Investing to reduce bills (2ieme part)
Heat pumps: more and more attractive?
It is also possible to feed a central heating system or by floor radiators with a heat pump (CAP). These devices use heat from the air or the ground (however small) to heat water circuit. A heat pump uses electricity for its operation and is characterized by its coefficient of performance (COP), that is to say the ratio of heating energy and the electrical energy consumed.
A COP 3 1 kWh means that electricity provides 3 kWh of heating; in other words, two-thirds of your heating is free (excluding initial investment). PACs most successful have a COP of about 4,6. For CAP ground water, using heat from the ground using buried sensors has 1 or 1,50 m, "it must have at least 1,50 field m2 m2 by a heat, for example 180 m2 for sensors needed a 120 m2 house, "warned Gilles Walterspieler, Viessmann, a manufacturer.
The initial investment that represents a PAC is high count for a new home 120 m2, about 18000 euros a CAP (about 6 000 euros), add heated floors (€ 65 / m2) and, a soil-water model, the sensors (3200 euros), plus their implementation in the field (1000 euros).
A tax credit of 50% of the CAP.
This invoice is nonetheless lightened by a tax credit of 50% of the CAP (if the COP is at least 3) and to 25% of the sensors (from 2006), putting the final score 14200 euros (or 118 euros / m2). Long reserved for new buildings, the installation of a CAP is now possible to replace an existing boiler, feeding a radiator heating (not heated floors). It must then invest in a pump "high temperature" (10000 euros, more sensors and earth).
These devices require specialized skills of the installer: "A Qualipac label should be born in 2006, but in the meantime you have to rely on word of mouth," says Jean-Marie Carton.
Existing and new: play solar map for hot water.
The boilers generally produce hot water instant, which is more economical than maintained balloon temperature (no heat loss) but less comfortable and two showers may be operated simultaneously. It is better to fill the boiler with a reduced ability ball, 50 (wall boiler) has 100 liters (ground boiler) at an additional cost of a 500 1000 euros, rather than ensuring the production of hot water by an independent electric ball. Choice in the new as in the existing, installing a solar water heater, which can satisfy different regions of 50 70% a% of domestic hot water (DHW), in addition to your current installation.
For a family of four, there must be a 4 2 m5 m2 sensors and a ball 300 liters, between 4500 5000 euros and euros. Will be deducted sometimes a grant from the Region, or the Department and, still, a tax credit (% 50 from 2006). Depending on your region and the energy currently used to heat your water (electricity, oil or gas), the return time of this investment is a 10 15 years (7 10 has years if energy prices increase yet 50 %). Please note, solar water heater arouse plenty of interest, leading to delays pose that can be long, and tents installers inflating prices.
The advantages of external insulation.
With the choice of an efficient heating, the other way to curb its energy bills is the insulation of the building.
If you build, opt for an external insulation. walls that protected the insulation from the weather (only the roof remaining isolated from the inside). "A polystyrene insulation can be covered with a simple coating, which comes less than a siding," says Bruno Peuportier, researcher School of Mines of Paris. Siding (steel, aluminum, wood, stone, etc.) is still required with an insulator such as glass wool. About twice as expensive as interior insulation, exterior insulation is more efficient because it eliminates thermal bridging, causes of energy loss (eg, at the junction of floors and walls). Thus, the outer insulation will facilitate new construction, obtaining the level of performance required by the RT 2005. It also avoids the presence of a 15 20 cm interior insulation, which can waste up to 4 or 5 m2 habitable, notes Marc Casamassima, of the Environment Agency and control of energy (ADEME) .
However, the external insulation. an existing building may face some architectural constraints and / or administrative (it changes the front and must therefore be subject to planning permission) that may require you to isolate the inside. Priority, insulate the roof, or, in case of lost roofs, their floor, "We can go up to 30 cm of insulation in the attic. In addition, the gain is negligible, "said Alain Bornarel. Allow about 8 euros / m2, included poses for the thick mineral wool 25 cm.
The wall insulation is more expensive - has to 10 15 € / m2 to 10 cm of mineral wool, more about 250 euros / m2 finishes - and involves a major project. "That's why you can choose to insulate the walls badly exposed, suggests Jean-Pierre Bosquet, president of Architecteurs, heating economies expect from this work, and therefore their return time is difficult to evaluate. "Prefer the conventional insulation, glass wool and polystyrene, a more experimental materials such as hemp and flax, or thin insulation (10 mm), consisting of an assembly of several layers of aluminum foil they are more delicate has implemented and are not subject to quality guarantees such as certification or Acermi DTU (unified technical documents) and technical advice of the scientific and technical Centre for building (CSTB).
Finally, only the traditional insulating qualify for the tax credit (% 40 from 2006), provided that the housing is completed for over 2 years.
Invest in quality double glazing.
Another source of heat loss, windows. Prefer the conventional double glazing (called 4-16-4 as compounds of two clear windows of 4 16 mm spaced mm) glazing has reinforced insulation (VIR), also called "low-emission". "With 0 ° C outside. It makes 5 ° C rating of a single-glazed window of a 11 12 ° C with a standard double glazing, 16 ° C with a VIR, explains Martine Olivier, head of product at Saint-Gobain Glass, and even around 17 ° C with an argon VIR. "(Models or the interpane space is filled with argon, more insulating than air). Cote prices, PVC window has double doors of 100 135 cm x equipped with double glazing VIR more argon back to 180 euros, against 140 euros for a conventional model.
The extra cost is minimal, whether in new construction or in existing (or a change of window costs has 900 1000 euros each, ancillary works and labor included). Moreover, in the current situation, the price of VIR can be underestimates by a tax credit (in 40 2006%; 2 years over housing). As for insulation of walls, the size of the investment and the difficulty of estimating the resulting savings can lead to replace only certain windows. Knowing that the most obvious gain is the living comfort. In winter, the removal of the cold sensation felt was close to poorly insulated windows often prompts to push the much needed heating. In summer, this reinforced insulation will prevent or limit the use of air conditioning, electricity intensive.