How we research prices

Last updated November 9, 2026

Every number on this site is traceable. Here is exactly how a guide is built.

Step 1: Gather published prices

For each project we collect prices from several independent kinds of source:

• Retailer and manufacturer prices: what the part or unit itself costs (for example, a water heater's listed price at a national home-improvement retailer).
• Cost surveys: national installed-cost ranges published by cost aggregators built from contractor quotes and homeowner reports.
• Government and industry data: efficiency standards, tax-credit rules, labor rates and trade association guidance (for example DOE, ENERGY STAR, IRS, BLS).

This research is done by an AI research assistant, which searches for and reads these sources.

Step 2: Build the range

We compare the sources and publish a low, high and typical price, plus tables broken down by type, size and add-ons. Where possible we split materials from labor, because that's what helps you read a quote. If sources disagree, the table shows each source's figure.

Step 3: Source check

Every price in a guide must trace to a source that was actually opened during research. Numbers that can't be sourced are left out rather than guessed. Each guide is checked against a set of rules before it can be published: at least three sources, a cited source for every price table, and a dated price check. The "Prices researched" date shows when the numbers were last gathered.

Step 4: Keep it current

Prices are re-checked on a schedule and whenever readers report a change. Each re-check updates the date at the top of the guide.

What our ranges include

Unless a guide says otherwise, ranges are national, in US dollars, and include parts and professional labor for a typical single-family home. Each guide's price box states exactly what its range covers. Permits, disposal and extras are listed separately where they apply.

Questions about a number? Ask us.