How did I save 20k€

at the E. Leclerc supermarket of Quimper

Fred Lachèvre, manager of E.Leclerc supermarket of Quimper

1. Problem is the roof

Most buildings in the world – starting with supermarkets - are heat sieves.

Most people live, work or study in buildings where they are too cold in winter, too hot in summer and where heating and cooling costs are very high.

In particular compagnies are plagued by these large expenses of heating / air conditioning.

E. Leclerc supermarket of Quimper, it is about € 300k ($US 345k) of annual energy expenses.

Roof is the main source of bulding’s thermal leakage.


30% of the energy of a building is lost through the roof.

More the building is lower and wider, more the losses are important from the roofs.

This reality of losses by the roof is therefore serious for gymnasuims or commercial hypermarkets like the E. Leclerc supermarket of Quimper.

50 million sqm of commercial roofs involved


There are about 50 million sqm of commercial roofing in France. Most are over 10 years old. They aren’t only poorly insulated but also covered with micro-cracks.

Commercial spaces therefore spends several million of euros each year to heat or cool their bulding and to repair micro-cracks.

1/3 of these energetic expenses can be used to develop the company.

It is also a brake on corporate real estate acquisitions : lessees are increasingly looking at the thermal efficient of the buildings they rent.

2. Why paint in white ?

In 2014 the bitumious roof (7 000 sqm of shingle) E. Leclerc supermarket of Quimper was 15 years old.

Micro-leaks were multipliying.


I didn’t really have the budget to make the RT2012 new roof or RTex standards : with the resumption of construction, proforma invoices amount to € 300k ($US 345k) (which corresponds roughly to the budget « energy » of the building). ​

Search for an alternative solution to an TIO (Thermal Insulation from the Outside)

In search of alternative solutions, I make two crucial discoveries during a trip to the USA.


1. Cool Roofs : 75% of Walmart have a Cool Roof. The principle of the Cool Roof is simple : a white roof returns solar radiation in space. Solar heat doesn’t enter the building. Air conditioning needs are therefore reduced.

2. Themal paints of NASA : These paints, based on ceramic nanoparticles, have a power of reflectance but also considerable emissivity and begin to find their application for buildings.

If I apply such a thermal and reflective paint on the building :


  1. I protect it from the heat that comes from outside (sun in summer)

  2. I keep the temperature of the interior (heating in winter)

  3. And if it can be more elastic I block the micro-cracks  

The biggest Cool Roof in France :

€ 20k ($US 23k) of energy savings in 1 year

At the end of 2014 I develop with two partners and a partner laboratory, a painting that meets my expectations.

In June 2015 I paint the 7 000 sqm of roof, leaving a quare of 10 sqm unpainted and thermal probes to compare.

The consumption results fall after one year : about 10% energy savings - about € 20k ($US 23k) – are linked to the Cool Roof installation. 

And for good reasons : i almost didn’t operate the cold-groups in summer. Temperature readings and infrared shots clearly show that heat is coming out of the unpainted square in winter.

In synthesis I have :

  • Less consumption in winter

  • Less consumption in summer

  • Delaying costly sealing interventions

  • Without disturbing the use of the store

I estimate the ROI of such a transaction at 5 years.

Calculation of IRR – Internal Rate of Return


Example of E. Leclerc supermarket of Quimper (« service » pack) :

Roof : 7 000 sqm, bituminous two-layer steel sandwich tank 1988

Pose of the Cool Roof France elatomer complex : June 2015

Initial invesment : € 18/sqm ($US 21/sqm) = € 140k ($US 161k) for 7 000 sqm. This therefore represents € 13k($US 15k) per year of depreciation on the product life (10 years)

Economy of annual consumption observes : € 20k per year

($US 23k/year).

Economy related to the cost of kWh (which undergoes an annual increase of 3%)

Economy related to the maintenance cost of the roof

(€ 1k/sqm/year or $US 1,2k/sqm/year) = € 7k ($US 8k)

Creation of a maintenance cost (about € 1,5/sqm/year -

$US 2/sqm/year for a conventional contract, € 2/sqm –

$US 3/sqm for a « packService » contract indicated here by CoolRoof France which guarantees 100% of the effectiveness of the device).

IRR is here aboved 28%.


Guided tour

Calcul du TRI - Taux de Rendement Interne 

Exemple du E.Leclerc de Quimper :

_Toiture : 7000m2, bac acier sandwich bicouche bitumeux 1988

_Pose du complexe elastomère CoolRoof France = juin 2015

_Investissement initial = 20€/m2 = 140k€ pour 7,000m2. Cela représente donc 14k€/an d’amortissement sur la

durée de vie du produit (10ans)

_Economie de consommation annuelle observée est de 20k€/an.

_Economie liée au coût du kWh (lequel subit une augmentation annuelle de 3%)

_Economie liée au coût de maintenance du toit (1k€/m2/an = 7k€)

_Création d'un coût de maintenance (environ 1,5€/m2/an pour un contrat classique, 2€/m2 pour un contrat

“packService” indiqué ici par CoolRoof France qui garantit 100% de l’efficacité du dispositif)

Le TRI est ici supérieur à 28%.

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(c) CR-France 2016 - SAS with capital of 100,000 € - RCS 812,775,443 on 29/07/15 in Quimper