You have been getting some great input on your question.  I have a couple of things to add, both new information as well as some variations on themes.

1) Someone mentioned closing the blinds in the room to reduce heat gain. Another option would be to install an exterior shade, awning or trellis to keep heat from getting into the room in the first place.

2) Instead of the black out shades, another option is window film.  Window film is probably less expensive and still allows you the views that you probably have from that room. 3M makes some fabulous products that relect heat and prevents it from entering the room.  They come in various thicknesses and tints that do not detract from the views. 

3)  Another person suggested looking at the age and performance of your windows. While this is an expensive option, it may be the most effective.  There have been so many advancements in window technology. Installing windows with both a low Solar Heat Gain Coefficient (SHGC) and U-factor, can really make a difference in keeping heat out.  If you replace windows, you could also install some operable windows or a vent to reduce the build up of hot air in the room and actually get it out.  This option would create a "chimney effect," based on the principle that hot air rises, and actually draws hot air out of the room.  Sounds like you have installed some AC in the room which will provide cool air to replace that hot air drawn up and out of the room. 

Best of luck to you, The Allen Construction Team

Hello Geoff,

If you are currently using a AC system I would suggest maybe looking into a few different options.

1)Try keeping some blinds closed during the hottest periods of the day (also helps from discolouring your furniture or flooring)

2) Circulating the air with multiple fans - also checking to see if the room is well insulated might prove to be beneficial.

3) check to see if your windows are sealed properly- are there cracks in the frame, do you seep gaps or see outside from the sides of the window etc.

4) If your home is a bit older it might be wise to have your windows checked. (what kind of glass are in your windows are they vinyl etc.)

Changing your homes windows can decrease your energy bill significantly and will help keep the "cool" in during the hotter months and "warmth" in on the cooler months.

Hope this helps!

There are severl things to consider first: 1) Was the proper double-paned, Low-E windows made for such a location installed? 2) Is the room properly insulated? 3) Does the existing HVAC unit have the capacity to cool the addition? If all these are yes's then you want to look at an auxillary coolling option. Simply cutting holes in the wall and adding an air-excahning fan may offer some relief, but if your system is being over taxed to cool this oven you will only have limited results. Having not seen the room I can't offer specific suggestions, but the whole project definitely needs to evaluated for the three things mentioned above.

Lastly, our clients facing simlar situations where a room was added, or porch was enclosed without thought of the above found relief with ductless split AC systems. They are very effitcient, quiet, and serve as an auxillary system moderating the extremes. This also gave them the option of closing their "sunrooms" off from teh rest of the house while continuing to keep them comfortable.

Hello Geoff,

In fear of giving you information that is obvious or that you already know, we move forward boldly and answer this question.  I had a similar addition on a previous home and it was difficult to keep it cooler in the summer months.  What ended up proving helpful was to put a small box fan on the floor outside of the room to draw the home's air conditioning into that space.  That teamed with controlling the sunlight with window treatments proved effective.  Thanks Geoff!

We installed a room window a/c. We are also going to install blaclout shades. Having difficulty finding someone to install the shades due to the materials that the room is made of.. A/C makes the room a dream come true.

Energy efficent windows are a good investment.

I'm from Wisconsin and we have a program called Focus on Energy which implements the ENERGY STAR program for improving energy efficiency of older homes. I'm not sure what you have in your region, but I specifically recommend starting with an expert company that can do a blower door test on your home and use an infrared camera to detect where you have air leakage and heat loss.

The number one cause of heat loss is air leakage. So insulation alone will not solve that problem. Leaky ring joists in the basement where the walls, floor, and foundation meet are one culprit... there is generally lots of inward air leakage here. And in the attic, there are a bunch of sources of air leakage, where warm air wants to rise and escape up and out. (So by the way, ice dams on the roof are not solved by adding more attic ventilation; rather they are solved by first doing air sealing, and second verifying or improving insulation.)

If you intend to DIY this, you can still hire a consultant to do the pre-testing and post-testing, and you might even be eligible for some financial incentives. If you hire a professional company to do it, the cost can be reduced by those incentives.

If you won't hire a pro, then here's a few rules of thumb: 

1) Remove fiberglass insulation from ring joists, and either use spray foam or rigid foam to insuate the ring joist, use spray foam to seal the rigid foam in place, minimum 2" thick and you can always fit the fiberglass insulation back in place again when complete.

2) Spray foam over top of wall plates in the attic.

3) Put a gasked on your attic hatch. If you have an attic ladder, buy a specific air sealing enclosure to prevent air leakage through it.

4) Find out if your recessed can lights are IC (Insulation Contact) rated or not. They will be labeled if they are. Build a sealed box around them allowing air space for heat build-up, and consider converting to LED lights so that there is less heat generated. If not IC rated, use cault to seal them to the drywall or plaster, and to close up the holes in the lights themselves.

That's a primer on things... there is more to be done, but these can help!

I would recommend starting with making sure all the existing windows and securely closed and locked.  I find windows partly open because they have been painted that way.  Take some time to make sure each window closes properly add weather stripping as needed.

Add wather stripping to all doors

check that all the heating ducts are connected securely

The best thing you could do for your home to keep the warm in and the cold out is to 1st. check your insulation in your attic if your not properly insulated the heat will escape. Another is making sure your windows are secured and latched. and proper weather seal is on your doors so draft cannot come in. 

Solar shingles are expensive and unproven.  I recommend Sun Power photo voltaic solar.  An average home is $20,000 to $30,000 and the return on investment is 4 to 6 years on a 25 plus year system.

1.  Add insulation in walls and roof.  2.  Air seal your home. 3.  Install Low E or better dual pane doors and windows.