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Heating a Greenhouse in D.C.

We live in the D.C. area and have a small 10x10 fully insulated greenhouse attached to our home. Until recently was heated by heat pump but 15 year old pump has failed (heat exchanger leaking and condensor may be too). We use the unit only to keep at about 50* in the winter - no a/c needed for plants. Q: what would be best replacement? Electric baseboard, wall forced air untit, gas space heater, new heat pump? Size?

Re: Heating a Greenhouse in D.C.


The most economical way is almost always to extend the heating system you have in the house now to also heat the greenhouse---this is rarely a problem in terms of heating capacity, since a small attached greenhouse requires only a few thousand btu's/hour.

This would assume you have the extra capacity on your present boiler/furnace to do the job (they usually do).

Could you post what type of heat you have now in the house (forced hot air, forced hot water, etc), the make of the boiler/furnace and the rated heat output---this would be on the furnace/boiler identification tag & would say something like OUTPUT: 75,000 BTU/HR.

Could you also list the total square footage of the house.

The site below has a calculator to determine the btu/hour you would need for your greenhouse--please also post this result.

Also Google "how to heat a greenhouse" for numerous info & sites on this topic.


Re: Heating a Greenhouse in D.C.


I was wondering how the heat pump worked for you?

Was cheap to run?

I would like to hear more about how the heat pump work for you?

Heating with hot water is a good way to heat a greenhouse. If you heat your house with a cast iron hot water boiler and want to use it to heat to greenhouse, you may need to watch out for thermal shock to the boiler. I heat some of my greenhouses that way and have cracked boiler sections because of that. It can be prevented with a little work, I used a Tekmar 157 controller and a pump from supply to the return.

Re: Heating a Greenhouse in D.C.

I think I would just go with an oil filled electric radiator.

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