3:00pm – We just barely made it!  Any longer without the air running and we would have started cooking up here.  The water and Gatorade supplies are about gone.  Now we’re all looking forward to some cold beer after the job is done.  What’s left is conecting all of the ductwork and this can be done while the air is blowing cold into the attic.  The first part of this stage is fitting the junction box.  This is a pre-fabricated cube constructed of insulation with one face connected to the output of the air conditioner, and up to five branches coming off of it (in our case we only have three.  The first thing we’re going to do it measure and cut holes for the three duct branches.  We do this first beause it’s easier to do before the junction box is mounted to the air conditioner, and it will allow the air to flow freely after it is mounted.  Now we measure and cut a square out of the face of the junction box that will fit to the air conditioner.  We fit it in place and use a liberal amount of silver tape (the installers best friend).  Now we connect the duct branches to the holes we cut in the other three sides in pretty much the same fashion.

5:00pm – The cold air is now running throughout the house and the thermostat is slowly starting to inch downward.  We still have a few things left to do, like connecting the exhaust pipes for the heater and clean up inside and out, but overall we’re saying ‘mission accomplished’ and we’re sitting down for a few well deserved cold beers…ringht under the air conditioning vent (-;

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6am – The helper and I are unboxing the new equipment and stageing it in the appropriate areas while the installer turns off the power to the old units, drains the freon and reclaims it.  by 7am, the new outside equipment is hooked up and ready.  Now we need to tear out the old system from the attic.

7am – I have a power strip connecting every fan that I own blowing whats left of the cool air into the attic space where they are working.  The fans are strategically positioned so that sweat doesn’t fall on them causing a short circuit.  Sweat is already pouring steadily.  The space is too small for all three os us to fit in there, so I’m going to run out and get them some kolaches while they do their thing.

9am – The front lawn looks like a nightmare trailer park scene from a “B” movie with scrap metal, wires, duct work, and torn insulation strewn all over the place.  I’m sure that if the neighbors knew what we were planning they would have re-scheuled their garage sale for another day, because we probably scared away half of their business.  It’s time for a kolache break and much needed re-hydration.

9:30am – We’re back on the clock.  The one piece of equipment that I’ve decided to leave in place is the Honeywell air purifier, an electronic filter that removes particles from the air with an electronic zap.  It works fine and is easy to maintain.  I just put the filters in the dishwasher once a month then let them sun dry and we’re good to go.  So basically the way things are going to be configured is from the air intake first comes the zapper, then the heater, then the air conditioner.  The installer has sold me on the idea of installing each component butt-up against each other rather than using a transition piece of insulation between each component.  This will streamline the installation and cut down on potential energy loss.

Enough for now, I’m getting hungry talking about kolaches (-;  I will continue the saga on the post.

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About a month ago as the temperatures were sustaining in the 100+ range here in Texas, we noticed that our 20-year old Trane system was running for about 5 minutes, cutting off for about 2 minutes, thn kicking in again.  The temperature was getting down to the 81 degree setting on the thermostat (…you see Mr. Obama, not everyone sets their air conditioning to 78), but the humidity was never getting below 50% because the unit didn’t run long enough to effectively bring down the humidity.  Basically it was short-cycling.  Now, we’ve never had this problem in the past so we ran a full perventative maintenance on the system and found that the freon level was down about 20%, but mostly that the clutch on the blower motor was starting to fail.  It was drawing some serious amps in order to kick in.  I could only imagine what the electricty bill was going to look like for this month!

Even though the Trane unit was still working, we decided it was time to get serious about replacing this old unit before we experienced an outage and at the same time, reduce our electricty bill.  Another thing that factored into our decision was that the adjoining central heating system was one of the old pilot light jobs that have been phased out some years ago due to safety concerns.  We contacted a couple of home air conditioners installers who quoted us on a new central air conditioning and heating systems and we finally settle on a Carrier 24ABB4 (14 SEER Rating) split system with Puron refrigerant, and a Carrier 58STA/STX heater.  There were more energy efficient systems available with a better SEER rating that would quality for the new tax rebate, but we could not justify the increased cost vs savings.  The system we chose will give us the best bang for the buck.

Now that we’ve signed on the bottom line and scheduled the installation date, all that is left is the perparation.  In the next post, we’ll tell you all about the installation process and the decisions we needed to make along the way.

• The overall cooling capability of the unit
• How often the compressor will turn on & off.  “Short-Cycling” prevents dehumidifying
• Factors heavily into the energy efficiency & operating cost
• Maintenance costs over the life of the unit

Strangely enough, the most common problem encountered in existing construction is OVER-SIZED units.  In studies performed by utility companies on the west coast, one found that slightly over 1/2 of the home air conditioners checked were a ton (12,000 Btu/h) or more oversized and another company found the same in 1/3 of the home air conditioners they checked.

Why is this so?  Because the correct method of calculating the optimum size of the unit needed is rather complicated and most contractor use shortcuts to save time.  Either that, or they just don’t know how to do it properly.  MANUAL J is the universally accepted standard. It was jointly developed by the Air Conditioning Contractors of America (ACCA) and the Air-Conditioning and Refrigeration Institute (ARI).  It is a lengthy publication, and rightfully so since it factors in all of the variables that must be considered to properly size home air conditioners.

It doesn’t matter whether or not you are talking about:

• Central Home Air Conditioners
• Window Unit Home Air Conditioners
• Portable Home Air Conditioners

The requirements are the same in order to provide you with the comfort you need while minimizing the operating costs and total cost of ownership over the life of the unit.  Contrary to what your parents may have taught you, the longer that home air conditioners run, the more efficient they are.  Ones that cycle on and off constantly are no dehumidifying the air AND they are eating up your electrical bill.

Our recommendations are:

• Do not try this on your own unless you have an engineering degree, a lot of time to spare, and enjoy reading 200+ page technical manuals -or- can buy or borrow a copy of Home Air Conditioning Software based on the Manual J Standard;
• If you go with a contractor, select one that specializes in Home Air Conditioners;
• Insist on getting a printout from you contractor of the Manual J data they used to calculate the optimum unit size of the home air conditioners.