Double Glazing vs Single Glazing: What’s The Difference?

Head in a spin about glazing? Curious for a breakdown of double glazed windows? Want to know which type of glazing is better? Don’t worry, you’re in the right place.

In this short-but-sweet guide, we’re going to cover everything to do with single glazing, double glazing, and the differences and advantages of each.

We know that it’s easy to get confused about what each type of glazing looks like and offers, so we’ve organised all the important information here in one easy-to-reach place

This will be especially helpful If you’re thinking about getting one of our insulated garden offices which come with double glazing pre-installed in the window frames.

All ready? Then let’s get to grips with glazing.

insulation and windows facade
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Single Glazing

Let’s start with the simpler of the two, single glazing. Windows that are single glazed have just one single pane of glass within the window frame – ie. just one glaze. If you look at a window that’s single glazed, it should be clear that there’s only one sheet of glass between the inside and outside of your garden building.

Despite being much older than its counterpart, single glazing does have a few distinct advantages that might make it an attractive buy. To get a better idea of its capability, we’ll take a look at its pros and cons.

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Pros of single glazing

  • Easily releases heat. Whilst this may be a negative in colder months, the increased thermal transfer through single glazing on a hot day may work in your favour – if you want to keep the interior cool.
  • Much cheaper to buy and install. Naturally, single glazing is also far cheaper than double glazing. This is simply because it’s made using less glass, as double glazing uses two sheets. The thinner design also makes it easier to install as the frames are cheaper.

Cons of single glazing

  • Cannot insulate. Single glazing provides practically no insulation to your house or garden building. As we explained earlier, heat is easily able to escape when it comes into contact with the window. If it’s cold, then expect to lose a lot of heat from inside due to this lack of insulation.
  • Flimsy and easily breaks. Since it is made from just one pane of glass, single glazing can be very fragile. It breaks easier, and can even shatter on impact. This means windows are more likely to get broken in general, but may also be a security concern.
  • No sound insulation. Just as with heat insulation, the one sheet of single glazing means that there’s no soundproofing either. That counts for sound coming both in and out.
  • Prone to condensation. Single glazing also suffers from condensation – when warm air cools down on a cold surface and turns into a layer of water. Since single glazing is so thin, it can often act as this cool surface and result in condensation.

Double Glazing

We’ve seen all there is to see about single glazing, but what about double? Double glazing is the standard in windows these days, but it’s okay if you’re not sure about the specifics.

Simply put, double glazing involves double the glass sheets – that means two layers of glass with a small layer of space in the middle. This space is either filled by gas or a vacuum.

Like we did with single glazing, let’s look at the pros and cons once again.

Pros of double glazing

  • Full insulation. The best and most important thing that double glazing has in its favour is the fact that it’s insulating. 

The small space between the two glass panes, whether filled by gas or a vacuum, is able to insulate by making it difficult for heat to transfer through the window. When you heat up your house, these insulating windows will keep the heat inside.

window pane with glazing
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  • Energy-efficient. Double glazing is energy efficient as it will help your garden room retain heat for longer due to the slowed thermal transfer. This means you won’t have to have radiators on for as long or spend as much money on your energy bills.
  • Better structure and safety. Thanks to the two layers of glass, double glazing is much more difficult to break, especially on impact. This means your windows won’t break as easily and, as a result, they’ll be much safer.
  • Sound-insulating. Since double glazing insulates heat, it also insulates noise. This means it will block out much of the unwanted noise coming from outdoors.
  • Less condensation. Thanks to the double-layered design of this kind of glazing, it’s much less likely to allow condensate to form. This is because the inner glass that touches the warm air will never get cold enough for condensation to form.

Cons of double glazing

  • More expensive. Unfortunately, double glazing is more expensive than single glazing is. Double glazing requires twice as much glass, a more complicated design, and a bigger frame and is naturally more expensive as a result.
  • Condensation can still happen. Unfortunately, there’s not a complete lack of condensation with double glazing. What occasionally happens is that the condensation forms between the two panes of glass – which can be even more frustrating because it can’t be reached.

The Verdict

When deciding between the two, several factors influence your choice. Consider the following aspects to make an informed decision:

1. Insulating needs

  • Double glazing: Ideal for garden buildings used year-round or during colder seasons. The two layers of glass create a barrier that minimises heat transfer. They provide better insulation and temperature regulation.
  • Single glazing: Suitable for seasonal or occasional use, especially in milder climates. It allows more heat exchange. It’s an excellent, cost-effective option if insulation is not a top priority.

2. Energy efficiency

  • Double glazing: Offers superior energy efficiency by reducing heat loss. In return, this can result in lower energy bills over time. This is beneficial if you plan to use heating or cooling systems in your garden room.
  • Single glazing: Less energy-efficient than double glazing. It may suffice for structures where maintaining a specific temperature is not crucial.

3. Budget considerations

  • Double glazing: Generally comes with a higher initial cost. For one, due to the added materials and complexity. However, the long-term energy savings may offset the upfront expense.
  • Single glazing: More budget-friendly in terms of initial installation costs. Best for garden building where energy efficiency is not a primary concern.

4. Climate and usage

  • Double glazing: Recommended for regions with extreme weather conditions. These include very cold winters or hot summers. It’s also suitable for garden buildings used year-round.
  • Single glazing: Well-suited for mild climates where temperature extremes are less of a concern. If your garden building is primarily a fair-weather retreat, single-glazing should work.

5. Aesthetic preferences

  • Double glazing: Offers a modern and sleek appearance. Plus, with the added benefit of reducing condensation. The extra layer can enhance the visual appeal of your garden building.
  • Single glazing: Best for a more traditional or minimalist look. Single glazing might also align better if condensation is not a major concern.

The choice depends on your specific needs, budget, and climate considerations. Evaluate these factors carefully to determine which option best suits your requirements.

Helpful Tips!

For single-glazing users

Use heavy curtains or blinds to reduce heat transfer. Consider draft excluders for doors and windows to minimise cold air infiltration. Enhance insulation with weather stripping around windows. In colder months, use thermal window films to add an extra layer of insulation. Regularly check for and address any gaps or cracks in the window frame.

These simple steps can significantly improve energy efficiency. They, in return, make your single-glazed space more comfortable.

Maximising double glazing benefits

Choose energy-efficient window treatments like thermal curtains. Use window films to prevent UV radiation, maintaining a comfortable temperature. Regularly check and maintain seals to prevent air leakage. Consider strategic landscaping to provide additional shade during warmer months, reducing cooling needs.

Combine double glazing with energy-efficient HVAC systems for optimal results. Doing so can help create a well-insulated and energy-conscious environment.


Now that we’ve seen all that there is to see when it comes to single and double glazing, it’s time to make an assessment: which type of window is better?

Well, with a huge host of advantages that are especially useful in the UK, we have to say that double glazing is the better option

The insulation and energy efficiency that double glazing offers is just too good to miss out on, not to mention how much stronger and safer it is! Single glazing is good if you would prefer a cheaper option, but in all other cases – and especially for insulated garden offices – you should pick double glazing.

Once you’ve chosen the ideal glazing, find out next what’s the best thickness for a log cabin!

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