Retrofitting your home to be more energy-efficient can appear daunting and overwhelming, particularly with the mass of (often contradictory) information our there. However, to achieve a successful low-energy retrofit there are a number of principles which must be considered, many of which apply whether it's new-build or retrofit. Michael is a Certified Passive House Designer and has also completed the Passive House Retrofit Delivery course and AECB CarbonLite Retrofit courses and has a wealth of hands-on project experience. This makes him an experienced guide in your retrofit journey. Fox-Groves Architecture is also a member of the Passivhaus Trust and Association of Environment Conscious Building (AECB).
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There are two main low-energy retrofit standards which we may consider for your project:
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Both must meet achieve a high level of performance, with EnerPHit being the most stringent. The AECB standard uses the same methodology but has slightly lower performance requirements and the certification process is less involved. In both case, we would model the house using the Passivhaus Planning Package (PHPP) which calculates the heating demand based on a precise specification of materials and products using the specific details of your house. The same approach can still be used to a lesser standard and cost, whilst still offering significant comfort improvements. Our retrofit strategy and thermal modelling can help inform a suitable retrofit strategy for your home, and you can also consider a phased approach, replacing elements as they reach the end of their service life.
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What are the Benefits?
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Comfort & Health: Comfortable temperatures are maintained even when it is cold outside. Careful consideration of the orientation, shading and detailed modelling also considers summer comfort. High quality windows, more insulation and minimised draughts means no cold spots, no mould and no condensation and very little energy is used to heat your house.
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Fresh Air: A Passive House has constant clean, fresh air provided via an MVHR system. The ventilation systems ensure that air is purified and pollutants are kept out. You can always open the window to let the outside in too!​
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Energy Bills: A home with retrofit improvements will offer significant reductions in energy usage, meaning savings from year 1, which will only increase over the lifetime of the building.
How do you build a low-energy Retrofit?
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A successful retrofit requires a lot of skill and expertise to design, but that's where we come in! The main principles and considerations for a successful low-energy retrofit are listed below:
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Accurate Design Modelling: All aspects of the design, detailing and equipment are modelled using the Passive House Planning Package (PHPP) using real-life climate data to verify the building performance including solar gain to maximise heat gains in winter whilst reducing the risk of overheating in summer.
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High levels of Insulation: Additional insulation is required - the strategy (internal or external insulation) will be dependent on the specifics of the house and its context, with careful consideration of moisture risk and use of appropriate insulation materials.
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Thermal Bridges: Thermal bridges (cold spots due to gaps in insulation) will be present in existing buildings and can have a significant impact on heat loss - these must be considered in the design, and we can develop details to minimise their impact. This can be calculated using thermal modelling software.
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Airtight Building Fabric: The air-tightness of existing buildings can be significantly improved through a variety of approaches and products - this means that you're not paying to heat your home, only for it to 'leak' out of your home.
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High-performance Windows: Triple-glazed windows with high-quality, thermally efficient frames ensure that there are no cold spots and also help to create quieter homes.
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Mechanical Ventilation with Heat Recovery (MVHR): MVHR provides fresh, purified air at a comfortable temperature throughout the home, but this doesn't stop you opening the windows too!
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If you're considering a low-energy retrofit, please get in touch to find out more.