Thanks David. Being precise and listing every point and sub point is tricky. English was my worst subject in school, I'm better at building bathrooms than building paragraphs. I work harder posting more information but like you mentioned everyone needs to dig deeper, find all the questions that need answering and then go about finding the correct answers and then confirming the source of the answer. I have spoken with my supplier and received info back from them direct, I then worked out my own math to confirm and then double check the Heat Loss table. We adjust the cable spacing only a little to try and fudge out dips and valleys. And never bring the cable in closer than spec'd. Again, I'll post my math and equations with as much detail as I can provide so people can understand the process I use to work out these calculations. I build stuff every day, I read and hone my skills everyday and I work with pros everyday. I have learned a lot and which each new project there is always the "X" factor. Your gut can tell you when something just doesn't look right and inspectors should be shown what your doing and not left out of the loop. We have a great group of men and women checking our projects here in Vancouver, get to know your local inspectors - it's worth it. My building inspector left my home raving about it yesterday - he went on to say it should be entered in a contest and hopes he gets to come back for the final so he can see my home completed. These are not monsters or people to avoid- they are your last double check on your project and honestly speaking you should be the last check on any project. It's your project - don't trust anyones opinion as fact. Work it out yourself or spend your time finding the right contractor. There are many guys out there who know what their doing, take out permits and do the job right. That said they seem to be the minority...

When I read the instructions for this heater, it says "cannot be used with a double-pole thermostat". Then it proceeds to tell you how to hook it up with a single pole external thermostat if you don't want to use the built-in one. You'll either need a different thermostat or a different heater, or use the built-in thermostat.

You can be sure it's less safe. The floors and exterior walls of basements are often impermeable concrete or masonry and any leaked propane remains and accumulates. Upper parts of a basement are typically wood structures and generally are not airtight so that any lighter than air gas can escape. There are often "crawlspace" sections and even vents. At worst, natural gas can escape up through the stairway and dissipate into the rest of the structure (or to the outside if that's where the stairway goes) so that no explosion danger is present. All the same, natural gas doesn't remain as a pool of flammable gas in the basement as propane does. As an aside, explosions are a risk on recreational boats and are not uncommon. The volatile vapor of gasoline is also heavier than air like propane. There's a risk of explosion because of the possibility of gas vapor collecting in the bottom of the hull. Larger boats with inboard gasoline engines have "sparkless" exhaust fans in the bilges that are turned on and run for several minutes before starting an engine, to remove gasoline vapors that can cause an explosion when the engine is started. For the same reason, in recreational size power and sail boats, compressed natural gas or (historically) alcohol are preferred for cooking appliances. I had a 35 foot sailboat some years ago and it had an alcohol range and oven, they're now less common. Boats that use propane have venting systems for the risk of vapor in the hull. It's also a reason that even smallish sailboats often have diesel engines, because diesel fuel vapor doesn't present an explosion risk as gasoline vapor does.

For this situation, in-floor electric will be much better. Its also a real plus in a bathroom where you are usually walking with bare feet. Just remember that in-floor heat only runs at a low temperature, so it will not feel as hot as your forced air or hydronic heat system (radiators or baseboard hot water). Running it at hotter temps would not feel good on the feet. Bruce