Insulating Sash Windows

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Welcome to Sash Window Refurbish

Experts in Sash Windows Repair & Restoration, Timber Windows & Timber Doors in east midlands

As we reach this time of the year once more, the short English summer has bid us farewell, and winter is making its way back. Winter brings many things that I adore:

  • The warmth of open fires
  • The indulgence of roasted marshmallows
  • The comfort of hot chocolates
  • The cosiness of slippers and fluffy hats

However, it’s worth noting those rattling drafty windows. They not only contribute to the charm of winter but lead to increased heating bills.

What Is Window Insulation?

A window that prevents heat loss from buildings by establishing an efficient barrier between the interior and the exterior is referred to as window insulation. This is particularly important in areas where there are significant temperature variations.

During the winter in the UK, the outside of your property is notably colder than the inside. Suppose your home lacks effective insulation, it will endure difficulties throughout the winter months.

Thankfully, several installation techniques actively insulate your windows. Thus, it helps in combating this issue. We will discuss them shortly.

Rubber Weather Sealing

DIY sash window draught proofing materials

Using rubber seals is one of the most effective techniques for window insulation. Window rubber seals, available in various sizes, can effectively seal your windows against the harsh winter weather, keeping your home warm while lowering heating bills. Additionally, rubber seals are easily available at local hardware stores or online for added convenience.

Layered Curtains

Curtains for draught proofing 

Layered curtains offer an excellent alternative to replacing single-glazed windows that might be too expensive. Single glazing is less efficient at home insulation compared to double or triple glazing as there’s only a single layer of glass separating you from the cold winter conditions. However, it’s still possible to insulate your windows by using layered curtains instead of paying an exorbitant amount for double-glazing.

By utilizing multiple heavy layers of fabric, layered curtains offer an outstanding alternative to double glazing. They provide a significant amount of insulation for your windows, helping to keep your home warm and cosy during those chilly winter evenings.

Draft Snakes

Are you tired of feeling the chill of an icy draft through your windows? If so, draft snakes might be the solution you need. These simple fabric cubes are placed underneath your window seals to effectively prevent drafts from entering your home. While they are not a long-term solution, they are a quick fix that can effectively keep out drafts throughout the winter sunsets.

Window Insulation Film

For superior window insulation, you can easily find insulation film online or at most hardware stores. It is a plastic window film that can be easily applied to indoor frames using double-sided tape. You can personalize the fit by heating the insulation film with a hair dryer to remove any wrinkles. This is an affordable yet highly effective way of insulating your casements throughout the winter.

Caulk or Recaulk Caulk Your Windows

Over time, the seals surrounding your casements can wear down, allowing drafts and moisture to enter your home. It is crucial to regularly maintain the caulk to ensure its effectiveness.

Now is the perfect time to inspect the caulk around the outside of your windows before the cold winter weather arrives. If you notice any cracks or damage, it is important to replace the caulk promptly, as it will no longer provide the necessary sealing.

Install a Low-E Coating

Low-emissivity (Low-E) coatings are highly efficient insulation products with exceptional benefits. By applying this specialized film to standard glass, you can effectively block harmful UV rays while retaining heat, resulting in a more energy-efficient home.

While installing Low-E coatings on smaller windows can be straightforward, it may be more challenging for larger windows. Inexperienced individuals who are not familiar with applying window coatings may find it beneficial to hire a professional to ensure the job is done accurately and efficiently.

Repaint and Seal Your Windows Against the Cold

To ensure optimum energy preservation, it is of utmost importance to insulate your wooden windows using the following technique:

  • Remove old paint: Use a paint scraper or sander to gently remove old paint from the wooden frames, especially damaged areas, until you reach bare wood.
  • Sand the area: Thoroughly sand the wooden frames after removing old paint to create a smooth surface for better paint adhesion and sealing tape.
  • Fill cracks and holes: Inspect the wood for cracks or holes, then fill them with wood filler using a putty knife. Level the filler with the wood’s surface and let it dry as instructed.
  • Repaint the frames: Once the wood filler is dry, apply at least two coats of high-quality exterior paint to the frames, ensuring complete coverage and moisture protection.
  • Ensure a good paint job: Take your time to paint carefully, paying attention to all corners, edges, and hard-to-reach areas. Properly sealed windows prevent moisture damage and maintain energy efficiency.
By following these steps, you can effectively seal your wooden windows, protect them from damage, and maximize their energy efficiency.

Install Weather Stripping

Weatherstripping is a popular form of window insulation. When the window is closed, the foam of the weather stripping expands and fills any gaps, effectively preventing air from getting out. This serves as an effective measure in protecting your home and reducing heating bills during the winter season.

Long-Term Insulation Solutions for Windows

If you’re fortunate, the temporary window insulation solutions mentioned earlier could suffice for one winter. However, you may encounter residue or find it necessary to incorporate blinds and curtains. On the bright side, there are long-term insulation solutions available, albeit at a higher cost initially. Once these insulation solutions are installed, you can enjoy a worry-free experience moving forward.

Secondary Glazing to Insulate Single-Glazed Windows

Secondary glazing minimizes draughts by installing a second glass panel into the window of period homes. However, it does not eliminate draught problems.

When you use secondary glazing, the window draught may still exist, but it will not enter the home because the second glass panel blocks it. However, this solution may cause mould and dampness issues over time, similar to some short-term solutions.

Although secondary glazing is a good option for minimizing draughts, it does not completely solve the issue. Additionally, it may affect the appearance of your windows and discourage some homeowners from using this solution. Therefore, Sash Window Refurbish offer a better alternative available - double glazing.

Double Glazing for Windows Insulation

At Sash Window Refurbish, we provide efficient double-glazing services utilizing vacuum-sealed technology. This technology is so advanced that our double-glazed windows deliver equal performance to triple glazing that is up to gas field standards.

New vacuum double-glazed unit

However, our vacuum-sealed double glazing is slimmer and can be easily installed into narrow rebates of older windows, such as slimline double glazing. Thus, making it an excellent solution for period homes that require efficient insulation.

Our team at Sash Window Refurbish can install this double glazing into your existing window frames seamlessly. This means that your windows retain their original style and character with no noticeable changes in appearance.

In addition, we offer a great solution for your windows that involves draught-proof and insulation. By draught proofing, we ensure that we completely seal your windows. This will eliminate cold air and reduce noise.

We recommend double glazing as the best insulation method in the long term. Although it’s a bit pricey, the benefits outweigh the cost. It is because you won’t need to displace your windows with temporary solutions like bubble wrap, blinds, or tapes.

Furthermore, double-glazed sash windows help regulate your home’s temperature by keeping it cool in the summer and warm in the winter. Even if you believe your windows cannot be double-glazed, we suggest reconsidering this option as it can greatly improve your home’s insulation.

At Sash Window Refurbish, we have successfully completed window work that other companies deemed impossible, despite the scepticism of many of our customers. We offer effective insulation solutions that stand the test of time. Suppose you seek a reliable and long-lasting insulation solution; we encourage you to contact us today to find out more.

When to Insulate Your Windows?

It’s recommended to insulate your windows before the onset of cold weather. Identifying which windows require insulation during this time can be a challenging task. However, the smoke test is an effective method to determine which windows will most likely need insulation.

Will Insulating My Windows Save Money?

Insulating your windows, whether through short-term solutions or double glazing, decreases your reliance on heating systems. Thus, improves your home’s energy efficiency and saves you money. Double glazing is particularly helpful in reducing your heating usage and locking in heat for longer periods, resulting in significant cost savings. In summary, paying attention to selecting the appropriate window insulation solution for your home can lead to greater financial benefits.


Suppose you’ve lately moved into a period property and need a quick way to stay warm throughout the winter, the short-term solution method discussed earlier is a great option. It’s also suitable if you prefer to wait until spring for a double-glazing replacement. However, keep in mind that these methods are temporary and may affect the style of your home.

We believe that double glazing is always the most effective insulation method. For more information about our double-glazing services for period homes at Sash Window Refurbish, please visit our services page and get in touch with us today.


My technician Andrew replaced all my sash windows that had rotten sills. Accessing the rotten sills was not an easy task. He explained to me what needed to be done in order to fix the problem. He is a great person and I’m happy that he was the one who did the job. He is reliable, tidy, friendly and very professional. I highly recommend him.



I hired Andrew and Alex a while back to repair my damaged sash windows. They were was very considerate and very patient as he did his job. A few days ago, I had another problem with one of my sash lock keys and I called him again to come and fix the problem. I’m very impressed that Liam responded quickly and he not only fixed the problem but he also gave me a spare key. What a great after sales service!

Alan W.


I’m very impressed with the new windows that Andrew installed and also the reconditioning job that he did on other sash windows. The quality of his work is by far more superior than what we got when we hired another company a few years back. We will certainly hire him again if any window work arises

Kelly (Sleaford)


Our decorator referred us to Andrew because some of the work needed a window expert. Andrew together with our decorator did a fantastic job. The work was done efficiently and to the highest standards. Andrew is understanding, committed and very professional. I recommend him without any hesitation.

Steaven Reader


Alex did a great job in fixing windows in our terraced house. The windows were broken, frames damaged and the wood was also rotten. Alex's job was high quality and he did it pretty fast. I was also very impressed that he was considerate of my son’s asthma condition and maintained cleanliness. Top work.



Andrew just recently replaced three sash windows in my Edwardian house. He also repaired and replaced some sills and draught proofed three windows. In addition to that, he also did some carpentry work. What I like the most about Liam is that he did a clean job. He is very professional and always updated me about the timescales and costs. He also did his job with minimal disruptions. I highly recommend him.

Cris M.