Dyna-Glo BFSS30NGT-4N 30K Blue Flame
#8 in Vent-freeFull review
A thermostat blue flame heater for a large natural gas room or garage. It works well, but the Mr. Heater dual fuel 30K has a longer warranty for little more.
Amazon $253.51$253.51
The Dyna-Glo BFSS30NGT-4N 30K Blue Flame is the better gas wall heater overall, rated 3.3 to 2.6. The Dyna-Glo BFSS30NGT-4N 30K Blue Flame leads on controls, heat output and value. The Dyna-Glo BF20NMDG-4 20K Blue Flame costs $42.82 less ($210.69 vs $253.51).
Dyna-Glo BF20NMDG-4 20K Blue Flame
#13 in Vent-freeFull review
A plain manual blue flame heater for a natural gas living room or den. Most buyers will get more for the money from a thermostat model.
Amazon $210.69$210.69
Prices were last checked November 2, 2026 and are subject to change; the price and availability shown by the retailer at the time of purchase apply.
Which should you buy?
- Choose the Dyna-Glo BFSS30NGT-4N 30K Blue Flame for controls (thermostat, electronic ignition vs electronic ignition), heat output (30,000 BTU/hr vs 20,000 BTU/hr) and value ($8.45 per 1,000 BTU ($253.51, 30,000 BTU) vs $10.53 per 1,000 BTU ($210.69, 20,000 BTU)).
Scores side by side
Each factor is scored 0-100 against the same fixed reference points for every vent-free gas wall heater; a clear win is highlighted. How we rank explains each one.
| Factor weight | Dyna-Glo BFSS30NGT-4N 30K Blue Flame | Dyna-Glo BF20NMDG-4 20K Blue Flame |
|---|---|---|
| Overall rating | 3.3/5 | 2.6/5 |
| Value 30% | 76 $8.45 per 1,000 BTU ($253.51, 30,000 BTU) | 61 $10.53 per 1,000 BTU ($210.69, 20,000 BTU) |
| Heat output 15% | 100 30,000 BTU/hr | 50 20,000 BTU/hr |
| Controls 20% | 75 thermostat, electronic ignition | 25 electronic ignition |
| Fuel 5% | 0 natural gas only | 0 natural gas only |
| Warranty 30% | 0 1-year warranty | 0 1-year warranty |
Specifications
| Dyna-Glo BFSS30NGT-4N 30K Blue Flame | Dyna-Glo BF20NMDG-4 20K Blue Flame | |
|---|---|---|
| Heat | ||
| Venting | Vent-free | Vent-free |
| Heat type | Blue flame | Blue flame |
| Maximum input | 30,000 BTU/hr | 20,000 BTU/hr |
| Minimum input | 15,000 BTU/hr | 10,000 BTU/hr |
| Heating area claim | 1,000 sq ft | 700 sq ft |
| Fuel and controls | ||
| Fuel | Natural gas | Natural gas |
| Thermostat | Yes | No |
| Blower | No | No |
| Ignition | Electronic (battery) | Electronic (battery) |
| Needs an outlet | No | No |
| Oxygen depletion sensor | Yes | Yes |
| Build | ||
| Warranty | 1 year | 1 year |