LED lights if you need supplemental ligt.

If you set heater for certain temps on/off using thermocube, it will heat only if/when needed. I just got a small infrared heater (about $40 CD, on sale) that I'll try out this winter with thermocube. (JMO, but I think this would be more efficient and economical than trying to heat with lighbulbs. Infrared heaters are supposed to be more efficient than electric heaters, since they channel the heat energy to specific objects within the room rather than to the ambient air. This is my first one, so I'll find out :)

BTW I hope you ordered thermocube with proper for you settings...

Another great gagdet is temperature reader/gun. You can check surface temps of leaves or any object, or air, just point&read. I have one like this (just $10 CD, on sale :)

LED bulbs are not heat free, there's a reason the LED fixtures have air vents, they just give off a lot less heat, fluorescent bulbs give off more heat, but its unclear how much more.....enough to heat a space...... not really, I would think, in fact the ballasts and bulbs act up in very humid or cold weather when you would need it the most (unlike LED) the thermocube should help your heater regulate. True trial and error. How old is the space heater? Like AC units everything is more efficient these days, don't pay to keep old ac units

Thermal energy is the most basic form of energy and every other energy source will eventually become thermal energy. Simply stating whatever light a bulb generates will become thermal energy in a matter of seconds. Remember light is also a form of energy. When light hits any surface part of it bounces off and part of it heats up the object a tiny bit. This will happen billion+ times second. If the object is black the conversion is very very quick. If the object is mirror then it will take a tad bit longer. Even simpler if a light source consumes 100W all of that will become heat energy. If there are plants in the room a tiny portion of that 100W (heat and light) the plant will use up to produce sugars.

Let us say you need 1000W of energy to heat up a room to comfortable levels, then it makes the most sense to get 1000W of the most efficient light since you will get both - lot of light and lot of heat. However, it will cost you quite a bit more to get a combined 1000W. Remember I mean 1000 true watts - the amount your lights actually draw.

The drawback is you would still need a space heater during the night.

Light source comparison: Any light source will produce heat, some actually depend on it like incandescent, flourescents and Sun itself. Difference is how efficient are they. Sun is considered 100% efficient and even then it only converts 40% of the energy to light - rest is heat. That is the theoretical limit of light sources - you cannot get better than that. Good leds convert about 15% of the energy to light, flourescents are about 10%, incandescent are around 3%. These are ballpark values.

Mike, is it possible to open up an opening somewhere to use heat from your in-house system , that would solve a big problem. You really don’t need a return register and than you can use led’s to your hart content. My shop has 3 registers, no return, don’t want anything from the shop going in the house, dust or whatever.

I would think the heat from the ballast of a fluorescent fixture will make the heat from the bulb seem inconsequential by comparison regardless which bulb you use.

tj

All bulbs put out 100% heat. Some of that heat is in the visible light spectrum that the plant can use. Incandescent 1% usable light. T-12;s 8%, T-8 = 12%, T-5 !4% LED;s !5%

These are not exact numbers but are close. If you need 1000 watts heat them get 1000 watts in lights and you are set. the higher the lumens per watt the more usable light your plant get

The heat is going to be virtually in exact same proportion to the wattage.

Guess the value would depend on how much wash you do per week but sure would be nice if one could recover the heat energy discharged by the drier while drying wet wash. If you timed your drying to be done at night when you most need the heat in your plant rooms, you might same some heating dollars. I don't think you could discharge the air from the drier directly into your greenhouse since you would also be discharging all the humidity/water from the clothes, but you might be able to build some kind of heat exchange gadget. I've wondered if I could do something like this in the winter to help heat my house....or to keep from wasting the heat from the drier. Problem is the steam/wet air in the drier line will condense back into water as it cools so you would have to have a low spot in the drier discharge line for water to run out or collect in a container. Perhaps you could use three or four old auto radiators (to make up enough air carrying capacity) and run the drier air through the water inlet/outlet and use the radiator drains as water drains to allow the condensed water to run out. Guess you would still have to have a space heater and lights since hopefully you don't do wash every night of the week :>)

I am going to sleep for a while, beyond me.,don’t understand.

My water heater vent is 60 feet long so that the condensate drains out the end with the heat extracted air. That air was dumped into the greenhouse and it worked very nicely. My washer is hooked up to a heat extracting sink so I get all the heat out of it before going down the drain.

Steve

Mike, I used a 1000w led light in my 6x4 grow tent and I was surprised that the temperature went up to 80F and when the light is off the temperature dropped to 55/60F

Amy

1000w is a lot. In relatively small and enclosed space (6x4) it should heat it up. Just like 1000W heater. IIRC, those units have buil-in fans to keep them from overheating. And are quite pricey to purchase I think? I have some notes saying that it takes about 2500W to heat up room that is 215sq.ft (insulated) - sorry for repeating, I mentioned it before. So it should take much less W to heat up a grow tent. Mike didn't say how big his porch is, and I believe that he wants to just "extend the time" for plants in it.

If I may ask: where is your tent - inside of basement or? Do you need higher temps for night/when lights are off, than 12 - 16&C?

I figure that there is not much difference in cost of heating with lights or with a heater. UNLESS one wants to keep temps relatively low - and that is the reason I suggested using thermocube. It is really like a thermostat, but for lower temps on-off. Problem with using it with lights would be that they get switched on and off, as temps fluctuate. And that is the reason I suggested using a heater wih thermocube; and using LED lights on a timer. I am not sure what plants Mike wants to keep there either; but most succulents can overwinter in temps close to 0*C. To be safe, I would keep them at about 3-5*C lowest temps or so. Obviously, this is not for growing seedlings or some high temps. plants.

IMO, heating space to lower temps with a heater and using LED ligts for illumination seems to be more economical to me... (but I am not an expert and hope I didn't make a mistake!)

A real 1000W led would cost an arm and a leg. I would bet that the actual power draw of that 1000W led fixture is lower than 300W. The ones I have seen on Amazon have a power draw less than 200W which is more manageable heat wise. That 1000W label is a marketing gimmick. No fan will be able to manage cooling a 1ftx1ft light fixture consuming 1000W.

Don't confuse light with heat. Watt is equal to heat. There is Kelvin light absorbing temp. Which is the ability of something absorbing the heat produced from the light.

The reason for heat shields on LED's is to reduce the LED from getting too hot. Over 150 degrees will destroy LED's. LED's produce more light per watt than any other source known to man right now.

Mike the most cost effective way to heat anything is by natural gas. With gas space heaters but watch out for the carbon monoxide. Even with using gas dryer vents. Elect dryer is okay due to no carbon monoxide emission. They come equipped with C-02 cut offs but I would use a C-02 alarm in the room for safety.

Using the vent from a gas water heater is also dangerous for the same C-02.

You might also get a portable

propane

Hello everyone and thank you so much. I decided not to use lights that make heat and keep the porch on the colder side for all my citrus and a few cactus that need dormancy and figs like I always have and they have done well. NO lights since on sunny days it gets pretty bright in there.

I already have about 10 florescent L.E D lights on 8 hours a day in house. So might as well split between those that could really use the light verses those that don't mind cold temps and darker environments))

I also got the the contolled plug in that Rina talked about, thanks Rina!!

I hope these CFL's produce heat

Just completed my first heating system for my seed grown Fukushu kumquat tree.

For this tree.

Steve

Steve

CFL bulbs will heat a bit, more than LED and less than incadescent. How much heat do you need? Do you also need light there?

I would recommend LED lights just for the electricity cost savings throughout the year or even just the shoulder seasons. For winter you could use an electric oil heater which do a good job only on the days you need it.

I own a thermal camera and can try to take a few photos of my LED lights/plants with thermal readings if anybody is curious. Unfortunately I sold all my fluorescent grow lights so I can't provide a good comparison to those (with precise thermal imagery).

Those bulbs are in there for the heat. They are old and getting replaced with LED's as they burn out. Indoor trees get the best then in the house and then outside till they die. The light fixtures are free and I have 4 electric heater I got for free but I only need 100 watts heat to take me safe down to -10F. I have blanket to go below that. The trees do need some additional light in winter in order to do well in spring.

Installed.

Steve

Steve

I also have some CFL bulbs that were free, and not buying new ones as they burn out. I didn't pay for them, but they use min. 23W and some more. So it is def. not extremely economical to use them (only if compared with incadescents). What wattage are yours? How many are you using?

If you need to watch cost of light/heating, you may be better with LEDs for light, and heater for the heat - if you can set it up to go on when needed. Oil as Kevin siggested, or even infrared. I have some LED tubes that are 19W, 4000k, 2200lumens.

You are in z6 - how cold does it get in winter? In my zone, it gets down to -8*F , often as low as -16*F and even bit lower on occasion. If whole set-up is outside, would plant need extra light? - especialy if enclosure is all glass.

Kevin

Hope you will post some readings...(btw, nice to see you around again!)

My bulbs are 23 watts. We can expect 1 out of 3 winters overall to go below 0-F. I have seen -10 in the past 15 years and our record is -25F

Second heater.

Install on Valentine pomelo tree.

Steve

Nice thermal images Kevin. Where did you get 48W 4ft led tubes?

Tropic - Thanks! They are made by Sunblaster and I got them from Amazon.
Rina - Appreciate the welcome back! Things have been too busy with work and I was away for a while. Decided that I need to put higher priority on my plants and growing again. If you need any extra CFLs for growing just let me know because I've switched out a lot around my house this year and they are just sitting around my basement.

Looked up those Sunblaster led tubes. Seems quite nice and convenient. Was trying to look up which leds they use and could not figure that out. I have some led lights that use the latest Samsung leds. They are super bright producing nearly 170lm/W and I actually have to dial them down. They also run quite cool without any heatsink. Wish I had a thermal imager too but they are quite expensive. For that matter I do not have a PAR sensor/meter either - lol.

Kevin, What business are you in for having nice toys? I purchased a thermal imager for work but came in while I was retiring so never got to use it. I was head of elect/instrum in a coke & iron mill. It was $2000 which was a good price at the time (2008). Shame nobody was smart enough to use it and it just sat there. Wish I could have taken it home with me.

Tropic - I tried to find out which LEDs Sunblaster used but couldn't either. The good thing is that they are tested and have a good spectrum as white LEDs, confirmed personally with my spectroscope.
I have a few PAR/light meters but recently got a scientific PAR meter which is pretty fantastic. It cost a lot but has a wider spectrum for LED light measurements. Something I've been wanting to get for years.

Stush - I'm a lead electrical engineer and work in nuclear power plants. What I've learned is that thermal imagery is a very technical and deep topic. It seems simple but to do it properly takes a lot of skill and knowledge. Much reading of procedures and standards!! At home I've been slowly building my own collection of quality tools.

I found that running t8s with electronic ballasts all together in the same case, especially if the ballasts overdrive the bulbs a little, produces a lot more heat than you would think when it comes to fluorescents.

Since I've upgrade my indoor grow area by adding 4 4 bulb fixtures air temp has gone up 4 degrees and I'm watering way sooner all around