The Rinnai EnergySaver EX08DTN rates 3.4 among direct vent gas wall heaters; the Dyna-Glo BF10NMDG-4 10K Blue Flame rates 1.9 among vent-free ones. The Dyna-Glo BF10NMDG-4 10K Blue Flame costs $1,225.89 less ($175.86 vs $1,401.75).
For a bedroom, office or small addition where steady, quiet, thermostat controlled heat matters more than purchase price. Skip it if you need heat through power outages.
Amazon $1,401.75A small manual heater for one natural gas room, including a bedroom where local code allows vent-free heat. Choose a thermostat model if you want it to hold a set temperature.
Amazon $175.86Prices 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.
These two sit in different venting classes (direct vent and vent-free), and each is scored against the reference points for its own class, so a rating says how well each does among its own venting peers. How we rank explains each factor.
| Factor weight | Rinnai EnergySaver EX08DTN | Dyna-Glo BF10NMDG-4 10K Blue Flame |
|---|---|---|
| Overall rating | 3.4/5 | 1.9/5 |
| Value 30% | 17 $175.22 per 1,000 BTU ($1,401.75, 8,000 BTU) | 25 $17.59 per 1,000 BTU ($175.86, 10,000 BTU) |
| Heat output 15% | 0 8,000 BTU/hr | 0 10,000 BTU/hr |
| Controls 20% | 100 thermostat, blower, electronic ignition | 25 electronic ignition |
| Fuel 5% | 0 natural gas only | 0 natural gas only |
| Warranty 30% | 100 5-year warranty | 0 1-year warranty |
| Rinnai EnergySaver EX08DTN | Dyna-Glo BF10NMDG-4 10K Blue Flame | |
|---|---|---|
| Heat | ||
| Venting | Direct vent | Vent-free |
| Heat type | Furnace | Blue flame |
| Maximum input | 8,000 BTU/hr | 10,000 BTU/hr |
| Minimum input | 3,000 BTU/hr | 5,000 BTU/hr |
| Heating area claim | - | 300 sq ft |
| Efficiency | 82% AFUE | - |
| Fuel and controls | ||
| Fuel | Natural gas | Natural gas |
| Thermostat | Yes | No |
| Blower | Yes | No |
| Ignition | Electronic (120 V) | Electronic (battery) |
| Needs an outlet | Yes | No |
| Oxygen depletion sensor | - | Yes |
| Build | ||
| Weight | 42 lb | - |
| Warranty | 5 years | 1 year |
