Therma Grow™ Greenhouse Heaters


Advanced Greenhouse Heater Technology

Therma Grow™ greenhouse heaters utilize exclusive, L.B. White Plant-Safe Technology™,  the only greenhouse heater certified to the stringent greenhouse emissions standards.

20% Better Fuel Efficiency Than Traditional Greenhouse Heaters

Therma Grow™ greenhouse heaters are advanced, clean-burning, direct fired models that offer 20% better fuel efficiency than traditional greenhouse heaters.  So when comparing thermal conversion or seasonal (year-round) efficiency, the Therma Grow™ greenhouse outperforms even the most advanced competitive products and it does so for less money.

Greenhouse Heater 10-Year Factory Warranty  

An Industry-Best on Propane Gas and Natural Gas Greenhouse Heaters

Therma Grow™ greenhouse heaters carry an unheard of 10 year warranty on the heat chamber and case, and have completely enclosed and protected components, making for years of trouble-free heating. The design combines efficiency, advanced performance, and long component life to reduce energy and maintenance costs, and help grow profits. These units can be mounted either inside or outside; giving growers flexibility and the ability to free up grow space. 

L.B. White is the pioneer in direct fired heaters and with 50 years of perfecting every aspect of our design which has led to our reputation for reliability, durability and serviceability.

When the fate of your plants is at stake…you want the rising star in Greenhouse heating protecting your investment… L.B White.

Greenhouse Heater Resources

Use the HEAT CALCULATOR or call our technical experts to help you select the correct size and quantity of heaters for your green houses. 

Technical Support – 1-800-345-7200

Key Features of the Therma Grow™
Greenhouse Heater

  • 10 year warranty against heat chamber and case corrosion
  • Two output sizes, 120,000 Btuh and 220,000 Btuh
  • Meet all OSHA emissions requirements for greenhouses.
  • Plus models provide even greater heat management features including 2-stage temperature control and heating and air circulation modes.
  • Dependable, fuel efficient hot surface ignition
  • Quick response, on-demand heat using Hot Surface Ignition
  • Easy integration with building controls
  • Only CSA Canada certified greenhouse heater
  • 100% test fired at our plant


Therma Grow™ Greenhouse Heater Specifications  

Model:  120 120 Plus   220 220 Plus
Btu/h Rating  120,000 65,000 & 120,000  220,000 120,000 & 220,000 
Heater Configuration:        
Hot Surface Ignition  Yes  Yes  Yes  Yes
Centrifugal Blower Fan  Yes  Yes  Yes  Yes
Air Movement (cfm)  1,100 1,100 1,750 1,750
Heat / Air Circulation Switch  Yes Yes
Inlet Gas Supply Pressure:        
Propane min./max. (in. w.c.)  11/13.5  11/13.5  11/13.5  11/13.5
Natural Gas min./max. (in. w.c.)  7/11 7/11 7/11 7/11
Fuel Consumption (max.)         
LP Gas (lbs./hr.)  6.8/3.0  6.8/3.0  10.2/5.6  10.2/5.6 
Natural Gas (cu.ft/hr.)  117.0/63.0  117.0/63.0  215.0/117.0  215.0/117.0
Electrical Requirements*      115/60/ 1 or  115/60/1 or 
Requirements  115/60/1  115/60/1  230/60/1  230/60/1
Starting / Continuous Amps  11.8/4.5  11.8/4.5  17/7 or 6.7/2.6  17/7 or 6.7/2.6 
Combustion Air Requirements:        
Indoor Installation (cu. ft./min.)  300 300 550 550
Outdoor Installation 
(in2 of exit area) 
120 120 220 220
U.S. standards for max 
heater discharge 
Combustion Performance 
CO (ppm rise)†  5 2.5 2.5 2.5
NO2 (ppm rise)†  0.5 0.3 0.3 0.3
CO2 (ppm)†  4,000 2,000 2,000 2,000
Ethylene (ppm) †  0.015 0.005 0.005 0.005
Air Temperature Rise (°Fahrenheit):  110 110 120 120
Minimum Clearance (ft.):        
Top / Sides / Back†  1/1/2001 1/1/2001 1/1/2001 1/1/2001
Blower Outlet†  6 6 6 6
Dimensions (in.)        
Length†  30.75 30.75 35.5 35.5
Width†  21 21 25.5 25.5
Height†  28.25 28.25 30 30
Steel Case Materials:  Galvanized 


Galvanized  White 
Shipping Weight (lbs.)  116 116 150 150
*Specify which voltage when ordering Therma Grow™ 220 units    
**Tri-shield coating consists of 3 unique protective layers including: a non-corrosive hot-dipped galvanized steel, an oven-cured epoxy primer and a baked, thermosetting polyester.
†Items that pertain to the Plus Models.      


Therma Grow™ greenhouse heaters are advanced, clean-burning, direct fired models that offer 20% better fuel efficiency than traditional greenhouse heaters.