According to the WWF, the only really effective way to reduce energy consumption in the building sector is by reducing the energy demand of the park already built, improving the levels of insulation in buildings.
ENERGY SAVING POTENTIAL IN HOMES
Betting on better insulated buildings would also help to reduce energy dependency from abroad, and reduce citizens’ energy bills, improving household income.
The absence of incentives, failures in administrative management, the lack of control of compliance with the regulations or the null information received by the users and owners of the buildings are some of the barriers that hinder energy rehabilitation.
To give an example, in France, all new public or private buildings built after 2010 had to be designed according to the low consumption standard, and become “energy positive” from 2020. For their part, the buildings already erected will have to be renovated to reach a consumption between 90 and 150 kWh/m2/year, and to pay for the necessary investments, fiscal and financial incentives have been provided.
For this reason, when you walk through a French city and look at the window of any Real Estate Agency, you can see that almost all the homes for sale have an energy rating from A to D at least. Here in Spain the majority of homes obtain an energy rating from D to G.
The uses of heating and cooling represent half of the final energy consumption of an average Spanish home, a figure that rises to 75% if consumption for the production of domestic hot water is also considered.
If the thermal envelope of buildings (facades and roofs) is not previously optimized, measures such as improving the energy efficiency of facilities or incorporating renewable energy in homes have very limited effects on improvement.
The approximate average cost of correct internal thermal insulation can range between €35 and €50/m2 with systems attached to the façade inside the homes.
CALCULATION OF INVESTMENT IN THERMAL INSULATION AND PAYBACK TIME:
If we take into account that improving the thermal insulation of a home can represent 50% to 70% energy savings, and that an average 80 m2 home consumes an average of 250-300 kWh per month. We can calculate the payback time of the investment:
- Exterior facade of a standard home = 20 mx 2.5 m = 50 m2
- Insulation cost: 50 m2 x €35/m2 = €1,250
Amortization:
Bearing in mind that by improving thermal insulation we can obtain savings of between 50% and 70% of energy,
- Average monthly consumption: 350 kWh x 70% = 245 kWh/month savings per month
- Energy cost = 245 kWh/month x 12 months x €0.14/kWh = €411.60/year savings
- Amortization: €1,250 / €411.60/year = 3.03 years
Potential savings once amortized:
If we take into account a useful life of the insulation of 30 years:
Annual savings: €411.60/year x 30 years = €12,384 – €1,250 = € 11,098 of total savings for an investment of €1,250.
TOTAL SAVINGS OF €11,098.00 FOR AN INVESTMENT OF €1,250.00