Preserving the charm of old buildings, saving energy: Window renovation for listed properties

Old buildings are considered true gems in our cities: whether stucco-decorated façades, historic shutters or charming double casement windows - the charm of bygone eras casts a spell over many people. But the nostalgic flair also brings challenges. Listed properties are particularly demanding when it comes to energy-efficient refurbishment. A key aspect of this is the replacement or refurbishment of old windows.

In this blog post, we show you how you can preserve the historic charm of a property while upgrading its energy efficiency. We shed light on technical, legal and economic aspects and provide valuable tips for owners and prospective buyers.

Listed buildings: between requirements and the desire to modernise

In the case of listed properties, the preservation of the historical substance is paramount. This includes not only façades and roofs, but also windows - often defining design elements of the building's appearance. The relevant monument protection authorities therefore attach great importance to the preservation or faithful reproduction of the original.

The classic replacement of old wooden windows with modern plastic or aluminium windows is generally not permitted. Instead, measures are required that are convincing in terms of both design and energy efficiency.

What does this mean in concrete terms for owners?

• There is Authorisation requirementfor every change to the window.
• Changes must be visually based on the original(material, colour, shape, opening mechanism).
• Ideally, the implementation takes place in coordination with specialist planners and monument authorities.

Technical solutions: How to renovate windows in listed buildings

1. have historical windows rebuilt

A frequently used method is to replicate the existing windows using modern technologies. This means

• Use of real wood(often oak, larch or pine)
• Detailed profiling, glazing bar divisions and window sills
• Integration of modern Thermal insulation glazing(mostly 2-fold, rarely 3-fold)
• Concealed sealing systems, that reduce draughts and heat loss

Such windows combine aesthetics and efficiency - and also increase the value of the property.

2. preservation with energy upgrading

In some cases, the existing windows can also be refurbished become:

• Replacing the glass panes with better glazing
• Installation of additional Interior window (box-type window)
• Sealing the joints and reworking the fittings

This method is particularly monument-friendly, but is not always technically sufficient - especially if the windows are badly damaged or warped.

3. example from practice: energy-efficient window renovation in a Berlin Wilhelminian style house

In a Berlin apartment block dating back to 1890, the entire window system was refurbished in keeping with its listed status. The owners opted for customised wooden windows with a historic look, double glazing and additional sealing levels. Despite the high investment of around €1,200 per window, the heating energy consumption was reduced by almost 20 %. The measure was partly financed by KfW funds.

The result: preservation of the façade, noticeable energy savings - and a significant increase in the value of the flats.

Is the effort worth it financially?

Even if the purchase costs for windows that are suitable for listed buildings appear high (between €800 and €1,500 per unit, depending on the design), the investment often pays for itself several times over:

• Reduced heating costsUp to 25 % of the heat loss of an old building is lost through old windows.
• Increase in valueEnergy-efficient refurbished old buildings achieve higher prices on the market.
• Attractiveness for buyers or tenantsBeautiful windows with a historic look and modern features are a strong selling point.
• Subsidies and tax advantagesThese reduce the effective costs considerably.

Targeted use of funding programmes

1. KfW funding - low-interest loans and grants

KfW provides funding via the programme 261 „Residential buildings - credit“ The involvement of a certified energy consultant is a prerequisite.

Important: The following applies to listed buildings Easier requirements to the energy targets.

2. BAFA subsidy for individual measures

BAFA offers attractive grants for individual measures on the building envelope, e.g. window replacement. The prerequisite is a previously drawn up refurbishment roadmap (iSFP).

3. Tax depreciation according to §7i EStG

The costs of renovating listed properties can be claimed against tax over 12 years - 9 years with 9 % each (owner-occupier) or 8 years with 9 % + 4 years with 7 % (landlord).

4. Regional programmes

Federal states such as Bavaria, Saxony, Berlin and North Rhine-Westphalia subsidise the renovation of listed buildings with Grants or state loans.

What about sound insulation and comfort?

Another common advantage of windows that are suitable for listed buildings is the Improved sound insulation. This can make a noticeable contribution to living comfort, especially in old city centre buildings. Multiple glazing in combination with high-quality wooden frames ensure a significant reduction in street noise.

In addition Draughts reduced, and the Room temperature remains more constant - which significantly improves living comfort, especially in winter.

Conclusion: Energy-efficient refurbishment without losing the charm of the old building

Replacing windows in listed buildings is no easy undertaking - but it is a worthwhile investment in the future. Those who renovate the old building with care and in consultation with the authorities will benefit in several ways:

• Preservation of valuable building fabric
• Energy saving and cost reduction
• Increasing living comfort
• Funding and tax benefits
• Higher property value

What is important is thorough planning, the involvement of experienced specialists - and patience during the approval process. After all, the end result is a home that tells a story - and at the same time meets the requirements of tomorrow.

Checklist: Window renovation in a listed building - what you should bear in mind