The three main issues that factor in to making the decision about whether to choose sash chain or sash cord are looks, durability, and cost. Assuming that good quality products are used, both are more than adequate to do the job and handle the required load.
The visual effect of sash chain can be dramatic, with different finishes creating a variety of effects. Bright brass-plated steel chain has the most noticeable finish, shiny and eye-catching. The copper-plated chain and the red bronze are more understated and often the most compatible in color with bronze weather stripping. The zinc-plated steel chain is clean and utilitarian.
In terms of durability, no one would argue with the fact that chain will outlast even the highest quality sash cord. Realistically however, today's sash cord products are engineered to last for decades, so in our opinion, longevity should not be weighed too heavily when deciding between the two products.
Surprisingly, sash cord has a greater working load limit than the equivalent-sized sash chain, although both are designed to carry many times the weight typically required. For example, our most popular sash cord, #7 Samson spot cord, has a load limit of 124 pounds, and our best-selling sash chain, the #8 copper-dipped steel chain, has a load limit of 75 pounds. Since an average-sized 1-3/8” single-glazed (non-insulated) sash weighs in somewhere between 10 and 20 pounds, both products are obviously more than adequate to do the job.
In terms of material cost, the sash chain is the more expensive option. A 100-foot roll of #7 Samson spot cord costs about $13.90, and 100 feet of the copper-dipped steel chain costs about $36.00. For comparison, we assume that replacing the cord or chain in both sashes of a typical double-hung window would require a total of about 20 feet total for either product. Using the sash cord, this would end up costing about $3.00 for the complete window. Using the chain the cost would be about $7.00 for the chain itself and an additional $1.50 for the sash fixtures, totaling about $8.50 for the same window.
Time invested in labor can vary. Some window restoration contractors feel that using chain is faster than cord since due to its weight; the chain drops easily through the pulley into the weight box without getting hung up anywhere along the way—always a potential problem with sash cord. Others find that working with the chain fixtures and crimping and cutting the chain make a tedious job even more so, and prefer the ease of cutting and tying a few simple knots in the cord.