Mr. Heater Big Maxx MHU80
#1 in GasFull review
A good value gas heater for a big garage or a small shop. Add a thermostat and the vent kit to the budget.
Amazon $545.19$545.19
The Mr. Heater Big Maxx MHU80 is the better garage heater overall, rated 3.6 to 2.5. The Mr. Heater Big Maxx MHU80 leads on warranty. The Mr. Heater Big Maxx MHU80 costs $417.81 less ($545.19 vs $963).
Modine Hot Dawg HD45
#10 in GasFull review
A proven two car garage heater from a commercial heating maker. Cheaper options give similar heat.
Amazon $963$963
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.
Which should you buy?
- Choose the Mr. Heater Big Maxx MHU80 for warranty (3-year warranty vs 2-year warranty).
Scores side by side
Each factor is scored 0-100 against the same fixed reference points for every gas garage heater; a clear win is highlighted. How we rank explains each one.
| Factor weight | Mr. Heater Big Maxx MHU80 | Modine Hot Dawg HD45 |
|---|---|---|
| Overall rating | 3.6/5 | 2.5/5 |
| Value 40% | 83 $8.52 per 1,000 BTU ($545.19, 64,000 BTU/h), output modeled from 80,000 BTU/h input at 80% | 28 $25.78 per 1,000 BTU ($963, 37,350 BTU/h) |
| Controls 25% | 40 electronic ignition | 40 electronic ignition |
| Warranty 35% | 50 3-year warranty | 25 2-year warranty |
Specifications
| Mr. Heater Big Maxx MHU80 | Modine Hot Dawg HD45 | |
|---|---|---|
| Heat | ||
| Heat output | 64,000 BTU/h | 37,350 BTU/h |
| Gas | Both | Both |
| Efficiency | 80% | 83% |
| Venting | Power vented | Power vented |
| Rated garage | 2,667 sq ft | - |
| Controls and build | ||
| Thermostat | No | No |
| Remote or app | No | No |
| Electronic ignition | Yes | Yes |
| Weight | 88.5 lb | 72 lb |
| Warranty | 3 years | 2 years |