Heater size

[mcmopar]

Looking for some help in choosing the right size garage heater. I have a pole barn that is 30x32 with 10 foot ceiling, I have enclosed a portion that is 20x32. The walls were studded and R13 faced batts covered by 7/16 OSB, the ceiling has a wooden floor to a loft and I installed R13 to the floor joists below that. There a 4 windows, an entry door and an 9x8 ft overhead door. I have a 115,000 BTU kerosene torpedo heater that I am now using but want to purchase a ceiling hung FA propane unit. I borrowed a friends 30,000 BTU ventless propane unit and ran that from a 30lb tank just to see what it would do, well it ate up the 6.5 gal of propane in short order and did not seem to add much heat to the space. In the calculator it recommends a 45,000 FA unit but I am not sure if that is big enough but I don't want to oversize as it will gobble up propane. I only heat this space for 5 hours a day and when it is 30 degrees outside it starts out at between 45 to 50 inside and I warm it up to 68 to 70. Thanks for listening and any help appreciated.

[dave67fd]

So i assume you only want to heat the enclosed 30x32 (960 sq.ft) area? The 45k unit might be ok but i would up to a 75k unit. If you had the 45k you also don't want it to be running longer than needed as well as too big as it may cycle more.

I would rather be more on the adequate side than the minimal. With a larger heater you may use more gas but typically will be more efficient at heating the space. There's alot of other factors that come into play. I have a 75k in my 1000 sq.ft shop.

[regguy1]

I have a 45K NG heater in my 26'x30' / R13 in walls and ceiling, it heats it very well. You're on the edge between 45K and 75K, Modine Hot Dawg comes in a 60K, you might consider that one. I have the Mr. Heater, it only comes in 45 and 75K

Modine 60K here: http://www.djsonline.com/modineunitheaters.htm
Reznor 60K here: http://www.djsonline.com/reznor_UDAP_Unit_Heaters.htm

You can see the 45K unit in the garage tour video link here:
(first link on top)
http://www.garagejournal.com/forum/s...d.php?t=140674

[mcmopar]

Thanks for the input, I have done some research on the Mr. Heater and the Hot Dawg. The Mr. Heater gets some bad reviews about not working right out of the box and needing new parts, the price is right but I don't want the problems I have read about. The Hot Dawg gets better reviews and seems to be more trouble free. I am on the fence but the difference in price may not be worth the issues with the Mr. Heater.

[Mmfh]

I just did a install on a Mr Heater 75k and the only thing I didn't like was a dent in the top of the cabinet. We decided not to worry about it and installed it anyway.

Works fine, No problems. The heater was put into a 30x40 pole barn and it was quickly decided that this heater wasn't big enough for that area. He bought a used 225k and we are going to see how that does instead.

Mm

[dave67fd]

Remember the 45k and 75k ratings are Input BTU's. The 75k has a 60k BTU Output.

[Terapin]

I have installed a 45k Hot Dawg inside my, as yet, uninsulated 24 x 24 shop space and I have had no problems. It runs quite a while now because of lack of insulation but still does the trick. I had heard that the Mr. Heaters were quite a bit louder and had also heard about problems out of the box. The Hot Dawg fired right up and has performed flawlessly since. I appreciate something a little quieter since I like to listen to music.

[mcmopar]

Thanks for all the input, but I still am uncertain about the size I should get. Dave67fd stated the input vs output and that is something to take into account. Any other feedback is greatly appreciated, and Hot Dawg looks like the one with less issues.

[dave67fd]

Although you may read some bad reviews with the Big Maxx vs the Hot Dawg you have to look at a couple of variables. Many of the older design Big Maxx series heaters did have some control board issues but a large percentage of these failures come from incorrect installations. Being a lower priced heater, more inexperienced do-it-yourselfers purchase them and do inadequate or improper installations. The newer series seem to be much more reliable and haven't heard of any real issues in quite some time.

Also being a lower priced heater increases sales considerably which result in a higher percentage failure rate vs units sold.

I have spoken with many more satisfied owners than unsatisfied ones.

Mr. Heater has i believe recently replaced their gas valves as well. They do have a pretty good customer service dept. and if required will send out any defective part with little to no questions asked.

Trust your gut and purchase as you see fit. I spent close to a year researching the heater i wanted and although price was a big factor i opted for the Big Maxx. Although i still need to run gas and vent, my preliminary electrical and therm start-up test was 100%.

[mcmopar]

Thanks for the info Dave, but how do you know you are getting a newer model of the Mad Maxx and not someones old stock that possibly has issues? When installing the heater what are the issues you refer to that are causing problems? Thanks....

[Mike007]

Based on what you posted, I'd say 45k is more BTU's then you will ever need.

[IONH]

I opted for a 75k BTU Mr Heater as opposed to the 45k. My garage is *mostly* insulated, with the exception of leaks around the two 7x9 doors. Garage total is about 24x32 with a ~8 foot ceiling. Heats up FAST with the 75k BTU heater. Much faster than my older 40k BTU torpedo heater and no smell.

I also used the ~$100 direct horizontal vent kit sold on Amazon for the 75k BTU unit.

[mcmopar]

IOHN, any issues with the big maxx? This continues to get clear as mud, some say 45 is big enough and some say get the 75. Waiting for Dave to let me know the issues with the install and how can I be sure to get the latest issue of the big maxx heater? Thanks..

[IONH]

What issue should I be looking for? I've only used it a couple times so far.

The first time I let it run for about 20 minutes to burn off all its packing oils. Let it cool down fully and fired it up again and it worked great that time to get the garage back up to temp (had the doors open to get the smoke out). Worked fine for another run after that as well.

[Mike007]

Originally Posted by mcmopar

This continues to get clear as mud, some say 45 is big enough and some say get the 75.

Let me put it this way. I have a 24 x 24 detached garage. Based on what you posted, I'd say my BTU loss would be higher then yours. I have maintained 62*F when the outdoor temp was 10*F. And it wasn't running constant. I timed it and it was running roughly 26 minutes out of an hour. Compare that to what you are requiring. My radiant tube heater is 25K BTU's (20K net). You can run either heater you are asking about. The smaller heater will use less fuel and the temperature swing will be less. The ignition system will cycle less as well. The bigger heater will make up faster and cost more. What more do you need to know?

[dave67fd]

Originally Posted by mcmopar

Thanks for the info Dave, but how do you know you are getting a newer model of the Mad Maxx and not someones old stock that possibly has issues? When installing the heater what are the issues you refer to that are causing problems? Thanks....

Well unless you buy from a odd ball unpopular company that has had them sitting for quite some time. These units sell pretty quickly. If you do decide on the BM buy from Northern tool. They usually have the best price. If your not in a hurry they have sales or free shipping on them once or twice a year. The heater has a 1yr manuf. warranty with additional 2yr warranty if you purchase it.

Installing a incorrect thermostat as well as hooking up the correct one incorrectly or possible rough mishandling or physicall damage can cause malfunction.

If the unit is received in good condition, handled with care and properly installed at the get go you most likely won't have any issues.

Read all the Northern reviews for the 75k unit. 4.6 stars out of 5 and 127 recomended reviews out of 132 is a pretty good percentage.

The Modine's, Sterlings and Mr. Heaters are pretty much all the same heater with suttle differences. The Modines and Sterlings have good reputations and have been around along time but you pay for them. They are all good heaters.

http://www.northerntool.com/shop/too...6365_200316365