Stains on your ceiling – warped flooring

As I write this on the 16th of October just after noon, the relative humidity outside is 90% with a temperature of 84 degrees F. In the AC business this is known as ‘just right’.

In the past 10 weeks I have visited two or three homes each week to inspect the cause of:

  • mildew around the ceiling registers
  • staining of drywall around ceiling registers
  • warping of hardwood flooring
  • musty odors inside the home
  • reports of high humidity readings on wall thermostats or hygrometers

The reason this involves an air conditioning contractor is that air conditioning is the cause. Or rather, many homes are not constructed properly to exist in this area with air conditioning.

To grasp the problem of the ceiling stains and the warping floor it helps to understand the term dew point. You have seen a glass of cold water sweat on the outside. Dew point is the temperature at which this occurs.

When the French built the first settlement at Mobile in 1700, dwellings may be wooden pikes driven into the ground with mud daub. None of the dwellings constructed of wood lasted more than a few years; everything rotted. This has always been a humid climate so they started building up off the ground on stone or cement piers. Other than the problem of termites this was a durable method of construction.

Pier And Beam House Plans Lovely Pier Footing Detail House Pier Foundation Details pierBefore air conditioning, homes built like these could last for centuries.

Enter Willis Carrier. While the inside of the home is drier, air conditioned homes can chill parts of the building components below the dew point of the ambient air and condense water – the same water that drips on the outside of the glass and puts those rings on your grandmother’s coffee table.

The main purpose of this article is to introduce some concepts that will be developed in future posts:

  • The connection between mildew in the home and relative humidity
  • The control of humidity with the air conditioning system
  • Methods of correcting the symptom
  • How the air conditioning ductwork contributes to mold and mildew
  • Using the air conditioning system to pressurize the conditioned space
mold by window

Mold on wall beside window

The picture above is actually not caused by air conditioning but occurs during the heating season. It is the same process but in reverse. I show it here because it illustrates what happens inside a wall. The mechanism is as follows: This poorly insulated window casing gets cold in the winter chilling the drywall below the dew point of the inside air. A curtain or other internal window covering can trap air against the window cooling the air below the dew point.

Bath fans, electrical openings and attic stairs are openings to the outside air. If the air pressure inside is lower than outside, wet air will be drawn into any openings.

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Since the house pressure is now lower, air will be drawn in to all openings in the building envelope. When this wet, high dew point air contacts cool building surfaces condensation of water vapor into water occurs. This chronic condition is the cause of mildew and mold.

This process also occurs in areas that aren’t visible. One place with a symptom that is visible is warped wood flooring. When wet air is pulled into a wood sub-floor high humidity without condensation can be enough to cause ‘cupping’ of flooring.

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Fresh-air-exchange

Pressurizing the home is one method used to use the air conditioner to correct a negatively pressurized home.

Posted in Air Conditioning, Ceiling Stains, Ductwork, Humidity, Mold | Leave a comment

American Standard Nexia Home Automation

Last Christmas my son and daughter-in-law gave us a new Alexa Echo Dot. At first I was concerned that this small device listened in to even whispered conversations. Seeing the little blue circle light up when I said anything close to ‘alexa’ was unnerving at first…

Empire of the Ants

But after a month or so I found myself welcoming my new robot overlord.

Within 15 minutes we had downloaded the Nexia app from Amazon and said, ‘alexa, turn down the kitchen to 70 degrees’ and, bob’s-your-uncle, I heard the air conditioner kick on. Nothing to it.

Let me explain what Nexia is and what is has to do with your heating and cooling system.

Nexia is a system of home automation that uses Z-Wave technology to control devices around your home without the need for communication wires. American Standard thermostats are available with Nexia built-in.

With Nexia installed you are able to control your thermostat from anywhere you have an internet connection, right from your smartphone.

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If you choose to you can link your American Standard system to Swinson Air Conditioning Secure Diagnostic Platform that monitors your system for errors and reports problems to us 24/7.

Nexia Diagnostics

Alert Screen

We can check that everything is ok

Zone Screen

It connects to our room-by-room zoning system to keep every corner of your home just the right temp or turn off unused areas

Runtime History

Lets us see how the system reacts to the outside world.

Think this is overly complex? In the five years since Nexia and our digitally control Platinum systems were introduced they are the most trouble free equipment  that we maintain. Here are some important facts:

  • Out of hundreds of Platinum Air Handlers we have yet to have a blower motor fail. Zero failures so far and that even includes lightning. We process wheelbarrow loads of other brand’s motors under warranty and out of warranty.
  • Two auxiliary heater boards
  • No fan control boards
  • No Electronic Expansion valve boards
  • Two router connection issues for thermostats

Nexia thermostats also come with a manufacturer’s 10 YEAR warranty when purchased with a new system.

So  who cares if Google knows that your living room is 74 degrees. Start enjoying the benefits of Nexia today.

Joan collins

Long live NEXIA!!

 

 

 

 

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Ewwwww!!! Swinson AC has a the only one in captivity

Heating and Air Conditioning systems do several things to the air in your home or office:

  • Cooling
  • Heating
  • Drying
  • Cleaning

When your system is performing the first two items on that list it is easy to notice when it isn’t working. The third, drying the air, is not quite as easy to perceive.

The last item, cleaning, takes effort to discover.

You might notice dirt around the ceiling registers or dust on tabletops and furniture. Maybe you have thought about having your ductwork cleaned.

Generally, of all the dirt and mold to be found in an air conditioning system about 5% by weight (if any) is found in the ductwork. The lions share is found in the air handler or furnace, in the cooling coil and the blower wheel.

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Here is a coil after we took a swipe from the face with a wirebrush

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Here’s the wirebrush

Cleaning the blower wheel is a task that has been designed into most blower systems. It is a nut and bolt removal to the outside for cleaning and re installation. This is not the case with the indoor coil. Up until we built our ‘gadget’ cleaning the indoor coil adequately required:

  • removal of the refrigerant from the system
  • cutting of the refrigerant piping
  • removal of the coil to the outside for cleaning
  • re installation
  • nitrogen purging
  • brazing
  • evacuation
  • restart.

Our fee for this job was in the $500-600 range. It is akin to surgery on an air conditioner.

But not any more. We (well mostly Jarrod) built a machine that we have used for about 3 years that allows our technicians to clean your indoor coil while it is in place in the air handler. No opening of the refrigerant system and it takes half the time. So it’s cheaper too.

There is one brand of coil, Rheem/Ruud that it doesn’t work on as well because of the configuration of the coil design. But in the past 3 years we have saved our customers thousands of dollars with our gadget and given them a clean new coil.

Because of the high cost of the old way, many customers would just live with the dirt, reduced performance and higher utility costs.

Give us call if you have been told that your coil is dirty and needs cleaning or replacement. Heat pump air handlers start at about $280 for coil and blower, slightly higher for gas furnaces and attics.

Have your system ‘Swinsonized’!

 

 

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Testing your home for leaks

A long time customer recently purchased a home. The customer replaced a defective thermostat with a newer version that displayed interior humidity. The heat pump system in their home was a better than average two speed system.

As a point of reference, this is not an old home but one built with the past 10 years or so in Timbercreek.

We received a follow-up call a few weeks later reporting that the new thermostat was registering above 70% relative humidity. We told them that we expected 50% even though it had been raining daily.

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After checking that the equipment was operating within expected limits, I recommended that the customer call a colleague who performs our duct testing in new construction.

Mark Kennedy

Mark Kennedy

Mark Kennedy with Home Energy Conservation scheduled an appointment with our customer to perform a ‘whole house blower door test’ and allowed me to tag along and watch. Before the technology was available that Mark is able to carry with him on the job, we would have had to crawl through the attic spaces looking for visible signs of damage or errors in construction, usually with inconclusive results. Now when we suspect building and/or duct leakage Mark is the first call we make.

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Preparation for Blower Door Test

Mark affixed a calibrated blower into the open front door jamb. By exhausting the interior air at very high rates he created a vacuum in the home. This pulls warm or hot air through any defects in the building envelope. This allowed the use of his next bit of magic – Infra-red imagery in real-time.

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Uninsulated areas of the ceiling where the wall joins – normal for 10 year old homes

Two hours of inspection revealed many openings that he included in his report to the homeowner. I have included of few of the images from that report:

Doggy door

Doggy Door to garage area

Recessed ceiling light fixture

Leaking recessed ceiling lighting fixture. There were dozens in this home.

Plumbing wall openings at top plate

During construction the top plate was left unsealed around plumbing stacks allowing heat and moisture into the home

Fireplace

The largest leak was from an open flue on a gas fireplace

Most of the problems found on this inspection called for repairs by trades other than HVAC. Also, some of the leaks will not be practical to correct. But the reason I am posting this is to let you know that here is a relatively inexpensive method to discover definitive answers to where the moisture is coming into your home. Or why your heating and cooling utility bills are higher than you expect.

Mark found aluminum windows that are leaking, flooring that was not caulked to the baseboards, etc.

With a report such as this any homeowner can develop a plan that allows them to know up front what the costs of correction will be with a reasonable expectation of success.

Once this plan is complete we will follow up with a second test. With that new measurement, we will calculate the size of an outside air duct to pressurize the home. This duct pulls in outside air, dehumidifies it and allows it to exit at low rates through the leaks that remain to be repaired.

The customer can monitor the hygrometer on the thermostat to evaluate the effectiveness of the corrections. I will post the results in this space when we’re finished.

Posted in Air Conditioning, Ductwork, Humidity, Mold, Odors, Technology | Tagged , , , , , | Leave a comment

Termites and your air conditioner

Pest control companies spend some of their time during inspections looking for wet areas under or around your home. These wet areas can attract termites. Drips from plumbing with just a few drops a minute are enough to cause the problem.

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Termite paths into your home

Air conditioners produce gallons per day and most installations dump this water right at the foundation of your home. Besides being unsightly and a possible source for mosquito breeding, chronic wet soil can draw termites to the foundation of your home. Foundation drainage

We offer the installation of a small drainage field at the exit point of the air conditioner’s condensate drainage. What is necessary is an area about 5 or 6 feet away from the outside wall of your home where we can dig and install this field.Foundation drainage-2

This drainage system may require periodic attention just like your air conditioner’s existing drain. But it will dry up the area at your foundation. Even if your home has no known problems this is a good practice to prevent future problems.

Posted in Air Conditioning, Condensate Drain, Humidity, Mold | Leave a comment

Water condensation under house

Yesterday I had a conversation with an insulation contractor regarding the installation of insulation (say that three times real fast) in a client’s attic. This prompted the post yesterday about water stains on the ceiling.

Today we were involved with a different client’s insurance adjuster regarding water damage on a floor. The flooring was buckled inside and an under house inspection showed water drops beading on the wood floor joists.

This home is probably 50 to 60 years old but we have seen new homes with similar problems. This home was constructed over a ventilated crawl space, uninsulated wood floor, finished wood interior surface.

This is the fifth home we have been involved with this summer but this time there is no ductwork under the home. If you read yesterday’s post linked to above you can see a pictorial description of the thermal properties that must be understood to address and solve this problem.

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The photo above shows several colonies of mold growing on the wood. Notice on the joist at left that the bottom has fewer colonies.

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This photo shows the underside of the plywood subfloor. The light patches are mold.

Sweating Floors

Overview of crawl space flooring system

Here is a drawing of the floor system showing one solution that I have used in the past when there is no ductwork in the space. The resistance from contractors is usually something along the lines that you can’t seal up the crawl space; that it must ‘breathe’. This is not the case. The goal is to establish a vapor barrier between:

  • the crawl space and the exterior wall/ambient air
  • the crawl space and the earth below

Caveat: This method only works with a gas permeable flooring surface. Vinyl sheet or ceramic tile is not gas permeable. A wood floor with polyurethane finish might be a problem. Older floors or the newer prefinished wood seems to work OK. But do your homework here before starting.

Also this method is inadequate for crawl spaces that contain air conditioning ductwork. We have a different solution for those spaces.

This method uses your air conditioning system to dry your floor and the floor system dries the crawl space.The reason it won’t work with the flooring materials mentioned is that vinyl sheeting prevents migration of moisture from the crawl space to the home. This blocks the path of dehumidification. It does work with a wood floor or carpet.

Section view of hanging sheet detail at exteerior wall

Section view at perimeter pier

Description of work:

Lay a sheet of 6 mil polyethylene sheeting north-south from one wall to the opposite wall between each set of the interior piers. Lay another sheet east-west , wall to wall atop the first sheet. Perimeter vents must be sealed tight, then nail a hanging sheet (two feet longer than the perimeter wall is tall) from the floor sill beam down atop the sheet you placed on the ground. Weight this sheet with bricks every few feet. Run this hanging sheet around the entire perimeter of the house.

Let this hanging sheet cover the access door so that you must push it up out of the way to enter the crawl space. Foam the ground sheet to each pier.

You will not achieve a perfect seal but the better job you do in sealing, the drier the space will be. The path for the moisture from the crawl space to the air conditioning system is restricted by the flooring. A leaky crawl space may overwhelm the ability of the system to dry the space.

The construction methods in use in many of today’s homes with crawl spaces are flawed and intended for another part of the country. I’ve seen this in new homes (recently), I’ve seen this in old homes, I’ve seen a home change occupants then develop the problem. The colder the home interior temperature, the worse the condensation problem will be. I have seen this problem for decades and, before blogs and Facebook, I’ve had to give this speech a thousand (OK maybe fifty) times complete with hand-waving and scratches on legal pads. I’m putting this together for an insurance adjuster and I’ll just email him a link. I thought since I’m writing this anyway I would share it with you. Hope it is of some help.

 

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Water stains on ceiling

Every August we receive a few calls from customers complaining of water stains on their ceilings. We arrive with a short rake and sometimes a leaf blower and find that their ductwork has been covered with blown-in insulation. We remove the insulation from the ductwork and the problem goes away.

Seems like it should work. Why have those cool ducts baking in a hot 120 degree attic when a little blown-in insulation will keep them cool. Sounded good to me. Until one day while chasing the cause of a water stain in Daphne and I put my hand down into 2 feet of insulation and felt soaking wet insulation around a perfectly sealed and insulated duct. I pulled all the insulation away and the problem was solved.

Here is a pictorial drawing of the thermal properties involved in the problem. In this duct buried in insulation, it is wrapped with 1.5″ foil faced wrap and covered with 4″ of blown insulation. In a ventilated attic, humid air of 91 degree dewpoint travels through the blown insulation and condenses on the 78 degree foil facing of the duct insulation.

Sweating duct

The blown-in insulation is causing the foil faced vapor barrier of the ductwork to cool down. This doesn’t occur when the ductwork is in the open attic. The solutions to hot ducts is outside the scope of this article. But always remember to instruct anyone installing insulation to install the insulation so as not to contact the ductwork.

Posted in Air Conditioning, Ductwork, Humidity, Mold | 1 Comment