Bio Green Phoenix 2.8 kW Review: The 240 V Greenhouse Heater

9,553 BTU, a stainless body and a circuit most greenhouses do not have.

Best for a Large House

Bio Green PHX 2.8/US Phoenix Greenhouse Heater, 240 V, 9,553 BTU

~$290

A stainless-bodied greenhouse fan heater with two separately switchable elements, a stepless thermostat and a summer air-circulation mode, running on 240 V.

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Specifications

Output	2,800 W total, 9,553 BTU
Elements	Two, separately adjustable at 1,000 W or 1,800 W
Supply	240 V, 60 Hz
Coverage	Manufacturer states rooms to 215 sq ft at about 6.6 ft average height
Thermostat	Stepless, range given as -58 F to 79 F
Circulation	Up to 16,000 cu ft per hour, fan-only mode available
Body	Stainless steel, floor standing or hung

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

What it does well

Two separately switchable elements means the heater can run at 1,000 W on a mild night and 2,800 W on a hard one, which cuts the short-cycling that ruins temperature stability on a single-stage unit.
A stainless housing is the right material for a permanently humid, splashed, fertiliser-dusted environment, and it is the specification that separates a greenhouse heater from a garage heater.
The air-circulation mode turns it into a summer fan. Moving air is the cheapest disease control in a greenhouse, so a heater that keeps working in the warm season earns its shelf space.
16,000 cu ft per hour is enough circulation to turn over the air in a 200 sq ft house many times an hour, which is what stops cold pockets forming at floor level under the benches.
A stepless thermostat rather than a three-position dial lets you set a genuine minimum, and the difference between holding 41 F and holding 50 F overnight is a large share of your winter running cost.

Where it falls short

240 V is the whole problem. Most domestic greenhouses have at best a 120 V outdoor circuit, and adding a 240 V supply to an outbuilding is an electrician's job with real cost attached.
9,553 BTU is a lot of heater for a small house. Oversizing degrades control, so on anything under roughly 120 sq ft the 1500 W Palma is the better appliance rather than the cheaper one.
The published thermostat range starting at -58 F is a sensor range, not a promise about what the heater can hold. What it holds depends entirely on your glazing, your leaks and the outside temperature.
It is a fan heater, so it heats air rather than soil and benches. Air is the thing that leaks out of a greenhouse fastest, which is why insulation and draught sealing pay back faster than a bigger heater.
Running 2,800 W through a cold night is expensive electricity. Work out the hours at your own tariff before deciding this is the cheap option compared with propane.

What owners report

Bio Green has a long-standing reputation among greenhouse growers, and owner reports on the Phoenix reflect that: the recurring notes are that the stainless body survives the environment, that the thermostat holds a setpoint properly, and that the fan-only mode gets used all summer. Where reports turn negative it is almost always the supply. People buy it, discover it needs 240 V, and either return it or pay an electrician. Check your circuit before you order.

The second theme is sizing, and it is the more expensive mistake. Growers consistently buy heater capacity rather than fixing the envelope, and a leaky house with bubble insulation missing will swallow 2,800 W and still run cold at the far end. Do the arithmetic first with the glazing heat loss calculator and then the heater BTU calculator, and read the insulating a greenhouse guide before you spend, because a roll of bubble insulation is a fraction of one winter's electricity.

Third, control. The built-in thermostat is good, and it is still a thermostat sitting inside the heater's own warm air stream, which is not where the crop is. Growers who care about a precise minimum tend to add a remote sensor or an external controller placed at plant height. Our heater thermostat versus external controller comparison covers when that is worth doing, and our Dr. Heater DR218 review covers a bundle that ships with an external controller included.

Who it suits

Growers with a house past roughly 150 sq ft that a 1500 W unit cannot hold on a cold night.
Anyone who already has a 240 V supply at the greenhouse, or is running power to a new build and can specify it.
Growers who want one appliance that heats in winter and circulates air in summer.

Who should skip it

Anyone with only a 120 V outlet. This unit will not run on it.
Owners of houses under roughly 120 sq ft, where it is oversized and will short cycle.
Growers who have not yet insulated and sealed the structure, because that is the cheaper fix.

Alternatives worth considering

120 V Alternative

Bio Green Palma 1500 W Greenhouse Heater with Digital Thermostat

~$161

The same maker's 1500 W unit at 5,100 BTU on a standard outlet, rated to about 120 sq ft, with IPX4 splash protection and a digital thermostat. For most domestic greenhouses this is the correct size and it plugs in.

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Off-Grid Alternative

Ashley Hearth Direct Vent Liquid Propane Wall Heater, 11,000 BTU

~$450

11,000 BTU with no electrical supply needed for the heat, using sealed combustion so nothing enters the growing space. The answer when running any circuit to the greenhouse is impractical, at the cost of a gas fitter and a flue.

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Different Strategy

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

~$178

Infrared heats the bench, the pots and the soil rather than the air that leaks out. On a leaky house it can hold root-zone temperature for less energy than warming the whole volume, and the external thermostat is in the box.

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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

+ Does the Bio Green Phoenix need a 240 V circuit?

Yes. It is a 240 V, 60 Hz appliance and it will not run on a standard 120 V outlet. If your greenhouse has only a 120 V supply, either budget for an electrician to install a 240 V circuit or buy a 1500 W heater instead. Any new supply to an outbuilding is an electrician's job.

+ How big a greenhouse will 9,553 BTU heat?

Bio Green states rooms to about 215 square feet at roughly 6.6 ft average height, and that figure assumes a reasonably sealed structure and a modest temperature lift. Your real answer depends on glazing, leaks and your local design low, so run it through the greenhouse heater BTU calculator rather than trusting a single number.

+ Phoenix vs Palma: which Bio Green heater do I need?

The Palma for houses up to roughly 120 square feet on a standard 120 V outlet, and the Phoenix for larger houses where you have 240 V available. Buying the bigger one for a small house makes control worse, because an oversized heater short cycles and the temperature swings more.

+ Is electric heating expensive for a greenhouse?

It is priced per kilowatt hour, so 2,800 W through a long cold night is a real cost, and it varies enormously by region. The cheapest kilowatt hour is the one you do not use: bubble insulation, sealing draughts and dropping the target minimum by a few degrees all cut the bill more than switching appliance does.

+ Can it run as a fan in summer?

Yes, it has an air-circulation mode that runs the fan without the elements, quoted at up to 16,000 cubic feet per hour. That is genuinely useful, because moving air is the cheapest fungal disease control in a greenhouse and it stops still humid pockets forming under the benches.

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.