The shoulder-season playbook: filling April and October before they go quiet

The shoulder season isn't a demand problem. It's a capacity problem you pay for in advance. Federal employment data shows that plumbing, heating and air-conditioning contractors barely shrink their crews between peak and trough. The weather, meanwhile, swings by a factor of almost four. So every April and October you're carrying close to a summer payroll against a fraction of summer's calls.

This playbook covers what the data actually says about the lull, the work that reliably fills it, ranked by how far ahead you have to plan it, and a dated calendar that books April in February and October in August. If it's already October when you read this, the second half of the calendar still has time in it.

What the data says about the lull

Headcount barely moves

The Bureau of Labor Statistics counts employees at plumbing, heating and air-conditioning contractors every month. Unadjusted for season, the low point is January or February and the high point is July or August, every year. But look at how small the gap is.

That's a sensible choice by owners. Good techs are hard to find, and laying them off in April to rehire in June is a losing trade. But it means the shoulder isn't a time to cut costs. The costs are fixed. It's a time to fill hours you've already committed to paying for¹.

The weather swings almost fourfold

Degree days measure how much heating or cooling the weather demands. Here are the Energy Information Administration's population-weighted U.S. figures for 2025²:

The honest reading: combined weather load bottoms out around May and September, not exactly April and October. April and October are the handoff months, when heating is fading and cooling hasn't started, or the reverse. Neither system is under stress, so neither breaks much. In most markets that makes the shoulder a band about two months wide in spring and again in fall. Where your market sits in that band depends on your climate.

Home energy use shows the trough

What households actually consume tells the same story from the other side. In 2025, April was the lowest month of the year for residential electricity sales, at 6.4% of the annual total, against 11.1% in July³. Residential natural gas use was 216 billion cubic feet in October, then more than doubled to 472 in November⁴.

October is the last calm month before heating season. Anything a homeowner should do before the first cold night has to happen then, which makes October a selling month for the right offers.

What the lull costs you

Put a number on the empty hours so the shoulder gets the attention it deserves. A worked example, every number an assumption:

• 10 techs, 160 paid hours each in April.
• 30% of those hours go unbooked in a slow week pattern.
• A loaded labor cost of about $45 an hour. (BLS puts mean HVAC tech pay at $31.14 an hour for May 2025, and wages are about 69% of total compensation for installation and repair workers⁵⁶.)

That's about $21,600 of payroll in one month producing no revenue, before trucks and overhead. Twice a year. The goal of the playbook isn't to make April look like July. It's to turn a meaningful share of those hours into paid work, and to put the rest to deliberate use.

The fill ladder: work ranked by how early you must plan it

Not all shoulder work is equal. Some fills a schedule reliably but needs two months of setup. Some can be pulled together this week but converts poorly. Rank your options by lead time and plan the long ones first.

1. Member tune-ups: the backbone

ENERGY STAR's maintenance checklist puts it simply: contractors get busy once summer and winter come, so it's best to check the cooling system in spring and the heating system in fall⁷. That's the shoulder, by design. If you sell memberships with seasonal visits, you already own the demand. The work is in booking it before the member forgets.

Book from a list, not from inbound calls. Start calling and texting six to eight weeks before the window, offer specific times, and group by neighborhood. A tune-up booked into a thin April week is worth more than one squeezed into a full June week, because the June slot could have been a paid repair. Our guide to maintenance plans covers visit content, and membership math covers why visits that actually happen drive renewals.

2. Unsold estimates: the warmest leads you have

Every replacement estimate a customer didn't sign in July is a lead that knows your name, your tech and your price. Many said no because a mid-summer replacement is disruptive, or because the repair got them through the season. In April, with mild weather and open schedules, that conversation is different.

Pull every unsold replacement estimate from the last peak season. Call the ones over a set value personally; text the rest with an offer of a fresh look. If prices have moved since the estimate (see A2L replacement pricing), re-quote rather than hold the old price.

3. Aging equipment: your job history is the list

Half of owner-occupied homes in the country are more than four decades old: the median age in the 2024 American Community Survey was 42 years, according to the National Association of Home Builders' analysis⁸. Age of the house isn't age of the system, but your own records are better than any purchased list: equipment type, install year and last service for every home you've visited.

Segment by system age, run a short campaign to the oldest third, and offer an inspection with a written condition report. Avoid scare language. "Your furnace is 17 years old; here's what we'd check before winter" is enough.

4. October-only: freeze prep and pre-heating safety

The American Red Cross lists the pipes that freeze most often: those exposed to severe cold, like outdoor hose bibs, pool supply lines and sprinkler lines, then pipes in unheated basements, crawl spaces, attics and garages⁹. A plumbing shop can turn that into a fall visit: shut and drain hose bibs, insulate exposed lines, check sump pumps, and drain water heater sediment. DOE's Energy Saver guide suggests draining a quart from the tank every three months to remove sediment¹⁰.

For HVAC, the fall visit is the heating safety check: burner, heat exchanger, flue and carbon monoxide. Book it before the first cold snap, because once it arrives, the same visit becomes an emergency call at the worst time of year.

5. Indoor air quality: an offer, not a pitch

EPA's guide to air cleaners recommends selecting a filter rated at least MERV 13, or as high as your system will accommodate, and says to consult an HVAC technician to find out what that is¹¹. That's a natural shoulder service: check the system, recommend the right filter, and, where a home has real air quality concerns, discuss filtration or ventilation options. Don't oversell. Filters reduce some pollutants; they don't fix a moisture problem.

The shoulder-season calendar

Plan backward from each window. The dates below assume a typical U.S. market where cooling season starts in late May and heating season in November. Shift them for your climate.

1. Mid-January

   Build the spring list

   Pull members due for spring visits, unsold estimates from last summer, and systems over 12 years old. Count the hours each list could fill.

2. Early February

   Open spring tune-up booking

   Text and call members with specific dates in March and April. Group by area.

3. Late February

   Follow up unsold estimates

   Re-quote where prices have moved. Offer install dates in April and early May.

4. March

   Aging-equipment campaign

   Short campaign to the oldest systems in your history. Offer inspections in April.

5. April to mid-May

   Work the shoulder

   Tune-ups, installs, IAQ checks. Use any leftover hours for training and truck stock before summer.

6. Mid-July

   Build the fall list

   Members due for heating checks, this summer's unsold estimates, freeze-prep candidates.

7. Early August

   Open fall booking

   Book heating checks into September and October before the first cold night.

8. September

   Estimates and commercial PMs

   Follow up summer estimates; confirm fall preventive maintenance with commercial accounts.

9. October

   Freeze prep and safety checks

   Plumbing freeze prep, water heater service, heating safety checks. Last calm month before November.

Watch the next four weeks, not last month

Most owners notice the shoulder when it shows up in last month's revenue. By then the empty hours are gone. The fix is a forward look: booked hours for each of the next four weeks against what your crew can deliver.

If a week three or four weeks out sits well below your goal, you still have time to run a tune-up push or work the estimate list into it. Two weeks out, you're scrambling. The capacity glossary entry has the basic definition.

app.tradeswork.app · Demand versus capacity forecast by week

In TradesWork, the owner intelligence page forecasts the next four weeks from booked hours plus typical late bookings, adjusted for the season, and flags any week at least 8 hours short of your capacity goal as thin. The memberships page lists visits coming due so they can be booked in bulk, and unsold estimates sit on a follow-up board with automatic texts. Those are the three lists this playbook runs on.

Shoulder-season checklist

The shoulder will come twice a year no matter what you do. What changes is whether it arrives as a surprise in your revenue report or as a list you started working two months earlier. For a deeper look at the HVAC side of the business, see our HVAC industry page; for plumbing, the plumbing industry page.