$440 electric bill and new AC question

[TxRabbit]

Thanks for all the advice! I will check out that book and see what we can do to insulate better if needed. Our attic access is just this board that slides over- no ladder.

One example from the book is regarding this board. Realize that the board is the only thing that is separting your super duper hot attic (likely) from your air conditioned space. Even though heat rises, heat also travels from hot to cold. So even though the attic is above, every single possible way for air to travel from the attic into the house has air blowing through it. And every lack of insulation has heat transfer.

You take foam insulation and basically cut it to the size of the board. You glue layer after layer of the hard foam insulation to the attic side of the board, until you have several inches that together will add up to the recommended insulation level of an attic. It's R39 or something like that here I think? Anyway, after you do that, you add weatherstripping so that when the board is just placed back into position there is something to deter the air from traveling through the crack that is between the board and what holds the board in place.

We do have ceiling fans in pretty much every room and they run all the time. The only ones that don't run are the ones in the guest rooms, which we have closed off.

Your ceiling fans should only be running when someone is in the room. Ceiling fans benefit cooling by providing an effect of air blowing on someone so that they can tolerate a higher temperature. They don't do anything to help against heat rising and if running in an empty room are just raising the cost of your electric bill.

The holes in the ceiling for the installation of each ceiling fan are potential pathways for hot attic air to enter your house. If there isn't expandable foam around the cracks that are caused by the electrical housing being installed in the drywall, then you likely have air flow. You can see if this is true if the insulation is gray because the insulation is acting like an air filter and particles are getting caught in the insulation. If you have such a hole in every bedroom, then you likely have lots of potential leaks.

Vent fans in bathrooms are the same. I took off the vent fan cover (I was painting) and in my leaky house, I could FEEL the blowing air in the crack between the fan housing and the dry wall.

ANY hole in your ceiling for any light fixture or any other thing is a potential leak. If you have can lights in your hallways, etc etc., then you likely have many potential pathways for hot air to enter your upstairs and you could likely benefit more than you'd believe from getting expandable foam insulation and whatever else is appropriate at each and every one.

That is a good idea about the drapes. We have plantation shutters in about half the rooms that keep them very dark. Does that have the same effect as the shades?

It has a similar effect in that the interior of the house is being protected from solar gain. Solar gain is the heat that is caused in the interior of your home because the things in your home get hot from having sunlight hit them. Imagine if you will your couch, which backs up to a window and gets the sun hitting it's backside all day. Feel the couch. It's hot, likely hotter than the air in the room. The heat in the couch will travel from the couch to the cooler room temperature air and cause your air conditioning to keep coming on because the couch is source of heat. I think it's called radiant heat transfer and it's the same principal as the purposeful ones that are put in the floors of bathrooms, etc., to have "radiant heat" as opposed to forced air.

If you can prevent solar gain, then you can help your a/c bill. Closed plantation shutters will definitely provide some protection from solar gain. If the windowside of your plantation shutters are hot, your shutters themselves are causing some radiant heat transfer while still preventing others, just like any other sunlight preventing window covering. And the more sunlight that is prevented, the great the protection against solar gain.

The film on the windows is supposed to protect MORE against the heat ever getting through the glass to ANYTHING on the other side. This is the principal behind Low E windows. If you have low E windows, then the film may not net that much.