To plan a winter garden already with the new building has many advantages in relation to a later realization. A so-called residential conservatory is a living room extension that allows you to sit in the sun even in winter with pleasant warmth. The glazing acts as an energy collector and warms the conservatory independently in cool months. Nevertheless, residential conservatories must be installed heating for the cold winter period. Find out about all the important aspects of the winter garden in this article!
the essentials in brief
- If you plan a winter garden during the construction of the house, you can align it perfectly and do not have to tear down walls afterwards.
- In most cases, wood, aluminum or wood-aluminum combinations are used for the support structure (steel or plastic are used less frequently). Wood blends in best with the surroundings of the garden, but also needs regular treatment. Aluminum, which is the most commonly installed, does not require this treatment, but is less in harmony with the environment and is rather unpopular with environmentally conscious builders.
- Residential conservatories are a heated living space extension. There are different heating technologies, and it depends on the individual heating profile. The conservatory consumes less heating energy overall throughout the year than compact rooms, but higher peak power must be available in winter.
The living conservatory
The living conservatory connects directly to the house and extends the living area of the house. Therefore, it is also heated. They are also called “lean-to” conservatories. Various design options for the additional living space are conceivable. For example, with a winter garden you can dine in the garden all year round. With the right cloud cover and orientation, the breakfast table is then also always in the sun. Likewise, the winter garden can be used as a living room or study. In addition, it is excellent to accommodate tropical plants or vegetable and fruit plants.
The cold conservatory
The cold conservatory is not an extension of the living space. This variant is usually a freestanding structure without direct connection to the living area and is usually not heated – if it is, then at most to about 12 degrees. In winter, the cold conservatory often serves as a refuge for frost-sensitive plants. Nevertheless, even here, if, for example, a garden bench is placed, the winter sun can be enjoyed a little more protected behind the glazing.
Planning and approval
Of course, conservatories must also be approved by the building authority in terms of building law and construction . This often leads to restrictions (and discord with neighbors) in the case of subsequent realization. Builders who take into account a winter garden directly during the planning of the construction of the house, do not have these problems. There is then also no need to subsequently tear down a house wall, and the size and orientation can be taken into account from the very beginning. The regularity of the conservatory in such cases is also already confirmed with the design documents of the overall project and the building permit from the building authority.
The distance areas to the neighbor defined in the public building law are decisive for the application. These are regulated in the building codes of the federal states and amount to an average of three meters or, in the case of taller buildings, the height of the building. In the case of extensions such as a conservatory, however, a so-called boundary development can be carried out under certain circumstances. Boundary development occurs when the distance falls below the minimum distance to be maintained. This is possible only with the express consent of the neighbors and a permit from the building authority. Here you can learn more about distance areas and boundary construction.
Design and construction methods
The construction of the winter garden consists of a foundation, the support structure and roofing. The foundation is poured concrete. The supporting structure can be made of wood, steel or aluminum, as well as wood-aluminum combinations (more rarely plastic). The roofing is made of glass (less often plastic).
There are high demands on the foundation of a winter garden. For a winter garden has a weight that should not be underestimated, so it can not be built on a terrace. In addition, the foundation must be frost-resistant. This already requires a foundation depth of at least 80 cm. For conservatories are usually used the following four types of foundations: Point, ring, strip foundations and foundation plates. Important are the following requirements for the foundation:
- Load capacity
- Waterproofing against moisture and frost resistance: Keeping precipitation and condensation water away from the structure
- thermal insulation
There are two common variants for the beam construction: the element or frame construction and the post-and-beam system.
Element or frame construction
The great advantage of the element or frame construction is that it hardly obstructs the view of the garden with construction elements (struts, brackets). This variant therefore offers the best field of view. In addition, the element or frame construction method is characterized by quick assembly on site, as the elements are prefabricated. Frame sizes are variable and can therefore be selected as desired. However, compared to the second variant – the post-and-beam system – this design has less stability.
Post and beam system (also called column and beam system)
The disadvantage of the mullion-transom system compared to the element or frame construction described above is that the view to the outside is obstructed to a greater extent by construction elements (struts, brackets). An advantage, on the other hand, is that this support structure is more stable. And this is not unimportant when roofing with heavy glass panels. Glass breakage also occurs less frequently here, as the mullion-transom system independently compensates for minor stresses. In addition, the construction is simpler than the first variant, but requires a longer assembly time on site, because the post-and-beam system is not prefabricated.
Beam construction material
The material for the support structure can be wood, aluminum, wood-aluminum combinations or steel.
Beam structures made of wood are very popular. It is natural to choose this material: The winter garden is always also about being in contact with nature – wood blends best with the surroundings of the garden and creates atmospheric connections from the outside to the inside.
It is possible to choose between different types of wood. The fact that wood is a natural and renewable material also makes it the preferred building material of the environmentally conscious builder. Compared to aluminum, which is energy-intensive to produce, wood has a much better eco-balance – and is cheaper!
In addition, wood has very good heat-insulating properties and is resilient and load-bearing. The disadvantages lie in the regular treatment that wood requires: The wood preservative glaze must be renewed at intervals (4-7 years) to keep the wood weather resistant in the long term. But this effort is manageable. If you have a garden, you are often busy with one task or another anyway – it’s part of the job and keeps you fit.
There are also wood-aluminum structures, which are aluminum on the outside and wood on the inside. Here, the advantages of both building materials are profited from (see below).
Aluminum winter gardens are most often purchased. This is due to the fact that they are very easy to care for and robust. It is light and therefore easy to work with material, which is also less demanding on the foundation. Weather resistance is high and the material has an almost unlimited service life. However, it is less load-bearing than wood or steel.
Compared to wood, aluminum has the advantage that it does not require regular treatments for long-term weather resistance. The disadvantage is certainly that the material aluminum is less suitable for the garden flair. Only wood is able to create a harmony of the winter garden and surrounding plants.
In addition, aluminum has poor thermal insulation properties: it is very conductive, so heat loss is to be expected. Therefore, the elements are thermally separated so that the inner construct does not have direct contact with the outer one. Thus, the special conductivity can also contribute to the fact that the heat inside is quickly distributed throughout the structure and also reaches cold areas where condensation collects. Nevertheless, wood as a building material has better thermal insulation properties.
For environmentally conscious builders, it should also be noted that aluminum consumes a lot of energy in its production and is therefore not valuable from an ecological perspective. Wood, on the other hand, is considered an ecologically valuable building material.
With wood-aluminum combination can achieve very good results. As a rule, this support structure is made of aluminum on the outside and wood on the inside. Here, the advantages of both building materials are benefited: The aluminum used on the outside does not require regular treatment and the charm of the wood is at least in the interior view. However, these combination solutions are usually also more expensive.
The first disadvantage of steel is obvious: it is very heavy. Thus, the entire winter garden increases enormously in weight, which in turn places special requirements on the foundation. Another disadvantage is that steel corrodes easily, which entails regular, quite costly treatments. For these reasons, steel is not the preferred material for conservatories for private use. On the other hand, steel is used for greenhouses or for elaborate, multi-storey structures where very high robustness and load-bearing capacity are required.
The glazing and its properties
The glass is the central element of the winter garden: it allows the free view out and the sun’s rays in. In addition, the glass fulfills the following additional functions: Thermal insulation, solar heat gain, sound insulation, solar control, burglary resistance, fall protection (overhead glazing). The classic roofing of a winter garden, of course, relies on real glass. But there are also roofing with plastic. The great advantage of plastic is the low weight, disadvantage is the poor visibility property. Often this is the right solution for conservatories that are not intended to be used primarily as living space.
Glass as an energy collector
The large glass surfaces provide solar heat gains. Therefore, a winter garden requires less heating energy than a compact room. It always depends on the orientation of the conservatory (optimal is the sunny or south side) and the size of the glass surface as an energy collector. In good conditions, it can be assumed that 200-280 days a year no heating operation is necessary to use the room at comfortable temperatures.
Compared to the house, the winter garden will not be possible to heat for about two months longer in the fall and spring. The radiation gains are then perfectly sufficient to keep the room pleasantly warm, if necessary. even heat adjacent rooms as well. Of course, the sun must not refuse its service for this and the location also plays a role here. Radiation density and gains are lower in winter.
Heat loss through the glass surface
On winter days with little (and little intense) sun, the large glass area is accompanied by a high heat loss, which is greater than in compact rooms. Therefore, please note: Even if a conservatory requires less heating energy annually than a compact room, it needs a greater heating capacity in winter to keep the room pleasantly warm – this heating capacity must then also be available (see below).
Insulating glazing for thermal insulation is now standard in new buildings and also in conservatories. In the case of insulating glazing, a filling gas (air or inert gas-air mixture) is located in a space between two panes, which counteracts heat loss due to its poor heat-conducting properties.
In addition, the so-called “low-E coatings” are used. This is a barely perceptible coating that reflects infrared heat radiation back into the interior.
Triple insulating glass, in which an additional third pane is used, is nowadays already standard in many new buildings – it should also be used in any case for the conservatory.
There are options for insulating glazing that exceed the energy-saving regulations of EnEV 2014 that must be complied with. However, keep in mind that very high thermal insulating properties of glazing are often accompanied by less solar heat gain. Professionals can find specific solutions to fit the location and orientation.
The winter garden roof
For the glass of the conservatory roof, the so-called overhead glazing, laminated safety glass (VSG) must be used for safety reasons. In this way, personal injury can be avoided in the event of glass breakage. Such a glass consists of two glass sheets, which are connected with a transparent film. In the event of glass breakage, such composite panes can not fall apart.
It is only possible to destroy laminated glass from the outside with great effort and noise. Laminated safety glass (LSG) is considered largely burglar-proof. Therefore, for protection against burglary, the walls of the winter garden can also be covered with laminated safety glass. Of course, such equipment is reflected in the price, but it is recommended, for example, in secluded residential areas.
The terrace roof
The terrace roof is a glazed roof that protects the terrace from the weather. Rain is then no longer a problem in the summer, garden furniture with upholstery and other items now do not have to be saved from heavenly flash floods. You already know it: An awning placed in position against rain only holds up until the water bubble that forms inevitably empties.
The glazing of a patio roof is laminated safety glass (LSG), as must be the case with any overhead glazing. Alternatively, and cheaper, you can also resort to plastic. The sides can be protected against wind by various systems (e.g. awnings, glass or window elements). This creates cozy and atmospheric rooms, where a summer rain shower can be very relaxed.
Heating in the living conservatory
The living conservatory is an extension of the living space, which must also be heated. In good conditions (location, size of the glass surface, orientation) between 200-280 days no heating is needed at all. Here, the solar heat gain (radiation gain) is sufficient to keep the conservatory sufficiently warm. In comparison with compact rooms, less heating energy is required over the year. However, the thermal insulation properties of the glass surface are much worse than compact rooms. Therefore, higher peak powers are also required in cold winters than is the case in compact spaces. The heating technology must then also be able to provide this. Otherwise, the pleasant stay in the winter garden is not possible, and there is a risk of permanent condensation and mold.
It is recommended to connect the heating system of the winter garden to the heating system of the house. For this purpose, it is necessary to resort to radiators or convector heating. Convector heating can also be well combined with other heating technologies. To ensure optimal air circulation (convection), the radiators are best placed in the coldest places.
Combinations of heating technologies or the decision for a heating technology should be based on the usage profile. Below you will find a description of the various heating technologies.
This classic and most common variant heats the air by means of radiators. The interior and exterior envelope are heated by the air rising from the radiators. In the process, heat is released to the outer shell so that the air becomes cooler again and sinks back down the walls opposite the radiator. Thereupon it is heated again by the radiator. The circulation of air is called “convection”.
Heating the living winter garden with heat pumps has the advantage of independent regulation of the indoor climate. The technique can be programmed to a temperature, which is then maintained independently. This includes not only heating, but also cooling. The disadvantage is that for year-round use of the winter garden, the rather low heating capacity will usually not be enough.
This heating technology also allows the use of various filters controlled by blowers. This can help to purify the air (e.g. in case of large pollen load and allergies) and dehumidify it. For allergy sufferers, this is a great advantage at pollen-intensive times.
Heat pumps are recommended especially when there is a lack of space. The blower technology is very flexible in terms of attachment. In addition, this heating technology is recommended when it is not necessary to maintain high temperatures throughout the day, because the winter garden is not fully used every day from morning to night.
There are a number of different heat pumps. In any case, for the plan to install them in a winter garden should consult with an expert. Heat pumps are not always suitable. Because it depends on the size and type of the winter garden and how and when it will be used – because the heat pump is not the most effective heating technology and will usually not be sufficient in the winter. The use of heat pumps should therefore be precisely matched to the usage profile. Here you can find a detailed article about heat pumps and their possible applications.
Heating residential conservatories with underfloor heating alone is not recommended. After all, this entails some disadvantages that cannot be dismissed and do not ensure optimal use of the additional living space:
- No air circulation: cold corners of the conservatory are difficult to reach by the heating. Condensation that forms there can then also dry off poorly. There is a risk of mold growth.
- It is comparatively difficult to react to fluctuating temperatures.
- The demand on the insulation of the floor panels is enormously high.
For these reasons, underfloor heating systems, if used, are often combined with convector heating systems. The radiators can be placed in the coldest parts of the window front and regulated as needed. The radiators are then also smaller than with convector heating alone, which in turn brings spatial advantages.
Heating by means of radiant heat works, for example, infrared radiators. Radiant heaters can be installed in the wall of the house or even in the glass wall of the winter garden. They create a pleasantly warm feel-good climate. Compared with convector heating or heat pumps, this variant is rather more costly overall.
Note that this heating technology is best used only in combination with convector heating. This is the only way to achieve adequate air circulation and sustainably prevent moisture and mold growth.
Baseboard or skirting board heaters
This variant is similar to hot water heating. Good heating performance is achieved with a small amount of water, making this heating technology extremely energy efficient. The heating strips are mounted on the large glass walls and distribute the heat economically and steadily on the surfaces that otherwise cool down quickly. Another advantage of this heating technology is that it can be very well retrofitted in self-assembly.
Again, this heating technology is best used only in combination with convector heating. This is the only way to achieve adequate air circulation and sustainably prevent moisture and mold growth.
Costs winter garden
It is not possible to make more accurate blanket statements about the cost of a winter garden. It always depends on the size and type of construction, and also on the company performing the work. In addition, many offers refer to retrofitting. Thus, one’s own ideas should be discussed in detail with the executing companies. It also depends on a smooth process without delays within the entire house building process.
Nevertheless, the following guidelines regarding the costs of a conservatory should be mentioned here as a precaution:
- The simplest version of a residential winter garden made of aluminum incl. Construction of the foundation and installation of convector heating can be estimated at least 2000 € per m².
- Wood-aluminum structures are usually more expensive than wood or aluminum structures.
- Constructions made of wood are usually cheaper than constructions made of aluminum.
- A simple design of a terrace roof made of aluminum incl. Construction of the foundation can be estimated at least 650 € per m².
Tip Talk to different providers and compare the scope of services offered. Also compare different reference objects. So you can get an idea of different sizes, types and prices.
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