| Nine possible systems and a consideration | | | | to justify an investment in district heating. An important |
| Until 250 years ago, wood and peat were the only | | | | consideration: if a district heating network already |
| means to heat a home. At present, there is a growing | | | | exists, reducing the heat demand of dwellings (e.g. by |
| variety of residential heating systems. It is not easy to | | | | improved insulation) is still a good idea, since new |
| formulate an opinion which system is best in terms of | | | | technologies allow producing more electricity for a |
| environment, economy and comfort. But does the ideal | | | | lower amount of heat. |
| heating system of the future really exist? | | | | 7. Coal stoves are regarded as an old-fashioned way |
| Each system has its own advantages and | | | | for residential heating. Nevertheless, they are still |
| disadvantages. Which technology is the best should be | | | | commonly used in many countries. They produce a |
| evaluated on a case by case basis, without any prior | | | | comfortable heat atmosphere and have a fairly good |
| exclusion of technologies. | | | | efficiency. But they are inconvenient to operate, and |
| Primarily nine different systems are being used today: | | | | CO2 emissions are high. In Europe, the market share |
| | | | of coal as an energy source for heating will probably |
| 1. Natural gas is the most environmentally friendly fossil | | | | continue to decrease. |
| fuel, especially when it is burned in a high efficiency | | | | 8. Most coal stoves can also burn wood or wood |
| boiler with heat recovery. Yet it requires a gas | | | | pellets. The influence of wood pellets on the global |
| network. And maybe natural gas should be used for | | | | CO2 emissions requires more investigation. Maybe |
| generating electricity? | | | | wood should ideally be used for CO2 storage rather |
| 2. The oil boiler is a similar system to the gas boiler, yet | | | | than energy carrier? |
| with a higher emission rate. It doesn't require a network | | | | 9. Solar energy. A solar water boiler can be combined |
| but a storage tank and road transport. The oil boiler is | | | | with low temperature heating. A wind or photo-voltaic |
| likely to loose market share in the upcoming years. | | | | system can be the energy source for electrical |
| 3. Electrical heating has been out of grace for some | | | | heating. None of both systems will be able to supply |
| time in some countries, but today it is again seen as | | | | large power, so they should be used in houses with |
| one of the heating systems of the future. An electrical | | | | small heating demand or combined with other sources. |
| system can be an efficient and cost-effective | | | | Photo-voltaic systems have the disadvantage that |
| alternative when electricity is generated from low | | | | they produce most power when the least heating is |
| carbon sources, or when the heating demand is | | | | necessary, but solar cooling is an application where |
| relatively low - for instance in new, compact, and well | | | | ambient generation will naturally match demand. |
| isolated houses. | | | | And to conclude a consideration. A house can be |
| 4. The heat pump. Since it takes over 2/3 of its | | | | seen as our third skin, while our second skin consists |
| energy output from the environment, it has a very high | | | | of clothes. Reinforcing both skins can save a lot of |
| efficiency. But a ground-water heat pump requires a | | | | energy, money, and CO2 emissions. The third skin can |
| large surface. It should be combined with a low | | | | be improved by a maximum insulation, an excellent |
| temperature heating system in a well insulated house, | | | | airtight construction, use of sun heat by intelligent |
| but the investment is only cost-efficient if there is a | | | | glazing, and ventilation with heat exchange. The |
| sufficient heating demand. A best practice solution for | | | | second skin can be improved by simply wearing an |
| relatively large buildings in temperate to cold climates. | | | | extra sweater! This allows setting the thermostat a bit |
| Reversible heat pumps could be used in climates | | | | lower - we know 1 degree results in a few % less |
| where there is both a heating and cooling requirement. | | | | energy per year. |
| 5. Domestic CHP (Combined Heat and Power) is an | | | | Or we could use electricity even more intelligently. In |
| emerging technology. It has the advantage that it | | | | Asia, so-called 'kotatsu' tables have an (electric) |
| makes fully use of the capacity of natural gas to | | | | heating element underneath and a blanket and they |
| produce electricity - a high quality energy carrier. But it | | | | are being used to heat just a small amount of space. |
| requires matching heat and electricity demand, and | | | | They're quite comfortable, provide the emotional |
| may produce too much heat for well insulated | | | | center for the home and one of the most efficient |
| dwellings with relatively low heat requirements. | | | | ways possible to provide high heating comfort to |
| 6. District heating with a central CHP plant is only | | | | occupants. A similar system exists in Southern Spain. |
| efficient in (compact) cities where buildings have a | | | | In short, it is not easy to compare a variety of heating |
| sufficient heat demand. So the better houses are | | | | systems, used in different climates to provide various |
| insulated, the less interesting it becomes. Only in cold | | | | lifestyles. |
| climates, the heating demand will still be large enough | | | | |