October 12, 2026 · Mitt Patel · 6 min read
You bought a generator in March for a job that won't be installed until April. Your books show a rough month. Your bank account agrees. But none of that tells you whether the generator installs themselves are actually making money.
Why this happens
Most shops buy equipment ahead of the job. A generator or EV charger might sit in the shop or the truck for two or three weeks before it goes in the ground or on the wall. If you record the purchase as an expense the day you buy it, that cost lands in whatever month the purchase happened, not the month the job closed out.
That timing mismatch does two things. First, it makes some months look worse than they are, because you bought equipment for jobs that haven't started yet. It makes other months look great, because you're collecting payment on install jobs where the equipment cost already got buried in a prior month's numbers. Second, and more important, it means you can never look at a single install and say what it actually made. The equipment, the labor, the permit fee, and the materials are scattered across different weeks and different reports. You can't compare a generator install to an EV charger install because neither one has a clean total cost sitting in one place.
The cost of not fixing this shows up in quoting. If you don't know that generator installs run a tighter margin than EV charger installs, you keep pricing them the same way. If a supplier raises equipment prices and your margin quietly shrinks, you won't notice until cash gets tight, and by then you've already quoted a dozen more jobs at the old numbers.
A worked example
Say you install a standby generator in April. The unit costs $3,800 from your supplier. You pay two technicians a combined $600 in labor to run the job over a day and a half. The permit costs $150. You bill the customer $6,000 for the whole install.
If you expensed the generator back in March when you bought it, your April books for this job only show $750 in costs against $6,000 in revenue, a margin that looks like 87%. That's not real. The true cost of the job is $3,800 plus $600 plus $150, which is $4,550. Against $6,000 in revenue, that's a margin of about 24%.
Now say you also did an EV charger install that month. Unit cost $900, labor $400, permit $100, billed at $2,200. Total cost $1,400 against $2,200 revenue is a margin of about 36%.
Without job costing, both of these jobs just look like revenue and expense lines scattered across two months. With job costing, you can see the EV charger install carries a better margin than the generator install, even though the generator job brings in more total dollars. That's the kind of thing you want to know before you decide which jobs to chase harder.
How to set it up
- Create an inventory or job cost account for equipment. When you buy a generator or EV charger unit, record it as an asset, not an expense, until it's installed. In QuickBooks Online this can be a simple "equipment held for installation" item or account.
- Tag every purchase to a job from day one. When the equipment arrives, note which customer or job number it's for, even if the install date is weeks out. Use the job or project feature in QuickBooks Online to attach the purchase right away.
- Move the cost to the job when the install happens. On the day the crew finishes the install, record the equipment cost, labor, permit fee, and any materials against that job. This is the point where the expense actually counts.
- Separate install types in your chart of accounts or job categories. Set up generator installs and EV charger installs as distinct categories so you can pull a report on each one separately, not lumped in with general electrical work.
- Run a gross margin report by job type monthly. Once a month, pull total revenue and total cost for each install type and calculate the margin. Compare it to prior months to catch drift in equipment pricing or labor time.
- Review permit and overhead costs separately. Permit fees vary by town and job type. Track them as a line item within each job so you can see if certain towns or job types run consistently higher.
Mistakes that undo it
- Expensing equipment the day you buy it. This is a common reason job margins disappear into noise. If the unit sits for even a week before install, the timing is already off.
- Lumping generator and EV charger costs into one "equipment" bucket. If you can't separate them, you can't compare them, and you'll keep pricing both the same way.
- Forgetting labor hours that don't get logged against the job. A tech who spends an extra two hours troubleshooting a panel issue needs that time recorded against the job, not absorbed into general payroll.
- Not including the permit fee in the job cost. Permits are a real cost of the install. Leaving them out inflates the margin and gives you a false sense of how the job performed.
- Letting old inventory sit uncategorized. If equipment purchased months ago never gets tied to a job, it clutters your books and makes it hard to trust the numbers.
Monthly checklist
- Confirm every equipment purchase this month is tagged to a specific job.
- Move completed installs from "held for installation" into job costs.
- Pull a gross margin report split by generator installs and EV charger installs.
- Check that permit fees and labor hours are recorded against the right job.
- Compare this month's margins to the prior two months and flag any job type that's slipping.
Common questions
Do I need separate accounts for generators and EV chargers, or can I use job tags?
Either works, depending on how your books are set up. Some shops prefer separate accounts in the chart of accounts; others use job or project tags in QuickBooks Online and pull filtered reports. What matters is that you can isolate the numbers for each install type when you run a report.
What if I buy equipment in bulk for several jobs at once?
Record the bulk purchase as inventory first, then allocate the cost to each specific job as it's installed. This keeps the timing accurate even when you're buying five units at once but installing them over several weeks.
How do I handle a job that gets delayed or canceled after I've already bought the equipment?
Keep the equipment cost in the asset or inventory account until it's installed, sold, or otherwise used. If a job cancels, the equipment cost stays on the books as inventory until you use it elsewhere or decide to write it off, which is a separate conversation depending on your situation.
Should labor costs include travel time and truck costs?
That depends on how you currently track labor and what level of detail is useful to you. At minimum, the direct installation hours should be recorded against the job. Whether you also allocate travel time or vehicle costs is a judgment call based on how precise you want your margins to be.
North Hudson Bookkeeping sets up job costing like this for electrical contractors and keeps it current month to month, so you always know what each install type is actually earning. The first call is free.
