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Home improvement

Sealing and isolating your strains

Who doesn't want to save money on electricity bills? A good place to start is to isolate your channels.

Isolation is not free, but as the old saying goes, sometimes you have to spend something to do something. If you add duct insulation, your monthly electricity bills savings will soon cover the cost, especially if you install the insulation yourself.

The problem with non-isolated channels

You need insulation – also around your ducts – no matter where you live. Insulation is not just about keeping the heat in the house. It also keeps the heat away from the house (or canal).

In an average household, according to the Department of Energy, about 20% to 30% of the heated or cooled air that flows through the channels is lost through leaks and non-insulated surfaces. The result is higher utility bills, wear and tear on the heating and cooling system, and difficulty maintaining the temperature in your home. In addition, non-insulated channels can collect condensation, which ultimately leads to rust. As soon as the channels start to rust, you need to install new channels.

Assess your channels

First, consider the position of the channel. The higher the extreme temperature between the air in the duct and the air surrounding the pipe, the greater your need for duct insulation.

Unfortunately, so many houses – especially newer houses – run through the attic with pipes. Unheated cellars, crawl spaces under the house and even garages are also unconditioned (neither heated nor cooled) pipes for pipes.

On the other hand, if your ducts run over the ceiling of a heated basement or in well-insulated walls and ceilings, your need for duct insulation is minimal. However, if the ducts have a lot of leaks, the air entering your rooms will not be as warm or cold as intended. Channel loss is important no matter what happens.

Then there is the duct material itself. Most heating and cooling ducts are made of metal. These are the bulky, gray, box-shaped channels that are so common everywhere. Sometimes metal channels are lined with a channel liner, a 1 inch fiberglass sheet that insulates the inside of the channel and not the outside. The duct lining is generally not a DIY installation. If your ducts are already lined, you don't need to insulate the outside.

Channel plate, like the channel lining, is also a glass fiber product. The duct plate consists of 1 to 2 inch thick plates made of rigid glass fibers and is coated with an aluminum laminate for a moisture / air barrier. It is supplied in sections that fit together like metal channels. The advantage of the duct board is that it is already insulated so that no further work is required as long as it is structurally sound.

Another product known as the flex duct is a round frame made of wires coated with fiberglass and coated with either film or plastic to withstand moisture and air leakage. Flexible ducts do not require additional insulation, but are susceptible to damage, especially from punctures. Since they are usually used for short distances, you should also check all flexible ducts when working on the rest of your pipes.

Types of duct insulation

If you have determined that your duct needs to be insulated, consider the type of insulation you want. To insulate the exterior, you can choose between sleeve-style insulation and ceiling wraps that literally wrap around the piping.

To install the sleeves, you either have to disassemble and slide on the leads before reassembling the leads, or – like many homeowners do – cut them open and wrap them like a blanket. In the end, it's probably best to buy the ceiling insulation.

  • Duct insulation sleeves: Come in pre-measured lengths. You can have an adhesive strip to make installation a little easier. Common sleeve materials include foam, bubble wrap, and glass fiber, all of which typically have a sheet-like outer surface to provide air and moisture resistance. Simply cut the sleeve with sharp scissors to mount your channels. As with any other insulation, use additional layers to achieve better insulation performance.
  • Self-adhesive foam with foil backing Channel insulation: Easy to install and to wrap irregular piping areas well. Most brands are supplied in rolls one foot wide and several feet long. Although fairly thin, it muffles sound well and can be combined with other shapes to increase insulation rating. The best thing is that you remove the fiber in this area of ​​your home. However, never apply any foam to your piping – only formulas designed for the application. Many foam products are flammable and toxic when burned.
  • Isolation of fiberglass and cotton channels: This type typically includes an aluminum foil to block moisture or air leaks. Rolls come in a variety of thicknesses, typically one foot wide and several feet long. It is often a cheaper form of insulation, although the final value depends on proper installation. Glass fiber and cotton can be cut easily.
  • Bubble wrap with foil back: If you choose a cheaper brand, you may not deliver the expected insulation and vapor barrier performance. Another disadvantage is that as reflective insulation, you have to provide an air gap between the duct and the insulation itself. To ensure this distance, special spacers are purchased. Alternatively, you can cut squares of insulation and line the length of the duct with these squares, tape or glue them, and then install the insulation. Use enough to ensure that the length of the outer insulation does not touch the channel anywhere. This is quite an effort. So think carefully before choosing this duct isolation style.

As new and innovative products are constantly emerging, these are by no means the only types of duct insulation available and will not remain the main types. When evaluating each type of duct insulation, consider the installation method, the disadvantages and advantages, and the insulation performance, which is referred to as the R-value. Talk to others about what works for them and rummage around before choosing insulation for part of your home.

Take your insulation R value into account

More important than the type of insulation (provided it is properly installed) is the R value of the insulation you are using. The R value is the measure of the ability of the insulation to prevent heat from entering or leaving the insulated object. The higher the R-value (literally resistance value), the better the insulation works. However, there is an upper limit for the effective R-value, since above a certain level the material costs are higher than additional savings.

Before choosing your duct insulation, determine the optimal R value for your region. Generally, the colder your climate is, the higher the R-value you need. Even then, different areas of the house may require more or less insulation. As a rule of thumb, at least R-5 material must be installed. To be precise, consult the Ministry of Energy's R-value table for duct insulation.

When choosing your duct insulation, use the R-value you need to determine which product – or combination of products – you need. Use more than one level if a single level does not provide the desired value.

Testing and sealing: the critical first steps

Well-meaning homeowners often make a few mistakes when isolating their channels. First, some don't know that you can't use fiberglass insulation with paper backing. The glass fiber itself is perhaps the most commonly used insulation for beams and walls. It's fine, but it doesn't take much to make the paper hot enough to burn. Never use anything that is not specifically designed for use with HVAC cables.

The second mistake is even more common: do-it-yourselfers often do not understand that they first have to seal the channels. Failure to follow this basic step will undermine your insulation efforts. Regardless of how well you install the insulation or how high the R-value is, even if the moisture / air barrier is attached to the outside of the insulation, this will not prevent air and temperature loss if your ducts are not structurally sound.

Some channels are more susceptible to air loss than others depending on the material and location, but any channel can leak. As you age, house debris, rust from moisture, animal intrusion, and a host of other dangers, your channels can get everything from pinholes to gaping cavities, loose and leaky connections between parts, or even possibly missing channels. Your beams or wall posts can actually form the "duct" run if part of your HVAC duct is missing – or the air can simply flow outside.

To ensure that you don't waste your time, money, and insulation, have a channel leak test performed before sealing the channels. A professional channel leak test identifies leaks in your home channels. The technician, commonly referred to as a duct blower door test, seals the air inlet and outlet registers before air is blown through the system. With the help of special tools, the technician can determine how much air escapes from your lines and where it occurs. Frequent problem areas are the registers and ventilation openings, in which they enter the room they care for, as well as the individual sewer connections (connections).

Testing your channels will of course increase your costs as most professional inspections cost between $ 100 and $ 200. Only a specialist has the necessary equipment and knowledge. So it's really not a DIY-friendly task. Still, spending the money will pay off in the end.

In addition, local building regulations are gradually requiring that a test be performed on the door of an entire house and a duct blower on new homes. How does this apply to you? At any point where you upgrade your channels that require planning permission, you must follow the current code. It is also a good selling point if you ever put your home on the market.

To find a specialist to carry out the work, contact your local utility company, HVAC service provider or specialized test company. The Ministry of Energy offers excellent tips for choosing your technician. Also look for energy efficiency credits that may be available through the utility or the state or federal government to test and insulate your cables. This can significantly offset your costs.

Sealing and isolating: get to work

Some sewer inspection companies seal the sewers for you and repair leaks and holes, either as part of the service or for an additional fee. Do what you feel comfortable with – if you are sure that you will do the sealing yourself, it will get messy.

If you decide to proceed without checking your channels, do a thorough inspection and look for rust, holes, badly damaged parts, loose connections, or missing parts. Start at the stove and air unit and work back to the last register in the house. Mark problem areas with a marker or chalk. Close your channels after the inspection and note a few tips:

  • Start with clean, dry channels. You don't need to wash them, but wiping them with a damp cloth or whisking them with a broom and making sure the surface is dry will make the sealant-channel connection easier.
  • Select the desired sealant or use a suitable product combination. Mastic is the most commonly used sealant, but a specially formulated canal sealant is also available in cans or sealing tubes. Silicone sealant works in small areas.
  • If necessary, choose an adhesive tape for the sealant. Special foil tapes work well or choose a mastic tape. Never use tape – it doesn't stick for long. In general, only use the tape yourself if you have no other choice. Each tape tends to deteriorate or peel off with age as the mastic cures to a stiff, permanent surface. However, when the tape is used with the mastic, it works very well.
  • Spread the mastic or sealant of the channel over the channel seams, joints and very small holes. Follow the product instructions for detailed application instructions.
  • Apply the mastic in a layer about as thick as nickel. An even, generous layer ensures that your channel never leaks again. Use a brush with stiff bristles or your fingers to spread the sealant. Wear rubber gloves to limit skin contact.
  • Wear old clothes during application. Mastic and other products must not be washed out.
  • Tape tears or holes larger than 1/8-inch in diameter with the selected tape. Cover with the mastic to get a permanent channel stain.
  • Seal all duct connections, holes and connections near the furnace. Also close the connection between the channel and the register. Use sealant wherever there is a connection or penetration. Remember that an over-seal is better than a remaining leak.
  • Work from the stove or air unit to the last (most distant) register in the house. This allows you to prioritize your sealing efforts and ensure that the key areas are covered. Holes, leaks, and gaps that are closer to the HVAC unit have higher air pressure than the more distant ones, so your greatest savings and efficiency gains come from a good seal on and near the unit. Leaks also often occur near the blower fan and where the pipes exit the furnace.

After the sealant is dry, the last step is to isolate the channels. The process is simple if you are using a wrap-style insulation product. Before you begin, read the product instructions and follow them wherever they deviate from the general guidelines for duct insulation:

  • Measure and cut your duct insulation a bit large to allow for overlap on each seam, both lengthways and at the ends.
  • Wrap the insulation around the duct so that the leading edge protrudes slightly beyond the previous piece.
  • Make sure the material is rotated correctly. The vapor barrier should point outwards and the glass fiber or other material should be against the channel.
  • If possible, staple first, then tape each seam both lengthways and between the pieces. With an overlap of 2 to 3 inches and secured with adhesive tape, each connection should be very secure and leak-free. Use a pressure sensitive vapor retardant tape for piping.
  • Glue any punctures into the vapor barrier of the insulation to avoid leaks.
  • Avoid compressing the insulation. Most insulation relies on the air space between its fibers to deliver the promised R value. If the insulation is compressed, flattened or compressed, its R-value drops enormously. Some compression is inevitable, e.g. B. in curves.

As soon as your ducts are sealed and insulated, you can have your cables tested again by a technician if you wish. Some companies may offer the "after" test for free. Following these guidelines and proper installation will ensure that your second test will blow away the first – pun intended – but even better, your electricity bills show the difference.

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