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Ventilation Tool

The Paint Booth Calculator That Became a Link Magnet

We built this calculator for WeSellFans, a Chicago industrial ventilation distributor. It reached the top of page 1 on Google, websites link to it on their own, and every new link helps the pages that sell fans show up higher.

Trusted by 5.0 Five-star reviews on Clutch (opens in a new tab)

We built this paint booth CFM calculator for WeSellFans, an industrial ventilation distributor. Other websites link to it without being asked, and every link helps WeSellFans show up higher on Google.

Try it below. Pick a booth type, enter the booth size, and you get the airflow a fan has to move.

Size your booth exhaust and make-up air

Pick how air moves through your booth and enter its size. You get the exhaust CFM, make-up air and heating load, measured the way OSHA measures it.

1How does air move through your booth?

The paint booth CFM calculator multiplies the area air passes through by the air speed. Crossdraft, semi-downdraft and open-face booths use width × height. Downdraft and side downdraft booths use width × length. Default speeds follow OSHA for dry-filter booths: 100 FPM for hand-held guns, 60 FPM for automatic electrostatic and 150 FPM in small booths. Make-up air equals the exhaust. Treat the results as planning numbers and confirm the final design with your booth maker and fire marshal.

Assumptions and defaults
  • A dry-filter booth, the common type. Water-wash booths follow only OSHA's velocity table.
  • Air speed is measured where air passes the work. That's the open face or the booth's cross-section for crossdraft, semi-downdraft and open-face booths, and the floor area for downdraft and side downdraft booths.
  • Hand-held or standard guns: 100 FPM, OSHA's minimum for dry-filter booths. Small booths: 150 FPM, the design speed in OSHA's velocity table. OSHA doesn't define a small booth, so you choose.
  • Automatic electrostatic with nobody in the booth: 60 FPM, OSHA's minimum for electrostatic spraying, or 100 FPM in small booths. Heavy or more flammable coating loads can need more.
  • The shaded band on the speed slider is OSHA's listed range for the setup you picked.
  • Packaged booth ranges come from published manufacturer ratings, not from code.
  • Make-up air equals the exhaust, as OSHA requires for spray booths.
  • Heating load is 1.08 BTU/h per CFM per °F for sea-level air, scaled by air pressure at your elevation. It's the heat delivered to the air, before heater efficiency.
  • The solvent check uses OSHA's dilution formula, 4 × (100 − LEL) × vapor per gallon ÷ LEL, and keeps vapor at or below 25% of the lower explosive limit. A blend uses the most demanding solvent in OSHA's table, so it runs high.
  • When the solvent check needs more air than the air speed gives, the larger number becomes the exhaust.
  • Intake louvers: OSHA caps air speed through make-up air openings at 200 FPM, so free area is CFM ÷ 200.
  • CFM rounds up to the next whole number. Heat rounds to the nearest 1,000 BTU/h.

Why we built a free calculator for WeSellFans

The goal was links. When other websites link to a page, Google trusts that page more and shows it higher. The pages that sell fans almost never get those links, because nobody writes an article and links to a product page.

So we built something people would want to link to: a free calculator that answers a common paint booth question. The calculator collects the links. Then it passes that trust on to the WeSellFans pages that sell, through links of its own.

How we researched, verified and published the calculator

We started with a question people in the paint booth business ask all the time: how much air does a paint booth need?

Then we published the calculator on WeSellFans.com with a plain-language guide around it. The guide is a full overview of paint booth ventilation requirements, and it shows anyone who reads it that WeSellFans knows paint booths.

A link magnet is a page other websites link to without being asked. Google counts each of those links (called backlinks) as a sign the page can be trusted. The calculator page keeps that cycle going on its own:

  1. The page shows up on page 1 of Google for paint booth searches.
  2. Writers looking for the topics the page covers find it and link to it in their own articles.
  3. Each new link adds trust, which keeps the page on page 1, where more writers find it.

The links keep coming without any outreach from us, and they keep putting the WeSellFans name in front of people across the paint booth business.

Links pass trust from page to page. When another website links to the calculator, the calculator page gains that trust. The calculator page then links to the WeSellFans pages that sell, so part of that trust passes on to them:

  • Make-up air units, direct-fired and indirect-fired
  • Paint booth ventilation
  • The automotive industry page
  • Axial fans, including tube axial and fiberglass duct fans

Those are the pages a real buyer lands on. Companies that build paint booths and shops shopping for exhaust fans or make-up air search for these products, and the extra trust helps WeSellFans show up higher when they do.

So the calculator does 2 jobs. It collects links that a product page would never get, and it hands that trust to the pages that bring in sales.

What the calculator did for WeSellFans

The calculator is one part of our SEO for ventilation equipment distributors work for WeSellFans. Its job in that plan is to help the make-up air unit pages rank higher on Google.

Along the way, it collects links and gets the WeSellFans brand in front of the paint booth business. The related case study covers the full engagement.

A link magnet works for any business whose buyers ask the same question before they buy. If your sales team answers the same sizing, pricing or “will it fit” question every week, that question can become a free tool that collects links for the pages that sell.

See if a calculator makes sense for your business. We’ll find the question your sales team answers over and over, and tell you honestly whether a tool for it is worth building.

Questions we get

Why build a free calculator instead of another article?

Write Good Code built the paint booth CFM calculator because a working tool is harder to copy than an article. Any competitor can rewrite an article. A calculator that does the math correctly gives other websites a reason to link to it instead of explaining the math themselves.

Why don't product pages get backlinks on their own?

Product pages rarely get backlinks because other websites link to pages that answer a question. A product page asks for a sale, so writers have little reason to cite it. A free tool collects the links, and internal links pass that trust on to the product pages.

Is a link magnet the same as buying backlinks?

A link magnet gets links that other websites choose to give, while bought links break Google's rules. Google's spam policies treat paid links that pass ranking value as a link scheme, and a site caught using them can drop in search. A link magnet carries none of that risk, because nobody was paid or asked.

Can you build a calculator like this for my business?

Write Good Code can build a calculator like this for any business with a technical product or service where buyers run the same math repeatedly. Calculators work best in industrial, engineering, and specialty trades. Step 1 is the intake call, where we find the question your sales team answers over and over.

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