Is it worth it to go bigger?

[Schwartzint1]

I believe I have narrowed my search down to a modine hot dawg heater for my garage. I have a 700sqft fully insulated (walls, door and 10' ceilings) garage with epoxy floors. It would be nice to keep it 50-60 degrees when I'm in it, and 40 when I'm not. I believe a 30,000btu would do the job. However the 45k btu is currently $20 or so more. Seems like a no brainer to me. Bigger is always better right? Well I don't know on this kind of thing. First garage heater. Will the 45k btu be much different noise or efficiency wise?

 

[mygarageone]

No bigger is not always better , unless you are drag racing.
I closer your htr is to the heating demand of the structure ,the better it heats.

You want the heater to run ,not come on and off all the time. The longer the run the more comfortable the room is. The longer the unit runs the more even heat you'll have.

It is also hard on the unit controls etc to come on and off all the time.

 

[jdcompman]

I think you're better off with the 30k unit. Right now I have a very similarly sized garage and a 45k heater. For me, I feel the heater cycles too often. As mygarageone said, bigger is not better when it comes to heaters. You're much better off having the heater run longer, than to have it be short cycling.

 

[Schwartzint1]

Awesome. Thanks a lot guys. I had a feeling the bigger is better wouldn't quite apply here.

 

[Coloradotrailrider]

I would think the 45k would have a better recovery time than the 30k after the garage door has been opened and closed. Just one application where bigger could be better. I certainly agree with cycle time though and not having to big of a heater.

 

[Shop Specialties]

It is easier to maintain temp than to go up and down in big swings.
Keep it 50* then bump it up to 60* when needed the 30k will be good. If you want to keep it 40* then bump it 10*-20* then you would better off with the 45K.

 

[wdrumheller]

I have an 800sq ft area that has 12' ceilings and I use an 80,000btu Mr. Heater Bix Maxx and it heats up really quickly. I keep it at 40 until right before I go out to the shop and then turn it to 65, and in about 15 minutes it's at 65.

So, I like the larger unit for the fast heating capability. It doesn't seem to cycle that often once it's up at temperature. So, it's one long cycle until it's at temperature, and then a short cycle now and then to keep things toasty.

I have found that leaving the "fan on" option running while I'm in the shop makes the heat more evenly distributed and more comfortable. It runs the fan all the time whether the heater cycle is activated or not. I think running a box fan near the heater might accomplish the same task.

 

[toyotadriver]

I think you should go with the 45k btu unit. Then, install a thermostat that allows you to have a 2 degree temp swing. For example, you set it at 60 degrees. The heater then comes on at 59 degrees and off at 61 degrees. That will ensure that it runs for a longer time per run.

I have an 80k btu Mr. Heater in a 30x40x10 well insulated shop and it does a good job. Your shop is more than half the size of mine and you live in a cold area. I think in very cold times, your heater will have a slightly hard time keeping up. A 45k btu should do it without a problem. There is only a 15k btu difference there.

 

[regguy1]

For the amount of cubic feet you have to heat the 45K would be the correct size, too big is not ideal but undersized isn't good either. I have a 26' x 30' and the 45K heats it fine, I did several calculations and 45K turned out to be perfect for the space. See it here: http://www.garagejournal.com/forum/showthread.php?t=140674&highlight=26'+30'+Garage+photos+videos

 

[regguy1]

I think you should go with the 45k btu unit. Then, install a thermostat that allows you to have a 2 degree temp swing. For example, you set it at 60 degrees. The heater then comes on at 59 degrees and off at 61 degrees. That will ensure that it runs for a longer time per run.

I have an 80k btu Mr. Heater in a 30x40x10 well insulated shop and it does a good job. Your shop is more than half the size of mine and you live in a cold area. I think in very cold times, your heater will have a slightly hard time keeping up. A 45k btu should do it without a problem. There is only a 15k btu difference there.

+1 here, good advice

 

[mygarageone]

I will say this again, no matter what size the garage is. A heat loss calc will remove any doubt about what size unit you need.
As far. As all this garbage about recovery if a door is opened or heating up the room fast , ignore that advice , it's not how heating systems are designed or sized. Unless you have have a semi loading dock , a much different story but you don't.
As far as a T - Stat with a + or - 1 degree swing which is actually a 2 degree swing , the heat anticipatory will take care of that. Because that's what it's designed for.

 

[Coloradotrailrider]

As far. As all this garbage about recovery if a door is opened or heating up the room fast , ignore that advice

Easy now, it was just offered as a thought not as advise. I'll leave the advise to you now