Start with what you already know
Every firm already has three numbers, even if they have never written them down: how many enquiries come in a month, roughly what share go unanswered in time, and what an average job is worth. That is the whole calculation. Everything else is multiplication.
The three inputs
- Enquiry volume. Website forms, missed calls, directory leads, email—everything that could become a booked job.
- Miss rate. The share that do not get a useful reply fast enough to still be “first in.” For a firm with no automated response, that is typically enquiries that land after hours, during a job, or in a busy morning queue. It varies firm to firm, which is exactly why we measure it instead of quoting an average.
- Average job value. UK heating and plumbing work can range from a routine callout to a boiler or heat-pump installation. Use your own average, not ours—a firm doing mostly service work and a firm doing mostly installs will land in very different places.
A worked example
Say a firm gets 80 enquiries a month, misses a quarter of those (20), and even a conservative one-in-three of the missed ones would have converted had they been answered fast. That is roughly 6–7 jobs a month going to whichever competitor answered first. At an average ticket of £600, that is £3,600–£4,200 a month. Over a year, it is comfortably into five figures—in jobs the firm already paid to attract and never saw convert.
That is not a dramatic number by design. It is a deliberately conservative one. Most firms doing install work will find their real number is higher once open quotes are included, because a £2,500 quote left unchased for three weeks is a bigger single leak than a missed £120 callout.
Why response time is the lever, not lead volume
The instinct when enquiries feel thin is to spend more on ads. But a slow reply loses the same share of enquiries whether there are 40 a month or 400—doubling ad spend just doubles how many are lost. The response-time problem has to be fixed on its own terms before more volume changes the bottom line.
Homeowners calling about an emergency or quote often go with whichever firm replies first, within minutes rather than hours. A firm replying in under 60 seconds and one replying in three hours are no longer competing for the same job by the time the second calls back.
How to get your real number instead of this one
This example uses round numbers to show the method. Your miss rate, average job value and after-hours pattern are specific to your firm. The Lead Response Audit measures them from your own call logs and a week of real response testing instead of estimating them.