Mr. Heater 30K Blue Flame Dual Fuel
#1 in Vent-freeFull review
The pick for heating a big room on either fuel with a thermostat and a long warranty. Add the blower kit for high ceilings.
Amazon $265.39$265.39
The Mr. Heater 30K Blue Flame Dual Fuel rates 4.5 among vent-free gas wall heaters; the Williams 3003822 Direct Vent Furnace rates 2.7 among direct vent ones. The Mr. Heater 30K Blue Flame Dual Fuel costs $1,024.61 less ($265.39 vs $1,290).
Williams 3003822 Direct Vent Furnace
#11 in Direct ventFull review
A strong value pick for heating a small home or cabin on natural gas with no power needed. Add the wall thermostat for automatic control.
HVACDirect $1,290$1,290
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.
Scores side by side
These two sit in different venting classes (vent-free and direct vent), 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 | Mr. Heater 30K Blue Flame Dual Fuel | Williams 3003822 Direct Vent Furnace |
|---|---|---|
| Overall rating | 4.5/5 | 2.7/5 |
| Value 30% | 73 $8.85 per 1,000 BTU ($265.39, 30,000 BTU) | 83 $43 per 1,000 BTU ($1,290, 30,000 BTU) |
| Heat output 15% | 100 30,000 BTU/hr | 67 30,000 BTU/hr |
| Controls 20% | 75 thermostat, electronic ignition | 0 manual control, push button ignition |
| Fuel 5% | 100 runs on propane or natural gas | 0 natural gas only |
| Warranty 30% | 100 5-year warranty | 0 1-year warranty |
Specifications
| Mr. Heater 30K Blue Flame Dual Fuel | Williams 3003822 Direct Vent Furnace | |
|---|---|---|
| Heat | ||
| Venting | Vent-free | Direct vent |
| Heat type | Blue flame | Furnace |
| Maximum input | 30,000 BTU/hr | 30,000 BTU/hr |
| Heating area claim | 1,000 sq ft | - |
| Efficiency | - | 66% AFUE |
| Fuel and controls | ||
| Fuel | Dual fuel | Natural gas |
| Thermostat | Yes | No |
| Blower | No | No |
| Ignition | Electronic (battery) | Push button |
| Needs an outlet | No | No |
| Oxygen depletion sensor | Yes | - |
| Build | ||
| Warranty | 5 years | 1 year |
| Released | 2018-10 | - |