print font size How to new heating in an older house

It is up to you to decide what will change about heating, but it is advisable to consult an expert (architect, designer, heating engineer). This is the only way to save unnecessary work and money. In our article, we will now focus on hot water heating solutions.

Why change the heating at all

You may have recently bought an older house with the proviso that you will completely renovate it, so together with, for example, insulation, new windows, change of partitions and the like, you are also counting on new heating. Or the heating system has simply survived, for example, sheet metal bodies are starting to corrode, an outdated boiler wants to be replaced with a new one, and the cost of operating the heating is high. However, you may want to change the heat source yourself. Another reason for the change can be wiring if it is in technically poor condition, or a completely different reconstruction (new electrical wiring, tiling, paving, kitchen reconstruction and others). When it comes to walls or floors and then new plasters are solved, it is better to implement everything at once.

"The design of the new heater is based mainly on the calculation of heat losses in the house or individual rooms. These are calculated according to the Czech state standard and the calculation is based primarily on the location in which the house is located, the properties of the building structures of the house and the purpose for which the room will be used. It is also necessary to take into account the type of heat source, "explains designer Světlana Votavová from EkoProjekt. Everything else is derived from this input information, including, for example, the size of the radiators, the dimensions of the pipes, the size of the heat source or the power of the circulating pump.

"Very often, I find that the performance of a heat source is very underestimated, while it also has a major impact on the life of this source and operating costs. For example, if a homeowner with a heat loss of 8 kW chooses a boiler with an output of 8 to 20 kW - due to heat loss, the boiler will switch on and off for most of the heating period (since around 0 ° C the house does not lose 8 kW, but about 4.5 kW ). In this case, it would be ideal to choose a boiler with an output of 2 to 15 kW (taking into account that the boiler is also preparing hot water), "adds the expert.

What can change

First of all, you are dealing with a heat source, hot water distribution and radiators, or underfloor heating, or you can buy convectors, for example. "A new circulating pump is also suitable, replacing the original with a variable speed pump. The two-position taps on the radiators are also being replaced by thermostatic valves with heads. Furthermore, it is possible to change the expansion vessel, which balances the water expansion pressure.

Previously, an open expansion vessel was used, currently it relies exclusively on pressure expansion vessels, ”recalls the designer. And he adds that a pressure expansion vessel is something other than an accumulation vessel that accumulates heat produced from a source, such as a solid fuel or biomass boiler or a fireplace. Thanks to this vessel, you do not have to cut the boiler's output, which saves it, and at the same time there is the possibility of connecting other sources (solar collectors, electricity - direct from the grid or from photovoltaics).

Heat sources

Most often it is a question of replacing an old boiler with a new one or a heat pump, another source can be a fireplace or a stove with an exchanger, the options are often combined. Each of us has different preferences, yet today the most used condensing boilers for natural gas, but also increasing the number of investors who prefer heat pumps, usually air / water (usually the heat pump consists of two units, where the outdoor unit is located at the house and the indoor unit is installed, for example, in the utility room or bathroom).

If you only need to change the source, for example a coal boiler for a gas boiler, check the possibility of installing a new source due to the size, type and connection to the existing hot water system. Remember: when replacing the source, whether you are considering a new boiler or a heat pump (which is usually possible when the house is insulated, which reduces its heat consumption), you need to know the heat loss of the house and the performance of radiators.

Piping

In the past, family houses used a self-weighted water circulation system based on different temperatures - heated water rises and pushes out cold, it falls down, then it heats up again in the boiler, rises again… In this system, metal pipes of larger diameters and usually heavy cast iron radiators, due to the large volume of water, the system was less well regulated. Today, heating reconstructions usually rely on forced water circulation, which is provided by a circulating pump. The only downside will be that you need electricity to run the pump, otherwise smaller diameter pipes are planned here and the radiators may have a more subtle wall and consume less water.

Where will the new divorces lead? It is essential that they remain hidden from our sight. "Classic pipes can usually be stuck in the wall or placed in the nickname (but this solution takes up space, and therefore is suitable mainly for large rooms, at the same time reducing the efficiency of heating). Then you can only see the radiators, not the wiring. And if you prefer hot water underfloor heating instead of radiators, the pipes will run through the floor. Underfloor heating is often combined with convectors, which are designed near the windows and serve as a 'heat shield' to prevent cold from the windows, "says architect Miroslava Karasová.

Piping materials

Světlana Votavová recalls that copper pipes are mostly used for distribution today; Although they are more expensive, they resist corrosion and work with them is faster, so the final price is comparable to steel, where the material is cheaper, but the price for work is higher. Furthermore, plastic pipes are used, more precisely - pipes composed of several layers of plastic and aluminum, which offer easier installation. The use of certain distribution materials affects the choice of radiators, especially their connections, as well as the volume of water in the system.

"Plastic pipes with an oxygen barrier and, for example, an aluminum layer are mainly used for underfloor heating. These are not massive pipes. Those designed for underfloor heating tend to be 16 or 18 millimeters in diameter, and pipes used for hot water distribution to radiators have about 28 millimeters at the source (eg boiler) (depending on heat output) and 16 millimeters at the radiator itself. , "Specifies the designer. We must also not forget to insulate the wiring in the boiler room and places where the pipes running along the surface are not used for heating.

Beautiful new radiators

Although the replacement of the heating system in the house is a purely technical matter, you will also enjoy the design - if you buy new radiators. First of all, let's reveal: can old radiators be replaced with new ones? Sometimes yes, other times no, it is always necessary to have a specific case assessed by an expert. Among other things, it depends on how the body is connected to the pipes, but also on whether the house already used the already mentioned gravity water distribution system - in his case, simply replacing the radiator "piece by piece" is often so technically demanding (if not impossible) that it pays to renovate the entire heating system.

Depending on the type of heating, we distinguish between hot-water, combined (hot-water + electricity) or electric bodies. From the point of view of materials, steel, stainless steel, aluminum, but also cast iron are often used, and in design products additionally wood or glass. Otherwise, the current design offer does not know too many restrictions - in addition to standard products, you can choose a radiator that is literally tailored, whether it is size, surface finish, color or other gadgets. The radiator then serves, for example, as a mirror, a painting or an interesting interior artifact; For example, photos of your choice can be printed on some products

"Today, panel radiators are the most common, but tubular radiators are also experiencing a boom in the form of bathroom ladders and also as purely design elements in ultra-modern interiors. A new type of radiator has also appeared on the market, which heats the space only in the front part of the body, so it has less heat loss, ”says Miroslava Karasová.

How to regulate heating

There are several options and they can be combined. For example, today it is common to fit radiators with thermostatic valves with heads either manually adjustable, programmable, or remotely controlled. In family houses, either equithermal control is usually added (the temperature sensor is installed on the north side of the house and the heating water temperature is controlled according to the outdoor temperature), or an internal programmable thermostat can be used, which is installed in the reference room (usually either the most used room, such as the living room, or the coldest room in which you need to provide enough heat - such as a study on the north side of the house).

In this case, the circulation pump is switched based on the temperature demand in the reference room and the heating water is permanently set to the heat source. There must be no thermostatic heads in the room where the room thermostat is fitted, other rooms, on the other hand, are "adjusted" using these heads.

Underfloor heating can also be equipped with a thermostat, you can regulate the temperature in each room separately or from one place for all heated rooms.

But time goes on, so today it is offered to connect the heating to the so-called intelligent control of the house - then you will control it even remotely, for example using a smartphone or computer.

One source is not enough

At present, heat sources are combined, and there is an incredible amount of variation.

"When repairing the house, we bought a new wood boiler and another gas boiler as insurance - when we go on vacation or the children are alone at home, we heat with a gas boiler. It's comfortable and safe. But because we like wood and our costs are the cheapest, we usually use a wood boiler. We installed radiators in the house, because we think that the heat they radiate is healthier for the body - it will not become as delicate as if we chose underfloor heating, "offers the reader Jiří. On the contrary, the reader Martin chose a combination of an electric boiler and a fireplace with an exchanger, at home they bet on underfloor heating in conjunction with a fireplace, which is connected to the hot water distribution in the house.

"We are more comfortable feeling the warmth of our feet, and we believe that the 'floor' makes the dust swirl less when the warm air slowly rises to the ceiling," says reader Martin. And the reader Eva again decided on a heat pump, which she supplemented with a fireplace stove with a hot water insert, and only because the heat pump has been happily used by her friend for several years and the fireplace stove was easier to install than if she opted for a fireplace. Obviously, each of them prefers something different, also for different reasons, but common to all is that they combine multiple heat sources. In addition to comfort, it is a practical aspect: if one source "falls out", the other remains available.

But when choosing, think about the future. Maybe you love wood and now you can't imagine ever drowning in something else. However, heating is an investment for several decades, so consider whether you will have not only enough wood in ten or twenty years, but also the strength needed to process it.

Chimney to the end?

When considering changing the heating source, you will, among other things, decide whether to keep the old chimney, reconstruct it or get rid of it at all. "You need a chimney for all solid fuel and gas boilers (except for the turbo boiler, which diverts the flue gases through the wall to the outside). And even if you do not plan to use it to remove flue gases from the heating after the reconstruction, it is better to keep the chimney and possibly use it to extract air conditioning from the sanitary premises of the building or the fume hood. Chimney removal is not recommended mainly due to the fact that it is often part of the load-bearing structure of the house, so the statics of the building could be endangered, ”recalls the architect. And let's add that the chimney must be inspected by the chimney sweep after each reconstruction.

But maybe you have a different opinion on your old chimney. "Our house even had three chimneys before the reconstruction and we had them all demolished. Due to the layout solutions and the fact that their renovation would cost us more than the construction of one new chimney, which we also did in the end, ”says reader Jiří. As you can see, renovating a new heater in an old house can really have many right solutions. So let's go back to the beginning - so that you do not make an unnecessary mistake when renovating the heating system, it is worth discussing your ideas with professionals, thanks to which you can save. Money and unnecessary worries for the future.

Fireplace as a source of heat

Are you considering buying a fireplace or fireplace as a source of heating? "Start at the chimney first - it determines where the fireplace or stove will stand. If the existing location does not suit you, you can change it, ie build a new chimney. Otherwise, the old chimney must be revised, or milled and lined. Its diameter affects whether you can buy a stove (150 mm) or a fireplace (200 mm). You also have a choice of fireplace or fireplace stove, either hot air or hot water. Each solution has its pros and cons, in general, fireplaces are easier to position, place and in many cases cheaper. In addition, they do not need as solid a foundation as a fireplace and can be transferred. I recommend providing an external air supply for the fireplace and stove, “says Mikuláš Hořánek from Atelier original HOŘÁNEK.

Temperature gradient

You need to know this information to know how much radiator area you will need. The temperature drop is given by three values, for example 70/60/20 ° C (if a boiler is used as the source) or, for example, 50/40/20 ° C (a low-temperature heat pump or condensing boiler is used here). Specifically, the first digit indicates the temperature of the water to which the source heats it, the second digit indicates the temperature coming from the radiators (floor heating), and the third indicates the room temperature.

Boiler and radiator output

Performance does not exist in itself, it is necessary to take into account a number of data, including insulation, building materials used, windows, room size and their orientation to the world, the volume and temperature of heating water and more. However, you can calculate the boiler output by multiplying the volume of the house in cubic meters, for example, by the number 50, ie 50 watts (some sources say that it is better to multiply the lower number, even 35, for insulated buildings, others prefer higher - recommend multiplying number 75, for uninsulated houses). Similarly, you can calculate the approximate power of a radiator in a room to a certain temperature gradient.

How long and for how much

The overall reconstruction of the heating system depends on many factors. For a better idea, here is a model example of a single-storey house with an attic of 160 m2. Heating reconstruction can take about 10 to 14 days.

And how to choose the BEST realization company? As with everything else, this also applies: find out as much information as possible (on the Internet, at the companies themselves, ask relatives and friends who have a similar experience) and compare individual offers according to the same parameters.

No major interventions

If someone opts for electric underfloor heating, there are no worries in case of renovation. Electric heating mats are ideal for renovations - such as bathrooms or corridors - and their installation is cheap and quick. Since the floors in older houses and flats are often insufficiently thermally insulated, it is advisable to first lay insulation boards on the floor - eg F-BOARD (Fenix ​​Jeseník) in thicknesses of 6 or 10 mm. Under standard conditions, the floor in which electric underfloor heating is installed is heated from 20 ° C to 28 ° C for about 1-1.5 hours.

However, with the mentioned insulation boards, the floor can be warmed up in just 10-15 minutes. You will especially appreciate this feature with additional comfortable floor heating - for example in the bathroom or kitchen. You can then place a heating mat or heating cable on the insulation boards and pull with a flexible sealant. In addition, the new floor with insulation board, mat or cable, sealant and final tiles does not exceed a height of 2.5 cm! Electric underfloor heating is universal and can be used for heating under any type of floor covering.

If we are going to heat the floor from tiles, the choice is clear - heating cables or mats. Cables and mats are also used for cork floors, and it is suitable to use thin ECOFILM heating foils under laminate and wooden floors. These foils combined with insulation boards are suitable as a dry installation system for renovations and additional installations of underfloor heating under carpets or PVC.

The article was published in the magazine Bydlení, stavby, reality.