The grace period was long, but now many old heaters are saying goodbye to the boiler room: You have to go to the junk. Since the beginning 2002 is the new Energy Saving Ordinance (EnEV) in force, which sets new standards for the consumption of fossil fuels and wants to drive all energy wasters out of the boiler room in the long term. Anyone who buys an old building with a heater, the before 1. October 1978 was installed, it must be replaced by a modern one within two years, replace energy efficient system. But even after the previously valid regulations, it was clear: Were the exhaust gas values during the annual check by the chimney sweep above the legal limit, must end the owner 2004 replace the heater.
That sounds annoying at first, but it's not! Because it's worth it – also for homeowners, who are initially not affected by the regulations -, replace the old stove. Modern systems have up to 30 percent higher efficiency: You consume up to 30 percent less gas or oil. What the legislator primarily intended to relieve the environment, also benefits the homeowner's wallet. The expenses for the new heating can be recovered in just a few years through savings in heating costs. applies: The better energy and technology are coordinated, the greater the savings.
WHICH ENERGY IS THE RIGHT ONE?
As a rule, it is most economical to modernize the heating system, to stay with the previous energy source. Standard boilers for oil or gas hardly differ in their price-performance ratio, Combustion technology has been decisively improved for both types of energy, so that the burden on the environment, especially through carbon dioxide emissions, is much lower than it used to be. In the case of the particularly environmentally friendly condensing boilers, gas boilers cost around 4000 to 5000 euros at least 1000 euros less than comparable oil-fired boilers. However, oil is usually cheaper, it also has the advantage, that you can fill your tank when market prices are low.
A plus of the fuel gas is, that no space is needed to store the heating energy. Especially the gas boiler without additional storage for hot water is still the classic for the modernization of old buildings with little space. Both oil- as well as gas systems are well suited to be combined with a solar collector to heat domestic water or to support room heating.
The use of solar energy is worthwhile, if the location of the house allows it, Collectors at the angle of 30 to 60 degree to be installed facing south. There must also be room for a sufficiently large memory, about 400 liters for bath water, respectively 800 liters to support the heating, to be available. The sun's energy can not only be used directly via collectors. Even the ones in the air, Solar energy stored in water and earth can be used with the help of a heat pump.
Direct heating with electricity has an unfavorable primary energy factor due to the high losses during production and is therefore only in exceptional cases according to the EnEV – for example in a very well insulated or little heated house – an alternative. Another eco-friendly option: Heating with wood in a modern form with pellets (see box).
WHICH TECHNOLOGY IS CONTEMPORARY?
Default for oil- and gas heating is the low-temperature technology today. The boiler used to run with one flow temperature all year round (boiler temperature) von 70 to 90 degrees and could not be optimally adapted to the seasonally changing heat demand. High heat losses occurred, the annual efficiency of such systems was only about 64 percent. A breakthrough in heating technology came at the beginning of the 1980s: New boilers were developed, which are suitable in terms of construction and material, relatively cool water, about 35 to 40 degrees warm, to pass through the boiler, without the formation of condensation and thus corrosion damage. Finally, modern control electronics make it possible, to regulate the boiler temperature flexibly depending on the outside temperature. This increases the annual efficiency to over 90 percent.
Condensing boilers work even more efficiently than low-temperature heating systems. As with the low-temperature boiler, circulating water for heating or hot water preparation is stored in the storage tank. In addition, however, the condensation heat contained in the exhaust gas is also used to generate heat. For this purpose, condensing boilers are equipped with particularly large heat exchangers for heat transfer between the flue gases and the heating water. In contrast to the “calorific value” – the amount of heat released from combustion – is meant by “calorific value” the total amount of heat from combustion and heat of vaporization. With the additional use of this evaporation heat, an efficiency of over 100 percent can be achieved.
The ideal addition to an energy-saving heating system in a well-insulated house is a ventilation system with heat recovery. It extracts stale room air, discharges it to the outside via an outlet in the roof, but first extracts the heat from it and makes it usable again either for the heating circuit or for hot water preparation. freshness, filtered air flows in through small openings in the outer walls. What for many, who prefer to ventilate with the help of open windows, which sounds, has a lot of advantages: The air in the room is always fresh, no mold can form in the rooms. Allergy sufferers can breathe easy – and sharp calculators rub their hands. Anyone who has a ventilation system installed in a new building, has to meet lower requirements for thermal insulation thanks to EnEV.
HOW DOES THE HEAT GET INTO THE ROOM?
Modern heating systems are suitable for radiator, Wand-, floor- and air heaters. Because of the lower temperatures, the radiators actually need larger surface areas than in the older systems. When modernizing the heating systems, however, the old radiators are usually sufficient, since the radiators in old buildings were almost always oversized. Surface heating systems are particularly well suited for interaction with condensing technology. Since the heat-radiating surface is very large, the flow temperature in the boiler may be particularly low – which promotes condensation and achieves a high degree of utilisation. Surface heating is by no means only of interest to builders: Industry has developed systems, which, thanks to their low installation height, can also be retrofitted in old buildings – for lower energy costs and significantly more comfort!
THE CHIMNEY - A RESTORATION CASE?
Which was a decisive step forward for heating technology and the environment – lowering the boiler temperatures to up to 35 City -, can play badly: the chimney. He has to deal with it now, that the exhaust gases condense on its walls. Which sooner or later leads to sooting in old models. That is why a modernization of the heating usually goes hand in hand with a renovation of the chimney: A glass exhaust pipe is placed in the brick shaft, plastic, stainless steel, ceramic or aluminum with a smaller cross-section.
With all boiler costs, temperature control, Installation and chimney renovation, modernizing the heating system is certainly no small investment. Under 4500 It will hardly be available in euros. But the money is well invested: The measure can have paid for itself after five to six years. Which helps: Numerous federal funding programs, countries and communities, which make the move to modern heating much easier, especially with low-interest loans.