The Municipality has already defined a project for the inclusion of an elevator and a new staircase, while improvements on the energetic behaviour of the buildings are addressed in the CERtuS project. Due to the change of use of the building, it is difficult to estimate values before and after interventions. Real consumption of the building is not useful, as the archive is sporadically used and is not comparable with the Centre that will be open to the public from 10 am to 8 pm every day. The energy performance has therefore been calculated simulating the new use of the building, both for current and future conditions. Nevertheless, lighting and HVAC system installed in the building are not sufficient to guarantee the use and enjoyment of the Centre by people. In order to meet higher comfort conditions, HVAC system should be resized and proper lighting should be guaranteed. This will result in an increase in the energy demand. However, the continuous use of the building will guarantee appropriate maintenance, thus avoiding costs associated to abandonment and will permit citizens benefitting from their heritage.



Economic/Financial Risks
Also if the building has limited dimensions and there is no need of major investment, the lack of public budget still remains a barrier. While the building’s envelope retrofitting will significantly improve the energy efficiency, performances and benefits of PV panels in this specific location are limited.Legislative Obstacles
The Old Town has been listed due to its historical values. In the case of Kapitain Etxea this entails that the external walls have to be preserved with no alterations. Solutions with high visual impact or which might harm the building’s integrity cannot be applied.
After the catastrophic fire in 1638, Errenteria started rebuilding the city. The most outstanding houses of the historic centre date back to this period. One of these ancestral houses is nowadays known as the Captain’s House (Kapitain Etxea in Basque). It is a terraced building of rectangular ground plan with a gable roof perpendicular to the principal facade made of sandstone ashlar. Although it initially had a ground floor and two stories separated by flat roofs, the upper part has suffered alteration: the floors are no longer at their original height and the openings interrupt the flat roofs. In 1925 the original building was divided in two and nowadays it is possible to distinguish the differences only between the roofs. There is one single row of openings on the ground floor and projecting balconies with forged iron railings on the first and second floors. While the right-hand side is residential, the left-hand side has been used for cultural activities, as a result of which the facade has been cleaned and the interior has been transformed in 1984.
Currently the building is used as part of the municipal archive, as it presents poor accessibility conditions and entrance has been restricted to municipal employees. The Municipality decided to refurbish the building to host the Center of the Basque Costume. The new use of the building will therefore require interventions aimed at improving accessibility and comfort conditions.


Building Envelope
The energy demand analysis of the current situation shows that windows and walls are the main weak elements and roof and ground contribute to thermal loses.
Opaque Envelope: Front and rear walls are constructed in sandstone ashlar, with a U-value of 2.60 W/m2K. Interventions are possible only in the inner surface and should guarantee the minimum floor area reduction. Insulation will use mineral wool and mortar render to achieve a U-value of 0.35 W/m2K. The roof is a timber structure in a bad state of conservation, which will be replaced by a similar but with improved insulation and waterproof materials, to reduce the U-value from 2.42 to 0.24 W/m2K. Slab on ground will also be improved, reducing U-value from 2.42 to 0.22 W/m2K.
Glazing: Existing glazing and frames will be replaced by low e coated, air filled windows and wooden frames in order not to modify the aesthetic of the building. The existing skylight will be eliminated to include PV panels.
One of the criteria to renovate the system was to avoid heat radiators and underfloor heating. Air Handled Unit (AHU) combining ventilation, heating and cooling was selected. Also if air ducts will be larger, the unique system will overcome the problem of lack of space. The AHU will be provided with a heat recovery system.

Current lighting system presents different types of luminaries, irregularly distributed and with high visual impact. The new system will be designed according to the standard values. Also if the system will be more efficient, actual values are below the recommended power, thus installed power will increase to meet comfort conditions.

The renovation scheme includes the installation of Photo Voltaic (PV) panels. Due to the small dimensions of the building, power supplied will not be high, being 3.4 kWp. Monocrystalline panels will be placed instead of the skylight. Despite it is not the best orientation, is the area which is less affected by shading and will reduce visual impact. 


Year of construction:
1650 (aprox.)
395 m2 / 1,362 m3
Building Use :
Municipal archive
 supp_zanca LEARN MORE:
Link to D2.1 pdf
Link to D2.3 pdf
Link to Guide or Brochure




Energy Savings
Currently, the building has a final energy consumption of 54,383 kWh in gas and 14,602 in electricity and a total primary energy consumption of 93,039 kWh. According to the renovation scheme proposed there will be no gas consumptions but the final energy consumption in electricity will increase in 9,464 kWh. Primary energy savings will be 44,919 kWh. Considering electricity and gas prices of 2015 in Spain, expenditure savings will be 4,971 € per year.
CO2 Savings
The CO2 savings are estimated in 4.95 tons per year.
RES Integration
12% of energy will be supplied by renewable energy systems. PV will provide a generation of 3,389 kWh.

Energy Savings 44,919 kWh
Costs 111,636 €
Savings 4,971 €/year
Simple Payback 22 years
CO2 Savings 4.95 tons/year



Payback Period
The project payback is 22 years considering the maintenance savings.
Total Cost
The total investment cost is 111,636 Euro, which represents an investment cost per square meter of 295 Euro/m2.
Economic Savings
The energy expenditure is 1.528  Euro/year.
The expenditure for maintenance after renovation is lower than before of 3.455 Euro/year. So, the economic saving, energy and maintenance, is about 4.971 Euro/year.

HVAC 21,540
Lighting system (internal) 26,624
Renewable energy 12,602
Building envelope 50,870
Investment for Renovation 111,636
Energy Performance Contract
The project involves a change of use of the building: from archive to museum.
So, it is not possible a comparison with the previous situation as regards energy consumption and the corresponding savings obtainable after the renovation project: the situation of employment, the climatic conditions, the light levels, etc, are very different.
Despite all this we can say that the restored building will produce energy and economic savings.

So, it is necessary a restructuring of the investment plan and a strong contribution by the municipality. The optimum scenario is:
·         Equity investment by the ESCo 10%
·         Grant for 88%
·         VAT facilty 2%

The type of contract to be applied could be a mixture between “garanted saving” (in fact, much of the investment is made by the Municipality) and the “first out”.
Duration of EPC
The duration of the EPC contract is of about 25 years for the long payback period.

Other considerations
This project should be considered as part of a building restructuring and redevelopment agreement, in which the energy actions are guaranteed and partly financed by an ESCO.
A public/private partnership in which the ESCO deals with the enlargement of services and as well as the management of the maintenance services  of the museum could allow to the ESCo to more invest reducing the municipality funding.
 supp_zanca LEARN MORE:
Link to D2.5 pdf
Link to D3.6 pdf
Link to D3.7 pdf