WelcomeInfoWork PackagesLinksFAQs

1.1 First step general questions 

How can I use the FAQs in general?

Answer: FAQ section gives brief and easy answers to the most frequent problems related to the refurbishment of historic buildings. Several advices and indications for the different phase of a refurbishment design are discussed, starting from the preliminary step of funding to the technical evaluation of energy saving solutions.  

What means listed historic building?

Answer: a listed historic building is one that the local government considers as heritage and preserves for interventions according to local regulations. Both local governments and global consortiums determine a list of the historic heritage around the world.  

What means 3encult and which role does it play for culture heritage?

Answer: 3ENCULT aims to bridge the gap between conservation and energy efficiency, which is not a contradiction at all. Historic buildings will only survive if maintained as living space and energy efficient retrofit can improve structural protection and “comfort”, both for users and heritage collections. Reducing the energy demand by Factor 4 to 10 is feasible also in historic buildings respecting their heritage value, if a multidisciplinary approach guarantees high-quality energy-efficiency-solutions, targeted and adapted to the specific case. 


Whom should I contact?

Answer: The interaction with the conservational authorities from the very beginning is crucial for a successful implementation of the refurbishment of your listed building. An additional and multidisciplinary working group must be found for evaluating possible interventions (architects; building physics-, lighting-, structural-, wood- and masonry experts). 

Which examination has to be done?

Answer: It depends on the legislation of your Country: e.g., in Italy there are no obligations to perform a measurement to certify the current Energy Efficiency class of your house. Evaluation is done by specific software packages that will automatically prepare an adequate report (this is not strictly true for some regions). Of course, these packages require data about how your building is made, in terms of both geometrical and material properties, so you would need to make some measurements. This is usually complicated for historical buildings, while a good engineer or architect will know enough about existing modern buildings, so a sound research will be needed at least to compile a draft report.  
How do I find out about the history of my house?

Answer: The history of your house could be found by consulting local libraries and local archives. Additionally there may be local historic associations that could inform about history Task 8.5 frequently asked questions of buildings, use and context. Certainly if the area is historic and protected and the building is listed there ought to be a historic description by the preservation authorities.  

What Style is my House?

Answer: The house style could be identified by consulting architecture history books, in local libraries and internet forums. Local library attendants, professionals or historians may help you to find the answer. In many cases, in a listed building a description related to the architectonic style has been filled by the local responsible preservation office.  

Requirements of the heritage office  

What does my state historic preservation office do?

Answer: State historic preservation officers evaluate the intervention projects proposed for a historic listed building and provide case-specific comments on admissible or not-admissible proposed measures, solutions and modality of intervention, based on adequate knowledge of current state of the building and on criteria of necessity, non- or reduced-invasiveness, minimum intervention, compatibility and possible reversibility. In a discussion with the building owner or responsible representative, alternatives and best acceptable solutions from a preservation viewpoint and a valorization of the historical good are evaluated together with the State officer until the final solution is agreed upon (for example, if windows may be replaced or not, an exterior insulation is possible.  

How can I contact the heritage office?

Answer: As particular, it is difficult to turn to the heritage office. However, in every local region there is an office associated to the local government. For that reason, from the project, the recommendation is asking directly the local government how to face it. Moreover, a previous step could be looking up in the heritage list available with the buildings considered as cultural heritage which could contain useful information.  

Why I could not renovate my listed building free without any conditions?

Answer: The building was declared as listed by the authorities, the community, by a smaller group of care-takers, by an individual or by national or international heritage preservation bodies. This was done to prevent the loss of its current qualities or values, which vary widely from architectural typology, material and construction techniques, artistic value, historic importance and other factors. The owner or the care-taker is responsible in keeping the object under observation and maintenance so that its value cannot be diminished or lost. If interventions have to be carried out on the object, these have to be controlled upon and agreed by the responsible preservation body and have to comply with specific criteria defined case by case. All for preserving the values of the building and its environment.  

Which aspects must be considered?

Answer: Architectural typology, material and construction techniques, artistic value, historic importance are key aspects. But conservational values are very controversial and also time's period and region specific, e.g. what was allowed in 1980 is today prohibited, or what is prohibited today could be probably allowed in future thanks to new available products; exterior insulation as full no-go in some regions, was possible somewhere else. A general request of conservators is the reversibility of the authentic intervention. i.e., it is required that interventions are possibly removed after any time's period.  

Can I start the renovation before I have authorization?

Answer: Before starting any renovation work an authorization is usually required in all the EU countries. Besides, if the building is listed, the conservator authorities must be involved Task 8.5 frequently asked questions since the early stages of the planning process. All the restrictions and mandatory requirements must be clearly agreed and analysed and planning submission process must be identified, including the involvement of all the relevant regulatory bodies and stakeholders. Local regulations can have significant differences country by country and region by region, and then an expert overview of all of them is always necessary.  

How long should I wait before I can start to renovate my house once I registered it as a heritage building?

Answer: The planning process depends on the approval process of the involved authorities. Municipalities, Conservation authorities and all the others stakeholders involved may have different time schedule for approval processes that are set by the national and local regulations. It is a key aspect of any renovation activity to identify the milestone for getting the approvals and then schedule the submission process.   

Financing & funding opportunities  

How do I Finance the Restoration of a Historic Building?

Answer: Usually there is the possibility in the different countries, to get subvention or tax abatement for energy retrofitting the building. To do this, you can get information generally with the responsible preservation offices.  

Where can I get funding?

Answer: According to the preservation value of the historical listed building, support funding for intervention and renovation may be possible through national or other legislative tools. In case of particular national or regional measures of support to economy, part of the intervention costs for renovation could apply for partial reimbursement or tax release under specific conditions. Energy efficiency improvement actions may fall under such cases. Information is usually readily advertised in the media, by suppliers of construction products and details may be found consulting professionals accountants and architecture/ engineering /preservation offices.  

How to get funding?

Answer: Get in contact with the responsible monument preservation administration. Professionals can advice you on the procedure and on how to fill in the application for funding support with all supplementary necessary documentation.  

Is There Funding Available from the National Fund?

Answer: The National Fund may have funding available for renovations of the historical buildings. This may come from general funding or from funding for specific interventions, like energy efficiency or improvement of health and safety conditions. In order to check the availability of any funding and to procedure to have access to it, the National Trusts websites can be consulted.  

Which economic quality aspect has to be considering here?

Answer: The selected measures for energy retrofit must always protect the building. For this reason the economic quality aspect depends on the type and the usage of the building.   

1.2 Evaluation Phase 

Material and construction analysis 

Which measurement methods are suitable /available to determine the heat resistance of an existing material/construction?

Answer: Any building has as a fundamental function the protection of people from weather, to maintain an acceptable level of comfort inside its structure; this implies that its envelope will e crossed through by heat or cold; so, heat is lost and gained through the building envelope, and heat flow (also referred to as heat transfer or thermal transmittance) occurs, to different degrees, in any structure. The heat transfer measure allows the evaluation of the thermal transmittance of building elements, the so-called U-value, which represents the heat flow per time unit that goes through an area of 1 square meter when there is a temperature difference of 1 degree between inside and outside [W/m2K]. Therefore, the U-value is dependent on the thermal conductivities of the building materials and their respective thicknesses. For the purposes of energy balance, the objects of these investigations are the elements of the outer envelope of the building, mainly walls and shutters; in fact, when they present high U-values, significant heat/cold losses have to be compensated by an appropriate heating/cooling system, so that the building energy efficiency will be greatly reduced. Generally, U-values are calculated with readily available software programs rather than measured in situ. However, U-value calculation programs were developed with nontraditional present-day building materials and construction techniques, rather than traditional buildings, in mind. For this reason, actual measurements of the U-value should be executed. 

Where can I learn more about hardware or other materials appropriate to my historic home?

Answers: There are many sources to learn about hardware to historic building: magazines like Traditional Building or Old-House Journal can provide valuable insight into the hardware, fixtures, or other materials appropriate to your historic home. There are also numerous sources in the web that you may consult but before doing any intervention you should consult an expert and the local authorities in charge of historic buildings (Soprintendenza in Italy). 

I would like to become a contact point for the energy efficient expert, how should I proceed?

Answer: You can find some information via the Internet, whether there are already specially trained energy consultants for historical buildings in the country. Often the Historic Preservation Office provides information material about this. 

Is it possible to make a blower door (pressurization) test also for historic building – and if yes, does it make sense?

Answer: Yes, it is possible also for historic buildings. Mostly the airtightness of historic buildings is poor and the flow rate necessary for the blower door test is high. If the flow rate of one blower door is too small, two or more blower doors can be applied simultaneously. If this test is done in conjunction with an IR thermographic test it can provide accurate information on the presence and location of air infiltrations and thermal bridges. This is because the difference of pressure increases the air volume passing through the infiltration points and makes them more visible to a thermal sensor and in some cases also to tactile feeling. Another solution for the measurement is to use tracer gas measurements instead of Task 8.5 frequently asked questions 9 the blower door test. This will give you information about the infiltration/exfiltration under real temperature and weather conditions. 

Are special material and construction analysis necessary if mechanical ventilation should be introduced?

Answer: If mechanical ventilation with air ducts should be integrated in historic buildings, the necessary holes and openings might be a significant change or irreversible damage to the original construction. The answer if this is possible depends on the results of analysis on the material and construction as well as the architectural and historic value from conservation point of view. Small holes are not a problem in most cases in terms of statics, but also small interventions have to be done in accordance with the cultural heritage authority. Within the 3ENCULT-project, several solutions how to avoid ducts were evaluated. 

1.3 Design phase 

Assessment of different renovation concepts for envelope constructions 

Which Software- Tools are suitable to evaluate different constructions versions in regard to their mold growth risk? 

Answer: There are several tools for the simulation of the behaviour of a building with regard to several parameters such as materials, structure and so on. For example heat and moisture transfer numeric simulation tools such as DELPHIN, WUFI. Blower Door Test helps the determination of the airtightness in concrete rooms. IR thermography measures the losses of energy through the façades and distribution system. Monitoring system measures the real indoor and outdoor climate as well as the climate components in the construction. 3D scanning enables the evaluation of the construction elements by scanning the envelope and elements. 

What are the advantages for contacting the renovation-expert?

Answer: A renovation-expert can provide useful guideline so as to actuate in historic buildings taken into account all the constraints and restrictions in the regulations of the region/country. Not only the forbidden actuations, but also the interventions allowed which could improve more efficiently the energy behaviour of the building. Thus, the expert could help in the detail about how to face all the steps in the refurbishment of a heritage building. 

I know that my organization doesn’t have plans, how can I get one? 

Answer: In some cases, the owner has the original plans of the building; therefore the first step is trying to get the original maps from the owner. However, sometimes it is not possible, above of all, in public buildings. In such case, the technical office of the local government could provide the maps for the building. In the cases of heritage the public institutions like the government usually has the original drawings or project. 

What paint colors are appropriate for my historic home?

Answer: Most often the design of building was changed through time several times. Thus detailed investigations sometimes yield a number of phases of color design on and in a historic building. Before the decisions can be done how the retrofit design will be, a restoration investigation is indispensable. The results do base the final judgment on the design. From technical point of view the color system could be a historical composition or a recent product, depending on the substrate and appearance. 

Will replacing my original wooden windows save money on energy?

Answer: If there are still original historic windows in the building, you should first check if these can be preserved, e.g. by renovating them and adding an extra new window at the interior. If the window is not worth of preservation, replacing an old window with single glazing by a new window with triple glazing and an insulated frame will annually save a considerable amount of heating cost. Even if the investment costs for the new window are taking into account, you will still have an overall financial profit. Additionally your annual CO2 emissions will decrease by approx. 70 kg per sqm of new window (in Central European climate). A window with similar properties has been developed in 3encult. It even meets the requirements for Passive House windows and at the same time can be adapted to meet the visual requirements for use in many historic buildings. 

What happens if windows are changed? 

Answer: Whenever a window is replaced, you should use this opportunity to install a new window with up-to-date insulation values. For most locations in Europe triple glazing and an insulated frame can be recommended, if this is compatible with heritage preservation requirements. A window with these properties has been developed in 3encult (SmartWin Historic). It even meets the requirements for Passive House windows and at the same time can be adapted to meet the visual requirements for use in many historic buildings. Whenever windows are replaced, the new window should have an airtight connection to the wall, in order to reduce heat losses and improve comfort. In order to avoid high humidity levels which could lead to mould growth at interior surfaces, a sufficient ventilation rate must be ensured, after airtightness improvements. The most reliable and comfortable method is to install a mechanical supply and extract air system with heat recovery. The risk of mould growth can additionally be lowered by insulating exterior walls, roof and basement ceiling with exterior or interior insulation. Window change might lead to different daylight availability. Going from historic single pane windows to climate adjusted double or triple pane windows reduces the visual light and energy transmissions. (The need for artificial lighting is increased). However, modern glass coating technologies can reduce this effect, e.g. today a triple glazed window can have the same light transmission, as a double glazed window a few years ago. Additionally the appearance of the building might be changed due to the installed float glass panes. Historic windows were produced with historic techniques (e.g. blowing cylinders, cutting and bending the hot glass), today's glass is produced in floating technique which gives perfect plane surfaces. These surfaces act as mirrors if they are viewed from outside. Single manufacturers are ready to produce historical appearing glass

What are the different technical approaches one can take to preserve historical landmarks?

Answer: When faced with the degradation of a historic building or sculpture, one must choose between conservation, preservation and restoration. Often, this choice is made by the architect or conservator of the project. 

What type of software should be used for the design phase of a ventilation system?

Answer: For calculation of the air quality depending on the flow rates and the control system, the software CONTAM from NIST (free download) is very useful. This sophisticated software is only necessary for research and development, for standard systems simplified design tools are sufficient. Some of them (such as CADVENT from Lindab) will help for 3D-design as well as all of the necessary calculations, such as pressure drop, sound etc. The Passive House Planning Package (PHPP) allows for a simple design of required volume flows and duct insulation. 

Assessment of different energetic concepts for historical buildings 

How can I find out, whether my house needs energetic renovation?

Answer: A first indicator of the inefficiency of the building could be reflected in the electrical/gas/fuel bills where the consumption is detailed. If there is any suspicion regarding the high consumption, our recommendation is to contact an expert in order to make a simulation/evaluation of the energetic demand for detecting any inefficiency. 

Can my house or my apartment be insulated subsequently from inside?

Answer: yes, nowadays there are adequate internal insulation solutions for any building. The hygrothermal situation of the construction should be considered.

Is it worth a subsequent internal insulation for my house or my apartment?

Answer: A subsequent internal insulation can effectively reduce thermal losses without altering the exterior façade of the building. The works must be professionally done in order to avoid moisture problems, mould growth, and condensation at the beam-ends. 

Can some moisture problems arise through using Interior insulation and what to consider?

Answer: Moisture problems can arise if the insulation is not properly installed. The choice of the insulating materials depends on the type of building and on the air-tightness after the retrofit process. A technician (building physicist) can establish the most appropriate materials. For example, in the 3encult project a capillary active insulation has been developed to avoid the vapor condensation on the exterior wall.

Can historic preservation also be “green”?

Answers: Many energy efficiency measures that are frequently applied to old buildings can, as a "side effect", prevent further deterioration of the historic building fabric. Here are a few examples: -Insulation of the exteriors walls with exterior or interior insulation systems increases the interior surface temperatures. This lowers the risk of condensation and mould growth. Exterior insulation also protects the building fabric from the influence of driving rain, pollutants, temperature changes and frost. For interior insulation you should always consult and expert, as it can sometimes cause additional moisture accumulation if poorly planned and executed. -Making your building airtight improves comfort and saves energy. At the same time airtight roofs are less prone to moisture damage, caused by damp indoor air that flows out through leaks and leaves condensate in the construction. -Installing a ventilation system with heat recovery can lower your ventilation heat losses by 90 %. In winter it removes damp air from the inside of the building and replaces it by dryer outdoor air. This way high air humidity levels are reliably avoided and the risk of mould growth can be lowered dramatically.

What happens if only on part of the building is insulated?

Answer: It is quite possible that parts of a historic building could not be insulated for conservatory reasons. In fact, the exterior walls of the same building can be very different due to thicknesses, materials and decorations. Starting from a multidisciplinary discussion between technicians and conservators, the optimal solution for each wall can be obtained. Obviously, the energy saving depends on the size of the insulated area and a new thermal bridge is introduced where the insulation ends. Therefore, humidity problems or mold growth have to be checked. 

Does heat recovery make sense in my historic building, even if good airtightness is not achievable?

Answer: The advantages of heat recovery systems are both, energy saving and comfort. The ambient air is preheated, hence there is no draft risk. This comfort argument still holds even if good airtightness is not achievable. Besides the infiltration losses, there is still some (but limited) effect of heat recovery. Consequently, enhancements of airtightness are more economic in case of a heat recovery system installed. 

1.4 Rehabilitation phase Realization of constructive measures 

Is there any condensation problem at the wall, if the window is no longer the coldest surface of the room?

Answer: In historic buildings before renovation, single glazing or older double glazing represent the coldest surface of the external envelope. The heating system of historic buildings was in general realized with individual stoves, causing negative pressure within the building by exhausting the combustion air via the chimney. This way, dry ambient air vented the building via gaps, openings and cracks within the building envelope. Visible condensation on the windows often alerted occupants to the need for ventilation to flush out interior moisture (so they opened the windows). 

I have difficulites making my building airtight because of old rafters and floor joists. What can I do?

Answer: Making old buildings airtight is often difficult when old rafters and floor joists intersect the airtighntess layer. In most cases the airtightness layer (e.g. plaster or membranes) should be carefully connected to the timber at each intersection. Depending on the circumstances appropriate tapes and sealants can be used. Often cracks in the wood are an additional obstacle for good air tightness. These should not be neglected. They can be filled with sealant. Possiblity is to drill a hole at the place where the crack is, with a diameter that is a bit wider than the crack. This hole is than filled with a wooden dowel. This way the crack can be almost perfectly sealed. 

Which method is available to check the achieved air tightness of a building?

Answer: Blower door (pressurization) test with one or more blower doors simultaneously and extrapolation to 50 Pa (if necessary). Tracer gas measurement (tracer decay method), if not inhabited, also possible (low cost method) with CO2. The blower door test plays a key role. This is a test recently introduced but already widely used in Europe on the applications of energy protocols related to buildings. The aim of the Tracer gas test is to investigate the level of air tightness of the external envelope of the building that means how much a building is permeable to the air infiltrations. To perform this evaluation the building is put in condition of controlled differences of pressure and temperature. Therefore the test result cannot be identified as a measure of the actual infiltration flow which has to be carried out with tracing gas. 

1.5 Monitoring phase Measurement techniques 

Is the installation of monitoring system necessary?

Answer: Before an energetic retrofit, a monitoring system can provide whether the existing heating and cooling systems operate properly and effectively, such as the room temperature agree with the set-temperature, the on/off-times are correct etc. Also, for example, the user behavior can be detected. Are the windows open during the winter when the heating is switched on? Based on these data, the first optimization strategies in terms of the thermal systems and also instructions for the user can be developed. After an energy retrofit the data from the monitoring system can also be used, to develop optimal control strategies for the thermal systems. A further possibility is the monitoring of critical construction details, like thermal bridges, dogging beam ends etc.. Accordingly arranged sensors can monitor such as the moisture situation in these parts. In this way arranged actuators (humidifiers, dehumidifiers, heaters, etc.) in the building can be controlled, after evaluation the data if it is necessary, so that the building structure is protected. 

Which kind of sensors is recommended to install in historic building?

Answer: The kind of sensor follows the measurement task, which follows the problem to be investigated. At first the problem or risk has to be defined, than a measurement set-up including technical questions and interpretation procedure could be defined. 

What Sensors and how should be placed to enable an assessment of the of mold growth risk?

Answer: For the assessment of a possible risk potential on biogenic infestation in the area of construction or even at room side wall surfaces, it is necessary to install the sensors very close to the point of interested. The measurement of the indoor environment alone is not suitable for the assessment of such risk potential. For this purpose it is necessary in the near field of the affected detail to measure the air temperature, the relative humidity and the surface temperature. With this sensor data it is possible to make a statement about critical climate conditions or occurrence of condensate in the near field of the detail. 

Visualization of monitoring data 

Which World Wide Web technologies are suitable to visualize real- time energy consumption of a building?

Answer: A smart meter for example is usually an electronic device that records consumption of energy in intervals of an hour or less and communicates that information at least daily back to the utility for monitoring and billing purposes. The term Smart meter often refers to an electricity meter, but it also may mean a device measuring natural gas or water consumption. 

What is a building management system?

Answer: A Building Management System (BMS) is a software high-technology computerbased system which is installed on buildings that monitors and controls the building’s mechanical and electrical equipment such as ventilation, lighting, power systems, fire systems, and security systems. It is a complex, multi-level, multi-objective, integrated, interrelated and complete intelligent design management information system, which combines software and hardware for managing the behaviour of the facilities of any building. The goal of a BMS is to set up a set of services both for monitoring and control strategies in a single application in order to automate the behaviour of the facilities in an easy and quick way to the end user. Thus, it is able to collect Task 8.5 frequently asked questions 14 the sensor data, store the information in a persistent way to create an historical log, show the information in a graphical user interface and run control algorithms by integrating different data sources.

Is the usage of a Building Management System useful?

Answer: The purpose of a Building Management System (BMS) is to automate and take control of the operations of the facilities and actuators in the most efficient way possible for the occupiers/business, within the constraints of the installed plant. Thus, through the archived data and other external data sources, it is able to execute control algorithms so as to determine the optimal control strategy and implement it. Therefore, it is beneficial in several ways: allowing the visualization of collected data for the current state of the building and optimizing the installations with the consequent energy savings, assuring the comfort parameters. 

Which database technologies are suitable to store big data?

Answer: Currently, there are a lot of database vendors which support big data, such as Oracle, PostgreSQL, MySQL, and SQL Server and so on. However, the most powerful are both Oracle and PostgreSQL. Oracle presents the best features in the market, but with the payment of a license. However, PostgreSQL is free-license, but some limitations in the performance and management of data. The final decision is a compromise between tow factors, how much data is expected and how much can be paid (cost factor). 

1.6 Assessment phase 

Which results are relevant for historic building?

Answer: Depending on the final usage of the building, different results must be evaluated. For example, in a museum with frescos and drawings, the most important value is the comfort parameters because the humidity, temperature or luminosity could damage them. Thus, assuring the indoor conditions for the preservation of the elements in the building is the most important results without taking special care for the energy issue. In other cases, the reduction of energy demand/consumption could be the main aspect, being the comparison between the energy demand/consumption before and after refurbishment the main result, in order to ensure the reduction of it, bearing in mind the user indoor comfort conditions. 

How can the results of the renovation be evaluated effectively?

Answer: The most relevant result in the assessment phase is the value of air tightness detected by the blower door test. It will show you how much infiltration/exfiltration through leakages will take place if no enhancement is done on airtightness. This air-change will not be part of the heat recovery, if such a system is foreseen. An air quality measurement before and after refurbishment is also relevant for the decisions in terms of ventilation. 

Which results are relevant for historic building in terms of ventilation?

Answer: Indoor air quality, energy consumption for heating and electricity, stability of the hygrothermal conditions within the protected zones.

How can the results of the renovation with application of efficient ventilation methods be evaluated effective?

Answer: In case of ventilation with heat recovery, the resulting ventilation losses after the renovation are the remaining infiltration/exfiltration (depending on the airtightness achieved) plus the losses of the active system (depending on the heat recovery rate). The result can Task 8.5 frequently asked questions 15 easily be calculated with Passive House Planning Packge (PHPP). The savings are in the range of around 10 kW/m²a. 

1.7 Environmental sustainability at urban level 

How is the context of cultural heritage identified?

Answer: Context of cultural heritage could be the immediate surroundings, the restriction for construction height and material prescribed in local building regulations. It could be a definition of a historical area and a buffer zone that secure the historic value. 

What is cultural heritage?

Answer: Cultural heritage could be values of public as well as of private nature. It could be values and property of common interest but also representing certain groups and belonging.

What is environmental sustainability at urban level?

Answer: Environmental sustainability at urban level is to maintain values of social technical and aesthetic character that sustain and integrate qualities of diversity.

What is the character and extent of a multidisciplinary method?

Answer: The multidisciplinary method ensures that all possible means are taken into account when it comes to integrate the qualities of diversity in development of urban historic projects.

How is energy and culture balanced when plan and program of urban area changes?

Answer: Energy and culture is balanced through a thorough investigation and action plan involving multidisciplinary aspects of energy and culture as past, present and future possibilities.