Review on 🔥 MH40NG Mr. Heater F272800 40,000 BTU Multi Natural Gas Garage Heater by Gerardo Cibrian

After installing both units, I found that 1 was quite sufficient to keep my 24' x 30' x 11' storage building warm (about 50 F). Some observations include that an 11' tall roof is almost too low for these heaters, as the recommended clearances are fairly substantial. While these heaters do not require (or provide for) a direct vent, proper ventilation is important - check the Mr Heater web site for ventilation guidelines (400 cfm fresh air per 100,000 BTU, or 160 cubic feet per minute for one of these heaters). Unless your building is very 'leaky', consideration for additional ventilation is needed and likely necessary. This does not add that much to the heater run time.These heaters and their associated thermostat (one came with a thermostat, the other did not - new units should have one) are powered by an built-in thermopile, a group of thermocouples that generate a 650 mV signal as long as the pilot is on. This means that no external electric power is required for the heater or the thermostat, but also means that you can not use just any thermostat with these heaters. Thermostats that use a 650 mV control are available, but many are set up to control larger furnaces and use 12/24V or even 120 V AC, so be careful if you need a new or replacement thermostat. One of my local home improvement stores carried a 650 mV thermostat (both had several as catalog items), but they both had a number of 12/24v DC and 120v AC thermostats in stock. The included thermostat has performed well so far (a couple of months), turning the heater on at the preset temperature and warming the building about 10 F before shutting off.In my application, the heater runs about 30 minutes per hour in really cold circumstances (15-20 F outside, cold for here in Texas anyway). A fan (or 2 - I'm putting in 2 ceiling fans) is a big help in getting the heat distributed throughout the building.Pros: Easy installation, no external electric required, complete w/ thermostat (new units),no direct vent requiredCons: Proper ventilation is required (common sense)