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

Freon prices on the rise again

We have received notice from several vendors today of a pending price increase on R22 refrigerant. If your air conditioner is more than 10 years old it is likely you have R22 refrigerant in your air conditioning system.

Swinson Air Conditioning’s last major purchase of R22 refrigerant was about 5 years ago. At that time we began a company transition away from R22 towards replacement ‘bridge’ refrigerants. We successfully completed that move so that refrigerants are not an issue our customers must consider.

We convert systems several times per day reclaiming the used refrigerant and installing our preferred replacement product. It has not been without challenges as the refrigerant properties are different. But we are able to change your existing equipment to eliminate the need for R22 refrigerant. Some of the components are off the shelf and readily available. American Standard/Trane Electronic Expansion Valves are converted by a little solid-state gizmo we designed and built ourselves.

Our converted systems can be recharged at less than half the cost of R22 saving you money. Everyone here has trained and developed our techniques to allow a seamless move away from obsolete R22 refrigerant.

Please read other postings on our blog for more information of this subject.

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Price increase on refrigerant

If your air conditioner is over 10 years old there is a good chance that it uses R-22 refrigerant. We have experienced a large price increase this spring after petitions filed with the United States Department of Commerce and the United States International Trade Commission against Chinese dumping.

Years of below market prices for R22 refrigerant have come to an end and we expect a doubling of R22 retail prices before the middle of this summer.


We have a solution that is actually less expensive than last summer. We are stocking on our service vehicles a replacement refrigerant that has demonstrated the capability to be a ‘drop in’ replacement for R22. Also it is currently less than half the price of R22.

Nevertheless, the least expensive path to air conditioning operation includes the immediate repair of all refrigerant leaks no matter how small. So, we have a bridge to the future that allows you to use your current air conditioning system until replacement is required.

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Aluminum Coils and Air Filters

Some of you have had to replace your air conditioner’s or heat pump’s cooling coil in the past few years. If your new coil is constructed of aluminum there are some changes you may be interested in. The changes are for the better in the long term but there are things you should know that will be reviewed here.

When, in the interest of efficiency, home air infiltration was reduced starting in the 1970’s the air inside of homes became more contaminated because the air was not exchanged as often. Some of this was noticeable to the occupants but other events were observed by your air conditioning technician.

Technicians started to notice that copper indoor cooling coils leaked refrigerant after 5 to 8 years of use compared to 20 or more years previously. One cause among others was the increased concentration of chemical compounds of chlorine and sulphur in household air. These compounds react with the copper tubing used to manufacture cooling coils.

A ForeFront Air Handlers Coil beauty color

American Standard ForeFront Air Handler All-Aluminum Coil

Some manufacturers switched materials and now construct their coolings coils with aluminum tubing which is not affected by these chemical compounds. One benefit we in the industry have seen is a large reduction in refrigerant losses because of leaks. These aluminum coils are actually reducing by a large factor the amount of ozone depleting chemicals released into the atmosphere. A larger benefit to the homeowner is the extended life of the outdoor unit. Running an air conditioner with an insufficient refrigerant charge shortens the life of the compressor.

But there’s always a ‘but’. Copper coils were performing a function I was unaware of. Copper is toxic to mold and it was treating the drain piping, after a fashion, with copper sulfate and reducing drain problems.

American Standard® started using aluminum in about 2005 and we have noticed a slow increase in the frequency of drain problems and, to the observant technician, a change in the color of the mold clogging the drains.


Light colored mold on the ground flushed from an aluminum coil

Aluminum is not toxic to mold so it provides none of the treatment that copper coils performed in the past.


Mold has three necessary conditions to propagation:

  1. Darkness or absence of ultra-violet light
  2. Water or damp air greater than 60% relative humidity
  3. Food

As conditions 1 & 2 exist in all air conditioning equipment, to break the chain of mold propagation we can eliminate # 3 – depriving it of a source of food.

Household dust is comprised of hair, fibers, skin cells and other small particles. Visible particles such as hair and fibers are easily caught with most air filters. But smaller particles require improved filters to remove them from the air stream and the cooling coil.

Fiberglass Air Filter

Fiberglass air filter

Don’t consider using this filter on an air conditioner. Small particles fly through it easily. This filter is ineffective in the control of mold.


Pleated media filter

Pleated media filters are better as they catch the smaller particles like skin cells; but they restrict the flow of air and reduce the efficiency of the air conditioner. Also in variable speed indoor units, that restriction causes the ‘smart’ blowers to speed up to overcome the restriction and increase electricity consumption.

Return Grille Filter

In-wall 5″ thick media filter


Cartridge media filter

There is now available an easy solution that requires little to no installation costs. Five inch thick pleated media filters that usually fit in your wall return air grille. These filters can be ordered online directly from the vendor. The source we have been using can be found here. Make certain you measure your existing wall grille before ordering. This is such a good option that we recommend replacing your wall grille to match the available filters if you find that necessary. We can replace the wall grille for you.

If your return duct system is leakproof and you are diligent with air filter replacement you can eliminate drain problems with your air conditioner.

Posted in Air Conditioning, Allergies, Condensate Drain, Dirty Sock Syndrome, Mold, Odors, Technology | Leave a comment

Fireplaces and your central heating system


Fireplaces offer a cozy view and a warm, radiant heat to enjoy in your home. But, if your primary source of heat is from a central heating system, a fireplace can waste the fuel it consumes along with the fuel used by the central system. It will also make the farthest places in your home colder. 

Fireplaces can be fueled by wood or natural gas. One pound of fuel requires 15 pounds of air for combustion. Unless your fireplace has an outside air source, this air comes from your already heated home air. In addition to combustion air, the heated flue pulls in another 15-20 pounds of air from the house to the outside.

00-tiling-fireplace-1208-xOpen fireplaces are a primitive method of home heating.


Glass Fronts can reduce the amount of air drawn from the home.


Wood heaters


regency-wood-insertFireplace Inserts

that contain a heat exchanger capture the heat that otherwise would go up the chimney with the smoke. They can provide heat to the home along with a central heating system.

If your primary heating system is a central gas, electric or heat pump system, the system should be turned off during operation of an open or glass-fronted fireplace. Wood Heaters and Fireplace inserts, on the other hand, can be operated together with a central system. In this part of the country they can produce much more heat than necessary to heat a home and are operated in a throttled condition. A variable speed fan on your central system can be used to distribute this heat to the rest of the home without causing a drafty feeling.

Prefabricated fireplaces now outnumber masonry fireplaces. They are much less expensive to build. I see very few of these with a heat exchanger like you would find on a fireplace insert, but that type does exist. The majority of these use gas logs with a triple-wall flue to the outside and have the efficiency drawbacks of masonry fireplaces as described above. There is a way to use these for home heating in an efficient manner: Vent-Free Gas Logs.


Vent-Free Gas Logs come with an Oxygen Depletion Detection System and do not produce dangerous carbon monoxide. They can be operated with a closed flue or without a flue. This makes them nearly 100% efficient in operation. They do present drawbacks compared to a central system; all products of combustion are dumped into the living space.

The products of combustion are:

  • trace amounts of hydrogen sulfide
  • large amounts of water vapor
  • Carbon Dioxide

Hydrogen sulfide is not noticeable to humans in trace quantities but it is a corrosive gas. Large levels of water vapor raise the relative humidity in the home and can cause sweating of glass and window sashes. Carbon Dioxide is non-toxic to humans but elevated concentrations can make you drowsy. This is controlled for with the Oxygen Depletion Sensor that is part of a vent-free gas logs device.

I’ll include a note here about Carbon Monoxide. Carbon Monoxide is toxic and accumulates in the blood. It is created through the incomplete combustion of hydrocarbon fuels. High accumulation in the blood can be fatal. The symptoms are similar to influenza. If you have propane or natural gas supplied to your home you should own one or more carbon monoxide detectors. They are incredibly cheap and very reliable.

Gas logs are a much cheaper way to achieve high efficiency gas heating. A comparable 96% AFUE efficient Gas Furnace can cost as much as $5,000 or more. But of course there is a trade off – Gas logs degrade the quality of air inside the home.

I remember going to an elderly aunt’s home in Mobile in the 1960s who heated her home with free-standing radiant gas heaters. The indoor environment was oppressive because of the elevated humidity and odor of combustion products. I didn’t, of course, know these causes at the time but the indoor air was unpleasant nonetheless.

New furnaces draw combustion air from outside the home, recover almost all heat from the fuel and then dump the products of combustion outside. All this without adding or removing anything from the air inside the home. Gas logs are used primarily to heat the room with the logs and to also enhance the ambiance. As nice and quiet as our furnaces are, they’re not much to curl up in front of.

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IAQ – Allergies and Asthma – Odors in your home

A visitor to your home will sense them more quickly than you. Prolonged exposure makes them invisible to you. You will often notice them when you first arrive home. Odors are part your body’s self-defense warning system.

Dogs, cats, hamsters, carpet, cooking, people all give off cells, hair, fur, gasses, VOC’s that are detectable to the human nose. To some people it’s just a smell. To some it can trigger an allergic, histamine reaction. I’m not an expert in allergies but my work involves dealing with the conditions related to humidity and air filtration. Controlling relative humidity in South Alabama is a larger part of maintaining comfort than in most other non-coastal locales. Mold grows in humid conditions so that makes air conditioning technicians a resource for controlling airborne mold inside the home. We apply and repair the equipment that controls humidity, and filters particulates from the air.

Newer houses are constructed to leak less air than older houses. This trend started earlier in the North as heating homes uses quite a bit of fuel. Energy efficiency in air conditioned homes moved this practice to the southern United States in the 1970’s. I mention this to point out that you live in a different structure from your parents. The home you grew up in during the 1950’s, 60’s, 70’s and 80’s exchanged air more freely with the outside which reduced the concentration of various pathogens and chemicals. Tightening up homes creates a different indoor environment but ventilation practices have not kept pace with these changes.

Ventilation – Kitchen range hoods carry steam and aerosol oils from cooking directly to the outside. The best way to keep cooling odors reduced is the kitchen range hood. Open the cabinet above your range. If there is no duct visible you probably don’t have a vented range.

Use bath exhaust fans after showering until the mirrors clear and then 15 minutes longer. Consider removing the inexpensive fan that came with your home and replacing it with a larger model. Quiet models with heaters for winter use save energy by heating the bath while you are damp from bathing. Removing excess humidity reduces the moisture necessary for mold spore propagation.

Air Filters – There are several options available here. Even the least expensive is effective if they are changed regularly. panel-air-filter-392070How often depends on your home: More often in summer, less often in winter. Looking at them is a good indicator of the correct interval.

Extended surface filters are a good option but are not always commonly available. air-cleaner-filtersThe advantage is that they offer less resistance to airflow while still filtering a very small particle. People that use them properly gain the advantage of clean equipment and extended life. The dirt that collects on the cooling coil accelerates corrosion that leads to refrigerant leaks and the moldy odor noticed when the air conditioner comes on. Customers sensitive to that odor usually call us asking to have the ductwork cleaned. Here is a photo from a few weeks ago.

Dirty indoor Cooling Coil

Dirty indoor Cooling Coil

Click on the image and you can see at the bottom where I cleaned a small section with a wire brush. The rest of that is mold living on the coil. It is more common to see this than not. Once mold gets started, it maintains itself very easily and is difficult for you to remove.

Carpet – Carpet can be cleaned. The pad under a carpet cannot be cleaned. Dirt from outside sifts through the carpet and pad and forms a silt-like layer on the underlaying floor. If you watch carpet being replaced, look at the fine powder on the floor under the pad. 3 month air filters last 3 months in a carpeted home, 6 weeks or less with wood or tile (2 to 4 weeks with pets). Air filters last longer in a carpeted house because carpet catches a large amount of dirt. Carpet in a home collects years worth of debris from shoes, skin cells from humans, spills, dust mites.

The dirt under the pad can have dust mites which can trigger allergies. It also has bacteria in abundance; not ‘can have’ but ‘has’. Interior relative humidity above 65% provides an ideal environment for mold. Mold propagates well in dark, damp places and bacteria is a food-source for mold.

A normally functioning central air conditioner will maintain right about 55% relative humidity (rh) many months of the year .  In the spring and fall during mild weather you will see 60 to 80% rh for extended periods.

If you are having allergic reactions and you have carpet, consider hard-surface flooring as an alternative.

Dirty sock syndrome – This condition mostly affects heat pump indoor units. The aluminum fin of the indoor coil becomes etched chemically in a short time of operation forming microscopic fissures in the surface of the fin. A cooling coil in a typical home has up to 300 square feet of aluminum fin surface. Mold growing on these 300 square feet gives off a moldy, dirty sock odor at the first start-up in the winter. The wet mold in the fissure is heated by the heat pump operation and gives off a very strong repugnant odor for a day or so until the heat kills it. In the fall we routinely switch between cool and heat which generates a new crop of mold and odor.

Containment – Laundry hampers, compost pails and closed garbage cans can prevent odors from building up in your home. Damp clothes, food scraps and household garbage emit products of decomposition that linger and accumulate in textiles in your home. Containing them reduces the odors.

Pets – Control of pet odors varies with the pet. In my life I have had hamsters, rats, birds, cats, dogs, iguanas and probably some that I forget. I won’t go into the varied types of odors and requirements of keeping down pet odors. Litter boxes, cages, and the pets themselves all require different measures. Assuming that each pet is cared for and their quarters are clean, there are still odors that can be readily detected by visitors. For this there is a magic bullet(s). Oxidizers. That annoying guy on the Oxiclean commercials is selling a product that uses this principle in cleaning fabrics. It can also be used to clean air.

There are devices available that generate oxidizers, mainly ozone and hydrogen peroxide. These are molecules that are dispersed into the living space from devices inside the return or supply duct. These devices consume less than 25 watts of electricity to power ultra-violet lamps.

Ozone and hydrogen peroxide react with mold and viruses in the ductwork and in the household environment killing them and/or stopping their propagation. Ozone (O³) is generated with a less expensive device than hydrogen peroxide (H²O²). Peroxides have a less noticeable odor than ozone. Also, there are limits to the amount of ozone you want in your home as it can irritate lung tissue. Peroxide generators are surprising in their effectiveness in eliminating odors inside the home. Installed cost of a peroxide generator is about $1,000.00 and they require an element replacement every 3 years at a cost of about $350.00. This gives an annualized cost of operation over a 15 year period of $165 per year or 44¢ per day. It is a luxury but it is a nice luxury. It can really make your home smell fresh with no masking odor. Also there is a reduction in allergens which can reduce histamine reactions.

Other points in your home to review are mainly structural in nature. Some structural issues are air conditioning related because of the temperature of the building materials and the humidity of the outside air. I will go other some of these items in future articles.


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IAQ – Allergies and asthma – Ductwork

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