Is this calculation free and private?

Yes, 100% of calculations execute locally in your web browser. No inputs or personal data are stored or transmitted.

What does the Greenhouse Heating BTU & Energy Calculator give me?

It works out Required Heater Output, Equivalent Electric Heater Rating, Temperature Difference ΔT and Estimated Natural Gas Consumption, updating live as you change the inputs.

What do I need to enter?

Just Total Glazing Surface Area, Minimum Inside Temp, Winter Design Night Temp and Glazing Heat Loss U-Factor. Every field has a sensible default you can start from.

Is my data uploaded anywhere?

No. The calculation runs in your browser with JavaScript — nothing you type is sent to a server or stored.

Does it work on a phone?

Yes. The layout adapts to small screens and needs no app or signup.

Greenhouse Heating BTU & Energy Calculator

Calculate supplemental heating BTU/hr and electric kW required to protect greenhouse crops against cold winter night design temperatures.

100% free
Private in browser
No signup
No watermarks

Total Glazing Surface Area (Sq Ft)

Minimum Inside Temp (°F)

Winter Design Night Temp (°F)

Glazing Heat Loss U-Factor (e.g. 0.70)

Required Heater Output (BTU/hr)

48,300

Equivalent Electric Heater Rating (kW)

14.2

Temperature Difference ΔT (°F)

Estimated Natural Gas Consumption (CFH)

48.3

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About Greenhouse Heating BTU & Energy Calculator

Calculate supplemental heating BTU/hr and electric kW required to protect greenhouse crops against cold winter night design temperatures. Enter Total Glazing Surface Area, Minimum Inside Temp and Winter Design Night Temp and the tool works out Required Heater Output, Equivalent Electric Heater Rating and Temperature Difference ΔT straight away. Everything runs in your browser, so your data never leaves your device.

How to use Greenhouse Heating BTU & Energy Calculator

Enter Total Glazing Surface Area, Minimum Inside Temp and Winter Design Night Temp.
Adjust the remaining options (Glazing Heat Loss U-Factor) to match your case.
Read Required Heater Output, Equivalent Electric Heater Rating and Temperature Difference ΔT in the results panel — copy or download what you need.

Key features

Shows Required Heater Output (BTU/hr)
Shows Equivalent Electric Heater Rating (kW)
Shows Temperature Difference ΔT (°F)
4 adjustable inputs, results update as you type
No signup, no limits

Frequently asked questions

Is this calculation free and private?: Yes, 100% of calculations execute locally in your web browser. No inputs or personal data are stored or transmitted.
What does the Greenhouse Heating BTU & Energy Calculator give me?: It works out Required Heater Output, Equivalent Electric Heater Rating, Temperature Difference ΔT and Estimated Natural Gas Consumption, updating live as you change the inputs.
What do I need to enter?: Just Total Glazing Surface Area, Minimum Inside Temp, Winter Design Night Temp and Glazing Heat Loss U-Factor. Every field has a sensible default you can start from.
Is my data uploaded anywhere?: No. The calculation runs in your browser with JavaScript — nothing you type is sent to a server or stored.
Does it work on a phone?: Yes. The layout adapts to small screens and needs no app or signup.

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