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 3.3. The ThermoMate PHF18B 18,000 BTU leads on turndown and safety. The Heatstar HS35LP 35,000 BTU wins on value. The ThermoMate PHF18B 18,000 BTU costs $23 less ($169.99 vs $192.99).
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.
Heatstar HS35LP 35,000 BTU
#13 in PortableFull review
For contractors heating buildings under construction or large ventilated work bays. The maker rules out homes and RVs.
Amazon $192.99$192.99
Which should you buy?
- Choose the ThermoMate PHF18B 18,000 BTU for turndown (turns down to 6,000 BTU vs one heat setting) and safety (CSA listed, low-oxygen shutoff, tip-over shutoff vs tip-over shutoff, flame-out shutoff; no safety listing published).
- Choose the Heatstar HS35LP 35,000 BTU for value ($5.51 per 1,000 BTU ($192.99, 35,000 BTU) vs $9.44 per 1,000 BTU ($169.99, 18,000 BTU)).
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 | Heatstar HS35LP 35,000 BTU |
|---|---|---|
| Overall rating | 3.9/5 | 3.3/5 |
| Value 25% | 54 $9.44 per 1,000 BTU ($169.99, 18,000 BTU) | 93 $5.51 per 1,000 BTU ($192.99, 35,000 BTU) |
| Safety 30% | 90 CSA listed, low-oxygen shutoff, tip-over shutoff | 50 tip-over shutoff, flame-out shutoff; no safety listing published |
| Warranty 15% | 0 1-year warranty | 0 1-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 a bulk tank only |
Specifications
| ThermoMate PHF18B 18,000 BTU | Heatstar HS35LP 35,000 BTU | |
|---|---|---|
| Heating | ||
| Heat output | 6,000 to 18,000 BTU | 35,000 BTU |
| Type | Portable | Portable |
| Use | Job sites and garages | Job sites and garages |
| Heats up to | 450 sq ft | 800 sq ft |
| Thermostat | No | No |
| Fan | No | No |
| Fuel and power | ||
| Fuel | Bulk tank | Bulk tank |
| Hose included | Yes | Yes |
| Ignition | Push-button piezo | Push-button piezo |
| Power needed | None | None |
| Safety | ||
| Safety listing | CSA | None published |
| Low-oxygen shutoff | Yes | - |
| Tip-over shutoff | Yes | Yes |
| Flame-out shutoff | - | Yes |
| Build | ||
| Noise | 32 dB | - |
| Dimensions | 15 x 11.3 x 21.7 in | 10.24 x 12.4 x 34.25 in |
| Weight | 14.6 lb | - |
| Warranty | 1 year | 1 year |