CTE HE 1, Limitation of energy demand: a matter of regulations

Limiting energy demand is a matter of regulation. The CTE HE 1, Limitation of energy demand establishes that buildings must have an envelope that adequately limits the energy demand necessary to ensure the thermal comfort of their occupants, according to the climatic situation affecting the building and its use. Additionally, it must prevent the occurrence of condensation moisture and minimize thermal bridges, in order to prevent load losses and hygrometric problems.

What is the energy demand of a building?

We understand "energy demand of a building" as the useful energy needed to maintain the comfort requirements inside, depending on its use and the climatic zone. Energy demand can be classified into demand for heating, cooling, domestic hot water (DHW), and lighting.

Is my building subject to the regulations of CTE HE 1?

Current regulations apply to all new constructions. In the case of existing buildings, it applies if there is an expansion (the area or volume is increased), a renovation is made (renovation or rehabilitation actions are carried out, beyond mere maintenance actions), or there is a change of use.

Current regulations foresee exceptions:

• Protected historic buildings (as long as stipulated by the competent administration). • Provisional buildings whose useful life does not exceed two years. • Industrial buildings (agricultural use, workshops, etc.). • Isolated buildings whose usable interior area does not exceed 50 square meters. • Constructions whose particular use requires the building to remain open to the exterior continuously.

Demand for heating and cooling

ENERGY DEMAND FOR HEATING:

The energy demand for heating of the home (limit heating demand) cannot exceed the value reached according to the following formula:

Dcal,lim = Dcal,base + Fcal,sup / S

• Dcal,lim (kW·h/m2·year): limit value of energy demand for heating.
• Dcal,base: base value of energy demand for heating (for each winter climatic zone).
• Fcal,sup: correction coefficient by surface of the energy demand for heating.
• S: usable area of the habitable rooms.

ENERGY DEMAND FOR COOLING:

The energy demand for cooling of the home (limit cooling demand) will depend on the climatic zone in which the building is located. Thus, it cannot exceed 15 kW·h/m2·year (climatic summer zones 1, 2, and 3) or 20 kW·h/m2·year (climatic summer zone 4).

Mechanical ventilation and energy efficiency

Undoubtedly, the best way to increase the energy efficiency of our building, and comply with what is established in CTE HE 1, is by minimizing demand. Therefore, it is essential to rethink new ways to condition our homes and consider efficient ventilation systems that do not imply a loss of load of the heating and cooling systems and do not endanger the environment or the health of our loved ones.

The installation of a controlled mechanical ventilation system (in which both the extraction of stale air and the supply of clean air are carried out by mechanical means) with high energy efficiency energy recoverers allows heating the interior of the rooms while minimizing energy expenditure and making the most of other energy-saving strategies (proper orientation of the building, airtightness and hermeticity of the envelope, energy recovery systems, etc.).