Top positive review
5.0 out of 5 starsAn Amazing, Robust and Powerful Portable Propane Heater; I Use it Daily in an Outdoor Greenhouse Dome Tent Office Space
Reviewed in the United States on October 27, 2013
I have, over the past few years, grown tired of trying to use a small portable electric heater (with two heat settings, rated at 850W and 1500W) to heat an 8.5 x 8.5 foot greenhouse dome tent (the ceiling of this dome tent averages 7' to 8.5 feet in height) that sits in my backyard and has been adapted for use as an outdoor office and meditation room. This outdoor dome tent, which occupies about 72 sq. ft., and about 585 cu. ft. of space, and which has translucent plastic tent walls, sits on the ground, and the floor is a tarp sitting on the ground, covered with some old carpets for a bit of comfort.
This dome tent is entirely uninsulated, and, due to the translucent walls that easily allow heat to escape even in the near-infrared (NIR) and visible light regions of the spectrum, it offers even far less insulation than would a tent structure of the same size/volume that used an opaque material such as green tent fabric. This dome tent is equipped with eight zippered screened windows (four near ground level, and four at a height of 6' above ground) and I always leave each window partially unzippered year-round to allow for the flow of fresh air into the dome tent; this is important at all times anyway for adequate ventilation, but it becomes doubly-important when using a portable combustion heater such as this heater inside a dome tent such as this!
So, as a result of the factors that I have discussed above, this structure has always been somewhat of a challenge to heat using the 1.5 kW electric heater whenever outdoor temperatures have falled significantly below about 55 degrees F, and it has been impossible to get the interior to anywhere near even 70 degrees F when outdoor temperatures have dropped to 50F or below.
So, I finally decided to stop using the portable electric heater and to upgrade to a protable propane heater that was rated and certified as indoor-safe, and that could deliver at least 8,000 to 9,000 BTUs of heat. I finally purchased (via Amazon Marketplace) this Mr. Heater MH9BX portable propane heater, which has heat settings of 4,000 BTU and 9,000 BTU, after careful research into each of the various brands and models of portable propane heaters available on the market. I particularly liked the stable and robust design of this heater, and the fact that it has auto-shutoff for tilting, auto-shutoff for low oxygen levels, and also because of the pilot light and the built-in piezoelectric igniter.
At the same time that I ordered this heater, I also ordered a Mr. Heater 12; propane gas hose, and a Mr. Heater inline propane gas filter for use with it.
When the unit first arrived, I tested it for a week using a 1 lb. propane tank as the propane fuel source, and then, when that first tank had emptied, I installed the propane fuel filter and the 12' hose running to a 20 lb. propane tank outside the dome.
I am extremely pleased with the performance of this heater. It is easy to use, and it produces a lot of heat, far more than my old electric heater did on its high power setting of 1500 W. In fact, I have run tests over the past few days (late October 2013, at an altitude of 1,000 feet in the Appalachian mountains, where we live) in the early morning hours, at about 4 AM (three hours before sunrise), where outdoor temperatures were about 36 degrees F with a 2-4 mph wind, and where the starting interior temperature inside the dome tent was also 36 degrees F. Using this heater on the High heat setting (it is rated at 9,000 BTU at this setting), the interior temperature of the tent was raised to above 70 degrees F within 6-7 minutes from start (this is amazing to me!), and was raised to 82 degrees F within 25 minutes of start; the interior temperature finally stabilized during each test run at about 83 degrees F while the outdoor temperatures were still at 36F.
Given the fact that this dome tent has a lot of interior volume for its floor dimensions, and also because this dome tent has very poor insulation (the average insulation rating for the translucent plastic tent material on the walls and ceiling is less than 0.1 R, and the floor, consisting of a tarp and some old carpets sitting on bare ground, also has about the same terribly poor R rating, and also beause of the fact that I always leave all 8 zippered windows in the dome tent partially cracked, I am amazed that this little heater is able to heat the interior to of this structure, in the middle of the night (therefore there is no incident heat from sunlight entering the structure) from 36F to 83F in a bit over a half hour; this is an increase in interior temperature of 47 degrees F (over outdoor temperature and over interior starting temperature) in a structure that is entirely uninsulated and that loses heat very rapidly! In fact, this is an acid test for a heater such as this, for this is a kindof worst-case test for a portable heater!
My above-cited tests, along with others that I have not enumerated here, show me that this heater, on the High heat setting, should be able to keep the interior temperatures of this totally-uninsulated dome tent at a comfortable level down to outside air temperatures of around 20 degrees F, and should be able to keep the interior temperature at "usable" levels down to outdoor air temperatures of below 10 degrees F/
If I could give this little portable combustion heater an Amazon rating of 7 stars instead of 5 stars, I would do so!
And now, since I am a scientist and an engineer, let me share a few caveats with you about the use of this heater, and of ANY portable propane heater:
Particularly if using this heater indoors, you will want to be absolutely sure to follow the manufacturer's safety recommendations to carefully check all propane gas connections for any possible leaks after installing, and to check them again prior to each use, tightening connections as needed to eliminate even small propane gas leaks.
When you are first starting the stove after having installed a new 1 lb. propane tank directly (i.e,. no hose used) to the heater, bear in mind that the pilot light will not immediately light, and that even when it first lights, it will likely go out (i.e., extinguish) a few times for the first 45 to 60 seconds, because of air present in the internal propane gas line. Thus, you may need to hold the pilot light control down for a few seconds to purge any air present in the propane line before the pilot light will stay lighted. In other words, after having changed tanks, remember to bleed the fuel line by holding the pilot light control down prior to sparking, else you will be "wasting" some sparks!
And, of course, once the pilot light has ignited and stayed lit, it is important to hold down the pilot light control for at least 30 seconds until the internal pilot light safety thermocouple has warmed up sufficiently to allow the pilot light to stay lit.
When you are first starting the stove after having installed a new external propane tank (usually a 20 lb. tank) using propane gas hose (they are available in lengths ranging from 5 ft to 12 ft) remember that ths hose will, at first, also contain a lot of air, and thus you will wish to bear in mind that the pilot light will not immediately light, and that even when it first lights, it will likely go out (i.e., extinguish) repeatedly a few times for the first 60 to 90 seconds because of air present in the internal propane gas line. Thus, you may need to hold the pilot light control down for a bit seconds to purge any air present in the propane line before the pilot light will stay lighted. Once any stray air present in the propane gas line has been cleared, the pilot light will then stay on continually. In other words, after having changed tanks, remember to bleed the fuel line by holding the pilot light control down prior to sparking, else you will be "wasting" some sparks!
Late Update, as of October 27, 2018:
This amazing little heater is still working perfectly! I love it!
