HELP! My upstairs air conditioner runs all the time!!!

TOTAL INVESTMENT:    $115
TIME:                                 4.5 hours
DIFFICULTY                     Easy
NET RESULT                     AC runs nominally now, consistent temperature in all upstairs rooms
                                           Big cost reduction during hot summer months

I was going nuts.  During hot months, the upstairs AC ran all day long.  Air temp wasn't consistent in the rooms.  The hallway was hot and rooms were freezing cold.  I compensated by upping the thermostat.  82 on the thermostat translated to 70-74 in the bedrooms depending on the day.  When it cooled off outside, it got hot upstairs, like 78 degrees.  I was pulling my hair out, and I don't have that much to begin with. 



Entryway window

Last summer, we were painting the entry way inside the house.  The contractor had a giant ladder.  I started to get a foggy recollection of a conversation I had with one of my friends at our last Halloween party.  Note: several margaritas were involved in that evening and evidently caused the fogginess.  Anyway, his friend had the same floorplan as our house, and the guy tinted the huge window in the entryway (left).  Hmmmmm.  We decided to tint the window as well as the storm door and two small glass windows beside the door (below).  Did I say that our front door and entryway window both face to the west?  That makes for some serious heat coming in at the end of the day.  I'm pretty sure if you nailed a steak to our front door on a hot summer day, it would be well done at dinner time.

My wife actually did the window tinting, which took about 2 hours and $25 of materials.  I may not have the numbers exactly right, because my wife was the project manager for this project.  We have a deal.  After we agree what to do, I don't interfere with her projects unless she needs me to carry heavy rocks or hold something.  I get the same respect from her.  One person wears the pants, the other is the cheap labor.  We switch up the project manager job, and the arrangement works quite well.  Needless to say, I don't have a tool list and don't have a clue how she did it.  I did monitor the financial results though.  Last year, our electricity bill went down $50 during the 3 hottest months of the summer. 

Think that fixed the temperature upstairs?  Not exactly, but it got a little better.  The AC ran a little less, but the thermostat still read a different temperature than the rooms.  I figured that would be easy to fix, because it was obvious that the thermostat was broken.  A trip to Lowe's got me a new Hunter thermostat for $50.  I installed the new one that evening in about 30 minutes with only a phillips #2 screwdriver, no choice words, but did have a celebration bourbon and coke.  My problem was fixed..........  well until it got hot the next day.  The next day the thermostat was wrong again.  My perfect plan was foiled, and I was stumped. 

I needed to ponder on this one.  Out came my tools:

• 750ml Makers Mark, crystal cup (not working this time), ice, Mexican Coke
• Recliner
• Home survey

On page 4, I read the following, "UNINSULATED CHASE IN ATTIC BESIDE TRAP DOOR ACCESS.  I RECOMMEND INSULATING OVER TOP OF THE CHASE".  Ironically, I'd just bought a $40 roll of insulation to fix another problem in my basement and had about $39 of the insulation left over.

Here's what I saw when I climbed into the attic.  By golly, I can see all the way down to my basement from here.  I'm also thinking that the insulation in the "top view" pic may have protected this location at one point in the past.

Chase - side view

Chase - top view

After feeling like a total moron for about 5 minutes, I got to work.  On the "top view" picture you can see the thermostat wiring that goes into a giant hole leading to the thermostat (right hand side).  YES!!!!  Attic air was butting up to the back of the thermostat.  No wonder it was reading the wrong temp. 

Materials:  Insulation (already bought from a previous job)

Tools:  stapler, flashlight, ladder, phillips screwdriver, razor knife, gloves, eye protection, mask

Time:   2 hours

Steps:

1. Remove thermostat
2. Cut insulation and shove enough to fill up the hole
3. Install thermostat
4. Cut insulation in sections to fit over chase
5. Staple in place
6. While I was up there, I also insulated the trap door
7. I still had insulation left, so I also insulated the dormer doors in the upstairs bedrooms (2 doors)

Insulated Attic Chase

Insulated attic door

Dormer door - insulated

I decided to take a gamble with the staples.  They're holding well so far, but I have doubts that they will hold the insulation in place for more than 5-10 years.  I also pondered putting weather stipping on the dormer doors.  That would probably help seal the door, but I didn't do it on this job.  Maybe later, when I get bored. 

The net effect of this part of the job was a 10% further reduction in power usage (about $15 per month) and consistent temperature throughout the upstairs.  When I say consistent, I mean within 2 degrees.  The insulated dormer doors help keep the bedrooms at a more even temperature, and the insulated trapdoor helps out, too.  My upstairs AC isn't running constantly, and I'm saving anywhere from $15-$65 every month.

This mod made a huge difference in our monthly budget as well as comfort.  At this point, I decided to go back to the pondering step above and read the entire home survey.  At my next house, I'll be fixing EVERYTHING before moving in.  Oh, and my advise on this one is to check the insulation in your house and fix what you find.  It's cheap and easy.

Before I let you go, I've got a few more important HVAC tips:

1. If you have an open floorplan like me (loft or 1 1/2 story), you should keep all thermostats on the same temperature.  In this situation, it's not any cheaper to run your upstairs on a lower setting.  All you will do is create an area of cold air on your lower floor.  You'll be much warmer with them set the same.
2. Change your filters every 3 months.  I change mine if the month is divisible by 3.  A clogged filter will provide less airflow for heat, run the furnace harder, and run up your bills. 
3. If you have gas heat, use programmable thermostats in the winter.  I drop mine 3 degrees at night and warm it back up 30 minutes prior to my alarm clock going off.  I don't change the thermostat in the summer time.  When it's 95 degrees outside, my units are working hard anyway.  I have a feeling that if I run up the temperature, it probably wouldn't ever come back down.

If you're interested in more money saving tips for your home click here.

Click here to read about another HVAC project that warmed up my basement significantly.