Bio Green Palma 1500 W Review: The Default Greenhouse Heater

5,100 BTU, two stages, IPX4, a digital thermostat and a standard 120 V plug.

Best for Most Greenhouses

Bio Green Palma 1500 W Greenhouse Heater and Fan with Digital Thermostat

~$161

A purpose-built greenhouse fan heater with 750 W and 1500 W stages, a digital thermostat, IPX4 splash protection and a summer air-circulation mode.

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Specifications

Output	1500 W, 5,100 BTU per hour
Stages	Two separately adjustable elements, 750 W or 1500 W
Coverage	Manufacturer states rooms to 120 sq ft at about 6.6 ft average height
Thermostat	Digital, range given as 32 F to 185 F
Circulation	5,800 cu ft per hour, fan-only mode available
Protection	IPX4, splash proof

Specifications above come from Bio Green's published specifications for this model. Treat pricing as approximate, since Amazon pricing moves.

What it does well

IPX4 splash protection is the specification that separates a greenhouse heater from a garage heater. You water overhead in a greenhouse, and a heater that is not rated for that is a hazard rather than a bargain.
Two stages at 750 W and 1500 W matter more than the headline output. A single-stage heater in mild weather cycles hard and swings the temperature; a half-power stage holds a steadier minimum.
The thermostat is digital and set in degrees rather than by a numbered dial, so you can hold 41 F rather than guessing at a position that might be holding 55 F and costing you double.
The fan-only mode keeps the unit useful all summer. Air movement is the cheapest fungal disease control in a greenhouse, and 5,800 cu ft per hour turns over a small house repeatedly.
It runs on a standard 120 V outlet, which is the entire reason it fits most domestic greenhouses where the 240 V Phoenix does not.

Where it falls short

5,100 BTU is not a lot of heat. Bio Green's 120 sq ft rating assumes a reasonably sealed structure and a modest lift, and a single-skin house in a hard frost will beat it.
It heats air, and air is what leaks. In a draughty house you will spend more on electricity than the price of the insulation that would have fixed it.
The thermostat sensor is in the unit, sitting in its own warm air stream, which is not where the crop is. For precise control you want a sensor at plant height, which means an external controller.
A fan heater dries the air it moves, and dry air near a heater plus cold wet air at the far end of the house is exactly the gradient that condenses water onto leaves.
There is no frost-only setting distinct from the thermostat, so the difference between holding 36 F and holding 50 F is a setpoint you have to get right and a large difference in your bill.

What owners report

The Palma is the unit most often recommended by growers who have owned several greenhouse heaters, and the reasons in owner reports are consistent: it is built for the environment, the thermostat holds a setpoint, and it does not fail the way an unrated workshop heater does after a season of humidity. Nobody describes it as powerful, because it is not. It is a correctly sized appliance for a domestic greenhouse. Our best greenhouse heaters roundup sets it against the larger and smaller options.

The commonest disappointment is a sizing error rather than a product fault. Growers buy 1500 W for a house that needs more, then conclude the heater is weak. Before buying anything, run the structure through the glazing heat loss calculator and the heater BTU calculator, and read the insulating a greenhouse guide first. Bubble insulation and sealed draughts routinely change the required output by a bigger margin than the gap between this heater and the next one up.

Third, the target temperature is where the money is. Holding a house at 50 F rather than just above freezing can double or more the energy used across a winter, and most crops people overwinter do not need 50 F. Decide the minimum from the crop rather than from habit, using the greenhouse temperature tolerance chart, and pair the heater with a circulation fan so the warm air does not sit at the ridge while the crop sits in the cold at bench height.

Who it suits

Owners of greenhouses up to roughly 120 sq ft with a standard outdoor outlet.
Growers holding a frost-free minimum over winter rather than growing a warm crop through it.
Anyone who has killed a workshop fan heater with greenhouse humidity and does not want to do it twice.

Who should skip it

Owners of larger or leakier houses, who need the 240 V Phoenix or an insulation pass first.
Growers wanting root-zone warmth for propagation, where heat mats or infrared over the bench do more per watt.
Anyone expecting to hold a big lift over outside air, because 5,100 BTU does not do that.

Alternatives worth considering

Step-Up Alternative

Bio Green Phoenix 2.8 kW 240 V Greenhouse Heater, 9,553 BTU

~$290

Almost twice the output, two stages and the same stainless greenhouse build, rated to about 215 sq ft. The catch is that it needs a 240 V circuit, which most domestic greenhouses do not have.

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Bench Alternative

Dr. Infrared Heater DR218 1500 W Infrared Heater with BioGreen Thermo 2 Thermostat

~$178

The same wattage delivered as radiant heat onto benches and soil, with an external dual heating and cooling controller in the box. Better for a propagation bench, worse for a whole house.

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Budget Pick

PELONIS Oil-Filled Electric Radiator, 1500 W

~$80

Half the money for the same wattage, silent, and with thermal mass that keeps releasing heat after it cycles off. It carries no splash rating, so it belongs well away from overhead watering.

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Keep reading

This review draws on published specifications, manufacturer figures and the consensus of verified owner reviews. We have not tested this product ourselves, and we say so rather than implying otherwise. As an Amazon Associate we earn from qualifying purchases.

Common questions

5 answers

+ Will a 1500 W heater keep a greenhouse frost free?

In a reasonably sealed house up to roughly 120 square feet, usually yes, for a modest lift over outside air. In a draughty single-skin house or a hard frost it will run continuously and still lose ground. Size it properly on the greenhouse heater BTU calculator and insulate first, because sealing draughts is cheaper than electricity.

+ Bio Green Palma vs a cheap workshop fan heater?

The difference is IPX4 splash protection, a stainless-grade build for humidity, a digital thermostat in degrees and a two-stage element. A workshop heater is cheaper and is not designed for a space you water overhead in. This is one of the places where the purpose-built version is worth the premium.

+ What temperature should I set a greenhouse heater to?

Set it from the crop, not from habit. Frost-free at around 36 to 41 F is enough to overwinter most hardy and half-hardy plants, and holding 50 F can cost double for no benefit. Check the temperature tolerance chart for the crop you are actually protecting.

+ Does the Palma need an external thermostat?

Not to work, because the thermostat is built in and digital. It is worth adding a remote sensor or external controller if you want the setpoint measured at plant height rather than inside the heater's own airflow, which is the usual reason a greenhouse reads warmer at the unit than it is at the bench.

+ Can it be used as a fan in summer?

Yes. It has an air-circulation mode quoted at 5,800 cubic feet per hour with the elements off. That is worth using: still humid air on the leaf surface is how botrytis and mildew establish, and moving air is the cheapest control there is.

Working out the figures for your own house and season? The Greenhouse Build & Growing Planner is the paid version of these pages: 8 printable worksheets you fill in with your own numbers, plus the full PDF, $29.

How this page was researched

Everything here is researched general information for growing vegetables, herbs, fruit and flowers, not professional horticultural, structural or electrical advice. Figures come from published manufacturer specifications, published horticultural references and verified owner reviews. We do not claim hands-on testing of the equipment described. Temperature, light and heating requirements vary by climate, crop and structure, so treat every number here as a starting point to check against your own conditions. Follow the label on any product you apply to an edible crop, follow local code for electrical and gas work, and consult a qualified professional for anything structural.