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jwmahloch · 12-10-2009, 05:51 PM

I found an online calculator to calculate the BTUH heat loss (British Thermal Units per hour) for a greenhouse. I have a 6x8 greenhouse so if I want to keep it 57 degrees inside and the outside temp is 20F then I need a heater that generates at least 5120 BTUH. My 1500 watt electric heater generates 5120 BTUH so I only need my kerosene heater when the outdoor temp drops below 20F. Based on our 10 forecast after tonight it will not be below 20F for the next 10 days. With the addition of my kerosene heater I can keep my greenhouse at 57 down to about 7F, below that the heaters would not keep up with the heat loss. Good thing is that it rarely gets that cold here in St Louis. Seems like we normally get about 3 or 4 arctic blasts every winter. I actually did some research on the low temp for each year back 10 years and it has not dropped below zero in the last 10 years here. That would mean we are in USDA zone 7 not USDA zone 6.

TIP: If you want to buy kerosene dont buy it at a home center or hardware store, you will pay $10/gal. Some gas stations sell kerosene. Today it was selling for about $3.60/gal and I bought 5 gallons so I should be set for the winter.

12-10-2009, 05:51 PM	#6 (permalink)
jwmahloch jwmahloch's Photo Gallery Location: St. Charles, Missouri Find me on the map! Zone: 6 - 7 Name: Jeremy Join Date: Oct 2008 Posts: 217 BananaBucks : 73,616 Feedback: 0 / 0% Said "Thanks" 0 Times Was Thanked 120 Times in 64 Posts Said "Welcome to Bananas" 3 Times	Re: Greenhouse Heat problem I found an online calculator to calculate the BTUH heat loss (British Thermal Units per hour) for a greenhouse. I have a 6x8 greenhouse so if I want to keep it 57 degrees inside and the outside temp is 20F then I need a heater that generates at least 5120 BTUH. My 1500 watt electric heater generates 5120 BTUH so I only need my kerosene heater when the outdoor temp drops below 20F. Based on our 10 forecast after tonight it will not be below 20F for the next 10 days. With the addition of my kerosene heater I can keep my greenhouse at 57 down to about 7F, below that the heaters would not keep up with the heat loss. Good thing is that it rarely gets that cold here in St Louis. Seems like we normally get about 3 or 4 arctic blasts every winter. I actually did some research on the low temp for each year back 10 years and it has not dropped below zero in the last 10 years here. That would mean we are in USDA zone 7 not USDA zone 6. TIP: If you want to buy kerosene dont buy it at a home center or hardware store, you will pay $10/gal. Some gas stations sell kerosene. Today it was selling for about $3.60/gal and I bought 5 gallons so I should be set for the winter. __________________ Jeremy