The down side to this approach which is used in 99.9% percent of the homes in the US is that the temperature is measured in one and only one location…the location of the thermostat.  If you lived your entire life standing in front of the thermostat then you would be experiencing perfection in home air conditioning.  But of course that it not how we live our lives.  We move from room to room and turn on appliances that generate heat, and then there are rooms that are unoccupied for the most part.  The contractors that built the homes and installed the air conditioning systems do their best during construction to route the ducts in the most efficient manner for the anticipated use of each of the rooms, but that is a ‘best guess’ approach at best since each family has their own dynamics and habits.

The best way to get the most out of your system without incurring additional cost is to BALANCE it using the dampers.  Dampers are the individual covers over each of the duct openings into your rooms.  Some homes have them in the ceilings, some are in the floor, and in a few rare occasions in the walls.  Dampers come in all shapes and designs, but the one thing that they all have in common is the ability to open and close the vents to varying degrees.

You do not have to be an HVAC professional to properly adjust the dampers within your to to gain energy efficiencies.  All it takes is a little common sense.  If a room is not being utilized regularly within your home, then close the damper for that room.  For rooms that are used more often than not, open them wide.  You can easily calculate the effect that this will have on your overall cooling costs too.  Before making any adjustments, have a watch with a second hand available and when your air conditioner cuts off, start timing how long it takes before it turns on again.  Now go ahead and adjust your dampers.  Now time the cycle again.  You should find that it takes LONGER between cycles after the adjustments which means you are now saving on cooling dollars!

Sample In-Line Damper

You can also take this concept to the next level with some help.  An HVAC professional can measure output at each vent location and install in-line dampers that will more efficiently control the air flow to each location.  In-line dampers are more efficient than the vent cover dampers.  They control air flow closer to the source which means less energy loss in the ducts themselves, plus the in-line dampers can achieve 100% shut-off to a vent which is usually not possible with the vent dampers…and it eliminates the noise  you get when vent dampers are closed.

An HVAC manifold gauge is needed in order to charge your system to the proper operating pressures, and this is not a screw driver.  It requires some specific knowledge in order to know how to work it properly, and also the specific requirements of the air conditioning unit that you are working on.  And then you have to factor in other things like what other components have been added into the system, the size and length copper tubing is being used, and a number of other factors that will tell the experienced air conditioning professional what the correct pressures should be for any given installation.  You can pick up one of these for as little as $50 or more but once again it is not something that even the most seasoned DIY handyman can use without some specific knowledge.

Last but not least is the welding of the copper tubing.  Welding is more of an art than a science.  All of the training in the world will never substitute for practical experience.  Welding requires knowledge of the proper size of tubing to use for the operating pressure of the system, a welding torch, solder rated for the copper tubing, and leak testing methods.  Copper tubing is used because of its pliability and it unique properties when it comes to creating welds.  Sweating copper tubing is an important aspect of the welding process in order to get the material to create the proper seal.

If you can get past all of these requirements and you feel that you have what it takes to tackle your own job, or even to become an air conditioning professional, then I wish the best of luck.  My only advise is to tackle each job like it is for your own home and avoid taking shortcuts that will result in a poor installation and an even worst reputation down the line.

Carrier AC systems using Puron

It has been almost a year to the day since we replaced our 2.5 ton unit that services the down stairs living space in our home, and now the upstairs unit has taken its last breath so it is time to replace it.  Both units were the original TRANE systems that were ‘state-of-the-art’ back in the 1970s, so we definitely got more than the average lifespan out of them.  We attribute that not just to the quality of the units, but just as much to the regular maintenance of the overall systems.

The new unit installed is a Carrier Model 24ABC6 which is a 2 ton units with a 14.5 SEER rating that matches the 2.5 ton Carrier Carrier 24ABB servicing the ground floor.  We live in a 1,5 story home so the three bedrooms, game room, and full bathroom upstairs is about half the square footage of the main floor.  It makes good sense especially when living below the Mason-Dixon line to zone the house as much as possible to provide cooling where it is needed without throwing away money by cooling areas that are mostly unused.  When the house is mostly empty from 7am to 5pm during the weekdays, we use the ‘schedule’ feature on our Honeywell FocusPro TH6000 Series programmable thermostat to set the temperature to about 85 degrees during those hours.  The only time it will kick in is if we are having some extreme heat.  However, the same setting for the upstairs unit will have it running more often because of the nature of heat rising.  That’s when you really appreciate having a smaller unit to service the areas that are needed because the power consumption of a 2 ton units is almost 1/2 that of the 2.5 ton system.

Electric powered Heater/Blower

The house was custom built back in the mid 70′s and the original owners were very quality conscious which is evident by most of the building materials used, yet it is obvious that the upstairs air conditioner was an afterthought from the original design. The gas line for the furnace that is used  for the 2.5 ton units was not extended to the attic to service the 2 ton unit and to try and retro fit a gas line to that area would be costly and somewhat dangerous.  As a result, the heating portion of the original Trane system as well as the new Carrier system we installed is powered by electricity.  Not the optimal solution by a long shot, but given our set of circumstances it is the best solution for us.

Lastly, since we had to tear apart the old unit and everything that was connected to it, we felt that this would be the ideal time to replace the ducts.  We decided to go with the Thermaflex product with fiberglass insulation with an R-6.0 rating which is a step up from the standard R-4.2 that is used in most new construction.  The higher energy rating means moe insulation and less energy loss through the ducts in that steamy attic.

Flex Duct Installation

Here is what a properly installed duct job looks like when it is completed.  Here we see liberal use of support straps to prevent the ducts from making contact with any surfaces to minimize energy loss.

Poorly installed flex duct

Here is another picture found on the web of a poorly installed duct job.  There is a serious kink in the line which obstructs air flow and the duct is actually touching the roof at one point which will transfer heat into the duct by contact and further degree the cooling capability.  I shudder whenever I look at it!

All in all we are very pleased with the job we did and the overall system performance.  The one thing that you can’t control when buying a new air conditioner is the noise level.  Some will run loud and some will run quiet…it’s a crap shoot.  We got lucky with this one.  I can’t even hear when it kicks in!

Is your air conditioner a central unit, or a window unit, or a portable unit? This will let me know the complexity of the system and potential points of failure.

Circuit Breaker Cabinet

When you turn the switch on, does anything happen at all?

• NO:  Check the Circuit Breaker to see if the system is getting any power.  It that doesn’t fix it, then I’ll be focusing on electrical issues as opposed to mechanical issues.

• Yes:  Most times this means that the unit is blowing, but not cooling.

Is the Thermostat turned all the way down?

• NO:  Sometimes (especially at the beginning of the season) thermostats are still set for winter heating temperatures and just need to be adjusted.
• Yes: Now I’ll be focusing on mechanical issues with the compressor and refrigerant levels.

There are a whole bunch of other scenarios, but this covers the vast majority of the situations that I encounter.  At this point, there is not much left that a typical homeowner can do other than to call out an air conditioning professional.

I’ve had people call and say “My air conditioner is not cooling…can you come out and fill it up with coolant?”  Now I know of a lot of ‘professionals’ in the business that would just say “Yeah, I’ll take care of that this afternoon” then show up and squirt some coolant in and take their fee, but what is really happening is that they are throwing a quick fit at a bigger problem.

Air conditioners should never lose coolant.  It is a closed system.  If the coolant level is low, it is because there is a leak in the system and that is the real problem that should be addressed by a professional.  Also, the fact that an air conditioner is not cooling as expected is not always the result of the coolant level being low, and adding more coolant to the system could damage it.

The dirty little secret in the air conditioning business is that most ‘professionals’ are good at installing new systems (because that’s where the money is), but very few have enough knowledge to diagnose and repair an existing system.  When looking for someone to do air conditioning repair, your best bet is to find them through references from satisfied customers rather than the Yellow Pages.

• Clear away any growth and debris that has collected around the outside unit so that air flow is not obstructed;
• Trickle your hose over the coils on the outside unit to wash off dirt and pollen to improve cooling efficiency;
• Replace your air filters to increase air flow within your home;
• Turn on your air conditioner now before you need it to make sure it is working properly before the hot weather gets here.

These few simple tips that should be performed every spring will help to save you a lot of potential sweat in the summer and keep your home air conditioners running at top efficiency.

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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10am – Now we’re on to the final piece of equipment, the Carrier 24ABB evaporator coil unit.  The same process takes place, clean off the flooring, place a new drip pan under the equipment, place and level the equipment for in-line installation, metal screws to attach to the heater then some silver tape to seal and the placement is complete.  We just need to connect the PVC drain pipe wiht a fitting and some glue, and also the plastic tubing for the overflow drain from the drip pan and we’re good to go.

10:30am – Now that everything is in place, it’s time to connect all of the wiring and tubing.  The wiring is pretty straight forward.  We strip the ends off of the old power and control wires, splice in with the new units and cap off and place it back in the enclosures.  As with any installation that is not new construction, you don’t get to see everything that is needed until you tear out the old equipment.  In our case, the physical dimensions of the old heater was much longer than the new equipment, and then factor in the absence of a transition piece between each component, and it was easy to see that the old gas line was not long enough to extend to the new heater.  Now we need to make a parts run to extend the gas line and some extra silver tape will always come in handy.

12pm – The heat of the day is catching up with us and we’re close to firing up the system.  The gas line extension is fitted in after the emergency cut-off valve.  We turn the gas on and bubble test the connections for leaks and there are none so we’re in business with a heater.  Now it’s time to run the copper tubing for the air conditioner, sweat solder it in place with the torch (and it’s a good thing there were no gas leaks!).  Now the installer goes outside to the blower unit to charge the system with Puron while the helper bubble tests all of the solder joints for leaks.  No leaks!  So we have a full charged Puron home ar conditioners system ready to test.

1:00pm – We power up the system and ther is frosty cold air blowing into the attic.  Without the ductwork connected, all of the cool air is blowing into the work area, so now the fans are no longer needed.  Now since we don’t have to worry about cooking ourselves in the attic we can take a lunch break while the system runs.  This is important not only for cooling off the work areas for our comfort, but to make sure everything is working properly, and especially that the drain is draining.  The worst thing that could happen is that the condensation flow is obstructed or improperly routed and you end up with water damage…not good.  The guys head out to get a bite to eat while I keep an eye on the condesnsation flow, and it’s a good thing because the placement of the unit was on a slight tilt that backed up the condensation flow back into the unit instead of out through the drain pipe.  So now I need to turn off the air conditioner until the guys get back so they can re-level the system and re-test.

Time for another Kolache break.  I promise that I’ll finish the story in Part 3.

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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.