Improvement measures in façade openings: Example in two houses with CE3X.
Improvement of energy efficiency by replacing glass and carpentry.
As we all know, one of the improvement measures that we can contribute when it comes to improving energy efficiency is to improve the thermal transmittance of all the gaps in the building's façades, whether for doors or windows..
If it is new buildings, as we already indicated in the post of bioclimatic design by orientations, it is convenient that the holes in each façade are adjusted to some reference percentages with respect to their total surface to help optimize energy demand, but also and depending on each climatic zone it will be necessary that both their thermal transmittance and the factor solar limit, adjust to some limit values depending on the climatic zone where they are. As established in the Order FOM / 1635/2013, of September 10, which updates the Basic Document DB-HE of September 2013, within Appendix D, in section D.2 Characteristic parameters of the envelope, in the case of a building located in Valencia, whose climatic zone will be B.3, the limit values for each opening will be adjusted to the following table.
In the case of energy renovation of buildings to get the maximum energy saving The glazing and carpentry should be replaced to improve their performance in order to reduce the thermal transmittance of the opening, reducing excessive heat losses from the envelope in winter and excessive solar gains from the outside in summer. Starting from this premise, we will propose several improvement cases to analyze and quantify with the CE3X program to what extent we can improve when we intervene in the gaps.
Housing built during the 50-60 years. Monolithic wood and glass joinery. (CASE 1)
Initial state of the property.
It is a house built in 1957, which has holes with wood carpentry, folding leaves with simple 4 mm glazing. thick, has two facades facing Southwest and East, as reflected in the following image.
In this initial state, the energy rating obtained from the home is a G.
Improved Condition: measures proposed for the rehabilitation of the hole.
It is proposed to act by replacing the single glazing with double 4/9/6 glass, as well as changing the wooden carpentry for another one made of PVC with two chambers, in this case more watertight with a permeability of the gap of 50 m3 / hm2, in both facades of the house facing Southwest and East.
Without having modified the percentage of the frame and defining solar protection devices to reduce the demand for cooling in summer (which should be added since we have facades with East and Southwest orientations), the result of said improvement applied to our openings allows us to improve a letter in final grade:
We have managed to reduce heating and cooling demands by 17.8% and 7.1% respectively, as well as global CO2 emissions by 9.3% and improve the home's rating to an F.
Housing built during the 60-80 years. Metallic carpentry and monolithic glass. (CASE 2)
Initial state.
It is a house built in 1966, which has holes with lacquered aluminum metalwork without thermal break, sliding with 4 mm single glazing. thick, with three facades oriented to the Southwest, North and West, as can be seen in the following capture.
In this second case, for the dwelling considered, the grade obtained is a G as we can see.
Improved Condition: measures proposed for the rehabilitation of the hole.
In this case, it is proposed to replace the single glazing with double 4/9/6 glass as well as the change of the metal carpentry without RPT for another made of PVC with two chambers, in this case more watertight with a permeability of the gap of 50 m3 / hm2, on the three facades of the house facing North, Southwest and West.
Without having modified the percentage of the frame and without defining any sun protection device, the result of these improvements applied to our holes allows us to improve one letter in the final grade:
And in short, we have managed to improve heating and cooling demands, saving up to 11.4% and 11% respectively, as well as reducing global CO2 emissions by 7.5%, improving their rating to a letter F.
Other improvement measures that should be considered together with those for the rehabilitation of the holes:
Along with the replacement of glasses and the type of carpentry, it will be It is convenient to apply other measures in the envelope of the house or building in which it is acted for improvement to increase energy efficiency and reduce losses to the maximum, among which the following stand out:
- Rehabilitation of facades incorporating thermal insulation.
- Incorporate thermal insulation in the shutter drawers to eliminate thermal bridges and possible air infiltrations.
- Replacing the blinds with others that incorporate thermal insulation, such as those with aluminum slats with polyurethane injected inside, in this way we not only reduce the solar factor of the gap in the months with the highest radiation received, but also improve the transmittance thermal gap.
- Improve as far as possible any thermal bridge in the façade, correctly solving both the encounters with structural elements and any encounter of the gaps with it (jambs, lintels and gutters).
- Any other measure that the technician considers necessary to ensure that heat is not lost in winter or there is excessive heat input in summer, including any type of solar protection, overhangs, fixed or mobile slat shutters, awnings, etc.
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Links of interest:
- Air conditioning equipment and CE3x qualification … HERE.
- Centralized mixed systems with boilers in series or in parallel CE3X … HERE.
- Guidance on energy certification or any project … HERE.
- The energy certificate in a single-family home … HERE.
- Unified tool leader and calener informative note of the CT … HERE.
- More than 30 practical cases in examples of energy certification …HERE.
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Article prepared by Jose Luis Morote Salmeron (Technical Architect - Energy Manager - Google plus Profile) Access to their website HERE, in collaboration withOVACEN.
