Greenhouse interior with suspended heating equipment
Shop by equipment

Unit heaters

Gas-fired forced-air heat for existing greenhouses—size BTU, quantity, and indicative package pricing on this page.

Unit heater sizing

Structure

Per house; gutter-connected width

Eave / gutter height used for heat-loss model

Approximate floor area: 2,880 sq ft

Envelope

Roof glazing drives heat loss. Pick the closest match to your existing house.

Climate & setpoint

Calculator output uses the same engine as our configurator quotes (3600-series pricing basis) and is for budgeting and discussion only—it is not a guarantee of performance, compatibility, or price. Final selection may change with gas vs electric, phase, installation, and code; your representative will confirm.

Understanding the results

Sizing starts from heat loss in BTU per hour. Required capacity depends on greenhouse size, outdoor design temperature from your ZIP, covering and insulation, and your target inside air temperature.

The live estimate matches forced-air heaters from our catalog and includes hanger and vent stack kits in the indicative package total. Results assume the dimensions and climate inputs you enter.

Indicative only—our team reviews assumptions, loads, and code-related details before any formal quote.

Equipment overview

Unit heaters are suspended, forced-air systems: a burner and heat exchanger warm incoming air, and a fan distributes that air throughout the growing space. Installations typically run on propane or natural gas.

They can serve as primary heat or as supplemental heat alongside boilers or perimeter systems. You will see them in gutter-connected houses, single-bay greenhouses, cold frames, and tunnels where winter production or frost protection is required.

In practice, heaters are integrated with environmental controls so heating stages operate only when required, while maintaining proper safety operation.

Frequently asked questions

Is the online heater estimate the final price?
No. The calculator reports indicative BTU requirements, heater quantity, and package pricing using the same heat-loss logic as our configurators. Final pricing and layout are reviewed by our team before a formal quote.
Why do you need my ZIP code?
ZIP determines the outside design temperature used in the heat-loss model. Without a valid 5-digit ZIP, the tool cannot look up climate design conditions.
What is included in the heater package price?
Indicative totals typically include the forced-air heater unit(s), hanger set(s), and vent stack kit(s). Controls, gas piping, electrical, and installation labor are not included.
Can I combine heaters with fans or cooling in one quote?
Yes. Use Add to quote list on each sizing tool, then submit one combined request from the bar at the top of the site.

Request a quote

Use Add to quote list or Quote this sizing only on the calculator above. Combine with other equipment from the bar at the top of the site when you are ready.

Request a quote

Related equipment

Mechanical ventilation

Exhaust and HAF fans for powered air exchange and mixing.

Open

Evaporative cooling

Fan-and-pad cooling sized for hot, dry climates.

Open

Growing benches

Portable, stationary, and rolling bench sizing tools.

Open

Natural ventilation

Roll-up sides and roof or wall vents for passive airflow.

Open