goodkamra, have you planted anything yet? It really depends on the specific annuals you buy. My petunias, for example, are pretty much jammed together with just a couple of inches in between at best. My fancy coleus, with the "fountain" shape and lanced leaves, needs room to show off. But I think your ten inches apart will look like a really spotty planting with many annuals. In fact, when you're planting a container you typically want to go a bit closer than what the little tag says on the plant. Linda's idea of the graph paper is a good one. Draw a circle to scale on the grid, and then take it to the garden center with you. When you find a plant you like, look at its recommended spacing and plot it to the circle. Different plants, different plots. Then throw in a few extra to allow for the scootching together you'll probably find you need to do, and you're set! I wish I'd thought to do this graph paper when I planted my 10' planter this year. Instead, I bought the plants in three trips. Bought a bunch, set them out on the soil and eyeballed how far they'd go. Bought a second bunch and planted everything. Bought the third bunch to fill in where things needed it. I enjoy shopping, but it certainly wasn't very efficient!

As someone in the business for 20 years and growing up in a HVAC family I would say your idea to consult a professional is the right thing to do and an estimate on new equipment should be free. A few things I have noticed. First your heater is probably too small to move enough air for the size of your house. This can affect the AC as well. Undersized systems usually affect the place farthest from the indoor equipment. Second the noise is not because of high efficiency. To the contrary it may indicate a problem with the blower system. Third never block air ducts or return air ducts as this reduces the efficiency of your unit and can cause damage. If you are adding onto your house you will need another or a larger system so perhaps adding a second system would be the best bet. My advice get a professional. The money you save in energy costs will be worth it in the long run. Good luck with it. Here is a link that might be useful: Ra-Jac Air Conditioners and Heaters Texas City TX

When we moved into a new house the inspection found that the old owners didn’t clean the electrostatic filter for the unit in the attic. It was a mess. We had to clean all the ducts and vents. They removed the old filter, used (real) duct tape to seal off the filter area Then I was able to use a filter in the return air. They said I should not use both or it would compromise the air flow.

Contact whomever you purchased the light fixture from and ask what their return policy is.