Steel vs Lead Sash Window Weights: Who will you put your money on?

07 December 2021

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What Are Sash Window Weights?

If you’re restoring or maintaining these windows, understanding the difference between lead sash window weights and steel weights is essential. The choice affects durability, functionality, and long-term maintenance. Sash window weights are the hidden counterbalances that make your windows easy to lift and lower. Traditionally, these weights are concealed in the window frame and connected to the sash via a cord or chain. The weight’s job is simple: balance the sash so it stays in place without slamming shut or being difficult to lift.

Historically, these weights were made from lead or cast iron, but modern alternatives include steel or composite materials. Each has pros and cons.

Lead Sash Window Weights

Lead sash window weights are known for their durability because lead is dense and heavy, providing excellent counterbalance for large or tall sashes. For heritage properties, lead weights maintain historical authenticity, and they do not rust, making them ideal for long-term use. Another advantage of Lead Sash Weights is that lead is denser and heavier than steel. As an example, one cubic inch of steel weighs 4.566 ounces and one cubic inch of lead weighs 6.644 ounces. This means a smaller sash weight cubic size can be used to acheive the same counterbalance weight than using steel. However, lead is more expensive than modern steel alternatives. Also, while lead is generally safe when enclosed in the window frame, care must be taken during handling because of potential health concerns.

Steel Sash Weights

Steel sash weights were created to replace traditional cast-iron and lead sash weights. If you're restoring any sash windows and the weights need to be replaced, steel is a great option, especially if you're exchanging single glazed units for double glazed. Steel is also denser than cast iron sash weights, which were also a traditional choice, so you're able to use heavier weights in the same size window, which will counterbalance the added weight of new double-glazed units in a lot of instances. Though not as heavy as lead weights per cubic inch, steel is heavy enough to be a modern replacement. Steel is also much safer to handle than lead.

Our Recommendation

We would recommend using steel sash weights where possible, due to the big savings you can make over lead weights. Lead weights certainly have their place, perhaps you have a limited sash box size (i.e. a wide but short set of sashes), and the weight needed to carry the sash won't fit if using steel. In this instance, you could always try adding lead make weights to keep material costs down. However steel weights will typically cover 90% of sash sizes. With steel being such a popular choice by joiners there are now many more 'ready-made' sizes available from stock which, in turn, means quicker deliveries.

With the cost of steel per tonne currently $756 and lead $1960 (source: London Metal Exchange: Feb 2026), it's easy to see there are savings to be made. How does this translate when pricing a job for a new sash window or replacing weights on a restoration project?

Below we show an example of a typically sized sash window of 1.2m x 1.0m and compare the cost of steel and lead weights.

Sash weight costs for a 1.2m x 1.0m window

• Steel sash weight cost = £30.00
• Lead sash weight cost = £50.00

Total saving of £20.00 per window

With timber prices also on the rise, any savings that can be made elsewhere will surely be welcomed. Hopefully, this has been of use and helped make your choice of sash weights an easier decision. If you have any questions, please get in touch with our sales team via phone or email and they'll be happy to help.

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