6 Best Free Online Greenhouse Heater Calculator Websites

Here is a list of best free online greenhouse heater calculator websites. A greenhouse heater is a device that regulates and maintains a user-defined temperature within a house. When new houses are built in colder regions, they are required to have a greenhouse heater in them. However, greenhouse heaters come in various heating capacities. Thus, it is essential to calculate the right greenhouse heater size or capacity before installing it on a house. To perform this calculation, you can try these online greenhouse calculator websites.

These websites help users determine the minimum greenhouse heater BTUs or wattage required to maintain a certain house temperature on colder nights. To determine that, these calculators require four input values namely Inside home surface area, minimum outside temperature, required home temperature, and heat loss value. Some of these websites also show the greenhouse heater size calculation formula. Based on the calculated heater BTU or wattage, users can figure out the correct greenhouse heater for their homes. To help out users, some websites also provide heat loss values of common insulation materials and walls.

These websites also offer related tools such as Fan Size Calculator, Plastic Size Calculator, Surface Area Calculator, Greenhouse Monthly Heating Cost Calculator, and more. Go through the list to learn more about these websites.

My Favorite Online Greenhouse Heater Calculator Website:

acfgreenhouses.com is my favorite website as it explains all input parameters and determines the right greenhouse heater capacity for a house in BTU.

You can also check out lists of best free Online Carbon Footprint Calculator, Household Carbon Footprint Calculator, and Online Vehicle Carbon Footprint websites.

Comparison Table:

Features/Website Names	Shows calculation formula	Defines input parameters	Offers heat loss value table
acfgreenhouses.com	✓	✓	✓
littlegreenhouse.com	✓	✓	✓
gothicarchgreenhouses.com	x	x	✓
hartley-botanic.co.uk	x	✓	x
greenhousecatalog.com	x	✓	✓
firstrays.com	x	x	x

acfgreenhouses.com

acfgreenhouses.com is a free online greenhouse heater website. This website helps users determine the size of heater (or capacity) they need for their homes. This calculation requires multiple parameters from users like the surface area of greenhouse (inside house area), minimum outside temperature, inside house temperature required, and heat loss value. Based on these input values, it calculates and shows the minimum BTU required to maintain a certain temperature in a house. It also shows the formula used to calculate the heater BTU value.

This website also provides a greenhouse covering health loss values of different insulation materials. Besides this, it also provides greenhouse exposed surface area values of different greenhouse kits. Now, follow the below steps.

How to calculate greenhouse heater size online using acfgreenhouses.com:

Visit this website and access the Greenhouse Heater Size Calculator.
Now, manually enter values of input parameters like surface area of greenhouse, inside temperature, etc.
Next, click on the Calculate button to start the calculation process.
Finally, view the calculated heater BTU required.

Additional Features:

This website also offers associated calculators such as Fan Size Calculator, Plastic Size Calculator, Surface Area Calculator, and more.

Final Thoughts:

It is one of the best free online greenhouse heather websites that helps users find the greenhouse heater’s size.

Pros	Cons
Shows calculation formula
Defines each input parameter

Home Page

littlegreenhouse.com

littlegreenhouse.com is another free online greenhouse heather website. This website offers a simple greenhouse heater-size calculator. This calculator quickly calculates and shows the minimum BTU needed to maintain a certain house temperature. To do this calculation, it considers four primary parameters namely Area of Structure, Minimum Outside Temperature, Inside Temperature, and Heat Loss Value. It also explains all four input parameters.

This website even provides the heat loss value of common insulations like 4 mil polyethylene, 11 mil woven polyethylene, Fiberglass, 8mm twinwall polycarbonate, and more. Plus, it shows the greenhouse heater size calculation formula. Now, follow the below steps.

How to calculate greenhouse heater size online using littlegreenhouse.com:

Visit this website and access this calculator.
Now, enter the values of area of structure, minimum outside temperature, inside temperature, and heat loss value.
Next, click the Calculate button.
Finally, view the minimum BTU needed value.

Additional Features:

This website also offers associated calculators like greenhouse monthly heating cost calculator, heather fuel conversion calculator, area calculator, and more.

Final Thoughts:

It is another good online greenhouse heater size calculator that anyone can use to calculate the minimum BTU heater output needed by users.

Pros	Cons
Explains input parameters
Shows calculation formula
Provides heat loss factor table for different materials

Home Page

gothicarchgreenhouses.com

gothicarchgreenhouses.com is another free online greenhouse heather website. This website helps users calculate the heater BTU required to maintain a certain temperature in a house during winter seasons. To perform this calculation, it required four inputs from users namely House Surface Area, Minimum Outside Temperature, Minimum desired temperature in house, and Heat Loss U-Factor. After performing the calculation, it not only shows the minimum BTU value required but also shows the minimum kilowatts needed from an electric heater.

To help out users, it also offers heat loss factor values of different insulation materials like 4-mil polyethylene, 6-mil polyethylene, Glass- single layer, fiberglass, acrylic double wall, and more.

How to calculate greenhouse heather size online using gothicarchgreenhouses.com:

Visit this website and access the Greenhouse Heater BTU Calculator.
After that, enter all four required input values.
Next, click on the Calculate button to start the calculation process.
Finally, view the calculated required heater BTU and kilowatts.

Additional Feature:

This website also offers a handy greenhouse surface area calculator.

Final Thoughts:

It is another good online greenhouse heater calculator that can calculate both the minimum heater BTU and kilowatts required to maintain a certain temperature during winter.

Pros	Cons
Provides heat loss factor table for different materials

Home Page

hartley-botanic.co.uk

hartley-botanic.co.uk is another free online greenhouse heater website. This website offers a straightforward greenhouse heater calculator. In this calculator, users need to enter the inside home surface area, minimum outside temperature on winter nights, minimum inside temperature required, and expected heat loss values to calculate the greenhouse heater BTU value. This website also answers common questions related to greenhouse heaters. Now, follow the below steps.

How to calculate greenhouse calculator size online using hartley-botanic.co.uk:

Visit this website using the provided link.
After that, manually enter all four required input values.
Now, click on the Calculate button to start the calculation process.
Finally, view the final greenhouse heater BTU value.

Additional Features:

This website also offers handy tools like square surface area calculator for a standard gable-end greenhouse structure and square surface area calculator for a lean-to-greenhouse structure.

Final Thoughts:

It is another good online greenhouse heater calculator that anyone can use without much hassle.

Pros	Cons
Explains input parameters

Home Page

greenhousecatalog.com

greenhousecatalog.com is another free online greenhouse heater website. This website offers a simple greenhouse heater calculator that determines the heather BTU output needed to maintain a certain temperature in a house during winter period. It also needed some input parameters to perform this calculation namely total square feet of exposed surface area, maximum inside temperature that you want in a house, minimum outside temperature, and heat loss factor. It also provides a table highlighting the heat loss factors of various insulation materials. Now, follow the below steps.

How to calculate greenhouse calculator size online using greenhousecatalog.com:

Visit this website using the provided link.
After that, enter all four required input values.
Now, click the Calculate button to view the final heater BTU value required.

Additional Features:

This website allows users to browse and purchase multiple greenhouse heaters, greenhouse supplies, and greenhouse coverings.

Final Thoughts:

It is another capable online greenhouse heater website that offers all the tools to calculate greenhouse heater size and capacity.

Pros	Cons
Explains input parameters
Provides heat loss of different insulation materials

Home Page

firstrays.com

firstrays.com is the last free online greenhouse heater size website. Through this website, users can find out the right heater size for their homes. To do that, users need to specify the values of some known parameters like Total surface area of greenhouse, type of covering material, minimum desired greenhouse temperature, and lowest expected outdoor temperature. Based on the provided values, it calculates both the watts of an electric heater and BTU’s for a gas heater. Now, check out the below steps.

How to calculate greenhouse calculator size online using firstrays.com:

Go to this website and open up the sizing a greenhouse heater.
Now, enter all required input parameters and their units.
Finally, view the calculated watts for the electric heater and BTUs for the Gas Heater.

Additional Features:

On this website, users can browse and purchase various greenhouse and reverse osmosis systems along with pesticides and nutrients.

Final Thoughts:

It is a simple and effective online greenhouse heater size calculator that calculates both required electric heater wattage and Gas Heater BTU units.

Pros	Cons
Uses covering material type instead of heat loss factor in calculation

Home Page

Frequently Asked Questions

How much heat required for greenhouse?

The amount of heat required for a greenhouse depends on several factors, including the size of the greenhouse, the desired temperature differential between the inside and outside, the local climate, the type of plants being grown, and the insulation and ventilation systems in place. Calculating the specific heat requirement for your greenhouse involves a bit of math and consideration of these factors.

How do you calculate heat loss for a greenhouse?

Calculating heat loss for a greenhouse involves determining how much thermal energy (heat) is escaping from the structure. The formula for calculating heat loss is based on factors such as the temperature differential between the inside and outside of the greenhouse, the area and materials of the greenhouse structure, and the U-value (thermal conductivity) of the materials.

What is the lowest temp for a greenhouse?

The lowest temperature for a greenhouse should ideally be above freezing to provide a suitable environment for most plants. However, the specific minimum temperature for a greenhouse depends on the types of plants you are growing and their cold tolerance.

What is the ideal temperature and humidity for a greenhouse?

In general, the daytime temperature in a greenhouse is ideal when it ranges between 70°F to 75°F (21°C to 24°C). This temperature range is suitable for many common greenhouse crops, including vegetables and ornamental plants. At night, the temperature can drop, but it's crucial to maintain a minimum nighttime temperature that doesn't drop too low for your plants. For most plants, a minimum nighttime temperature of around 50°F to 55°F (10°C to 13°C) is suitable.

Do greenhouses work in winter?

Yes, greenhouses can work in winter, and they are often used to extend the growing season and protect plants from the harsh winter conditions. However, the effectiveness of a greenhouse during the winter months depends on several factors, including the type of greenhouse, the insulation, heating, and ventilation systems, and the specific needs of the plants being grown.

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