FAQs

Categories:

General | Financing | Ventilation | Design tools (PHPP) | Components | Component Award 2016

 

GENERAL

 

Is it cheaper to retrofit step by step than in one shot?

With a step by step retrofit, the investment is spread over several years. In doing so, each component can be retrofitted when it has reached the end of its service life, maximizing the utility of the investment in energy efficiency.
As less money is required to complete an individual step rather than a complete retrofit, work can be started sooner to realize savings on energy bills sooner. The financial gains can be greater than the additional costs specific to the step by step retrofit process (e.g. setting up scaffolding several times).

Are there special products available for step by step renovation?

There is a manifold of Passive House components available on the market. Most can also be effectively used for retrofits. Some products can be used in an adapted form or as part of an optimised concept for renovations. Some special products are in development and we expect the number of available products to increase in the future.

How can renewable energy sources (RES) be integrated into a renovation project?

When changing the roof or the facade, the integration of Photovoltaics (PV) can be meaningful, if it does not have a negative impact on the architectural quality of the building. It makes sense to use the produced energy on site in combination with heat pumps and to feed any surplus into the general grid, if possible.

What is the most cost-effective first retrofit step?

It differs from building to building. This can be accurately analysed with the Passive House design tool - Passive House Planning Package (PHPP). In principle, an overall step by step retrofit plan should be designed outlining the costs and savings of each step. The savings that one can achieve from each step can be calculated and then allocated in the next retrofit step.

What should be prioritised in a step by step retrofit - the renewables or the building fabric?

Definitely the building fabric. By improving the energy performance of the thermal envelope you are reducing the primary energy demand of your building considerably. The small remaining demand can then be covered by renewable energy much easier.

Is the EnerPHit standard suitable for my building?

In energy retrofits it is often difficult to meet the Passive House criteria, even if you use the same components (for the walls, roofs, windows, etc.) as with new buildings. Some parts of the buildings are not accessible, so some thermal bridges would remain. This is why the EnerPHit standard has been created for renovations close to the Passive House concept.

What are the main requirements for EnerPHit certification?

You have two options to certify a renovated building to the EnerPHit standard:
1. If the heating demand is not above 25 kWh/(m²a) (calculated using the PHPP) or
2. If all the building components meet the requirements for Passive House certification.
For both cases there are also requirements for thermal bridges, airtightness and the primary energy demand, with slightly lower standards than for Passive Houses. Additionally there are basic requirements for moisture protection and thermal comfort.

Can we have a fireplace in an EnerPHit building?

A Passive House is very cosy without a fireplace, but technically, yes it is possible. Instead of an open fire place,  an airtight wood stove which receives the combustion air from the outside needs to be used. The stove should be as small as possible as the heating power tends to be much too high in very efficient houses.

Can we open the windows in an EnerPHit building?

Windows can be opened whenever you like. Window opening is not necessary, however, because the heat recovery ventilation system constantly provides sufficient amounts of fresh air without any uncomfortable draught. In summer, the ventilation system can be turned off, if desired, and windows can be opened for ventilation.

Is there any requirement that has to be fulfilled in the intermediate steps of a step-by-step refurbishment?

The approximate insulation level or efficiency level of the intermediate steps should be defined in the Overall Retrofit Plan (ORP) before the implementation of the first step. The certifier will make sure that the ORP complies with the requirements for EnerPHit renovation. If one adheres to the levels defined in the ORP for each step, you will achieve the EnerPHit standard for the building as a whole in the end.

What are the wider societal benefits to undertaking energy efficient refurbishment?

The refurbishment of the building stock provides an opportunity to create local jobs, stimulate the economy and at the same time generate savings. For example, in Germany, the KfW handles the promotional programs on behalf of the Federal Government. The programs for energy-efficient construction and refurbishment receive favorable terms through German federal budget funds to provide financial incentives for higher energy efficiency levels in the housing sector. Recent studies show that in Germany, energy efficiency refurbishments of buildings is a win-win situation for the home owners, the environment, the economy and the federal budget, according to a study by Forschungszentrum Jülich.

FINANCING

 

Is the Passive House retrofit standard EnerPHit always the best economic choice for step by step refurbishment?

A retrofit to an energy efficiency standard lower than EnerPHit may save on initial investment costs, however in the long term, more money will be spent on energy bills and the building will not hold as high of value. The less efficient an existing building is, the higher life-cycle costs will be. The EnerPhit standard seeks for an optimal investment in different climates and different architectural contexts

How can we effectively follow a refurbishment that will last 10 or 20 years? Who will take care of that?

The EuroPHit project will produce exemplary refurbishment plans that anticipate the overall workflow for the step by step retrofit. Using these plans, along with the construction details for each step, future design and construction teams will have a thorough understanding of what has already been done and what remains to be completed.

How can step-by-step refurbishments be financed?

Step-by-step refurbishment constitutes the most appropriate approach, in most cases, for energy efficient refurbishment, both from the building perspective (modernisation where and when needed) and from the point of view of the house owners with limited financial resources. Building retrofits generate energy savings over the lifecycle of the investments, therefore long term financing is needed. Getting finance right is the first step in the provision of the complete solution.
The financing of step-by-step refurbishments is a key element of the EuroPHit project. Significant levels of research and industry interaction is informing the development of financial guidelines which will provide an economically viable and attractive solution. The intention is that financial institutions will offer financing for step-by-step refurbishment projects that meet certain criteria.

What are the market barriers to financing refurbishment?

The EU has identified the following barriers to the use of financial investments for sustainable energies (SE) in buildings including energy savings and renewable energies:
• High pre-investment development and transaction costs partially due to small size of projects, especially in the residential sector;
• Information failure on the part of customers: lack of customer awareness and a very high perceived risk of new more efficient technologies by both users and financiers, mistrust in energy audits, benefits initially invisible;
• Information failure on the side of commercial financial institutions (CFIs): general lack of sustainable energy (SE) finance experience within commercial financial institutions, lack of dedicated time and resources to develop SE capacity and activities in-house;
• Lack of visibility and scale of SE finance: SE projects often represent a relatively small niche business for major banks;
• High perceived end-user credit risks;
• Low collateral asset value of SE equipment and difficulties creating creditworthy financing structures. Collateral value is low because for most SE projects equipment represents a sizeable share of total project cost with high portions of engineering, development and installation costs;
• Energy savings as revenue is foregone by financiers: cash flows from saving energy are not (yet) conventional revenues in what is still an asset-based culture in financing. This discourages commercial financial institutions entry into this market. Energy cost savings should be incorporated into lenders' analysis of free cash flow and ability of borrowers and end-users to meet debt service payments ;
• Even where payback periods are short and economic benefits clear, SE projects are often not implemented because of high upfront costs;
• In the rental sector: Spilt incentives between building owners and tenants;
• In the residential sector: long payback periods, lack of contractors, small project size and lack of support for holistic retrofits.

What are the legal barriers to financing refurbishment?

The EU has identified the following legal barriers to the use of financial investments for sustainable energies (SE) in buildings including energy savings and renewable energies:
• Public sector: the rules of public budgeting – including the annual budget cycle and multiannual savings cash flow – make it difficult for public entities to finance energy efficiency investments from savings in energy costs (similar rules exist in large companies);
• Public sector: local authorities may have to finance energy efficiency investments from their investment budget whereas the resulting savings are credited to the operational budget;
• Residential, joint home ownership: Ambiguities in the legal standing of joint home ownerships and lengthy and cumbersome decision-making due to a large number of decision makers (residential sector); In the case of properties which are managed by housing management companies, steps for renovation are only undertaken with great reluctance, especially if the proportion of rented units is very high. Here, better living comfort and yield (profitability from rental) are not always aligned. Statutory regulation of renovation cycles normally do not include energy efficiency investments
• Residential and rental sectors: uncertainties related to tenant-owner issues and building ownership;
• All sectors: not considering life-cycle costs in procurement decisions.

What are the barriers to undertaking refurbishment in residential buildings of joint home ownership?

Specific issues arise with blocks of flats with individual owners, whereby owners' associations need to be involved in line with the specific legislation and practices. It should be noted that achieving energy savings in multi-apartment buildings with common heating/cooling systems often depend not only on the overall energy efficient retrofit of such buildings but also the behaviour of end-users. It is also important to ensure that such renovations pay due attention to the ventilation systems, maintaining a healthy indoor environment. The cost for individual energy metering in multi-apartment housing renovated to EnerPHit standard can form a significant fraction of the total running costs, as energy costs are so low. In some pilot projects individual metering of heating and hot water has been omitted for this reason.

How can the owner-tenant dilemma be overcome?

The following are some suggested ways to overcome the owner-tenant dilemma for refurbishment projects:
• Collect relevant information to understand the context of the community.
• Analyse the needs of the residents by observing routines and behaviours.
• Make tenants an integral part of the retrofit process, by understanding their needs and responding to them appropriately.
• Provide ‘show projects’ to demonstrate how the completed project will look and feel.
• Establish confidence between the different parties by being approachable and trustworthy.
• Continued communication and interaction with different stakeholders, using a range of different methods.
• Ensure that the construction works are undertaken in a sympathetic way, causing minimal disruption to residents and the local community.
• The owner should not increase the rent more than the expected heating costs savings, This way both sides will benefit from a financial profit.

What are the existing financing models for refurbishment in the EU?

Funding sources and promotional programs offered in Europe are listed on the following webpages of the EU, see http://www.buildup.eu/financing-schemes. Schemes are catalogued as follows:
• Europe-wide funds
• National/regional schemes for individuals
• National/regional schemes for municipalities, social housing
• National/Regional schemes for residential Buildings
• National/Regional schemes for non-residential Buildings

What is a one-stop-shop for refurbishment?

One of the major barriers perceived in scaling up the amount of retrofits taking place is the fragmentation of the retrofit process between measures/organisations and how clients can access the information they require. One-stop shops, where multi-disciplinary teams can undertake all elements of a refurbishment project, are considered to be a way of alleviating a number of issues in the retrofit market.
One-stop-shop models are where multi-disciplinary teams can undertake all elements of a refurbishment project, including surveying, design, construction, and financing. This may involve one or more organisations, working in a joined-up way, to provide an end-to-end offering for a client. Potential business models for one-stop-shops are being explored as part of the EuroPHit project.

What is the value of quality assurance in refurbishment projects?

The issue of quality assurance is extremely important, especially when aiming for a demanding performance standard such as EnerPHit. Quality assurance procedures ensure a consistently high level of value for money for all. Improper quality assurance could jeopardise the certification of projects and lead to potentially expensive remediation measures. Through research and industry engagement, the value of quality assurance in refurbishments is being thoroughly considered as part of the EuroPHit project.

What are redemption grants and how are the used?

In case of a step-by-step retrofit (as in the case of the EuroPHit project which implements the EnerPHit standard) a repayment bonus financed from a grant (redemption grant) can be used in connection with loans to reward the borrower when certain efficiency targets of the EnerPHit standard have been achieved.
The KfW, Germany, used redemption grants in their promotional programs for the energy retrofits of residential buildings. The redemption grants are refinanced out of the government budget. As soon as the retrofit achieved a certain level of energy efficiency comparable to the requirements of the energy saving ordinance for new buildings a repayment bonus was rewarded. The efficiency targets are defined as the calculated total primary energy demand of the whole building in kWh/m²/year.

VENTILATION

 

Is the ventilation system noisy?

A ventilation system, that is designed and executed with care will not be audible in standard operation mode. Most ventilation units should be installed in a utility room or another area not too close to the bedroom. Ducting systems needs to be fitted with silencers. The home will also be better protected against noise from outside.

Is it necessary to install a mechanical ventilation system with heat recovery (MVHR)/HRV, or may I use windows for ventilation?

Using windows for ventilation can help reduce pollutants in the indoor air but it is not suitable for energy efficient building renovation. Buildings with very low energy consumption and very high airtightness levels have a mechanical ventilation system combined with heat recovery (MVHR/HRV). This system ensures a healthy indoor microclimate and as a benefit you save more than 10 times the heating energy, compared to the electric energy for running the ventilation system.

Does a ventilation system need maintenance?

Yes. Air filters need to be replaced once or twice a year. The ductwork is normally protected from dust by the filter and doesn't need to be cleaned. If your ventilation system doesn't have automatic flow balancing, the airflow volumes should be recalibrated after several years.

What are suitable ventilation concepts for renovation?

Depending on the floorplan, centralised systems with a heat recovery unit for several apartments or decentralised systems with one unit for each apartment can be used.  Cascading ventilation concepts are recommended, if the floor plan is suitable becausethey need less ducting and are more efficient. Ventilation units integrated into windows still do not have the necessary efficiency but products are in development. Ventilation systems always need to fulfill two criteria: 75% heat recovery efficiency as defined by the PHI and a max. electrical consumption of 0,45Wh/m³ of ventilated air.

What is cascading ventilation?

In a cascading ventilation concept some of the living areas are treated as overflow zones. This means that there is less ductwork required and the amount of ventilated air is minimized.

In which refurbishment step should a Mechanical Heat Recovery Ventilation (MHRV/HRV) be installed?

Once the airtightness level is upgraded (at least 1 air changes per hour at 50 Pa), which should be achieved upon the upgrade of walls, roofs, floors, windows and doors, a MHRV/HRV must be installed. If a MHRV/HRV is not installed as soon as the airtightness level is achieved, the risk of extremely poor air quality within the building is very high and it will not be safe to live/work in it. Moreover, without a MHRV/HRV the moisture content within the building will rise considerably putting the building fabric at risk.

The exhaust air outlet and fresh air inlet are often situated close to each other in Passive Houses and EnerPHit retrofits. Does this cause problems with mixing fresh and exhaust air?

In many countries there are strict regulations for the separation of the exhaust air outlet from the fresh air inlet. Experience from Passive Houses shows, that giving different directions of the airflow through the exhaust air outlet and the fresh air inlet is sufficient to ensure good air quality.

I love cooking. Will the heat recovery ventilation be able to vent off all smells and vapor?

The air inlet in the kitchen should have a grease filter. If you cook large meals frequently, an additional kitchen hood with a carbon filter is recommended. It should preferably recirculate the air instead of venting it off to the outside, as this causes high heat losses.

DESIGN TOOLS (PHPP)

 

Does one need simulations in addition to the Passive House Planning Package (PHPP)?

Generally, one has to be careful with simulations as they are only as accurate as the data you use to begin with, leaving a lot of room for error. The seemingly exact results they give can be misleading and the PHPP is certainly more fool-proof in this sense. In terms of hygrothermal simulations, once proven build-ups for any particular climate are known, such simulations are typically unnecessary and don't need to be done for each repeated use of the same construction type. For overheating, cooling, and dehumidification - areas that play a role in your locale, PHPP Version 8 has been calibrated using dynamic simulations. If, in the end, you want to use dynamic simulations, there are a variety of programs from which to choose from on the market, although they are all far more expensive than the PHPP.

Where can I find suitable climate data for EnerPHit verification with the Passive House Planning Package (PHPP)?

If climate data for your locations are included in the PHPP, you should use these. For all other locations you can use the climate data tool on www.passipedia.org for orientational calculations (iPHA membership required). Before renovation work starts you should contact a Passive House Certifier in order to receive validated climate data for your location.

COMPONENTS

 

Which basic principles should I adhere to if my first retrofit step is to upgrade all windows and doors?

In principal an overall step by step retrofit plan should be in place from the beginning, thus the upgrade of the thermal envelope is defined in particular the type, thickness and location of a new insulation layer. The window/door jamb, head and sill details must be designed to minimise or avoid any thermal bridging/air leakage/condensation risk. If the windows and doors are being installed prior to the upgrade of the walls, these should be located along the future wall insulation layer, safeguarding the integrity of the new windows/doors and the existing walls. There will be two types of window/door installation detail sets: one for the first retrofit step of upgrading windows/doors installation on the existing wall, and another for the upgraded windows/doors installation on the upgraded wall.

COMPONENT AWARD 2016

 

Read the Component Award 2016 FAQs in German

 

You should base your offer on your experiences with similar projects. For unforeseen additional expenditure, please state an hourly flat rate .If you can already foresee certain extra costs (that are incurred frequently although they may not arise in every project), you may offer optional extra costs relating to services. These costs will not be included in the Component Award provided that they are actual additional costs.
 
In order to prepare a realistic offer, you should inquire about the services which you do not provide yourself, or you should estimate the costs yourself if possible. You can also participate in the Component Award together with a partner company (specialist planner or contracting company). Although such cooperation is not mandatory, it is expressly desired!
 
The location may be chosen freely by the participants. For taking into account of any regional differences in assembly costs, extra costs should be stated for each 100 km of distance.
 
The ventilation heat losses are calculated from 77 % of the required maximum supply air volume flow rate = design volume flow rate (corresponding to the number of persons per housing unit, this is 30*3=90 m³/h). The design value should be entered into the evaluation tool.
 
The interior walls are also solid, masonry should be set for assessing the expenditure. The wall thicknesses can be calculated from the floor plans.
 
The storey height is 2.7 m. The space volume of an apartment is therefore 184 m³.
 
As always, we will be pleased to help with any questions that you may have and wish you much success with the development of the ventilation solutions.