When sizing up a new air conditioner, heat pump, or HVAC unit, it is common to hear the pros throw around terms involving tonnage, saying for example, you need a 3-ton or 4-ton unit.  For reference, 4 tons is about the weight of an adult elephant!  But don’t be alarmed: they’re not talking about the weight of the unit!  This is a throw-back from the 1800’s and the term stuck.  You may also hear pros refer to the capacity of HVAC units in terms of BTUs.  Did you know these terms are related?  Here’s how they originated:

Historical Perspective

Before the modern air conditioner was invented, people used to cool buildings in the summertime using ice harvested from rivers and lakes. Gathering the ice from farther and farther north and shipping it down south, or storing it from winter until summer, meant a lot of ice was lost to melting.  A BTU, which stands for British Thermal Unit, is the amount of heat required to raise 1 pound of liquid water 1 degree.  But, when water is below freezing (less than 32 degrees Fahrenheit), the amount of heat needed to melt ice is 143 BTUs per pound.

How the Math Works Out

A ton weighs 2,000 pounds, so to melt a ton of ice it takes (143 BTU/lb) x (2,000 lbs) = 286,000 BTUs.  How quickly the ice will melt depends on how quickly you heat it.  If you apply the heat uniformly over a 24 hour period, the ice will have absorbed (286,00 BTU) / (24 hours) = 11,917 BTUs per hour.  That number is generally rounded up to 12,000 BTU/hr.  So, a one ton air conditioning unit has the capacity to cool up to 12,000 BTU/hr.

Sizing an AC Unit for Your Home

When comparing costs of different HVAC units, be sure you are comparing similarly-sized units.  Central air conditioning units frequently have the capacity coded into the model number: for example, model RDR36 would be a 36,000 BTU unit, or expressed in tonnage – with 12,000 BTUs being the heat needed to melt 1 ton of ice – the model RDR36 would be a 3-ton unit (= 36,000 / 12,000).

Multiple Factors Affect Sizing

If you have a 2100 sq.ft. home, a 2-ton heat pump will not be adequate; you’ll need maybe a 3.5 or 4 ton unit. Here’s where having a professional who can do a site visit helps. There are many things that contribute to sizing an HVAC system, other than the number of square feet you want to cool.  Here are just a few:

• How well the house is insulated and when it was built
• The numbers and sizes of the windows and doors in the house
• The color of the roof: darker ones absorb more heat
• The height of the ceilings
• The overall shape of the home: long narrow houses lose more heat (through walls) than a more square house of the same size.
• The size of AC’s condenser, and whether it is positioned in the shade or in the sun
• The efficiency of the cooling unit, often expressed as a SEER rating, or seasonal energy efficiency ratio (see our post What’s Your SEER?).

Moral of the Story

Knowing the number of BTUs that will be required to heat and cool your house effectively is not only important in choosing the right size furnace and air conditioning system, but it can also tell you whether your existing system may be too large or too small… yes, a system that is too large will not cool effectively, so bigger is not always better! (read our post Think Bigger is Better?)  Now that you know that tonnage does not refer to the weight of the unit, and how to convert from tons to BTUs, you can more readily compare units. Proving yet again that knowledge is power!

If you live in the Nashville and surrounding area, and need some help figuring out the right BTUs and tons for your home, we’ll be happy to help.  Plus, if you haven’t had your spring tune-up yet, now’s the best time!  Call on us at 615-802-2665.

Cooling an empty house – either when you’re gone during the day at work, or when you’re away for an extended vacation – seems like a bad idea since it uses electricity and energy, and wastes money. So, it’s natural to assume that the best way to save money is to turn it off when not in use, right?  Not so! Here’s why:

While you’re gone, the house heats up, but it does so unevenly – with some areas or materials retaining pockets of cooler air and others having pockets of warmer air.  This can cause condensation inside the walls, around pipes and around windows, while indoor humidity rises.  In Tennessee, it’s like we always say: it’s not the heat, it’s the humidity!  The increased humidity in your home attracts bugs and greatly accelerates mold growth.  Over time, this moisture and mold can damage a house, causing fowl smells, wood deterioration and warping, buckling of wallpaper, peeling paint, and can damage sensitive artwork, electronics, and bottled wine.  High humidity also greatly increases allergens in the air – bacteria, mold, fungus, and dust mites –  which get deposited in your living space.  Remember: the number one thing air conditioning provides is dehumidification!

What’s the Solution?

The best solution is to turn the air conditioning down a few degrees but not completely off when not in use.  If you’re going to be gone for less than 12 hours, we recommend turning the thermostat up by no more than 4-6 degrees.  This way, you won’t come home to a humid, stuffy house and your air conditioner will not have to work very hard to cool the house down to your “normal” setting.  On the other hand, if you’re going away on vacation for a week, we recommend turning your thermostat up by no more than about 7-10 degrees.  This will allow you to save the maximum amount on cooling without risking damage from humidity.  A good rule of thumb to keep humidity at bay is to never set your thermostat higher than 82 degrees.

Programmable Thermostats to the Rescue!

Here’s where having a programmable thermostat is ideal.  You can set it to automatically be a few degrees higher during the portions of the workday when you are away, so you won’t need to remember to do this manually each day. Most thermostats also have an “away” setting you can use while on vacation.  Don’t want to come home to a hot house?  Many smart thermostats give you the ability to reset the temperature remotely, so you can turn down the temperature a couple of hours before you return.

Other Summer Vacation Tips

Do not steam clean carpets during the summer. This will increase humidity and cause moisture to be retained in the carpet and padding (especially if you’re turning the thermostat up!), and thus increases the mold and allergen problem.  It’s best to clean carpets during the winter months, when humidity is lower, and room heat can aid in drying the carpet and pad more quickly.

Do not leave exhaust fans on while you’re on vacation.  This only serves to exhaust the already cooled air and makes your air conditioner work harder.

Remove any standing water in the house – whether from a pet’s water dish (assuming you’re not leaving your pet behind), or in saucers around plants.  Water your plants the night before and pour out any excess water just before leaving.  Many plants are able to take in moisture from the humidity in the air, and leaving standing water around only attract bugs and mold… especially if you are raising the thermostat up several degrees.

Check out our many posts for more helpful tips to get the most out of your heating and air-conditioning year round.  If you live in the Nashville and surrounding area, Interstate AC Service is here for you!  Call on us at 615-802-2665.

Here in Middle TN, we use our air-conditioners more months of the year than our heat. In fact, the average electricity consumption for Tennessee households is 33% higher than the national average (EIA, 2015 report) and is among the highest in the nation! So anything that can help keep us cool while also saving money is a welcome relief!  Here are some tips to help you stay cool and save money during the summer:

First, let’s look inside your home…

1. Install a programmable thermostat:  According to the US Dept of Energy, this can save you hundreds of dollars per year – and not just during the summer months, but year-round!

2. Use LED lights:  LED bulbs are 75% more efficient because they eliminate most of the heat produced by traditional lighting… which means your air-conditioner doesn’t have to work as hard.

3. Circulate the air:  Use a fan to keep the air moving, especially on upper floors.  Moving air causes faster evaporation from the skin and has a cooling effect – making it feel up to 8 degrees cooler – without touching that thermostat.

4. Smart cooking:  Decrease indoor heat by using a microwave oven, rather than your thermal oven or stove, whenever possible.  Better yet, eat foods like salads that do not require cooking.  If you must boil or bake, do so in the evening when it’s cooler.

5. Use exhaust fans wisely:  Make sure you turn on the vent fans in areas that create moisture, like the shower, bathroom, kitchen, and laundry room, and turn them off as soon as most of  the moisture has dissipated, so you’re not exhausting cold air to the outside!  If you do not have exhaust fans, consider installing some.

6. Replace air filters:  every 3 months or more frequently, if needed. If you have spring and summer allergies, buy the higher quality air filters that can filter out pollens.

7. Keep the sun out:  Use drapes, blinds, shades or screens to block the sunlight, especially during the hottest part of the day, or when you’re not at home.

8. Get a tune-up:  Regular maintenance by your HVAC system professional will keep your air-conditioning running at optimal efficiency and will address potential failures, thus saving you money in the long-run.

9. Optimize air flow:  Make sure all supply and return vents are open and unblocked. Keep all doors and windows closed and make sure they’re well-sealed.  Seal any leaks in the ductwork and around windows.

10. Insulate the attic:  Adding attic insulation, while making sure the attic is well-vented by keeping the eaves unobstructed, is the best investment you can make. And it pays for itself by saving you money year-round.

Now, let’s see what can be done outside your home to keep you cooler and save money….

11. Clear it out: Keep the area surrounding your outdoor unit clear of all obstructions 2-3 feet all the way around. Don’t allow the lawn mower to discharge grass clippings into the unit. Weekly, remove debris such as leaves, pollen, and twigs from the top and sides of the outdoor unit, and keep plants and shrubs trimmed. If the outdoor unit is crowded by a fence or shrubs, or if the bottom few inches is buried under mulch, air-flow will be restricted, which decreases your air-conditioner’s efficiency, reduces its life span, and damages the unit.

12. Provide shade: Keep your outside unit in the shade as much as possible. This can boost air conditioning efficiency by up to 10%.

13. Light colors:  Just as wearing light-colored clothing helps keep you cooler, painting the exterior of your house a lighter color, or having a lighter colored roof will keep the home cooler. Although your house won’t absorb as much heat in the winter, the net energy savings in summer far exceed the energy penalty in the winter, especially in our region of the country.

14. Upgrade your windows. Installing double or triple pane windows will save energy year-round. But, if you can’t do that, try adding a reflective window film to your existing windows.  This will reflect heat before it can come through the glass, and it’s transparent, so you can still see out.

15. Update your HVAC: If your HVAC system is more than 15 years old, you can cut your utility bills by up to half if you switch it out for one of the new higher efficiency units. Or use some of the newer technologies, like a mini-split, in certain areas of your home.

At Interstate AC Service, we’re here for all your heating and air-conditioning needs.  If you live in the Nashville or surrounding area, call on us at 615-802-2665.  Let us help you keep cool this summer.

Sunlight is a free and limitless source of energy. Solar energy produces no air pollution or hazardous waste. Solar-powered air-conditioning makes sense since it’s typically hottest when the sun is shining… and that’s when air-conditioning use is most in demand! Switching to solar could reduce your heating and cooling costs by half.

Solar air conditioning refers to any cooling system that uses solar power, which is typically supplied by photo-voltaic (PV) cells, engineered into solar panels. Solar has been around a long time, and many products are now in the 4^th (or later) generation.  They are available for both residential and commercial applications. Here are just a few of the types of solar air-conditioners to choose from:

Off-Grid: Units that run 100% on solar power run on DC power. These are referred to as “off-grid” because they do not require power from the utility company, e.g., they don’t have to be plugged in. An example of this type are solar-powered window air-conditioning units. They operate on DC power only (from solar panels), and use external battery backup (usually good for about 8 hours operation). The battery is so that the unit will continue to function even when the sun is not shining, like at night. A window unit is expensive – $2-3,000 – but it can be used totally “off-grid” which means there are no energy costs during operation.

Hybrid Systems: Hybrid systems use solar power when available and supplement that with regular electricity (AC power) as needed, and do not require batteries. During the day, solar power provides 90% of the system’s electricity. At night, it switches over to regular grid power. Examples of this type include room-sized/area-sized units, like a mini-split, or whole-house units, like a hybrid heat pump. One advantage of hybrid systems is that they can also provide heat during the winter.  [Check out our previous posts on mini-splits: What You Need to Know About Mini-Splits, Cooling an Add-on Space, Saving Energy and Improving Comfort] .

Solar-Ready Systems: These are systems made like “traditional” central air-conditioning units, in that they use 220V AC power, but some of the electricity feeding it can be obtained from solar panels. The Lennox SunSource Home System is one such system. The more solar panels you add (from 1 to 16) the more money you can save in energy costs. You can start small and expand over time, adding other appliances, such as the home’s water heater, making a total home energy system.

Misconceptions

There are many misconceptions when it comes to solar. For example:

• Solar panels do not have to be in full sun to operate. They also operate in partial sun or shade.
• Solar panels do not have to go on the roof. They can go just beside the outdoor unit.
• Hybrid solar units are not bigger than normal air conditioners. In fact, because of their more efficient design, the compressor can actually be smaller than in a traditional unit. And a smaller compressor consumes less electricity!
• Solar units are actually more efficient the hotter it gets outside, because more energy is collected in the thermal hybrid collector.
• Installation costs are comparable to that of conventional units, and prices of solar units have come way down.
• Using solar does not compromise comfort in any way, and the units do not look awkward or obtrusive. In fact, according to the U.S. Department of Energy, National Renewable Energy Laboratory, a solar-powered unit will increase your home’s value substantially and can help your home sell faster!

Advantages are Environmental, Economic, and Comfort

There are numerous advantages to solar.

• Solar air-conditioners are quieter than traditional units. The ones that run on DC power – such as the hybrid mini-splits – are so quiet that you can walk right up to it and not even know it’s on.
• Solar units last a long time. Most have at least a 10-year warranty (with some parts having more), and some manufacturers have performance warranties of up to 25 years.
• Most hybrid or solar-ready units offer seasonal energy efficiency ratios or SEER values in the 21-26 range, as compared with traditional HVAC units which have SEER values around 14.  [See our post: What’s your SEER? Does it Matter?]
• Solar units are typically Energy Star certified, very efficient, and prevent greenhouse gas emissions.  Plus, they use the new R-410A refrigerant, which is more environmentally friendly.

ROI: Fast Payback

The payback period for a complete system (solar-powered heat and air) is about 2-5 years. With tax credits, the cost of installation can be paid for within the first 6 months of operation! Plus, many vendors offer interest-free financing. The federal solar tax credit, also known as the investment tax credit (ITC), allows you to deduct 30% of the cost of installing a solar energy system from your federal taxes. The ITC applies to both residential and commercial systems, and there is no cap on its value. The 30% tax cut was extended through 2019, and then gradually decreases each year from 2020 through 2022, where it levels off at 10%. What’s more, a solar-powered home can actually earn money: if your house is not using all the power it is generating, you may be able to sell excess power generated back to the utility company!

It is easy to see that if you get tax breaks for installation, the system saves you half on your energy bills and you can sell energy back (making money from the system throughout its lifetime), that a 2-5 year payback can actually be quite realistic.

**Interstate AC Service is not a reseller or installer of solar panels.

Count on Interstate AC Service to help keep you up-to-date on the latest technologies. If you live in the Nashville & surrounding area, know you can rely on us for all your heating and air-conditioning needs.

In our last post, we talked about some of the things to consider when calculating the peak cooling capacity for an add-on space. In this post, we’ll discuss some options for providing cooling to your add-on space.

Window air conditioner

This option is usually the first one homeowners dismiss, and with good reason. Although it may be cheap to install, it is very costly to run, unsightly especially if you can easily see it from the front of your house – and noisy. If you are cooling a basement space, you might not even have a window you can use! Assuming your add-on space is conducive to using a window air-conditioner, you’re still left with a heating dilemma, and more than likely will need to use either a portable room heater or add-on baseboard heat (see our post “5 Ways to Heat Local Spaces”).

Tying into your existing central HVAC system

Often, adding ductwork to your add-on space in order to connect it to your existing central HVAC system can be difficult or impossible, but this can be a great solution for providing both heat and air-conditioning. But, even if you can do it, doesn’t mean you should. Here are some things to consider:

• Is your current HVAC system rated to carry the additional load or will adding the additional space mean your existing system will now be under-sized, making your whole house uncomfortable?
• Will the add-on space need to be a separate zone, so you can control the thermostat independently of the rest of the house? This is often the case when your add-on space is in an area with vastly different needs from the rest of the house: a room that is only used occasionally, a room that is underground, or has lots of windows (a sunroom), or a room with special equipment or machinery.

To see if tying into your current HVAC system is a viable option, you’ll need to consult an HVAC professional.

Ductless Mini-Split an Ideal Solution

A ductless mini-split is often an ideal solution for most homeowners because it by-passes the expense of ductwork and is extremely efficient to install and operate. Mini-splits are available as air-conditioning only units, or as a heat pump offering both heating and cooling. Here are just some of the reasons why a mini-split might be a solution for your add-on space:

• Ease of Installation: It only requires access to an electrical outlet and a single small hole in the wall (about 3″ diameter, to accommodate refrigerant lines) for the indoor wall-mounted unit. The majority of the system sits outdoors.
• Energy Efficiency: Because there is no loss of energy through ductwork (which accounts for up to 20% of the energy cost), these systems are exceedingly efficient. While your typical central HVAC systems may have SEER ratings of 13 or 14, a ductless mini-split offers SEER ratings of 20 or more (see our post What’s Your SEER?).
• Zoning: A mini-split is ideal for a room that is only used occasionally or is closed off part of the time: if no one is in the room, there is no reason to pay to heat or cool the space. It is also ideal for a room that will have vastly different heating or cooling requirements from the rest of your house, such as a sunroom or attic bonus room. A ductless mini-split can even be added to a room currently fed by your central HVAC system, but is hard to heat and cool compared with the rest of your house.
• Features: Many of the latest crop of mini-split systems offer a multi-speed compressor, wireless remote control, programmable timer, and many other innovations.
• Easy to Maintain: Most have washable, re-usable filters. Plus, it is much quieter than even the quietest window air-conditioner, and there are health benefits by not having ducts, which can gather dust, debris, and mold.

Counterfeit and illegally imported refrigerants pose real safety and health concerns to HVAC technicians and consumers, as we detailed in our earlier post (see Beware of Fake Refrigerants!).  In recent years, with the curtailment of the refrigerant R-22 and its subsequent rise in price, this problem has gotten worse.  Now, there is much more scrutiny by the various authorities such as the EPA, IRS, and customs officials.

The Industry Fights Back

The HVAC industry now has much greater focus on recordkeeping and knowing the source of all supplies. To fight against counterfeit labeling, one refrigerant manufacturer has added a patented security hologram that provides immediate visual verification that the refrigerant is a genuine DuPont product.  The Izon® label is a unique 3D security system and contains an embedded code that allows for greater product tracking and traceability (see more info here).  Some refrigerant suppliers have begun routinely testing the contents of refrigerant cylinders they receive, using a halide test or a portable refrigerant analyzer, to spot contaminants and counterfeit products before they wind up in a consumer’s system.

What You Can Do

Here are some things you do, to avoid becoming a victim of counterfeit refrigerants:

1. Price: If the pricing you are quoted seems too good to be true, it probably is. The going price per pound for R-22 is about $45-95, and for R-410a it is $30-70. Know what you’re getting and whether the price includes installation. Get quotes from multiple suppliers. If one seems crazy low, it could be it is an illegal import or counterfeit.

2. Selling to Consumers: Although you can find cylinders of refrigerant selling online for much cheaper, it is illegal for a retailer to sell directly to consumers or to anyone who does not possess EPA 608 certification. If they will sell directly to you without this certification or do not ask to verify your certification, that is a big red flag!

3. Know your Supplier/Contractor: How long has your supplier or contractor been around? What is their reputation? Can you get in contact with them when you need to? Seek online or first-hand reviews from their customers. Verify that your HVAC technician carries Section 608 certification from the EPA. If they can’t or won’t show you proof of certification, that is a big red flag.

4. Verify the Cylinder: Look closely at the labeling of the refrigerant your technician is using. Product names such as R-22a, 12a and 290 should not be used in a residential HVAC system. Verify that the technician is adding refrigerant from a cylinder that is clearly marked to be the “right” kind (if your system needs R-22 that it says R-22 on it) and has the manufacturer’s name on it.

5. Label Your Unit: Always insist your contractor/installer label your unit with the type of refrigerant they added. If they did use a legal R-22 substitute, such as R-422D, make sure it is labeled as such. That way, the next technician working on the system won’t put R-22 in your now 422D unit.

Important Tip
If you’re having to add refrigerant to your system, it means you have a leak (see our post Fix the Refrigerant Leak Now!). If you have an older HVAC system that uses R-22, consult a reputable HVAC technician to see if it makes sense to continue investing in your existing system or if you’d be better off replacing it with a system that uses the more environmentally friendly R-410A refrigerant. Unfortunately, R-22 charged units are not compatible with R-410A refrigerant, so you’ll have to replace the entire system (to help you weigh the pros and cons, see our post Repair or Replace?). On the bright side, if you do invest in a new unit, it will be more environmentally friendly and energy efficient, so you’ll save money on your monthly cooling costs, and those long-term savings can really add up!

Counterfeit and illegally imported refrigerants have existed in the HVAC industry for years. With R-22 increasing in price due to the government phase out (see previous post An Update on the Refrigerant R-22), people are doing anything they can to get their hands on cheaper solutions. Some refrigerants coming into the U.S. from other countries are not just imported illegally, but they are counterfeit, posing safety and health concerns to technicians and consumers. If you are having your air-conditioning system serviced, be alert to the various scams out there!

Unapproved Substitutes

Several companies have been penalized by the federal government for illegally marketing and selling other hydrocarbon products such as ES 22a as a replacement for R-22. (see  EPA vs EnviroSafe and EPA vs Northcutt).  According to the EPA,  use of ES 22a –  a refrigerant meant for window air conditioning units – creates the potential for explosion and fires, and is a serious risk to human health and the environment. R-22 air conditioners weren’t built to handle the level of pressure or flammability these substitutes pose. In particular, R-22a, which uses propane, creates a fire hazard. Approved alternatives to R-22 do exist, such as R-422D, so check with your HVAC contractor.

Unapproved Additives

Some vendors have blended the refrigerant with flammable substances such as propane and butane, or with a pine-scented odorant (see R-22a Safety). These have been sold under the names OZ-12®, HC-12a®, and DURACOOL, to name a few. Use of flammable refrigerants as a retrofit in equipment that was designed for non-flammable materials presents risks to consumers, equipment, and service technicians, and will void your equipment’s original manufacturer’s warranty. There are stories where the compressor burst into flames, the technician sustained serious burns, and the siding was melted off the house!

Counterfeit Refrigerants

Some counterfeit or contaminated refrigerants have counterfeit labels on the cylinders and packaging, so you can’t tell what’s actually inside. Contaminated refrigerants can cause a variety of issues, ranging from increased energy use and decreased cooling performance, to significantly reducing the operating life of your system, and causing injury and equipment failures.  Plus, many counterfeit  products contain ozone-depleting substances which are illegal. In China, 18 people were arrested from 4 criminal gangs, and 5 illegal production facilities were found, along with 11 storage warehouses and 2 sales offices. Over 28,000 canisters of fake R-134a and other refrigerants were confiscated along with 20 tons of raw materials (see report here).

Contaminated Refrigerants

Many refrigerants, including R-22, R-134a, R-404A, and R-410A, have been found to be badly contaminated (see report here). One of these contaminants is methyl chloride (also called R40 or chloromethane). It reacts with the aluminum and metal alloys used in the internal components of your HVAC system, causing corrosion and a volatile by-product that burns on contact with air. Exposure of the system’s contents to air and/or moisture could result in production of a strong acid and violent chemical reaction. This contaminant was responsible for a fatal apartment fire in 2014.

In our next post, we’ll tell you what the HVAC industry is doing to fight back and what you can do to avoid becoming a victim of fake refrigerants.

Cleaning the air conditioner coils is part of regular spring and summer HVAC maintenance and is something homeowners can do themselves. Dirty coils can adversely affect your air conditioner’s performance, and when the heat index creeps up past 100 as it has the past few days you need to get every bit of cooling you can from your air conditioning equipment! Any debris on the coils increases the static pressure across the coils and reduces your system’s efficiency. Clean coils can boost your cooling capacity by up to 30%!

Symptoms of Dirty Coils

The coils are the part of your system where the actual transfer of heat occurs. Anything that insulates them will not only impact efficiency, but also will increase operating cost, and increase the likelihood of equipment failure. If you find your compressor keeps getting louder with each passing month, or that the compressor is overheating and turning itself off (leaving just the fan still running), cleaning the coils is a great place to start to remedy the situation.

Start With the Basics

1. Check around your outdoor HVAC equipment and eliminate all obstructions within 3 feet all around the unit. That means trimming bushes, weeding, and removing all debris. Don’t allow the lawn mower to discharge grass clippings onto the unit, or allow mulch or leaves to bury the bottom few inches, because it will restrict airflow, which will decrease efficiency and damage the unit.
2. Check to see whether any of the fins have been damaged by mowing equipment, hail, or other calamity. Fins are the fine metallic blades that surround the condensing unit. If they have been bent, crushed or have rocks lodged in them, this will need to be remedied.
3. Check to make sure the foundation upon which the outdoor unit sits is level. This is typically a concrete pad, but could also be plastic or rubber. Often, due to settling, erosion or drainage issues, these can crack, sink or become unlevel.  This puts strain on coolant lines, and could bend or break copper or electrical lines, or cause water to puddle in the unit. Make sure the pad raises the unit out of the dirt and that there is adequate drainage around it, so that water does not pool near it during a hard rain.
4. Don’t forget that you must turn the unit off before cleaning it. This doesn’t mean simply that the unit is not running (e.g., set to a higher temperature), but rather the unit should be turned off at the switch usually a separate 240V power box near the unit – or at the circuit breaker box.

With these things addressed, you’re ready to start cleaning the coils.

Coil Cleaners

Many manufacturers make coil cleaning products to aid in dislodging the contaminants on the coils. Some coil cleaners come in foaming aerosol cans, others are liquids or powders that must be mixed with water and used in a pump sprayer, still others are solvent sprays. Generally, these coil cleaning products are highly acidic or alkaline, and are harmful when inhaled or when they touch skin, causing irritation and in some cases burns. If you plan to use any of these coil cleaning products, be sure you are not downwind of the spray and that you are wearing gloves and eye protection. And here’s a tip: if you’re using them in a pump sprayer, this stuff can eat out the seals, so you’ll need to use a special heavy-duty chemical-rated sprayer.

> > > Note: All types of coil cleaners are strong chemicals and must be handled with care. The manufacturer’s directions should be read carefully and followed precisely to provide the best results.< < <

What About Detergents?

Many coil cleaners are referred to as “detergents,” but do not confuse this with dishwashing detergents or laundry detergents! Never use those types of detergents on your HVAC equipment, as most have chemicals in them that are corrosive to metals. The aluminum, copper and metal alloys used in the manufacturing of fins and tubing, as well as the unit’s plastic blower wheel and diaphragm (in the case of mini-split systems), are more sensitive and must be cleaned with a safe, non-acid cleaner.

Technique Matters!

Whether you’re using a coil cleaner or not, you’ll need a water source.  Never use a pressure washer!  Doing so could damage the coil fins and disperse chemicals into unwanted areas. Instead, use a standard garden hose. Begin by spraying the water from the inside of the unit outward, rather than from the outside inward, to prevent pushing debris further into the unit. Once you are certain all the debris has been dislodged, you can do final rinsing in all directions. In cases where there might be a thick film of dust, pollen, and grass clippings around the unit, a shop-vac can be used to remove such debris before washing the coils.

Our Recommendation

We recommend coil cleaner chemicals only if you have several layers of oily grime and only if they are used by a professional. Here’s why: These cleaners, especially the foaming kind, can spread into hard-to-reach areas. If they are not completely rinsed out, they can corrode the metal and damage the unit. Coil cleaners are tough chemicals that can not only burn holes in your clothes (which is why you must wear protective equipment), but can damage paint. Consistent use of these cleaners over time can dissolve the outer metal and diminish the life of the coil, so we do not recommend them for routine maintenance. We recommend using just a garden hose and water.

Results

After cleaning the external unit, and turning the A/C back on, you may notice that it is many times quieter than it was before. That’s because the motor can work less and cool more efficiently. Few routine chores will pay off more handsomely, both in comfort and in dollars saved, than a simple coil cleaning. You’ll also prolong the life of your air conditioner and have quieter operation. So what are waiting for?

Perhaps you’ve read or listened to one of our earlier posts entitled “Fix the Refrigerant Leak Now!” so you know how expensive refrigerant leaks can be! With the phasing out of R-22, a “shot of Freon” (as it is often called), could run you $400 or more. And there’s no telling whether that will last a couple of months or a couple of weeks! Plus, it is detrimental to the environment, causing a depletion of ozone in our upper atmosphere. If you recharge the system several times, the oil in the compressor will deplete enough to damage the compressor, and then you may require a major and expensive repair! A properly-working air conditioner does not consume or use up refrigerant, so if it is running low on refrigerant, there is a leak somewhere in the system. But where? In this post, we’ll talk about the most likely culprits.

Schrader Valve

The Schrader valve, also called the core valve, or service valve, is the port you hook up to when servicing the system. That’s why finding a leak here can be so elusive: while it is in use, it doesn’t leak. It’s only when it is not engaged that the leak can be detected. Often, this can be as simple as putting a soapy solution around it and watch for bubbles to form, or using an electronic leak detector. The Schrader valve can become leaky when debris gets stuck in it, or when the rubber o-ring deteriorates. It used to be that to swap out the valve with a new one required removing all the existing refrigerant in the system (pumping it down) first. But now there are some specialized tools that allow you to swap out this valve while the system is still under pressure. After swapping it out, the system can be topped off with refrigerant. Consider yourself lucky if this is the problem because it is easily repaired.

Condenser Coil, Evaporator Coil, or Accumulator

The evaporator coil picks up heat from indoor air, and the condenser coil releases heat into outdoor air, so these coils are essential for heat exchange. Either or both can develop leaks over time. In some cases, you may be able to hear the hissing sound emanating from the coil and can determine where the leak is. What’s more likely is that the coil has developed microscopic “pin holes” in several places. That’s because these coils are typically made out of copper, which is particularly susceptible to pollutants such as formaldehyde which is often found in our homes in flooring, furniture, hairspray, and cleaners. Formaldehyde turns into formic acid which causes corrosion on the inside of the tubing. Ironically, newer systems that meet the government’s mandate for increased efficiency may be more susceptible to these kinds of leaks. That’s because A/C manufacturers found they can raise the efficiency of their equipment by using thinner copper in their evaporator coils, thus allowing faster heat transfer. Some A/C manufacturers have switched to aluminum coils to lessen the probability of this type of corrosion. Heat pumps typically have accumulators made of steel, which will rust over time.  Any of these types of causes are very expensive to address because they require replacement of the coil or accumulator which is a very expensive part, plus it requires a complete depressurizing of the system (withdrawing all refrigerant or “pumping down”).

Joints, Seals, Lines and Tubing

Vibration of running the system, as well as environmental pollutants, can cause joints, rubber seals and copper tubing to weaken, split, separate, or rust. A lawn mower or nail may have punctured a line. Steel parts will rust if not galvanized or made rust-proof. Age is also a factor, because the system is under high pressure causing the walls of the tubing to thin and weaken over time. These leaks can be hard to find and may require disassembly of the unit. To locate the source of the leak may involve injecting a tracer (a fluorescent dye) into the system and then re-checking the system about 10 days later using a UV lamp to see where the dye has leaked out. Once the source is found, the joint, connection, or hole in the tube can be fixed by re-soldering, cutting it out, replacing it or by-passing it. The diagnosis and repair of these conditions can be time-consuming and thus expensive.

A Dilemma

Depending on the age of the air conditioner or heat pump, and the type of refrigerant it uses, you may be faced with a dilemma: You may need to consider replacing it rather than repairing it. Weighing the costs can be tricky, so you’ll want to read our post entitled “Repair vs Replacement.” Keep in mind it is possible to repair one refrigerant leak and have another one develop in a different location shortly thereafter. Whatever you decide, doing nothing is not an option. Sure, the cost to repair or replace your system may be higher than simply adding another “shot of Freon,” but not repairing a leak causes recurring expenses that will only escalate, risks major damage to your system that could be even more costly, and injures the environment.

DIY? Not!

Finding the source of a refrigerant leak requires the use of specialized tools and supplies, specialized training, and is something few homeowners can do themselves.  Recharging the system with refrigerant whether the “old” R-22 or R-410A equivalent, or the new refrigerant R-422 is definitely not something a homeowner can do since it requires a government license to order and use these refrigerants. Depend on the experts at Interstate AC Service to diagnose the source of your leak, fix it, recharge your system, and get your air conditioner operating at peak efficiency.

Tim Thomas, VP Sales & Marketing, Culer, explains how a new space cooler works and saves energy.

One of the oldest ways of conditioning air is evaporative cooling, which cools air through the evaporation of water, rather than through the use of compressors and refrigerants.   Evaporative cooling is how cars of the early 1950’s were air-conditioned (see a previous post here).  A Nashville-based company called Culer has developed a new space cooler using a patented nozzle that combines water and air under low pressure to form extremely small particles of water.  When exposed to air, these water particles instantly evaporate and cool the surrounding air.  We interviewed Tim Thomas, VP of Sales & Marketing at Culer, to learn more.  Here’s how he explains how their space cooler works.

It takes a lot of energy to go from a liquid to a gas.  If you can cause evaporation, you are going to be very efficient at creating a cooling effect.   Air conditioners have to have a compressor to evaporate and then condense a refrigerant, so you are exchanging heat in a not very efficient manner.  Because it’s a closed system it takes a lot of energy.  We use a low pressure pump to run a small fan inside.  Then, by using very fine water particles in a concentrated air stream, we are able make evaporation happen immediately.  The magic happens in the nozzles.  Our nozzles are what I call hydro-pneumatic:  they introduce both water and air in the same nozzle.  Based on the geometry we call flow blurring, atomization occurs inside the nozzle, and when water exits, it’s already atomized.  It doesn’t just rely on the pressure behind it.

How can a Culer be used in a home to save energy?  The Culer AC home series as a complementary product to an existing whole house HVAC system.  Instead of setting your air conditioner at 78 degrees you could raise it to 80-82 degrees.  Then place the AC series product in the room you are occupying, to cool that specific area or zone that you are in, thereby saving money because you’re able to run your whole house system at a higher temperature.

There are several models of Culer products, each made for indoor or outdoor areas of different sizes. Our patented nozzles make our technology unique, and it is completely scalable. We can make products for the home all the way up to our professional unit, which includes six larger nozzles as well as a 30-inch fan that can handle up to 3,000 square feet and can be used in both indoor and outdoor locations. The features of the product are very simple. There is an on-off button and a control for a 3-speed fan.  The cooling effect activates the low pressure pump; this pressurizes the water which then goes up to the nozzle.  The dial in the middle allows you to fine tune the amount of water you introduce into the air stream.  For a very hot, dry environment you would set the dial to use more water, and for more humid areas you use less.  The port can be positioned up or down by 15 degrees, and rotated horizontally up to 180 degrees. To activate the unit, all you need to do is put one gallon of water in it.  For a single-port device, one gallon of water will last around 12 hours.  Pour one gallon of water into the fill port.  Put the cap back on and make sure it is sealed tightly as that tank will get pressurized.  It uses 12-volt DC power, which is compatible with any vehicle – whether it’s a boat, an RV, or a standard automobile or truck –  and you can simply plug it into that vehicle’s system.  The AC 200 has 2 ports and two atomizing nozzles that can be operated in independent directions, and costs only about 12-cents per day to operate.