If listed. These heaters have been tested & approved by the AGA( American Gas Association) similar to UL . They are also approved by the IFGC as a back up heat source only. Some states/ cities may not allow them for use at all. I've been in the business for 25 yrs & have installed many of these heaters with ODS pilot. Haven't had any of my customers die from 1 yet From time to time the odor may be stronger than others. Never can tell when someone will add too much odorant to the gas
Been piddling in HVAC field for the last 17 years.
I needed to replace my first floor system and couldn't justify the money for a two stage variable speed 95% gas furnace for back up heat only on the first floor (and that was at my cost). Also couldn't justify the cost of a wood fireplace insert for back up heat. Went with a 14 SEER variable speed heat pump and used a vent free fireplace insert and absolutely love it with no problems. Best bang for the buck money I spent for heating. I have another system upstairs and another one downstairs, and both ECM fans move the warm air from the vent free fireplace very well. Run the gas logs for a couple of hours in the morning to bring up the heat, then let the heat pumps take over. Usually use the fireplace for no more than three months out of the year. Again, no complaints.
Forgot to mention, that ventless heater was the first one I ever put in because I really never thought that highly of them in the past. Figure there is no better advertisment than having something in your own home. I now have no qualms reccomending one.
Also knew of a licenced plumber who installed a water heater in his own home and killed himself due to the venting. Point being there are many small things that can get you.
I've got six various gas dectectors in the house.
Sure beats running the heat pumps..........
Depending on how much you're paying for electric, the heat pumps could be much cheaper to run (less electric strip heat). Complaint on heat pumps from people use to gas or oil is the air discharge temp from the registers. On average, with a properly installed duct system with R22, your discharge temp will be under 98 degrees, less than your body temp, so the air actually feels "cool" even though you can/could maintain 72 degrees no problem.
However, with a proper ducted system using R410A, your average discharge temps will run over 98.6 degrees (warmer than your body temp) thus the air will feel warmer coming out of the registers.
General rule of thumb out in the field dealing with homeowners is that if the customer is over 60 years old and has an oil furance or gas furance, worst case is duel fuel the system (running gas/oil with heat pump) but do not put in a heat pump only because you WILL get a call to come back out telling you that the system is not heating properly even though the t-stat is set for 74 and guess what, using three different thermometers, it is actually 74 degrees in the house, but it still feels "cold"