Short answer
Work backwards from three things: what a booked job costs you in ads, what that job is worth, and how many extra jobs your crews can actually take. Multiply cost per booked job by the jobs you can handle, and that is your budget. Start with a test budget big enough to buy real data, then raise spend only when the return on ad spend clears your break-even.
"How much should I spend?" is the first question every HVAC owner asks about Google Ads. The honest answer is a formula, not a number. Here it is, with the math worked out.
Why "spend X% of revenue" doesn't work
You will hear rules like "spend 5-10% of revenue on marketing." They are a starting point for a spreadsheet, not a Google Ads plan. They ignore the things that actually decide whether ads make you money:
- How much a click costs in your city this month.
- How many clicks turn into a call or a form.
- How many of those calls your team books.
- What the average job is worth.
- Whether your crews have room for more work.
Two companies with the same revenue can need very different budgets. A duct cleaning company in a small town and an AC repair company in a big hot metro are playing different games.
Step 1: Know your own numbers
Before you set any budget, pull four numbers from your field service software or your books:
- Average ticket. What a typical repair, tune-up or duct cleaning job brings in.
- Gross margin. What is left after parts and labor. This sets your break-even.
- Booking rate. Of the calls and forms you get, how many become booked jobs.
- Capacity. How many more jobs per month your techs can take without hurting service.
If you don't track booking rate today, start now. It is the number most owners guess at, and it moves your ad results more than almost anything else.
Step 2: Estimate what a click costs
HVAC is one of the more expensive home service categories on Google. In many metros, clicks for searches like "AC repair near me" often land somewhere around $15 to $60, and sometimes more. Smaller markets are usually cheaper. Prices also swing with the season: AC searches spike in the first heat wave, and heating searches spike in the first cold snap.
Google's Keyword Planner gives a rough range for your area. Treat it as a guess. Your real cost per click shows up in the first few weeks of running ads.
Step 3: Do the math
Here is the chain from ad dollar to booked job. The numbers below are an example, not a promise. Swap in your own.
| Step | Example number | Result |
|---|---|---|
| Cost per click | $20 | |
| Clicks that call or fill a form | 25% | $80 per lead |
| Leads your team books | 60% | About $133 per booked job |
| Average ticket | $800 | About 6x return on ad spend |
Example: at $133 per booked job and an $800 average ticket, every $1 on ads brings back about $6 in revenue. That is the low end of the 6-10x ROAS range we aim for.
Now look at what happens when the website is slow and the phone goes to voicemail. Same $20 click, but only 10% of clicks turn into a lead and only 40% get booked. That is $200 per lead and $500 per booked job. The same $800 ticket now returns about 1.6x. Same ads, same budget, very different result.
The budget is rarely the real problem. Conversion rate and booking rate decide whether a budget makes money. Fix those first and every dollar goes further.
Step 4: Set the budget from capacity
Once you know your cost per booked job, the budget almost sets itself.
Example: your crews can handle 30 more jobs a month. Your cost per booked job is about $133. That is roughly $4,000 a month in ad spend. Spending more than that buys calls you can't serve, which means missed calls, angry customers and wasted money.
If you can't estimate cost per booked job yet, start with a test budget and measure.
How big should a test budget be?
Big enough to get real data. If clicks cost $30 and you spend $600 a month, you buy about 20 clicks. That is not enough to tell what works. We like to see at least 100 clicks a month on the core services before judging a campaign. At $20 to $40 a click, that often means a test budget in the low thousands per month.
If that is more than you can spend, narrow the focus instead of spreading thin. Run ads for one or two high-value services in the area closest to your shop. A small budget on a tight target beats a small budget on everything.
Plan for the seasons
HVAC demand is not flat, and your budget shouldn't be either.
- Peak season (first heat wave, first freeze): demand and click prices jump. Put more budget here if you have capacity.
- Shoulder seasons (spring and fall): fewer emergency searches. Good time for tune-ups, maintenance plans and duct cleaning.
- Don't switch off completely. Accounts that go dark lose momentum, and competitors keep the customers you would have met.
Where HVAC budgets leak
Most wasted spend comes from a short list of problems:
- Paying for searches like "HVAC jobs," "AC parts" or "how to fix my furnace."
- A service area that reaches towns your techs don't want to drive to.
- Ads running at night when nobody answers the phone.
- A slow mobile site with no click-to-call button.
- No tracking, so nobody knows which calls came from ads.
We wrote a full list in 9 Google Ads mistakes that waste HVAC budgets. If your site is the weak link, see what a site built to book jobs looks like.
Should some budget go to Local Services Ads?
Often, yes. Local Services Ads charge per lead, not per click, and show above regular search ads. Many HVAC companies run both. Which one deserves more of your budget depends on your reviews, your market and how fast you answer. We compare them in Local Services Ads vs Search Ads for HVAC.
When to spend more
Raise the budget when three things are true:
- Your return on ad spend is clearly above break-even.
- Your crews have room for more work.
- Your team is answering and booking the calls you already get.
Increase in steps, not leaps, and watch cost per booked job after each step. If it climbs fast, you've hit the edge of profitable demand in your area for now.
The bottom line
A good HVAC Google Ads budget isn't a guess or a percentage. It comes from your cost per booked job, your ticket size and your capacity. Get those numbers, run a real test, and let the return decide how much to spend next.
That is how we run every account at Prompted Leads. Our Google Ads for HVAC work is built around booked jobs, not clicks. A past client of ours grew past $1M in annual revenue with the same playbook. Your first month with us is on us. You pay Google for the clicks, there's no contract, and we only make money if you do.
Want this done for you?
Your first month is on us. You pay Google for the clicks, we do the work, and you only keep paying us if the numbers are there.
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