Center for Education and Raising Awareness of Energy Efficiency â€“ Energis in collaboration with one of the most significant windows and doors manufacturers in the country and the region FTM doo Novi Travnik presents the Guidline to windows, with goal to educate visitors of portal Energis.ba and help them make educated decisions when installing and
Center for Education and Raising Awareness of Energy Efficiency â€“ Energis in collaboration with one of the most significant windows and doors manufacturers in the country and the region FTM doo Novi Travnik presents the Guidline to windows, with goal to educate visitors of portal Energis.ba and help them make educated decisions when installing and retrofitting the windows.
The technology of high-performance windows may beÂ impressive, but the benefits are equally compelling. And these benefits extendÂ beyond the more obvious ones.
Savings in Heating Costs
First and foremost, high-performance windows areÂ energy-efficient. They offer immediate savings on home heating costs. DependingÂ on the house design and the existing levels of efficiency in the rest of theÂ building, switching to high-performance windows should yield 9 to 18 percentÂ reductions in space heating costs (Fig. 40).
Savings in Cooling Costs
Concerns about energy efficiency are not limited justÂ to the heating season. In many parts of Bosnia and Herzegovina, summertime heatÂ requires space cooling. High-performance windows work equally well at keepingÂ the heat out in the summer months. The same low-E coating that keeps infraredÂ (heat) energy inside the home in the winter keeps unwanted heat out in theÂ summer. This keeps the interior cooler and cuts down on the need for airÂ conditioning.
Studies have shown that, for most of Bosnia andÂ Herzegovina, it is still appropriate to choose your windows on the basis of theÂ ER number. Exceptions to this rule are those few locations where airÂ conditioning costs are high relative to the amount spent on space heating. InÂ these few cases, consider west-facing windows with a lower solar heat gainÂ potential.
In houses with conventional windows, air leakage,Â drafts and radiative heat loss all contribute to occupant discomfort which theÂ heating system must try â€“ usually with only limited success â€“ to overcome. ButÂ high-performance windows are better insulated and maintain a much higherÂ surface temperature on the interior glazing. This characteristic, together withÂ effective weatherstripping and proper installation, makes the windowÂ “feel” warmer to the occupant.
Higher Humidity Without Condensation
Improvements in comfort extend beyond the reduction inÂ drafts and cold spots near windows. During the winter, outside air is very dryÂ and can significantly lower the relative humidity (RH) inside. This in turn canÂ lead to annoying static electric shocks when touching doors or light switches,Â as well as dry throats and other irritants.
If you try to compensate by humidifying the air, thenÂ once you get above about 40 percent RH, there is the risk of condensationÂ forming on the windows. This reduces visibility and can lead to deteriorationÂ of the frame components and mould growth.
High-performance windows can change all this. TheÂ higher inside glass temperatures and improved thermal performance of edgeÂ spacer and frame components allow much higher RH levels inside (Fig. 41). ThisÂ can reduce if not eliminate RH-related problems associated with poor windows.Â Since higher humidity levels are possible with better windows, this meansÂ reduced static shock, improved health, and healthier plants. Fig. 41 shows theÂ relative humidity at which condensation will start to form at the center of theÂ glass with different types of glazing. However, condensation will usually formÂ at the edge of the glass at a lower relative humidity.
Lower Sound Transmission
The heavy gas fills in high-performance windows, whichÂ reduce conductive and convective heat losses, also reduce sound transmissionÂ from the exterior to the interior. The greater the number of panes, the betterÂ the sound absorption. Sound attenuation is complex, depending on frequenciesÂ and other factors; some benefit may be realized with high-performance windows.
The advent of high-performance windows is allowingÂ larger glazing areas to be incorporated into house designs, in both newÂ construction and renovations, without the penalty of either high heat loss inÂ the winter or high heat gains during the summer. This not only enhances energyÂ efficiency and improves the view, but it also lets in more daylight, which mayÂ lead to reductions in the use of electric lighting.
You save twice when you take advantage of this naturalÂ light: first, you save on electricity used for lighting; second, because aÂ conventional light bulb uses only 15 percent of its energy for lighting andÂ wastes the other 85 percent as heat, you lower the home’s cooling load inÂ summer. This is especially the case in larger buildings.
Increased Passive Solar Potential
Conventional south-facing glazing offers, at best, aÂ break-even proposition in terms of balancing heat gains and losses. In otherÂ words, the energy that south-facing windows gain during the day through solarÂ inputs is about equal to the energy they lose through radiation, convection,Â and conduction heat loss during the night.
High-performance windows are changing all this. WithÂ the right selection of low-E coatings and gas fills, it is now possible forÂ most windows to gain more energy during the day than they lose at night.
With window frame areas kept to a minimum, it is nowÂ possible to have even larger window areas and still obtain net energy gains. InÂ addition to saving on space heating costs, this can give the house a brighter,Â more open feeling
Reduced Mechanical Complexity
On a cold winter night, conventional windows (RSI 0.35Â or R-2) lose about ten times as much heat as an equal area of a reasonablyÂ well-insulated wall (RSI 3.52 or R-20). It is for this reason that architectsÂ and heating contractors have been forced to locate heating registers,Â convectors and radiators directly under windows. This compensates for the highÂ heat loss and air leakage in close proximity to these windows.
Lower air infiltration and the reduced conductive heatÂ loss of high-performance windows may make the practice of perimeter heatÂ distribution less important. It is now possible, thanks to high-performanceÂ windows, to locate heating registers on interior walls, either at the floorÂ level, or near the ceiling. This reduces the length, diameter and complexity ofÂ heating duct layouts. Discharge outlets on an inside wall near the ceiling mayÂ provide more comfort, especially with air conditioning.
Reducing the length ofÂ duct or piping runs in the home saves on capital material costs as well asÂ installation time, in either new homes or renovations. Shorter duct runs withÂ smaller diameters can also mean smaller fans and less energy to run the fans.Â In some cases, cost savings may offset the additional costs of upgradingÂ windows.