One shop, two trades, one program
A large share of the contractors we work with run both trades out of one building with one set of trucks. Plumbing and HVAC SEO is usually sold as two separate programs, which double charges you for the authority both trades share. The overlap is substantial, and treating it deliberately is worth real money.
Where the two trades actually overlap
More than most agencies price for.
Domain authority is shared completely. A guest post earned for a plumbing term strengthens the domain that your HVAC pages sit on, and the reverse is equally true. There is no separate authority pool for each trade, which means paying two agencies to build authority for one domain is paying twice for the same asset.
Local signals are shared as well. One business profile, one service area, one review stream. A customer who leaves a review after a drain cleaning strengthens the profile that has to rank for furnace repair in January. Splitting the trades across separate profiles, which some contractors are advised to do, usually weakens both.
- Domain authority is a single pool serving both trades
- One business profile, one service area, one review stream
- Technical work on the site benefits every page on it
- Seasonal complementarity, which is the real prize
Where they genuinely differ
Overlap is not sameness, and the pages have to reflect that.
Search terms barely overlap at all. Someone with a blocked drain and someone with a failed furnace share nothing in their query, their urgency profile or their expectations about price. Every service line still needs its own page built around its own searcher.
The seasonal shape differs too, and that is the most useful difference. HVAC has two sharp peaks with quiet shoulders between them. Plumbing is far flatter, with weather driven spikes rather than a season. That means plumbing work can fill the shoulder weeks when HVAC demand is at its lowest, which is exactly when HVAC content should be being written for the coming peak.
How we run a combined program
One keyword allowance, allocated deliberately across both trades.
The practical decision is how to split the keyword allowance. A combined shop covering both trades and several service areas exhausts twenty keywords immediately, which is why Platinum at forty or Titanium at one hundred is the usual recommendation rather than an entry tier.
The allocation itself should follow revenue rather than search volume. Plumbing terms often carry higher volume while HVAC replacement carries a far higher ticket, and a split made on volume alone quietly directs the program toward the cheaper work.
- One program, one budget, one authority build serving both trades
- Keyword allowance allocated by revenue rather than by search volume
- Seasonal scheduling so plumbing work fills the HVAC shoulder weeks, which is exactly when the HVAC content for the coming peak should be written
- Separate pages per service line, because the searchers share nothing
- Cross links between the trades where a job genuinely spans both, such as a water heater that sits inside a mechanical room you already service
The mistake we see most often
Two agencies, one domain, and neither one aware of the other.
The common arrangement is an HVAC agency and a plumbing agency working the same domain without coordination. Both build authority to the same site and each invoices for it. Worse, they frequently target overlapping general terms, which means the contractor pays two agencies to compete with each other for the same position.
The other version is a contractor who leads with one trade and treats the other as an afterthought on a single combined page. That page ranks for neither trade properly, and the trade that was treated as secondary usually turns out to have been the one with the easier terms to win.
Questions about combined trade programs
Should we run separate programs for plumbing and HVAC?
No, in almost every case. Domain authority and local signals are shared completely, so two programs means paying twice for the same asset. What you need is one program with the keyword allowance allocated deliberately across both trades.
Should we have separate Google Business Profiles for each trade?
Usually not. One profile with an accurate primary category and both trades represented tends to outperform two thinner profiles splitting the same review stream between them. Reviews from either trade strengthen the profile both depend on.
How should the keyword allowance be split?
By revenue rather than by search volume. Plumbing terms often carry higher volume while HVAC replacement carries a far higher ticket, so allocating on volume alone quietly points the program at the cheaper work.
Does running both trades help with seasonality?
Considerably, and it is the most underrated advantage of the model. Plumbing demand is far flatter than HVAC and fills the shoulder weeks when HVAC is quietest, which is exactly when HVAC content should be written for the coming peak.
We lead with HVAC and treat plumbing as secondary. Is that a problem?
Often, because the secondary trade usually turns out to have the easier terms to win. A single combined page ranks for neither trade properly. Giving the second trade real pages frequently produces faster results than pushing harder on the first.
We already have two agencies, one per trade. What should we do?
Consolidate, or at minimum get them coordinating. Both are building authority to the same domain and each is invoicing for it, and they frequently target overlapping general terms, which means you are paying two agencies to compete with each other for one position.
Does adding plumbing content hurt our HVAC rankings?
No, provided each service line has its own page. Authority is shared across the domain, so plumbing content strengthens the site your HVAC pages sit on. The harm comes from combining trades onto single pages, not from covering both.
Which trade should we start with?
Whichever has the weaker existing coverage relative to its revenue. Most combined shops have built out one trade properly and left the other as a services list item, and closing that gap is almost always faster than making a well covered trade marginally better.
Do combined shops rank worse than specialists?
Not in our experience, provided each service line has a real page behind it. Search engines assess pages against queries rather than judging how many trades a company lists. What does hurt is a thin combined page trying to cover both, which is a page quality problem rather than a consequence of running two trades.
Where to go next
One program, both trades
Send us your domain and tell us how the revenue splits between the two trades. We will come back with an allocation across both, what each side can realistically win, and what it costs as a single program rather than two.