Short version? For a tent, get the AC Infinity Thermoforge T7 (£119). It's 1000W with ten proper heat levels, so it nudges the temperature up instead of blasting it. Want app control without buying a controller too? The Vivosun AeroFlux 700W (£109) talks to your phone straight out of the box. Watching the pennies? The Gorilla 2kW Ceramic Heater is £34 and heats spaces up to 40 m³. Proper room, proper cold? The Lighthouse 3kW Heater at £49. And if you go for a plain fan heater, run it through the Grow Gadgets Temperature Controller (£23.95). It holds the room to within 1°C, which the dial on a cheap heater won't.
The best grow room heaters
AC Infinity Thermoforge T7 1000W
AC Infinity's smart heater. It works to a temperature or a VPD target and throttles itself up and down, rather than clicking on and off all night like a cheap fan heater.
- 1000W PTC
- 10 heat levels
- Temperature and VPD control
- 4 inch duct ports
- PWM control over ten heat levels, so the tent doesn't see-saw between too hot and too cold
- Two duct ports. Run it closed loop to recirculate warm air, or open loop to pull fresh air in
- Fan-only mode for when you just want air moving
- ETL certified, with tip-over detection and overheat protection
Vivosun AeroFlux 700W Smart Grow Tent Heater
Built for tents, and the one to pick if you want phone control without buying anything else. No external controller needed. It connects to the app out of the box.
- 700W PTC
- 5 heat levels
- App and VPD control
- Day and Night recipes
- Set a minimum temperature or a VPD range from your phone and it adjusts the heat itself
- The Recipe feature runs separate Day and Night settings. Handy, because lights-off is when tents go cold
- Tip-over protection, overheat shut-off and V0 flame retardant materials
Gorilla 2kW Ceramic Grow Room Heater
About the size of a toaster and thirty-four quid. Heats spaces up to 40 m³ and shifts up to 120 m³ of warm air an hour, which is a lot from a box that small.
- 2kW ceramic
- 2 heat settings
- IP21
- Fan-only mode
- Metal casing and an IP21 rating, so it's happy in a humid grow room
- Dry heat. It won't add to a damp problem
- Adjustable thermal cut-out if it gets too hot
- The fan runs on its own too, so it doubles as a circulator in summer
Lighthouse 3kW Heater
For a proper room in a proper cold snap. Three power settings, a thermostat, and it doubles up as a fan when you don't need the heat.
- 3kW
- 3 power settings
- Heater and fan
- Thermostat
- Brings a large space up to temperature quickly
- Overheating safety protection built in
- Simple, sturdy build that copes with a busy grow room. Lighthouse rate it as quiet running, too
Lighthouse Ecoheat Thermostatic Tube Heater
Low, steady warmth for greenhouses, sheds and the cold end of a grow room. Four lengths, from 45W up to 240W.
- 45W to 240W
- Digital thermostat
- Timer, Delay and Cycle modes
- Up to 25°C
- The display shows the room temperature and your target, so you can see what it's up to
- Timer, Delay and Cycle settings from 1 to 24 hours
- Switches itself off if the room drops 10°C within 10 minutes, then restarts once things settle
Sizes: 45W, 355mm £29.45, 80W, 655mm £29.95, 135W, 965mm £37.45, 240W, 1265mm £39.95. The 80W is only 50p more than the 45W, for what it's worth.
Grow Gadgets Temperature Controller
Not a heater. It's the bit that makes your heater behave. Plug the heater into it, set a target, and it holds the room to within 1°C.
- 3,500W max load
- 9°C to 50°C
- Probe included
- Settings memory
- 3,500W of headroom, so even a 3kW fan heater fits under it
- Keeps your settings after a power cut, so you're not starting again every time the power blips
- Runs a cooler as well, so it earns its keep in summer
Keeping lights-off warm
Most tents aren't cold when the lights are on. The lights see to that.
It's the other twelve hours. Lights go off, the extraction keeps dragging in cold air from the loft or the garage, and the temperature falls off a cliff. Big swings between day and night are what you're trying to stop, so the heater's real job is to hold the floor up overnight. It doesn't need to turn the place into a sauna.
- Measure it first. Pop a min max thermometer in the tent for a night and see how low it really gets. Then you know what you're fixing.
- Slow the extraction down at night. Less cold air coming in means less work for the heater. A speed controller does this nicely, and our EC fan controller guide covers the options.
- Put a thermostat in charge. A smart heater does it itself. A plain fan heater wants a controller, or it'll run flat out until someone notices.
- Keep it clear. Away from plants, reservoirs, water and anything that can drip on it, with plenty of space all round.
- Mind the socket. Big heaters get their own wall socket. Not a shared extension lead, not daisy-chained with the lights.
Other heaters and bits we stock:
At a glance
Smart heaters manage themselves. Fan heaters are cheaper but want a controller. Tube heaters just tick over.
| Heater | Type | Output | Control | Price |
|---|---|---|---|---|
 AC Infinity Thermoforge T7 |
Smart PTC | 1000W | 10 levels, temp and VPD | £119.00 |
 Vivosun AeroFlux 700W |
Smart PTC | 700W | 5 levels, app, VPD | £109.00 |
 Gorilla 2kW Ceramic |
Ceramic fan | 2kW | 2 settings, basic thermostat | £34.00 |
 Lighthouse 3kW Heater |
Fan heater | 3kW | 3 settings, thermostat | £49.00 |
 Lighthouse Ecoheat Tube |
Tube heater | 45W to 240W | Digital thermostat, timer | From £29.45 |
 Grow Gadgets Controller |
Thermostat | Up to 3,500W load | 9°C to 50°C, within 1°C | £23.95 |
Prices as at November 2026. Check the product page for the live price.
How to choose
- Tent in a loft, garage or spare room? A smart tent heater. The Thermoforge T7 if you've already got (or fancy) an AC Infinity controller, the AeroFlux if you want the app without one.
- Bigger room or an outbuilding? A 2kW or 3kW fan heater, plugged into the Grow Gadgets controller.
- Just keeping the frost off a greenhouse? A Lighthouse Ecoheat tube heater. Cheap to buy, gentle on the meter.
- Warming seedlings and cuttings? That's a heat mat or a heated propagator job, not a room heater. Our propagator guide has those.
- Whatever you buy, read the lights-off bit above first.
Damp as well as cold? Our dehumidifier guide picks up from here.
Quick answers
Do I need a heater in my grow tent in winter?
Usually, if the tent lives in a loft, garage or outbuilding. The lights keep it warm while they're on. It's lights-off when the temperature drops, so that's when a heater earns its keep.
What size heater do I need for a grow tent?
For a tent, a small smart heater like the 700W Vivosun AeroFlux or the 1000W AC Infinity Thermoforge T7 is the usual place to start. Whole rooms and outbuildings are 2kW to 3kW fan heater territory.
Can I plug a 3kW heater into an extension lead?
Best not. A 3kW heater draws around 13A on its own, so give it a wall socket to itself and keep the lights and other heavy loads off it.
Do I need a thermostat with a fan heater?
Yes. The dials on budget fan heaters are basic. A plug-in controller like the Grow Gadgets Temperature Controller switches the heater on and off to hold the room to within 1°C.
Will a heater make my grow room more humid?
No. Ceramic and PTC heaters give off dry heat, and warmer air brings the relative humidity down. That's why the smart heaters can work to a VPD target.
Is a tube heater enough for a greenhouse?
For keeping the frost off an insulated greenhouse, often yes. The Lighthouse Ecoheat tube heaters run from 45W to 240W with a thermostat up to 25°C. To warm a cold space up quickly you'll want a fan heater.
Still stuck? Give us a ring on 020 8686 9643 or email info@thehydrobros.com.
Or pop into the shop for a natter: Unit 12, Progress Business Park, Progress Way, Croydon CR0 4XD.
More grow guides
- Best dehumidifiers for grow rooms
- Best EC fan speed controllers
- Best grow tents by size
- Best propagators for cuttings and seeds
- Grow tent setup guide
- How to cool down a grow tent
The Hydro Bros Team. We sell this kit and talk growers through it every day in our Croydon shop.
