Shop Heater Size

[MarkOPKS]

Long time browser here but finally starting our shop project next week or so.

We are building a 30x36x10 post frame building with an insulated roof and full air/vapor wrap. 2 windows, 2 walk doors, an 18x8' garage door and a 10x8' garage door both insulated. I'm looking at electric heaters since our rate is .074/kwh and I'm not exactly into the option of running gas from the house over to the shop (gas service is on opposite side of house). This would be heated just on an as-needed basis while I'm farting around out there and probably not run constantly since I can keep temp-sensitive materials in our 1 car attached and insulated garage. We are going to have electric run to the building but will not have enough power for a 240 outlet.

My gut sends me to a box-style wall or ceiling mounted 110/120v setup and a sweatshirt. Am I missing anything obvious here that would be a better option?

Thank you!

 

[mike93lx]

Unless it is portable and sitting next to you, 120v is a waste of time.

Seems silly to build something that big and run such basic electrical

 

[finn]

Might work if you live in Florida.

Wouldn’t work here, though.

 

[MarkOPKS]

Good to know. I called the power company to see if they can pull more service from the street and upgrade our house from 1950 so will be curious to see what that runs. Thank you!

 

[mike93lx]

Good to know. I called the power company to see if they can pull more service from the street and upgrade our house from 1950 so will be curious to see what that runs. Thank you!

Why do you need a service upgrade? What is the current feed and loads?

Unless you are rocking 60a service and all electric appliances, or have a huge particular load, you likely have enough overhead for a 30a 240v circuit.

 

[3rdgendslmech]

Why do you need a service upgrade? What is the current feed and loads?

Unless you are rocking 60a service and all electric appliances, or have a huge particular load, you likely have enough overhead for a 30a 240v circuit.

Shop that size and trying to heat it you'll probably need at least 60 amps. A single 5000w heater pulls about 21 amps. You'll need either 2 of those (2-30 amp) or a single 7500 watt which takes a 40 amp breaker.
If you can, go for at least 100 amp service. You'll have enough to run those heaters and have some left over for lights, and some tools to tinker around with

 

[MarkOPKS]

Right now our whole property is on 100 amp service (built in 1950 and never upgraded). Our power company may eat the cost of an upgrade since we would be using more power but they have to come out to evaluate and we wanted to move forward with the shop without relying on them.

I'm not sure our current load, but we don't have enough wiggle room to run the house and a 240v according to the electrician. We are planning on a 50a sub panel in the shop for now. For example when we were still running our AC a few months ago, the lights in the house would dim for a second when the AC kicked on. Part of our goal if we do upgrade is to have plenty of power for at least a couple 240v in addition to our dryer. Plans are to get a camper one day which would be nice to be able to plug in.

If we upgrade the house to 200a, I'd take the current 100a panel and put it in the shop.

 

[Jackfre]

You may want to consider the type of service you are getting. Overhead is mentioned, but as this is new, I would suggest that you think about running your service underground. By considering the advantages of doing so you may also be able to put a gas line, with proper separation, into the same trench.
As far as how much heater you need...it is exceedingly difficult to gauge. Do you live in Miami or Minot?

 

[MarkOPKS]

The house service is overhead from the street, but we're running the service to the shop from our current panel underground. They're going to do an oversize conduit and leave a pull string in it for if/when we upgrade.

I'm in KS so our winters can be pretty cold but not MN or WI cold. If it's above 50 or 55 degrees I'm good.

 

[3rdgendslmech]

What about oil heat? I haven't been around one in a while but I seem to recall the 2 we had in our old shop ran off of a 20amp 120volt circuit. If you aren't leaving it on all the time I don't think the cost of heatin oil will be too costly. Plus they heat an area faster.

 

[Blazinzuk]

I have a 30x40 shop 12.5' ceilings.

I have r24 in the walls, a combination of 1" foam board, and R19 fiberglass Batts. No windows. A single man door and 2 12'x12' garage doors. Also r49 in the attic

Currently I have a 1500 w heater out there. It has kept it above freezing. But any colder than about 10 and it's not comfy.

I plan on getting a 5000 watt electric heater as a backup to my waste oil heater. Which is not yet working due to me needing to build the chimney for it. So the electric heater is gonna happen soon. I expect that 5000 watt heater to keep it from freezing. But I really doubt when it is in single digits or below zero it will keep it comfy. I think 2 of them would though.

Oh get ceiling fans. Has made a huge difference in my shop

 

[mike93lx]

Right now our whole property is on 100 amp service (built in 1950 and never upgraded). Our power company may eat the cost of an upgrade since we would be using more power but they have to come out to evaluate and we wanted to move forward with the shop without relying on them.

I'm not sure our current load, but we don't have enough wiggle room to run the house and a 240v according to the electrician. We are planning on a 50a sub panel in the shop for now. For example when we were still running our AC a few months ago, the lights in the house would dim for a second when the AC kicked on. Part of our goal if we do upgrade is to have plenty of power for at least a couple 240v in addition to our dryer. Plans are to get a camper one day which would be nice to be able to plug in.

If we upgrade the house to 200a, I'd take the current 100a panel and put it in the shop.

the power company will not pay for a service upgrade. All they own is the wire to your house and the meter. More than likely, if you "upgrade" to 200a, they won't actually change anything. it will be on you to replace the feeder from the overhead through to your panel as well as the panel itself.

unless you have a bunch of high demand electric appliances, 100A may be fine for both the house and a shop.

it may be worth talking to the power company about the dimming, as they may be able to check the voltage drop to see if a bigger overhead or transformer are justified.

 

[nomadskidoo]

When you run a trenched line,run a Cat 5 wire for www&TV,maybe even a water line,if ever needed there there.

 

[MarkOPKS]

Thanks for the good tips everyone. I know the power company won't upgrade us to 200a, but our meter and line from the street are both really old which is what I was hoping to get upgraded. I like the Cat5, water line, and ceiling fan ideas for sure.

 

[mike93lx]

one other item to note, is that unless the 100a panel in the house is almost brand new, I would not repurpose it. a 100A main breaker panel is about $70, sometimes a little more to include a bunch of new breakers. IMO, it isn't worth reusing old gear to save that kind of money on a project that is so long lasting.

 

[bowhuntr311]

I would definitely research another fuel source heater. A modine style heater with a 110fan on it will be alot more electrical friendly than an electric heater. You could run a 100lb LP cylinder and hardline it to the outside it wouldnt be in your way.