It is possible to make a solar "heater" for your sunroom, that will hold the heat during the night.
Just paint several (maybe a dozen or more) gallong milk jugs black, fill them with water, and place them where they'll get the most sun for the longest amount of time. They will gain a LOT of heat, and release it slowly back into the space during the night.
The smaller containers heat up more quickly if you don't get a lot of sunlight; if you get a LOT of sun during most days, you can use a black 55gal drum (it takes the big drum longer to heat up, but then it loses heat more slowly, as well).
When I had a green house, I put the jugs along the front of the greenhouse wall, under my greenhouse bench, and they released warm air to the bench all night. It is an amazing idea!
Just paint several (maybe a dozen or more) gallong milk jugs black, fill them with water, and place them where they'll get the most sun for the longest amount of time. They will gain a LOT of heat, and release it slowly back into the space during the night.
The smaller containers heat up more quickly if you don't get a lot of sunlight; if you get a LOT of sun during most days, you can use a black 55gal drum (it takes the big drum longer to heat up, but then it loses heat more slowly, as well).
When I had a green house, I put the jugs along the front of the greenhouse wall, under my greenhouse bench, and they released warm air to the bench all night. It is an amazing idea!