Hot Dawg 45,000 BTU Natural Gas Garage Ceiling Heater

I think you are asking if the use of B-Vent changes the venting requirements outlined in the installation manual. The answer is no. Assuming B-Vent is what is required by code and the inspector in your area, the venting prodigal certified by ETL would not change.

This version has a single stage gas valve and aluminized heat exchanger as apposed to stainless steel. If you want either of those options or the others that Modine offers, they can be special ordered through a Home Depot store. Chris 978 651 3301

The Modine Hot Dawg is often referred to as a garage heater because that is where it is most often installed. However, it is often the heater of choice in other applications; such as green houses and work shops. As to whether it is best choice for your application I can not tell you because I am not on site and can not speak with authority as to the codes in your state. To get a definitive answer you would need to speak to either a qualified licensed heating professional, in your area or the code enforcement official your town. But let me say this, I think the idea of heating a crawl space to prevent it from acting as a heat sink to the area above makes perfect sense. Heat chases cold. The greater the differential in temperatures the faster this occurs. So by raising the temperature of what is typically a unheated area, can often make the adjoining living space a lot more comfortable. Typically you do not need to get them to the same temperature. Just lowering the temperature difference is enough to greatly increase the comfort in the living space. Often when customers complain about cold bed rooms above a garage, I tell them to heat the garage. They usually ask, Why would i do that? I then tell them you already are, that is why the bedrooms are cold, you are just not doing a good job of it, which is why the bedrooms are cold. If you add the capacity to heat it you most likely won't use significantly more energy, you will just be more comfortable and have greater control.

There are angle brackets that come with it for mounting to the celling.

No, you have to purchase one separately. That's nice because then you can decide for yourself if you want one that's programmable or not.

Multiple options 16 to 24”.

That might be a stretch for a 45k. My 45k is in a 576 sq ft garage, one common wall with house, 8 ft ceiling, some insulation. I think it's just right (Northern Ohio on Lake Erie).

I am unsure what a "roof installation kit" is. So I would say no it doesn't. What comes with this item is just the furnace. All other items such as venting material, thermostat, hangers, pipe, ect. are sold separately. What comes with this unit is outlined in the installation manual. A PDF of which can be found under the header, "info and guides" on the Home Depot product listing page.

Square footage of floor space along with the structure's volume are only two of the factors that go into sizing a furnace. As an example I am sure you could envision its going to be a vastly different heat load if the structure in question is in Alaska than if it were in Florida. The proper way to size a furnace is to do a heat loss calculation. There are plenty of free programs on line for this. I personally use the Slant Fin heat loss calculator that can be down loaded for free at either the Droid or Apple ap store. Once you put the factors into the program. Again dimensions, location, building material, lineal feet of outside wall, the program will calculate the heat loss on the coldest hour of the coldest day of the statistical year. The logic being, if you can replace what the structure will lose on the coldest hour of the coldest day of the year, you can keep it warm. Thus I typically then select an appliance with that figure as an output. The only time I vary from this is with garages. For example the heat loss calculation on my garage came to 45000 BTU's but I installed a 100,000 BTU unit. Why? Because I don't keep my garage heated. I keep it unheated and only turn the heat on when I am doing a project. If I sized the unit to my heat loss, I would not have the extra capacity to raise the temperature quickly on a cold winter day. Sizing it to my heat loss would make sense if I was keeping the structure at a constant temperature but I am not. Instead I want to be a able to bring in a snow covered vehicle and heat it up in a reasonable period of time. If you have further questions you can reach me at 978 651 3301 Chris

If you look under the header "Info and Guides" on the Home Depot product listing page you will find a PDF of the installation instructions. The venting requirements begin on page 6 and run to page 11. The instructions outline the methodology that has been tested and certified by ETL the third party testing agency that Modine uses. No other venting methods are acceptable or approved. Nor are any modifications acceptable. As todays venting requirements tend to vary appliance to appliance, it is my experience that the inspector will typically ask for the instructions and will inspect the installation based on the what is outlined in the certified installation instructions. As the use of 4" is not covered in the instructions it can not be used.