How to Choose an Energy-Efficient Home and Control Your Energy Costs

Energy-efficient home: what does the energy performance certificate tell me?

Also known as “energy passport”, this quality label informs the future buyer/tenant about the energy consumption of a property as well as its polluting emissions. The requirements regarding the energy needed for heating and for domestic hot water production, as well as those regarding CO2 emissions, are detailed and summarized in three classes:

1. The energy performance class is based on the thermal envelope, the technical installations, the environmental aspect of the energy source used, with renewable energies being the best rated.
2. To determine the heating requirement, the thermal insulation class takes into account the thermal quality of the walls, roof, slab, windows, type and quality of construction, as well as the orientation of the building.
3. The environmental performance class depends on the CO2 emission.

A, B or C house... So classy!

Each of these three classes varies from A to I according to 9 decreasing levels of performance. Here are a few points of reference: a house classified as A is said to be passive, i.e. its energy consumption is almost zero. These are recent constructions built since January 2017, to which the acronym NZEB for “Nearly Zero Energy Building” is attributed.

Slightly older, B-rated homes are considered low-energy and therefore energy-efficient.

C-rated dwellings are less expensive and are still energy efficient. They require little or no insulation work.

D, E or F homes: can do better

Often heated by electricity, D-rated homes were generally built in the 1980s and 1990s. An older house or flat will be classified as E or F, unless it is in a poor state of repair and needs major work, as the energy performance certificate does not imply any obligation to renovate. However, it will tell you in detail what you need to invest in. Indeed, a section “recommendations to improve the energy performance of the building” with potential energy savings in kWh/year and cost reductions in euros is provided to guide the future owner. The term “thermal sieve” is used from class F and below.

Energy-efficient housing: what you can check yourself

The energy performance data and thermal insulation class specified in property advertisements can be used as a first step in your search for an energy-efficient home. The energy performance certificate provided by the landlord/seller will complete it by offering you a solid guarantee. However, in order to find the property that will be the most comfortable and the least expensive for your budget, certain criteria should be taken into account. The exposure of the property, its luminosity (don't forget the lighting costs), the presence of a veranda, whether it is semi-detached, and the age of the heating equipment will all have a significant impact on your next bills. Still, insulation should be examined as a priority.

Insulation to be inspected from top to bottom

The insulation of a house is not limited to its external walls. Is the roof new? Has the attic been renovated? Find out about the type of insulation used and its performance. Are the windows old? Double or triple glazed? Are they regularly checked for tightness? This information can be obtained over the phone before you visit, but once you are there, rely on your senses: cold walls to the touch, traces of mould or simple condensation should alert you. Sometimes all you have to do is walk past a bay window to detect a trickle of fresh air that could put a chill on your finances...

Ventilate to limit heat loss

Finally, don't forget that thermal comfort requires healthy air, i.e. air that is efficiently renewed, which leads to more or less heat loss. An efficient ventilation system will, in the short term, be a real asset for your heating bills. Controlled mechanical ventilation (CMV) with single or double flow, distributed mechanical ventilation... So many good (or bad) points to tick off on your checklist.