ThermoMate PHF18B 18,000 BTU
#5 in PortableFull review
For ventilated garages, workshops and job sites where a rolling 18,000 BTU cabinet heater beats a tank top. The manual rules out homes, RVs and living quarters.
Amazon $169.99$169.99
The ThermoMate PHF18B 18,000 BTU is the better propane heater overall, rated 3.9 to 3.6. The ThermoMate PHF18B 18,000 BTU leads on turndown and value. The Mr. Heater Little Buddy MH4B wins on warranty and safety. The Mr. Heater Little Buddy MH4B costs $100 less ($69.99 vs $169.99).
Prices were last checked November 11, 2026. Product prices and availability are accurate as of that date and are subject to change; the price and availability shown on Amazon or the retailer's site at the time of purchase apply. As an Amazon Associate we earn from qualifying purchases.
Mr. Heater Little Buddy MH4B
#10 in PortableFull review
For heating a small tent, blind or ice shanty with ventilation, where a light one cylinder heater is all that fits. Follow the maker’s vent rule of at least 4 sq in of fresh air.
Amazon $69.99$69.99
Which should you buy?
- Choose the ThermoMate PHF18B 18,000 BTU for turndown (turns down to 6,000 BTU vs one heat setting) and value ($9.44 per 1,000 BTU ($169.99, 18,000 BTU) vs $18.42 per 1,000 BTU ($69.99, 3,800 BTU)).
- Choose the Mr. Heater Little Buddy MH4B for warranty (3-year warranty vs 1-year warranty) and safety (CSA listed, low-oxygen shutoff, tip-over shutoff, flame-out shutoff vs CSA listed, low-oxygen shutoff, tip-over shutoff).
Scores side by side
Each factor is scored 0-100 against the same fixed reference points for every portable propane heater; a clear win is highlighted. How we rank explains each one.
| Factor weight | ThermoMate PHF18B 18,000 BTU | Mr. Heater Little Buddy MH4B |
|---|---|---|
| Overall rating | 3.9/5 | 3.6/5 |
| Value 25% | 54 $9.44 per 1,000 BTU ($169.99, 18,000 BTU) | 6 $18.42 per 1,000 BTU ($69.99, 3,800 BTU) |
| Safety 30% | 90 CSA listed, low-oxygen shutoff, tip-over shutoff | 100 CSA listed, low-oxygen shutoff, tip-over shutoff, flame-out shutoff |
| Warranty 15% | 0 1-year warranty | 100 3-year warranty |
| Turndown 15% | 95 turns down to 6,000 BTU | 0 one heat setting |
| Ignition 10% | 100 push-button piezo ignition | 100 push-button piezo ignition |
| Fuel options 5% | 50 runs on a bulk tank only | 50 runs on 1 lb cylinders only |
Independent measurements
ThermoMate PHF18B 18,000 BTU
No independent test published yet.
Mr. Heater Little Buddy MH4B
| Tested by | Heat output | Noise | Run time | Conditions |
|---|---|---|---|---|
| Full Moon Adventure Club (YouTube) | - | - | 6.8 h | One 1 lb propane cylinder, run until empty in a 200 sq ft room and timed by time lapse. The reviewer reports 6 hours and 48 minutes of heating. |
Specifications
| ThermoMate PHF18B 18,000 BTU | Mr. Heater Little Buddy MH4B | |
|---|---|---|
| Heating | ||
| Heat output | 6,000 to 18,000 BTU | 3,800 BTU |
| Type | Portable | Portable |
| Use | Job sites and garages | Indoor (ventilated) |
| Heats up to | 450 sq ft | 95 sq ft |
| Thermostat | No | No |
| Fan | No | No |
| Fuel and power | ||
| Fuel | Bulk tank | 1 lb cylinder |
| Hose included | Yes | No |
| Ignition | Push-button piezo | Push-button piezo |
| Power needed | None | None |
| Safety | ||
| Safety listing | CSA | CSA |
| Low-oxygen shutoff | Yes | Yes |
| Tip-over shutoff | Yes | Yes |
| Flame-out shutoff | - | Yes |
| Build | ||
| Noise | 32 dB | - |
| Dimensions | 15 x 11.3 x 21.7 in | 12 x 9.75 x 10.2 in |
| Weight | 14.6 lb | 5.8 lb |
| Warranty | 1 year | 3 years |
| Released | - | 2010-01-13 |