Legal

Affiliate Disclosure

How we earn money and why it doesn't influence our calculator results.

Last updated: May 10, 2026

The short version

WattMath is an independent calculator hub. When you use our tools to model solar payback, EV ownership costs, heat pump ROI, EV charging costs, or home battery sizing, the math and results are based on public data from authoritative sources — not on which company is paying us.

Some links on WattMath are affiliate links. If you click one and request a quote, sign up for a service, or make a purchase, WattMath may earn a commission from the partner company. That commission costs you nothing. The partner pays it from their marketing budget, and your price is identical whether you arrive via WattMath or directly.

How WattMath makes money

We earn revenue from two sources:

1. Display advertising. We serve ads through Google AdSense and may add other ad networks in the future. These ads are selected by the ad network based on page content and the visitor's general interests, not by us. We do not place sponsored content disguised as articles or calculator results.

2. Affiliate partnerships. We work with reputable companies in the residential energy and EV space whose services we believe are useful to our audience. Our current and planned partners include:

  • Solar quote marketplaces: Solar.com, Palmetto
  • Portable power and battery manufacturers: EcoFlow, Anker, Renogy, Jackery
  • EV charging equipment and accessories: Amazon Associates, ChargePoint, Wallbox
  • Other adjacent partners as we add them

This list will change over time. The disclosure principles in this document apply to every partner we work with, current or future.

How affiliate relationships affect our content

They don't. Specifically:

  • Calculator math is not influenced by partners. A solar payback calculation in Tennessee returns the same numbers whether you arrived from a partner's website, a Google search, or directly typing in our URL.
  • Methodology and assumptions are published. Every calculator includes a "How this is calculated" section explaining the formula, data sources, and assumptions. You can validate the math yourself.
  • We recommend the same partners to everyone. We do not route higher-bill users to higher-commission partners or otherwise tailor recommendations to maximize our payout.
  • We correct factual errors when readers point them out, regardless of whether the correction harms a partner relationship. The federal residential solar Investment Tax Credit, for example, expired December 31, 2025 under the One Big Beautiful Bill Act — we say so plainly, even though it makes solar look less attractive than the now-outdated 30% credit that some partners' websites still reference.
  • Display advertising is separate from editorial content. Ads are clearly labeled and visually distinct from calculator results, methodology sections, and articles.

What we will not do

To remove any ambiguity about our independence:

  • We will not alter calculator math to favor a partner.
  • We will not suppress information about products, programs, or competitors who are not our partners.
  • We will not promote partners over non-partners in our calculator result rankings or comparisons.
  • We will not place affiliate links inside content that is presented as editorial or methodological.
  • We will not accept payment for positive coverage or to omit negative information.

FTC compliance

This disclosure is provided in accordance with the Federal Trade Commission's Guides Concerning the Use of Endorsements and Testimonials in Advertising (16 CFR Part 255).

WattMath has material connections with the companies referenced in our affiliate links. These material connections include receiving compensation when readers take qualifying actions — such as submitting a quote request or making a purchase — after clicking through from WattMath.

In addition to this page (linked from every page footer), we display a short, plain-language disclosure block on every page that contains affiliate links, placed near the relevant call-to-action so you see it before you decide to click.

Cookies and tracking

When you click an affiliate link from WattMath, the partner's affiliate network (most commonly CJ Affiliate, Impact, or Amazon Associates) places a cookie on your device. This cookie tells the partner that the action came from WattMath, so we receive credit if you complete a qualifying action within the network's attribution window (typically 7 to 90 days, varying by partner).

We do not have access to your personal information through these cookies. The affiliate network reports aggregate conversion data to us — not individual identities. For details on what each network collects, see their privacy policies:

For details on our own data practices, see our Privacy Policy.

Questions or concerns

If you have questions about our affiliate relationships, want to report a misleading link, or have feedback about our methodology, contact us at [email protected].

WattMath is operated by BP Technology Advisors LLC.