Mr. Heater 20K Radiant Dual Fuel
#5 in Vent-freeFull review
A radiant heater for a drafty room, shop or cabin up to about 700 sq ft on either fuel. Radiant heat suits spaces where warm air escapes.
Amazon $209$209
3.4/5
A thermostat infrared heater for a large natural gas room, basement or garage. It offers a longer warranty than most budget rivals.
- 30,000 BTU/hrOutput
- Natural gasFuel
- InfraredHeat
- YesThermostat
Check price at Amazon$257.67
Price checked November 2, 2026. As an Amazon Associate we earn from qualifying purchases.
Pros
- Five ceramic plaques give radiant heat that warms people and objects directly
- Thermostat cycles the burner to hold a set temperature
- Runs with no power, so it heats through outages
- Two year warranty, longer than ProCom or Dyna-Glo give
Cons
- Natural gas only, with no propane conversion
- The manual allows only its smaller KWP210 and KWN209 series in bedrooms or bathrooms, not this one
- Floor stand and blower cost extra
- Sold on Amazon by a third party seller
How it scores
The rating comes from 5 measured or published factors, each scored 0-100 against fixed reference points for its venting. How we rank explains each one.
Specifications
| Model number | KWN523 |
|---|---|
| Heat | |
| Venting | Vent-free |
| Heat type | Infrared |
| Maximum input | 30,000 BTU/hr |
| Heating area claim | 1,000 sq ft |
| Fuel and controls | |
| Fuel | Natural gas |
| Thermostat | Yes |
| Blower | No |
| Ignition | Push button |
| Needs an outlet | No |
| Oxygen depletion sensor | Yes |
| Build | |
| Warranty | 2 years |
| Released | 2016-07 |
Alternatives in this venting
Heatstar HSSVFRD20NGBT 20K Radiant
#6 in Vent-freeFull review
A natural gas radiant heater for a mid size room or workshop that comes complete with blower and thermostat. Pay the premium if you would otherwise buy a fan kit.
Amazon $259.99$259.99
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
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