Need advice on heater for small shop

[Bbp78]

Hi, I'm hoping someone can provide some opinions and guidance. I'm sure this has been asked before several times and I apologize in advance if this is answered frequently. I live outside Philadelphia, PA and built a 16'x24' shop a few years ago for my woodworking hobby. I have a Propane Unit heater, but I never installed it because it needs to be vented through the roof and I need to buy a large 120 gallon Propane tank. During Covid, those tanks ended up increasing to around $1,500 but they are now back down to around $800 or so from what I've seen. I'm not too wild about this heater because it requires me to buy the tank, vent it and then have Propane delivered when needed. I'm thinking about buying an electric heater instead since it doesn't require any of those things. I have recently discovered King heaters KB models in case you were wondering what I was thinking about buying. My concern is that I have 60 amp service and the electric heater may require 30 amps. The only other things I would run while the heater would be on is 1 tool at a time. I have a Sawstop table saw, and other standard woodworking tools. Is this an issue if I install a 30 amp heater and only have the 60 amps? Or do I install one of those DIY mini splits since I don't have air conditioning either? I understand that will be more money probably, but I'd like to try to get this right when I do it. My roof is a little unique as the shop is shaped like a walk out horse shelter with a loft in the front that overhangs the front exterior wall by 4'. I don't know if any of that makes sense. In the back of the shop the wall is 10' tall, 7' from the back wall the ceiling is 148" tall and at it's highest peak in the loft which overhangs the front of the shop it's 15' from the ground. Thank you in advance if you have read all of this and for any guidance you can provide, it's greatly appreciated. I put so much time and money into building this shop, I need to finish this part and make it more comfortable.

 

[chinboys]

How much time will you spend in this shop?
Is the time spent in the shop a regular schedule?
How well insulated and draft free is the shop?

You may be better off wearing electric or battery supplied clothing as this set up warms you directly as opposed to the air, the space l, and the things in the shop which take time and hence cost money (therms or wattage of energy)

You can go with electric infrared heating... Tubes or a parabolic radiant resistive element heat. The effect is immediate and you are bathed in the radiation.
You turn it off and the heating stops.

If the shop is well insulated and free from drafts, then it makes sense to use propane in an heat exchanger heater to vent the wet and "hot" exhaust outside. You can use a programmable thermostat to maintain a low unoccupied temp and then program it to preheat before you show up and maintain while you are there working.

 

[Briansshop]

If you get the shop sealed up and insulated,a mini split works great. I run mine year round.

 

[ipgenie]

If you get the shop sealed up and insulated,a mini split works great. I run mine year round.

Depending on your skills, you may be able to install the mini split for less than the propane option, sell the unit heater and in a few years break even on the cost. I can heat with my mini cheaper than with propane.

 

[billt460]

I have 2 of these. One in my 3 car garage (980 sq. ft.) And another in my house. I can't say enough good about them. I even put a CO detector right next to them and they never made a sound. Flued propane heaters waste too much heat. This unit wastes none. You can also buy a fan kit for it that is easy to install.

Robot or human?

 

[cvairwerks]

For a temporary basis, I stuck a window unit that both heats and cools in the front extension of my garage. Takes about 20 minutes to take it from the low 30's to a reasonable 65 or better. I run it only when I'm going to be out there. It's a 240 volt unit and is on a 20 amp pair. Actual draw is well below that.

 

[Notgrownup]

If it’s well insulated I would do a Mr cool diy small mini split. But your panel might be under sized for that or a PTAC. The more effective ones are 208 v
If your woodworking like me I want the humidity control as well. Mine runs all year round.

 

[drivesitfar]

Your shop and tools sound nice. Any pics that you can share to give us a better look and maybe more ideas might be helpful but not necessary. It would help to mention which part of the USA world you live in though.

For me in the PNW (think Seattle) it rarely gets below freezing so clothing usually can fix any lack of warmth. Some of our members get to -35 in their winters so I’m guessing clothing might not be good enough.

I’m watching along and maybe I’ll have some more information to share cause I’m planning on building a woodshop about that size in 2026.

 

[Bbp78]

Thank you all for your replies, I appreciate it. I plan on insulating the roof soon, I have held off insulating the ceiling as I was concerned about the cathedral roof not being ventilated and possible mold growth if I seal it up, but my neighbor told me that I shouldn't have an issue with that (I hope he's right, lol). I did insulate the 2x6 walls and the front roof during construction, so that's all done, I just need to insulate the main rear roof. I'm currently still working (only 46) so I only work for an hour or so on the weeknights, but not every night and on the weekends I'm out there for 3-5 hours a day give or take. I have 2 children under 5 so my time is limited now. I would like to do the mini split, but now I'm concerned with only having a 60 amp service. One of my old neighbors was an electrician and he helped me run the power underground and hook up the sub panel and I did all the wiring. I regret not running a larger gauge wire and installing a 100 amp service. I've really driven myself a little nuts with this as I simply can't make a decision. I have the Propane unit heater, and would just need to get the tank which I've seen some on FB marketplace for cheaper possibly and vent it and run the gas line and I'll be done, at least for heating. The mini split sounds great, but I'm not wild about running another feeder wire. My neighbor who is a retired HVAC contractor who has a propane unit heater in his shop for the last 40 years and told me that's the best way to heat it and pushed me in that direction, walked away in frustration today telling me I need to make a decision and he's not going over this again, lol. He doesn't have AC and just doesn't use his shop on the 90 degree days. I installed a nice oscillating industrial fan last year which helped in the summer. Now summer is a distant memory and I think maybe I'll be okay without A/C again but when summer comes back, I might have a different mindset. Anyway, as you can tell, I don't know what the hell to do. Again, I wish I had installed a larger service in my sub panel. Sorry for all the rambling and thank you again for your time and expertise.

 

[nadogail]

I have an Electric Unit Heater in my workshop. It requires no ventilation, nothing but clean electricity.

Obviously my heating needs are minimal.

 

[Skiff Builder]

I have 2 sources of heat in my 1100 sq ft shop. 60 miles S.E. of you on NJ coast. 9' ceilings. Run a ceiling fan on low while heating.

1. King Elec unit. 7500w/240V/ 31.25Amp/ 40 Amp 2 pole Brkr/ 3' of 8 Ga copper whip. I usually run it on just one of the two heating elements. Works fine, a bit of fan noise. I tried a 30 amp breaker as a test. Running both elements full hot- It has never tripped that breaker.

2. 30k BTU Blue flame Nat Gas unvented wall unit. Simple, fast, quieter than the King. Yes, aware of fumes- but with 3 overhead doors and 6 louvered flood vents, I never see condensation on any glass nor have my tools rusted.

Only heat space when in use/ occupied. Will start off running both units. Shift to just elec once to 65 deg.
Both were very easy install and work well for my boat building / woodwork / veh maint application.
I felt I would kill a Minisplit with fiberglass/wood sanding dust.

 

[ipgenie]

Thank you all for your replies, I appreciate it. I plan on insulating the roof soon, I have held off insulating the ceiling as I was concerned about the cathedral roof not being ventilated and possible mold growth if I seal it up, but my neighbor told me that I shouldn't have an issue with that (I hope he's right, lol). I did insulate the 2x6 walls and the front roof during construction, so that's all done, I just need to insulate the main rear roof. I'm currently still working (only 46) so I only work for an hour or so on the weeknights, but not every night and on the weekends I'm out there for 3-5 hours a day give or take. I have 2 children under 5 so my time is limited now. I would like to do the mini split, but now I'm concerned with only having a 60 amp service. One of my old neighbors was an electrician and he helped me run the power underground and hook up the sub panel and I did all the wiring. I regret not running a larger gauge wire and installing a 100 amp service. I've really driven myself a little nuts with this as I simply can't make a decision. I have the Propane unit heater, and would just need to get the tank which I've seen some on FB marketplace for cheaper possibly and vent it and run the gas line and I'll be done, at least for heating. The mini split sounds great, but I'm not wild about running another feeder wire. My neighbor who is a retired HVAC contractor who has a propane unit heater in his shop for the last 40 years and told me that's the best way to heat it and pushed me in that direction, walked away in frustration today telling me I need to make a decision and he's not going over this again, lol. He doesn't have AC and just doesn't use his shop on the 90 degree days. I installed a nice oscillating industrial fan last year which helped in the summer. Now summer is a distant memory and I think maybe I'll be okay without A/C again but when summer comes back, I might have a different mindset. Anyway, as you can tell, I don't know what the hell to do. Again, I wish I had installed a larger service in my sub panel. Sorry for all the rambling and thank you again for your time and expertise.

I picked up a 120 gallon used tank half full for $100 a few years ago. I keep it full as an emergency spare but really don't have a good reason to keep it around anymore. Tank costs have gone up but if you keep an eye out you might find a deal. You can have the existing unit heater running in probably half a Saturday if you find a tank. Rental is probably an option but over time you'll pay a lot more.

If you go mini split, you might find that your 60A service is enough. I'm in Idaho and two winters ago my 18K Pioneer was putting out good heat at -15 F. It's on a 20A 240v circuit but my Emporia Vue energy monitor says in the past month the peak 15 minute demand was 4.1A so it's very easy on power. Turning it on in a cold shop is sure to have a higher demand for a while but once warmed up they settle down and just idle along.

Whichever way you go, having heat in the shop is fantastic.

 

[Bbp78]

Thanks everyone, maybe the mini split is the way to go if I can get by on a 20 amp circuit. I'm familiar with Mr. Cool but I didn't know about Pioneer until recently. Does anyone know if they're similar quality? Do I need hyper heat? The Mr. Cool I'm liking at on costco.com says it's good down to -5 which would be fine for me outside Philadelphia and I don't think it's hyper heat. My shop is under 400 square feet but I have the tall cathedral ceiling. Does anyone know if the 18,000 btu would be enough? It says it would cover 500-699 square feet of coverage.

 

[Bbp78]

I just thought of another question. For a mini split, do I need to leave it on when I'm not using the shop or can it warm up or cool down a shop within an hour or two if I turn it on before I want to work? I'd hate to leave it on when I'm not out there but I'm not sure if it takes a while to get a space comfortable or not if you don't. Thanks again.

 

[fitter30]

Doesn't matter what kind of electric heat 3.41 btu per watt.

 

[WildBill]

I have 2 of these. One in my 3 car garage (980 sq. ft.) And another in my house. I can't say enough good about them. I even put a CO detector right next to them and they never made a sound. Flued propane heaters waste too much heat. This unit wastes none. You can also buy a fan kit for it that is easy to install.

Robot or human?

I also have a couple of those, only stopped using them in my shop because I installed a mini split. They are really great, adding the fan kit makes them crank out tons of heat.

 

[WildBill]

I just thought of another question. For a mini split, do I need to leave it on when I'm not using the shop or can it warm up or cool down a shop within an hour or two if I turn it on before I want to work? I'd hate to leave it on when I'm not out there but I'm not sure if it takes a while to get a space comfortable or not if you don't. Thanks again.

Its hard to heat everything back up if it gets really cold, and they are not the same as a big gas heater or something that puts out 80k btu so they take a little while to heat everything up. Most mini splits only let you turn the "normal" temp setting down to around 60F but have some sort of frost protection setting that goes lower. My Mr.Cool has a setting called comfy temp that turns it off and on at set temps, I set mine to turn on at 40F and off at 50F when I am not in the shop and then turn it to normal mode at 65F or so about an hour before I go out. They are incredibly efficient so it doesn't cost much to leave them on, and its nice from a humidity standpoint to have them running. If I actually had any sort of insulation I would probably just leave it at 60F all the time in the winter.

 

[ipgenie]

I've got an 18k Pioneer and a 9k Senville in my house, both ordered through Amazon. The Pioneer says it heats to -13. The Senville is 5. Both make heat at lower than rated temperatures. Both have been reliable and were a good value, $950 and $700. I did the install and had a tech do the pressure test and vacuum in order to qualify for our power companies rebate program. That was $1200 so it was a total of about $1000 parts and labor out of pocket before federal credits.

I assume if you turn it on in a cold shop, it'll run full power for quite a while. Depending on the BTU rating it could seem like forever to warm up from below freezing. I don't have one for my shop yet but I am planning on one when I get more done. I'll probably set it to freeze protection most of the time.

 

[ipgenie]

Doesn't matter what kind of electric heat 3.41 btu per watt.

This is true for resistance heat but not strictly true for all heating systems powered by electricity.

A mini split or heat pump doesn't create heat like a space heater, it transfers heat from one side of the system to the other. This can be 4x more efficient than resistance electric heat even though the process is purely electric. The COP is a way to measure this efficiency. A COP of 2 means it can produce 2x the BTUs of resistance heat using the same amount of electricity. As it gets colder outside, that COP value goes down because it requires more energy to transfer the avaliable heat from the cold outside air to the inside structure.

Some split systems are more efficient than others and can function at lower outdoor temperatures but at some point they will be unable to transfer heat. Some will have electric resistance heat strips in them that are powered on when the compressor system is unable to transfer enough heat.

A resistance heater will produce the same amount of heat and draw the same amount of power anytime it's powered on.

 

[Notgrownup]

Propane will be the fastest way to get warm And probably the most efficient in my redneck opinion. A mini split will be the most effecie if you want constant climate control.

 

[PoorUB]

Propane will be the fastest way to get warm And probably the most efficient in my redneck opinion. A mini split will be the most effecie if you want constant climate control.

Only if you oversize the propane heater.

A properly sized heater will just keep the temperature under control, but most people go a bit crazy and put in a larger than needed heater. If a 24,000 BTU mini split running a COP of 2 in the cold will heat it, you shouldn't put in a 60,000 BTU propane heater either, or a 45,000 for that matter, but everyone oversizes their heaters.

Here in North Dakota, a buddy heats his 24x32 garage on 17,500 BTU. Most people would put maybe a 30,000 BTU or most likely a 45,000 BTU gas heater in that garage and it would be way oversized with the 30,000 BTU.

 

[dscheidt]

Only if you oversize the propane heater.

A properly sized heater will just keep the temperature under control, but most people go a bit crazy and put in a larger than needed heater. If a 24,000 BTU mini split running a COP of 2 in the cold will heat it, you shouldn't put in a 60,000 BTU propane heater either, or a 45,000 for that matter, but everyone oversizes their heaters.

Here in North Dakota, a buddy heats his 24x32 garage on 17,500 BTU. Most people would put maybe a 30,000 BTU or most likely a 45,000 BTU gas heater in that garage and it would be way oversized with the 30,000 BTU.

with garages, there are other considerations beyond steady state heat loss. IN many environments extra capacity is needed for faster recovery, either because the space isn't heated when not in use, or because they're garages and opening big doors lets all the hot air out. that can mean a bigger than ideal system, or a secondary source of heat.

 

[Briansshop]

Moisture is a problem with LP.

My shop is about 1100 sq ft,sealed up and insulated as good as a typical house. I don't remember the size of my mini, but you can see the wall unit in this pic.



That small thing keeps the shop 63* winter, 78* summer. I only turn it off during Fall/Spring when the weather is nice enough to have the doors open.

The most impressive thing about the mini is the outside temps can be in the low 20s and it still blows out WARM air! I'm planning a move and building a bigger shop - 4000 sq ft - and it'll have a multiple zone mini system for sure.

 

[PoorUB]

Moisture is a problem with LP.

Only with an unvented heater. Vented heaters do not produce any moisture that may get into the space.

 

[mepstein]

Buy a mini split and keep the temp low in the winter. Install your propane heater and use it for auxiliary heat when you use the shop. Control it with wifi so you can turn it on an hour before you want to go to work. Buy a smaller tank since it's just for occasional/as needed use. The mini split will also dehumidify in the summer. That's important for tool health and keeping mold and mildew under control.
If you don't have good heat and a/c, you will never be comfortable in the shop and it will become a storage shed instead of a comfortable place to work and hang out.

 

[Bbp78]

Hi everyone, thank you again for your replies, I got busy at work the last couple of days. I've taken two steps forward, and now it looks like I'm going back one step. I've decided to move forward with the propane unit heater. I dont think I mentioned it before, but my neighbor installed my heater in the ceiling a few years ago, so that's already done. I found a brand new tank supplier around an hour away who sells tanks for $800 which is a good deal it seems like. I called a local Propane dealer yesterday who sent out a rep today to look at where I was placing the tank, etc. to make sure it's up all up to code before I get the tank. Where I was going to put it is no problem, the problem is that it's 154 feet from the street and the truck hose is only 150 feet long. They will not take the truck off the pavement. He recommended I buy a 30 lb tank and see how long that lasts and if not very long, get a few more or a few 100 lb tanks. Either way I'll have to take them to get filled which I'm fine with, but the 100 lb tanks would be heavy when filled, so I'm a little concerned about that, especially as I get older. Son of a gun, I didn't anticipate this problem. I could put the 120 gallon tank in the yard closer, but then I'd have to run a propane line underground and I'm not sure I should DIY that. I really don't want to pay to have it done. It's always something, lol.

 

[Bbp78]

To clarify, the $800 tank is for a 120 gallon (420) tank.

 

[tncatadjuster]

Mini-Split for the win. Im on my third year and really glad the way its working out. I had no idea it would heat so well, much cheaper than propane was costing me.

 

[Bbp78]

tncatadjuster, is yours on a 20 amp breaker do you know? I'm just nervous about the power draw since I only have 60 amp service. What brand do you have? Thanks

 

[tncatadjuster]

Mr Cool DIY 24K 220V , I’m on 50 amp for the shop and never had a problem running other equipment. I never turn it off unless out of town. Heating is about 1.5 times expensive as cooling, 3,200 s.f. High Tech stuff.

 

[Bbp78]

Wow, your shop is 8 times bigger than mine, lol. That's great to hear yours is working so well. I have a high cathedral ceiling, I wonder if that's an issue with the mini split, I'll have to look into that.

 

[ToolsRCool]

#1: Insulate. Ceiling, walls, door kit. Close up any air drafts. This will run your heater way less, no matter which you chose.

Natural gas is the lowest cost form of purchased energy. I don't think anybody can beat that combined with a high efficiency furnace in a well insulated area. Sounds like this is not an option for you though. Only way to beat it is to use solar with a mini-split. I am using this for my home A/C.

A lot of peeps are switching to mini-splits in garages as they are dual-function. They are decently efficient with power usage, and usually require a circuit breaker 1-2 sizes smaller than an equivalent central A/C unit. They can and do work as heaters, so this makes it a simple solution. Many qualify as Energy Star on taxes as well. An added bonus is they are super quiet. They can and do get dirty though, their thin and closely spaced fins on the indoor units are part of their efficiency, but that also requires cleaning to stay efficient. Best to gravity drain the indoor units for A/C, or use a traditional furnace style condensate pump if you must. ALL of the mini condensate pumps that go up into the indoor unit ****, I have burned through all makers of them. A single channel mini-split is fairly easy to install. The indoor unit hangs on a wall plate that screws into the studs. Outdoor unit is best mounted on a wall bracket to be up off the ground. Same level as the indoor unit is best if possible, greatly shortens runs of the refrigerant lines. 240V usually supplied to the outdoor unit only, then that feeds the indoor unit via a small 3 wire cable. Insulated copper line set between the two. Single small hole in the wall between the two. That's it. Outdoor unit comes pre-charged. You flare and install your line set, vac, leak check, then just open the valves on the outdoor unit and hit it.

The vent-free propane or natural gas wall units work well, and even better with a fan. I put one in my neighbors basement, he loves it for power outages. They will add moisture to your garage air though. If you put up a vapor barrier atop your insulation, this may not be a large issue then. A lot of exposed flame on these, watch what garage vapors you are using around them.

Ventless propane and resistance heating are the easiest to install, but most costly of the options to operate.

 

[Bbp78]

Thank you ToolsRCool for your thorough response, I appreciate it. I'm going to finish insulating the roof, everything else is already done. Maybe I'll call Mr. Cool tomorrow to see if they can help me size how many BTUs I need with the cathedral ceiling. My propane heater has to be vented through the roof so I shouldn't have much moisture from what I understand if I went that direction.

 

[ipgenie]

Hi everyone, thank you again for your replies, I got busy at work the last couple of days. I've taken two steps forward, and now it looks like I'm going back one step. I've decided to move forward with the propane unit heater. I dont think I mentioned it before, but my neighbor installed my heater in the ceiling a few years ago, so that's already done. I found a brand new tank supplier around an hour away who sells tanks for $800 which is a good deal it seems like. I called a local Propane dealer yesterday who sent out a rep today to look at where I was placing the tank, etc. to make sure it's up all up to code before I get the tank. Where I was going to put it is no problem, the problem is that it's 154 feet from the street and the truck hose is only 150 feet long. They will not take the truck off the pavement. He recommended I buy a 30 lb tank and see how long that lasts and if not very long, get a few more or a few 100 lb tanks. Either way I'll have to take them to get filled which I'm fine with, but the 100 lb tanks would be heavy when filled, so I'm a little concerned about that, especially as I get older. Son of a gun, I didn't anticipate this problem. I could put the 120 gallon tank in the yard closer, but then I'd have to run a propane line underground and I'm not sure I should DIY that. I really don't want to pay to have it done. It's always something, lol.

If you own the tank you can buy propane from any supplier. Buy the new tank, then have a supplier who will leave the road and enter your driveway come fill it.

That's a crazy policy. Hardly anybody within several miles of my house could get their tank filled if the limit was 120' from the road. Our delivery driver backs at least 150' up the driveway along side my shop, then runs the hose out 50' or so to fill the tanks and I'm fairly close to the road compared to a lot of my neighbors.

I guess an alternative is to put the tank on a small trailer and pull it out to the road to fill it. A 120 gallon tank is small and would only need a small cheap trailer to carry it. Just leave it on the trailer next to the shop.

 

[PCustoms]

If you own the tank you can buy propane from any supplier. Buy the new tank, then have a supplier who will leave the road and enter your driveway come fill it.

That's a crazy policy.

This

Unless you live down some crazy goat path on the side of a mountain, around here everything gets filled via a truck that had to leave the road.

 

[Bbp78]

Lol, I know right. I live in the Philly suburbs and told my wife, how the hell can't they fill this thing, it's not like I'm in the middle of nowhere. I think my lot is only 150' deep so I'm confused as to how the tank is 154' when it's 15-20' back from the property line. I'm going to get out the lot details from Settlement to confirm the 150' and I'm going to remeasure myself. Maybe the guy made a mistake. Ipgenie, that's a good idea about setting the tank on a trailer. PCustoms, you made me laugh with your goat path comment, I don't live anywhere like that, lol although I wish I did sometimes.

 

[Bbp78]

I wanted to provide an update, thank you all again for all of your guidance. I measured the tank location and I came up with 152' from the street. I called the propane company to see if there are any options to fill it but I decided Friday night after working in the shop for a couple of hours at 40 degrees that I'm going to go with a mini split. I called Mr. Cool and they recommended an 18k BTU unit for my shop with the cathedral ceiling. My neighbors brother installs mini splits on the side, so I'm waiting to hear to see if he's interested in giving me a quote. If it's crazy expensive, I'll just do a DIY one myself but I'd thought I'd check with him first. I've had it, it's time to get this shop conditioned to use year round. Thanks again.

 

[drivesitfar]

crazy how the propane company wouldn't have 4 more feet of hose or pull in your driveway. did you call another propane company or is there only one in your area. if the mini split will keep you more comfortable and pay for itself in a few years i'd say comfort is what you're looking for. good luck and hope you get this figured out. just an FYI. my kids built an office (think big shed) about 15 x 20 behind their old house a couple years ago and got talked into an off brand mini split that worked ok for a few months and then needed a repair and unfortunately the brand didn't provide parts and repair guys in their area wouldn't work on it. I can't recall the name and they moved so I don't want to ask to bring it up, but do your research.

good luck!!

 

[PoorUB]

I measured the tank location and I came up with 152' from the street.

That one spot is the only option for a tank? I have had people set tanks 500 feet from their house and run underground poly gas line to the house.
One house I can think of they set the tank on the corner of the property, up but the road and planted a hedge around it. It was a couple hundred feet to the house.

 

[Bbp78]

If I go the propane route, I would move the tank up closer and run a line underground. My neighbor thinks that's the way to go. He is concerned that the mini split isn't designed for my application as I would keep it off when I'm not working out there, which is most of the time. Since I would maybe use the shop on weeknights for a few hours at the most and on the weekends for 4-6 hours a day. He thinks they are designed to keep a temperature within 5 degrees or so and in cold weather it would have difficulty getting the shop warm in a timely manner. He also said the minisplits are more expensive and complicated to service as I would need to get an hvac company out If I have an issue. He said the propane heater is much simpler to work on since I'm not dealing with refrigerant, etc. I need to call more propane companies to get their thoughts on the length I'm at but everything I've seen online says the max hose length is generally 150'. Thanks everyone for your help.