How to select and install a lock for a plastic door to a balcony. From latch to comb: Palladium fittings for plastic windows and balcony doors Inserting a lock into a plastic balcony door

Plastic sheets appeared on the market relatively recently. But because of their qualities and properties, they quickly gained popularity among customers. Ease of installation anywhere in the house or on the street, reliability and “retention” of heat in the house, harmonious design and discreetness - these are the advantages that plastic doors have.

Features of plastic doors

Such doors are ideally adapted to temperature changes and particularly high humidity thanks to the synthetic materials that make up the plastic. Light weight has a good effect on transportation and installation of the door.

The difference between plastic doors and others lies in the materials. Previously, low-quality, cheap plastic was used, which lost its neatness over time. Now, in the era of replacing all windows, entrance and interior doors, there are entire corporations that create and supply plastic doors with different fillings.

These can be doors with sound insulation or doors with a heat retention function. They are made of a special frame, which is selected specifically taking into account the load. It is worth noting that, in addition to the variety of designs, there are different types of locks for PVC doors.

Locks

Manufacturers of PVC doors do not try to diversify the types of locks in any way - all locks are completely identical in type and mechanics to each other, without any fundamental changes. The difference lies only in the subtlety of installation - it all depends on which profile was chosen for the door. From this it is determined which locking device will be installed subsequently.

When purchasing plastic doors, you don’t need to think about how to install a lock on this door. Everything is much simpler: when ordering the required door, taking into account the size, the required type of locking device is immediately selected from the price list provided by the contractor.

There are two main types of locks that are mounted on the door leaf - mechanical and electronic. Mechanical locks are simple, popular and are installed on every eighth door out of ten. The composition of such a device is quite simple: there is a body, bolts and an important part of all locks - a secret mechanism.

The secret mechanism is divided into two types.

Suvaldny- this is a certain set of plates on which there are special slots. Thanks to such slots, the bolt is activated when the lock is opened and closed directly with the key. Locking devices with such filling are quite difficult to break into, but due to the structure of the case, it is possible to use only a certain number of plates.

Cylinder– mechanism with a teardrop-shaped block. It consists of a block in which there is a rotary cylinder and a certain number of spring-loaded pins. Each pin is divided into equal parts in a special combination. Raising the cylinder, as in the case of turning the bolt, is carried out only if the key coincides with each pin in the desired lift. Cylinder locks are suitable for interior doors, as they are easy to use and convenient. But they may not withstand hacking and open.

Electronic locks- These are modern locking devices that are currently gaining particular popularity, because they are a reliable solution that can prevent access to a certain room, area or house. Such a mechanism consists of a control panel, an electronic unit, a sensor that receives a signal, and a wire. This device is controlled remotely. This is both its advantage and its disadvantage.

Locks by type can be divided into electromechanical and electromagnetic. Among them you may find:

code – the code must be entered directly from the keyboard;
intercom - opens thanks to a special key-tablet, which also differs in its shape and functions;
biometric is an expensive and reliable type of product that can only be opened thanks to a fingerprint or palm print entered into the database.

Features of locks

As manufacturers say, installing locking mechanisms into doors yourself is almost impossible, because the selected lock size may differ from the dimensions that were originally intended for it. In this case, it turns out that the lock will not fit, and the frame of the door leaf itself will be damaged. Manufacturers have put up for sale custom locks that are made directly from plastic. Their structure has the same properties as PVC doors, they are identical in size and do not exceed the width of the profile. All this is aimed at ensuring that the lock does not rest against the filler or the glass unit itself.

Mortise locks They are popular because of their aesthetic appearance - they are discreet and do not protrude, but for greater reliability you can also install an invoice. As noted earlier, the lock on a plastic door can be mortise or padded. It is worth noting that, according to their properties, they are also divided according to the “points” of locking.

Single-point locks. As their name implies, this type is equipped with only one closing mechanism. There is no need to tightly lock the door; in terms of reliability, it is completely unsuitable for installation outdoors. The best option for such doors is interior installation.

Multi-lock. A more reliable option in terms of its characteristics. Has two, three or more locking mechanisms. It tightly attracts and connects the door and the leaf, which increases reliability against burglary. Unlike single-point locks, where the point of contact is in the middle, there are several of these points. With such a lock, sound insulation appears and the heat in the room is retained.

How to adjust?

With the high demand for plastic doors, there is a growing trend of problems that arise with these doors. One of the problems is that the door leading to the balcony has sagged and the lock no longer locks, or the handle does not turn completely. Most likely, the door actually sagged due to the fact that most of the time it is in the open state, and then it simply falls to the floor, shuffling both it and the hinges. The lock on the door does not match the hinges on the body, which is why it is not possible to close the door.

In this case, you need to contact the master who installed the doors, since he has all the tools necessary for this. You can adjust the lock using a hex key, which you need to tighten the pin (mechanism) well or, conversely, slightly loosen it. If the lock breaks down, it is necessary to replace it and not try to repair it, since this idea will lead nowhere and may aggravate the current situation.

To change the locking device, you need a screwdriver and a Phillips screwdriver. You need to open the cover behind which the mechanism is hidden, unscrew it and remove it, then replace it. Replacing a balcony door lock is quite simple, because the mechanism itself is hidden behind plastic in the handle itself - this makes the task of replacing it easier. You just need to purchase a handle that fits the door. It is worth remembering that when installing locks, not only the choice of the locking device itself plays an important role in the reliability of the door, but also its correct installation. If you make reckless mistakes, the blade will not be able to adhere to the frame, the handle will not turn completely or get into the desired position. It is also possible to completely disable the lock.

If the balcony is insulated and is often used as a separate room, some elements of the plastic door are constantly subject to stress, which ultimately leads to their breakage. It is quite easy to fix if you have knowledge about fittings for plastic doors. Before purchasing the necessary elements for balcony shutters, you need to learn about the types and features of components for them.

Features of latches

The latches that are installed on plastic balcony sashes are designed to secure them. This prevents the door from opening when the lock is not closed. This element is often called a “smoker’s latch”, since if you go out to the balcony frequently, it is not necessary to lock the door. Closing the plastic profile is enough to prevent smoke from entering the room. Such products are divided into several types:

roller;
magnetic latches on the balcony door;
fall ones.

The first type of latches consists of a roller, which is mounted in a special metal box. A groove is created on the balcony frame into which the roller should fit when the sash is closed. Such latches securely hold the profile, but do not require much effort when opening.

Magnetic latches consist of two strips. One of them is metallic and the other is magnetic. The first is fixed on the profile, and the second on the frame. When closing, the slats are aligned and magnetized to each other. Thanks to such devices, the balcony sash is securely held in the closed position.

The halyard latch for PVC balcony doors is created on the roller principle. Such objects have a latch, which is supported by a spring and helps close the balcony by falling into a groove on the frame. To open a sash with such a latch, you must use a special handle.

It is worth noting that the halyard and roller latch on a plastic balcony door stops functioning effectively if the structure is skewed. In this case, they need to be adjusted. The magnetic latch can continue to function even if it is slightly misaligned.

How to choose a balcony lock

The plastic door to the balcony should reliably protect the room from the penetration of cold air. Plastic doors also effectively muffle noise. But in order for it to perform its functions, it must be adjusted correctly. At the same time, it is important to install only high-quality fittings into the plastic balcony door so that it closes securely. The main elements that have to be replaced after prolonged use are the handle and the lock. The lifespan of the structure depends on the quality of these elements.

When choosing, you should pay attention to such characteristics of fittings as:

wear resistance;
strength;
optimal cost;
compliance with quality standards.

You should not purchase too cheap accessories, as they may be of poor quality.

Types of handles

Handles for plastic balcony doors are divided into several types:

one-sided;
bilateral asymmetrical;
with burglary protection;
with standard locking mechanism;
shell;
petal.

They can also be divided by material, shape and color. Thanks to the large number of types of such products, you can choose suitable fittings for almost any plastic sash. When purchasing, you need to select fittings based on your requirements.

The described products can be installed on the balcony door either on one side or on both. Products of the first type have a fairly simple design and are easy to use. Such products are quite popular because they are less expensive and easy to use.

Double-sided balcony door handles are made of the same shape and connected using a metal rod. This type of product is more convenient to use.

If the balcony is located on the lower floors, it is worth purchasing accessories that are burglar-proof. A special mechanism allows you to reliably protect the apartment from penetration from the outside.

Often, apartment owners purchase products with a locking mechanism. This is necessary in order to prevent children from entering the balcony. This is convenient, since the balcony is not locked, but it is securely locked and cannot be opened by a child.

A design called a “petal” is often used. Such products are made from the same type of plastic as the sash. Such products are not equipped with a locking mechanism and are secured using self-tapping screws. The caps of the fastening elements are closed using special decorative elements.

Shell handles are also common. They are made from plastic and aluminum. They are usually installed on the outside of the balcony sash. They allow you to conveniently close the door from the balcony. They are more popular than double-sided products, as such products are compact and cheaper. The compactness of such products is important if the balcony is narrow.

Advantages and disadvantages of double-sided pens

The products described are quite reliable and simple, so they can be used for a long time without breakdowns. Most often, such products are made of metal. Also, double-sided balcony handles have other advantages:

Many design options for similar products. If desired, you can purchase products that will match the interior of the apartment.
Such products are easy to use. The locking mechanism of the double-sided handles works quite softly, so you don’t need to make a lot of effort to open the sash on the balcony.
Double-sided handles are made of materials resistant to temperature changes.
Such products can be installed on a profile of any width.

But the described type of handles also has disadvantages. You should not install such handles if the apartment is located on the ground floor. This is due to the fact that such products are easier to break into than one-sided ones. When choosing double-sided handles, it is worth installing special devices that prevent entry into the apartment.

If the balcony is protected by bars, you can use double-sided handles even without an anti-burglary mechanism.

How to install a balcony handle

Installation of the handle on the balcony sash is carried out as follows:

First, the standard handle is removed;
after this, the location for installation of the new product is marked;
using an electric drill, through holes are created in the profile;
after this, the metal strip is removed from the end of the sash;
a groove is created at the end of the blade for installing the locking tongue of the lock;

Traditionally installed metal-plastic structures are not equipped with locks for plastic balcony doors. This is connected both with the general concept, which considers balcony doors as interior doors, that is, located indoors and not requiring additional locking devices, and with the designs of the locking mechanism of these doors themselves.

But the practice of their everyday use has given rise to the need, in some cases, to install additional devices that block access to the balcony or, in most cases, on the contrary, protect against unauthorized access to the apartment from the balcony.

Why do you need a lock?

Installing locks on doors leading to the balcony is necessary in the following cases:

when there are small children in the house - to prevent them from going out onto the balcony without parental supervision;
when the apartment is located on the first or upper floors and the balcony is not additionally equipped with glazing or bars - for “uninvited guests”, simply thieves, to enter through the door;
when extremely inventive and intelligent animals (usually large dogs) live in the house, who easily learn to open doors by pressing the handle with their paws.

To protect yourself, your loved ones and pets, it makes sense to replace the door handle with a handle with a lock. Unlike latches, which fix the closed position of the balcony door, but do not prevent it from opening freely, both from the side of the room and from the balcony, a lock completely prevents this possibility.

There are several possible designs. All of them are adapted for installation in a metal-plastic balcony structure, allow you to change the handle and lock yourself, and differ only in minor technical details.

Types of locks

Of the locking devices used that can be installed in a PVC balcony door, the most common are locks with a cylinder mechanism. They are widespread and are installed both on entrance metal or wooden doors, and on interior doors that do not require special complexity or increased secrecy for the lock. This is exactly what most locks adapted for balcony doors belong to.

The principle of operation of the cylinder mechanism is that inside the drum - the locking cylinder - there are spring-loaded cylinders located in one or three planes, which, when the key is inserted, take a certain position and their protrusions do not interfere with the rotation of the key in the cylinder.

This system can have very high degrees of secrecy, preventing it from being opened by selecting a key or using all kinds of master keys, but the main advantages are the very small size and interchangeability of the lock cylinder, which can be replaced without disturbing the design of the entire door as a whole.

The second type is level locks. The principle of their operation is fundamentally different from the operation of a cylinder mechanism. The locking element of the lock, the latch, is activated mechanically by turning the key inserted into the keyhole, which lifts the spring-loaded plates with protrusions on one or both sides and thereby releases the latch of the lock for its free extension or, on the contrary, closing.

This type of lock is characterized by more bulky dimensions, is installed exclusively in the body of the door itself, and in the event of a breakdown of the mechanism or loss of the key, the door cannot be opened without breaking the structure. Considering the fragility of the design of metal-plastic PVC doors, the installation of such locks in balcony doors is very rare and is usually not provided for either by their design or by manufacturers.

According to the degree of fixation, locks are single-point - when the locking is performed at one point - usually at the point of extension of the standard lock latch. Usually this is sufficient for doors that do not play a significant barrier function, and for multi-locking doors - in which fixation occurs at several points (usually three) by extending the lock bolt in the area of the door handle and at the upper and lower points of the door. The use of a safe-type multi-locking mechanism, in which crossbars secure the door in four directions, is practically not used in balcony doors, since the unreliability of the door structure itself makes the use of such locks pointless.

Where are the locks installed?

The lock (its locking device) can be either separately located - not combined with the door locking mechanism, or integrated into the locking device, which makes its use more convenient and does not require any design changes to the door. The first time a lock is used is extremely rare. Requires a change in the door design and is practically not used in plastic balcony doors. The second one is widespread and there are a lot of manufacturers who produce replacement balcony handles with a built-in lock.

The lock can be installed both outside and on the side of the room. Usually it is enough to install only from the side of the room. Moreover, the lock may not be fully functional, but have a push-button or leaf lock, which prevents the door handle from turning, both from the living room and from the outside. If the goal is to prevent a child or animal from opening the lock, this is quite enough, but if we are talking about protecting against unauthorized entry through the balcony, of course, it is better and more reliable to use a cylinder mechanism with keys.

The cylinder mechanism can be located either indoors - in this case, when the lock is locked, the possibility of opening the door from the outside, from the balcony, or from the inside is completely eliminated. In this case, you can open the door with a key from the side of the balcony, and from the side of the room it is locked either with a push-button or a leaf lock. This scheme is also used very rarely, since it is meaningless. Exceptionally rare cases when the entrance to a room is arranged through a balcony - rather relates to the commercial use of premises on the first floors of buildings, when balconies are converted into vestibules or additional space.

Lock installation

Installing a lock with your own hands is not difficult. In terms of time, this manipulation will take no more time than replacing a broken door handle.

For installation, you need to select the necessary door handle in the store, equipped with either a cylinder lock with keys or a simple latch; it is desirable that the name of the manufacturer of this handle and the fittings that are installed on the doors coincide.

After this, you need to remove the old handle without a lock. All you need is a Phillips screwdriver. At the base of the handle, a decorative plug is pulled back and rotated 90°. The two self-tapping screws that secure the handle are unscrewed, the handle together with the square pin is pulled out, and a handle with a lock is installed in its place. Screwed on with old self-tapping screws, or those included with the handle, the decorative plug is returned to its place.

The only condition is that the holes for the screws match. It is advisable to take measurements between the centers of the holes on the old handle before purchasing a handle. But in the vast majority of cases, the sizes of handles with locks are standardized and are suitable for installation on almost any model of fittings.

Let's sum it up

Installing a lock on balcony doors allows, in some cases, to increase comfort, prevent accidental opening of the door and relieve additional mental stress typical of suspicious and anxious people, especially if they leave their home for a long time, going on vacation or on a business trip. While not a panacea for burglars, a lock on a door handle is sometimes useful, at least its presence does not in any way spoil the appearance of the door or its functionality.

Reading time: 8 minutes.

The latch is a mandatory element of the fittings for a balcony door made of PVC profile. For a home craftsman, information about its purpose, classification and operating principle of each type will be useful. Tips from the practice of using balcony latches will also be useful.

Purpose of the latch

The plastic door latch is a very useful, convenient and functional part of modern door hardware. The simple principle of operation, similar to the operation of the latches on the doors of kitchen cabinets, allows you not to be distracted by monitoring the position of the door. The latch mechanism is designed for the door to be opened freely by a person (if necessary) without applying any serious effort. But at the same time, the closed position of the door leaf is not disturbed by strong gusts of wind. Keeping the plastic door from swinging open while the door lock mechanism is in the unlocked position is the main task of the installed latch.

Another, household name for the mechanism is the smoker’s latch. The explanation for this is simple: just slam the door shut and the smoke will no longer be drawn into the living space; Tightly closing the balcony door with a lock is not required for a short visit to the balcony or loggia. If you use a one-way lock (its handle is located on the side of the room) and there is no latch, the door cannot be closed when exiting to the balcony. So, the usefulness and necessity of installing a latch on the balcony door is obvious.

Types of door latches

The main difference between the latches used is in the locking mechanism. Based on this feature, the following types are distinguished:

Sagging of the door leaf, its skew, or changes in the geometry of the frame structure can disrupt or make it impossible for the roller and latch to function properly. The working latch (in the form of a roller or beveled tongue) must fit exactly into the striker clamp mounted on the frame. Emergency adjustment consists of adjusting the door leaf using the fittings screws. During the setup process, the position of the door relative to the frame opening is adjusted. In this case, the leaf can be raised, lowered, shifted to the right or left, its top or bottom, and adjusted the force of pressing the sash to be opened to the frame. If this adjustment does not help to establish the correct operation of the latch (in general, this is very rare), you will have to dismantle and reinstall one of the parts of the mechanism. Usually they move it in the desired direction and attach the bar with the groove.

The magnetic latch does not create problems in this regard. If the initial installation is correct, its correct and reliable operation will not be affected by a slight misalignment or sagging of the door.

Installing the magnetic latch takes a few minutes

Another characteristic difference between latches. If the halyard and roller ones close with a characteristic click, then the magnetic ones hardly disturb others.

Due to the fact that the functional elements of the latches are attached to the end part of the frame and door profile, they are not visible from any viewing angle. This feature helps to preserve the strict classical aesthetics of not only the door, but also the entire structure installed in the opening.

Caring for all types of latches is very simple. Periodically, their mechanisms are wiped from dust, dirt, debris and lubricated (except for the magnetic latch plates) with a special product for window fittings. Any silicone grease or regular machine oil (spindle) will also work. The main thing is to be sure that the lubricant composition used does not include resins, acids and other aggressive substances.

External handle

Handle - plastic petal

To close, or rather pull, the door from the street side, it is necessary to provide a special external handle. Made of metal, more often of durable plastic, the handle visually resembles a shell or petal in shape. A plastic shell is much more pleasant to the touch, especially in the cold season. But it is easier to break if used carelessly, and the material itself has a tendency to break down under prolonged exposure to sunlight, freezing temperatures and other external factors. The main advantages of a more expensive metal handle are resistance to mechanical loads and a long service life. Typically, the outer door pull handle is located at the same height as the lock's rotary handle. This position for closing the door is very convenient.

You can do without an external shell handle only if the door lock mechanism is double-sided, that is, internal and external rotary handles of the lock are required.

Double-sided handle for a plastic door

The choice of external handles in specialized companies and construction supermarkets allows you to choose a copy with a convenient ergonomic shape and the desired color.

When installing yourself or replacing latches, it is advisable to use screws: no shorter than 30-35 mm– for fastening the roller cylinder with a safety margin; no longer than 19 mm– when installing an external handle (this ensures that the screw will not reach and damage the glass unit during installation or further operation of the handle).

Latch Installation

When starting work, you need to be sure that in the near future its position relative to the frame opening will not change. If necessary, you will have to independently set the position of the door leaf and the pressing force against the frame when closing it with the rotary handle. The door hinge screws will help with this. Now let's move on to the main installation. A screwdriver or a more convenient screwdriver will be enough; for marking, take a pencil.

The easiest way is to install a magnetic latch. No special setup or precise installation is required. Both strips are simply attached at the same level - to the end of the door and the frame profile. A slight shift in relative position will not in any way interfere with the correct operation of the latch.

Opposite the latch, make a mark with a pencil and attach the striker in the center of the groove.

Another thing is with the roller and halyard latch mechanism. In both cases, the exact position of the bar with the groove relative to the latch is required. Without any doubts or measurements, we attach the latch itself to the seat of the balcony sash. Opposite its center, we draw a line with a pencil and draw this line outward so that it is noticeable when the door is closed. Having closed the door, we mark a similar mark at the same level, but on the frame. At this height the center of the grip of the strike plate should be located. Now we fix the bar with the lock along the mark with one screw and check the correct operation of the mating elements. If the result is negative, the bar is shifted and the performance is checked again. If further adjustment is not required, the bar is secured with a second screw.

The entrance balcony door is quite rarely equipped with a lock - in an apartment it plays the role of an interior door, separating the living space from the loggia or remote balcony. The doors to the balcony are not designed to protect the home from penetration, therefore they are structurally made of light and less durable materials than the entrance ones.

A lock for a balcony door may be needed to prevent small children or overly intelligent pets from entering the room. Sometimes a loggia is made into a small living room, workshop or office, and its owner wants to avoid access of unauthorized persons to his personal space.

A lock for a wooden or plastic balcony door can serve as additional protection against penetration if the home is located on the ground floor of the building and the balcony or loggia is not glazed.

As a rule, entrance doors to balconies are not highly durable and wear-resistant, so the locks installed in them differ from the types intended for entrance door leaves.

Fig. 1 Locks on plastic balcony doors - appearance

It makes no sense to install a door-mounted lock on a balcony door - usually the locking mechanism is placed in the handle. In addition to its small size, it must be lightweight, and its design must have a simple mechanical locking system - balcony doors are classified as interior doors.

Types of balcony locks

For installation in door handles, the following types of small-sized locking mechanisms are used:

Cylinder. They have a small cylinder for placement, the degree of their secrecy is determined by the number of locking pins - for balcony handles it is more practical to use the simplest designs.
Handles with fixation. Most doors have simple handles with a key that prevents them from turning.

Rice. 2 Cylinder lock mechanism - device

The following types of locking mechanisms can be installed directly into the door leaf:

Mortise. They are inserted into the end of the leaf, the locking tongue is fixed in the recess of the door frame.

Magnetic latches. In this case, a strong magnet serves as a lock, preventing small children or animals from opening the sash.

Locks for sliding systems. These devices are specially designed for structures with parallel movement of the door leaf relative to the frame.

According to their design, locking handles can be divided into several types:

Double-sided with rotary knob. The design can be used to lock windows and balcony sashes; the handle with a locking mechanism is installed indoors, and the knob is installed outside.

Steam room. During installation, the locking mechanism is placed inside the room, and the outside handle is used to close the door from the outside.

Steam room with a button. Such types are usually installed in sanitary facilities to prevent external access; sometimes they can be used for similar purposes in PVC balcony sheets.

Single. They are installed indoors; a separate handle is used for external opening.

Rice. 3 Types of door handles: double-sided with wing; steam room; steam room with button; single

Locks for sliding PVC balcony doors

Sometimes in large apartments or country cottages they use accordion-type doors to the balcony or sliding structures. In the latter case, when opening, the door leaf moves parallel to the frame - this design requires the use of a special mechanism for closing, different from analogues for swing structures.

Mechanical constipation

The easiest to install and use are mechanical locks, consisting of a retractable latch and a metal plate that secures the tongue in the closed position.

Rice. 4 Locks for sliding sashes: overhead and mortise

There are two types of locking mechanisms installed on the entrance plastic door and methods of their placement for closing sliding balcony doors:

Invoices. The lock is installed on the door frame, and a lining is fixed on the front side of the door leaf and a recess is made for the retractable tongue. This design is easy to install and has a low cost.
Mortise. The locking mechanism is cut into the door leaf, a lining with a slot is attached to the frame and a recess is made for the retractable tongue. Installation of this type of lock is similar to conventional mortise locks; it differs only in the design of the tongue, which has a cap hook at the end to prevent the doors from opening to the side.

Electromechanical (magnetic) locks

The door is closed using an electromagnet, which holds the door in the closed position due to a powerful magnetic field. The devices are expensive, inoperable in the absence of electricity, and therefore are rarely used in everyday life.

Fig 5 Design and external electromagnetic lock

Installing a manual locking mechanism yourself

Before installing a handle with a lock on the door, you should purchase fittings from the same manufacturer - it will optimally match the parameters of the door leaf and will not disturb the aesthetic appearance.

To install a lock on a plastic balcony door to replace the old handle, you do not need a special tool other than a Phillips screwdriver; the work consists of several simple operations:

We remove the old handle. To do this, turn the plastic decorative trim 90 degrees and unscrew the screws securing the old handle and remove it.
Install the new handle and secure it with screws.
We check its functionality with the key turned in the keyhole.

Rice. 6 Installation of a balcony lock

If standard handles are installed on the entrance door to the balcony, you should consider the following - it is easier to make a modification by replacing the conventional rotary handle with a model from the same manufacturer with a built-in lock. If you have sliding balcony sashes, it is more aesthetically pleasing to embed a locking mechanism with a hook into the leaf than to use cheaper overhead models.