3 car garage btu recommendations for heater

[rxvalk]

Looking to install a heater in the garage to work on the bike during the winter. 3 car garage 700 sq ft with 10 inch ceiling. Walls and ceiling insulated.
Contractor recommends electrical due to instillation cost as well as frequency of use (maybe 12-14 times a winter).
Most heater calculators reccomend 20 yo 30 thousand btu. Lows around high teens to 20s most nights.

Is this enough to get it comfortable to work in jeans and a sweatshirt if I turn the heater on an hour or two before I start.

Thanks in advance

[WilliamRS]

here is a btu calculator:

http://www.calculator.net/btu-calculator.html

[Jersey mike]

I think it's best to err on the side of a little bigger is worth the few extra $$ in the long run.

the 10k BTU difference between 20k & 30k BTU your contractor suggests to me getting a 30k+BTU service would be the best decision.

since your garage is insulated, keeping it at 50-55 degrees on a daily basis would not be a big drain on the pocketbook and when you are ready to work in the garage it should only take about 30 minutes or so to warm up to your comfort zone of working in a sweatshirt, say about 60-65 degrees.

[TallRider]

I had a 24 x 30 garage in Ill, heating guy told me about 35,000. Friend had a  reg 2 car garage same size heater ran all the time never shut off never got over 50 deg. I went with 100,000 BTU gas hanging heater.  Could go from 15 deg ice on the floor to 68 in 20 minutes. Problem is if you do not keep it warm a small heater will take a long time to get up to temp with a cold floor. Large heater I had had a large volumn fan blew hot air on floor and warmed everything it hit with air quickly. Cost me 20 to 25 month to keep heat on at 65 deg. My rule is Dbbl or triple what t
hey say. Pool heater here in FL bought the biggest I could get. Same with the boat. Maxed the HP out on the engine. I cruise at half throttle 30 MPH. Everyone else runs full throttle to keep up. Easier on fuel costs. But the best heat is radiant heat for garage. Circulation pump on large water heater. Best heat. I was in I'll over thanksgiving at a large poke bldg 6 x 120 114 ft ceilings with radiant heat in floor. Warmer than your house. But would have had to install when building. Rule of thumb bigger is better. Good luck.

[MarkT]

A temporary soln is get a couple fans and blow house air into the garage.  Assuming it's attached of course.  Have one fan on floor stand, and send the warm air over to the garage door.  Put the other fan on a high stand so it's up near the ceiling to blow the air near the door, out into the garage. (Have not tried a fan in the garage on the floor, to blow the cold garage air into the house - probably work as well. )  2 car garage, it will be low 60's out there in a half hour if the house is at 68 and outside temps around zero. Cheaper to run the house gas furnace than electric heat in the garage.

[The emperor has no clothes]

One of my garages had a setup with the hot water heater having a line to a blower in the garage. It was a pretty simple setup. I'm not sure how efficient it was but it worked good. The water heater was in the garage also so it made it pretty simple.

[Kep]

If you meant 10 ' ceiling ...I come up with 32,000 btu...so I would go with a 40,000 btu..not much more in equipment cost and you will only burn what gas you need to heat the space ...also will not take as long to heat up when you want to do a quick project on short notice. Own my own HVAC business , been in the trade 31 years .

[gordonv]

Where do you live (city or country)?

Your heater provider should be able to tell you the answer to your question.

My brother has a home hot water tank in the garage, and has the water line going through the floor of the garage with a water pump on the heater. A lot cheaper than a proper boiler and such. Keeps it at a high 50' temp, so it doesn't get condensation.

Be careful with heating it from the house, you don't want exhaust fumes coming from the garage to be able to get into the house.

Personally, I would get a little wood stove. My access to a garage is one that is a wood shop. Projects are made, scrape wood is saved till the colder months. The guys hang out there in the winter mostly as a man cave, away from the wives, and drink beer. I would say it is the size of 4 cars. Takes about 1 hour to warm up. Unheated the rest of the time. So it is the radiant cold that keeps things that way.

I would go in first thing in the day, start a nice fire, then come back a few hours later when you want to work.

There is almost always wood somewhere to be had. Scrap pallets. Fallen tress.

[art]

Where do you live (city or country)?

Your heater provider should be able to tell you the answer to your question.

My brother has a home hot water tank in the garage, and has the water line going through the floor of the garage with a water pump on the heater. A lot cheaper than a proper boiler and such. Keeps it at a high 50' temp, so it doesn't get condensation.

Be careful with heating it from the house, you don't want exhaust fumes coming from the garage to be able to get into the house.

Personally, I would get a little wood stove. My access to a garage is one that is a wood shop. Projects are made, scrape wood is saved till the colder months. The guys hang out there in the winter mostly as a man cave, away from the wives, and drink beer. I would say it is the size of 4 cars. Takes about 1 hour to warm up. Unheated the rest of the time. So it is the radiant cold that keeps things that way.

I would go in first thing in the day, start a nice fire, then come back a few hours later when you want to work.

There is almost always wood somewhere to be had. Scrap pallets. Fallen tress.

You bet me to the punch. I was going to say the same thing. A wood stove is very inexpensive and will put out lots of heat and can be used all day for almost nothing. I love the feel of heat from a wood stove.

[cookiedough]

I think it's best to err on the side of a little bigger is worth the few extra $$ in the long run.

the 10k BTU difference between 20k & 30k BTU your contractor suggests to me getting a 30k+BTU service would be the best decision.

since your garage is insulated, keeping it at 50-55 degrees on a daily basis would not be a big drain on the pocketbook and when you are ready to work in the garage it should only take about 30 minutes or so to warm up to your comfort zone of working in a sweatshirt, say about 60-65 degrees.

60-65 degrees needing a sweathshirt???  How about shorts and a t-shirt more like it.  Ya gotta remember NO wind either in the garage out of the elements. 

I'd go bigger is better but get one that is reliable and energy efficient.  If I had the desire or need to keep my 2 car garage heated to work more on stuff than 2-3 hours tops just getting bundled up is all in 20 degree temps,  I would do it, but don't see the need for me anyways in the winter months, but surely would be nicer.

My very rich mansion owner up the street 4 years or so ago asked me to help him out in his 70 degree heated garage when it was 10 degrees outside and blustery.  I was bundled up had to strip down to sweatpants and t-shirt and was still dripping sweat and t-shirt wringing wet sweat hotter than my house set at 66 degrees in the WI winter months. 

[rxvalk]

Thanks for the replies so far guys. I'm in Omaha Nebraska

[PharmBoy]

I have a shop building which has 350 cubic feet more than your garage.  It stays warm and toasty all winter with one NG 30,000 BTU "Mr. Heater" wall mounted heater.  It can be wall mounted or stood up on the floor and has a thermostat on the control which keeps the shop at a constant temperature as soon as you find the proper setting number for the temperature you want. Get the "Radiant Heat" unit instead of the "blue flame" unit.  The blue flame unit will discolor the paint above it if mounted on the wall.  I had two of them installed when I built the building, but only use one since it will more than maintain a 70+ degree temp.  They come in either natural gas or propane units.  Picture is of shop when new, considerably more cluttered 4 years later.

[Alpha Dog]

I am a fan of this method and it is quite cost effective.  That heater is about 200 dollars at a Rural King or Tractor Supply. This heater is vent free and over 99 percent effecient.  You can get the tank and outside hook up for nothing from you local  LPG supplier. Inside hook up is just a few dollars.   Buy your fuel in August as it is the cheapest month.  This year in southern Ohio it was less than a dollar/gallon in August and early Sept.  Of course if you have nat. gas I imagine that is quite cost effective also.
Chuck

[Misfit]

I installed a 45000 BTU Hot Dawg forced air heater in my garage and am very happy with it. 

[chief120865]

Live in Wisconsin, have a three car detached and insulated garage similar in size to yours. I have a 50K BTU natural gas ceiling mounted unit. I keep at 45-50 all winter, runs minimally. I can crank it if I want anytime.  Prefer to keep at a minimal because it gets cold here, and with warm up cycle it does take time to get the ambient heat (especially the floor) warmed up (air temp not a problem). Also, if taking from extreme cold to warm everything will condensate as it warms up. Get the bigger BTU, I had the wall units which worked admirably, but had a hard time keeping up in cold Wisconsin.

[gordonv]

Personally, I would get a little wood stove. My access to a garage is one that is a wood shop. Projects are made, scrape wood is saved till the colder months. The guys hang out there in the winter mostly as a man cave, away from the wives, and drink beer. I would say it is the size of 4 cars. Takes about 1 hour to warm up. Unheated the rest of the time. So it is the radiant cold that keeps things that way.

I would go in first thing in the day, start a nice fire, then come back a few hours later when you want to work.

There is almost always wood somewhere to be had. Scrap pallets. Fallen tress.

You bet me to the punch. I was going to say the same thing. A wood stove is very inexpensive and will put out lots of heat and can be used all day for almost nothing. I love the feel of heat from a wood stove.

I like the smell and sound of a wood fire, even in a heater. The shop uses a wood stove. My brother has a glass door heater, these can also have a electric blower. It is a dry heat, so a pot of water or kettle on the top keeps some moister in the air.

[ptgb]

768 sqft in mine.... close to same climate here in Ohio. I put in a 45,000 btu hanging natural gas heater. Nice and warm.

If you can do natural gas, I would over electric, unless you have your own hydro-dam in the backyard. That's if you are gong to keep it a steady temp all the time.

I keep mine at 50 degrees when not working there, put it up to 60 when out there. For NG furnaces, if you too big, the heater will short-cycle causing it to never get up to a full constant temperature, causing condensation problems in the heater.

[J.Mencalice]

Omaha?  Endless supply of the yellow stuff?  A corn-burning stove is a choice for consideration, sir.
I believe that those made in Canada are of the highest quality.

[The emperor has no clothes]

Where do you live (city or country)?

Your heater provider should be able to tell you the answer to your question.

My brother has a home hot water tank in the garage, and has the water line going through the floor of the garage with a water pump on the heater. A lot cheaper than a proper boiler and such. Keeps it at a high 50' temp, so it doesn't get condensation.

Be careful with heating it from the house, you don't want exhaust fumes coming from the garage to be able to get into the house.

Personally, I would get a little wood stove. My access to a garage is one that is a wood shop. Projects are made, scrape wood is saved till the colder months. The guys hang out there in the winter mostly as a man cave, away from the wives, and drink beer. I would say it is the size of 4 cars. Takes about 1 hour to warm up. Unheated the rest of the time. So it is the radiant cold that keeps things that way.

I would go in first thing in the day, start a nice fire, then come back a few hours later when you want to work.

There is almost always wood somewhere to be had. Scrap pallets. Fallen tress.

You bet me to the punch. I was going to say the same thing. A wood stove is very inexpensive and will put out lots of heat and can be used all day for almost nothing. I love the feel of heat from a wood stove.

Wood stoves are very nostalgic for sure. But I have memories cutting and chopping for DAYS ON END. Getting enough wood to survive Alaska winters is enough to make a 13 year old boy cry. 

[Jess Tolbirt]

with a 10 inch ceiling it shouldnt take much to heat it

[rxvalk]

Thanks guys

Went with the 30,000 btu Natural gas heater. May go higher BTU's later but for now this fit the budget.

Joe

[bscrive]

I have a 26x30 attached garage and I have a 45000btu radiant natural gas tube heater on the ceiling.  I usually keep the garage heated all the time at 16C in the winter.  If I need it warmer it only takes a little while to get it to 20C (70F).  It only costs me about $200 for the winter season to keep the garage nice and toasty.  The great thing about radiant heaters is that they heat up objects and not the air.  When your garage floor is heated it becomes the main heating element in the garage.  I can lay on my garage floor in -40C temps and I am still warm because the slab is warm.  Most other heating systems keeps the air warm about 18" and above but the floor is cold as hell.

[jdp]

Gas is best, I had an electric 240volt hanging on the wall can't remember the BTU but for a well insulated 2 car garage I just went with one of those heaters on top of a propane tank and I can work in jeans and a tee shirt in the winter, just keep an extra tank handy.