Best for
Buyers who want a purpose-built, IPX4-rated heater for less than the Bio Green Palma, or who need 3000 W of output on 240 V for a 12x16 twin-wall house.
#18 in the buying orderHeatingBuy when needed
Dr. Infrared DR-218 Greenhouse Heater
The cheapest splash-rated greenhouse heater with a 3000 W option, if you have a 240 V, 20 A circuit and can live with specifications the maker does not publish.
- Current price
- $119.99 for 1500 W, $129.99 for 3000 W at drheaterusa.com
- Checked September 20, 2026
- Review type
- Independent desk review
- Not a physical product test
Skip if
You need a published BTU rating, thermostat range or warranty term before you buy. Dr. Infrared prints none of them on the product page, and its warranty page returned an error when checked.
Hidden cost
A 240 V circuit for the 3000 W model, and the risk of buying without a published warranty term. Running cost is about 27.5 cents per hour at 1500 W and 55 cents at 3000 W at the June 2026 US residential rate.
Why it made the list
The buyer case
IPX4 splash protection, an adjustable thermostat with over-heat protection, and a 3000 W, 240 V variant for $10 more than the 1500 W model, which by conversion is about 10,200 BTU per hour.
Compatibility comes first
1500 W runs on 120 V. 3000 W requires a 240 V, 20 A circuit per the manufacturer. The BTU figures on this page are our conversion at 3,412 BTU per kW, not a published rating.
Installation boundary
Same rules as any greenhouse heater: low, clear of spray, on a GFCI-protected circuit sized to the amperage, with a remote thermometer at the far end.
Our verdict
A defensible value pick for a dry, well-managed house, and the cheapest route to 3000 W. If you want the specifications in writing, pay the extra for the Bio Green units.
Primary sources
Product facts come from these direct sources. They are kept separate from the purchase button, and none is rewritten through an affiliate redirect.
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Canopia Portable Greenhouse Fan Heater 1500W NA
Check a current US distributor
A purpose-built 1500W fan heater is a better fit than an exposed household space heater, but the greenhouse heat-loss math still decides whether it is enough.
- Best for
- Small North American greenhouses needing frost protection on a correctly sized circuit.
- Skip if
- Your heat-loss calculation exceeds the output, the greenhouse has no safe GFCI-protected supply, or you expect a 1500W heater to hold warm-growing temperatures through severe cold.
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Bootstrap Farmer 24V Greenhouse Thermostat
$115.99
This is a proper 24V climate-system thermostat, not a universal plug-in controller for any heater or fan.
- Best for
- A greenhouse heating or cooling system designed for 24V thermostat control.
- Skip if
- You are trying to plug a normal 120V appliance directly into it. That is not what this thermostat is for.
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Bio Green Palma 1500W Greenhouse Heater
$149.99 at biogreen-products.com
The default heater for a 6x8 to 8x12 twin-wall greenhouse: 5,120 BTU, a real thermostat, IPX4 splash protection and a two-year warranty on a standard outlet.
- Best for
- Owners of a 6x8 to 8x12 greenhouse who need frost protection or a modest overnight hold on a single GFCI-protected 120 V circuit.
- Skip if
- Your heat-loss math needs more than about 5,000 BTU per hour, you have single glass in a cold climate, or you cannot give it a GFCI-protected outlet of its own.