How we calculate

Each cost figure comes from a named published source, with a low and a high for the stated job. Guides link to those sources and record their update dates when available, along with the dates they were accessed. An undated source is marked as undated. Notes explain differences in scope rather than treating every range as identical.

The displayed low is the median of the sources' lows. The displayed high is the median of their highs. The median is the middle value when figures are put in order; for an even-sized set, it is the average of the middle pair.

The typical cost is the median of the sources' stated averages when any are available. Sources without a stated average do not contribute a midpoint to that calculation. If no source states an average, the typical cost is the median of each source's midpoint between its low and high.

Derived figures below 1,000 are rounded to the nearest 25. Figures of 1,000 and above are rounded to the nearest 50. Exact halfway values round up. Published source figures are kept unchanged. Estimator totals are rounded only after additional work has been added.

The water heater guide uses the following published figures for a standard tank. Angi's stated average is its overall national replacement average; Fixr covers gas tank-style units only. HomeGuide does not state an average in this dataset.

Angi: $600 to $2,500; stated average $1,348.

HomeGuide: $600 to $3,100; no stated average.

Fixr: $1,000 to $2,700; stated average $1,900.

In source order, Angi, HomeGuide and Fixr, the lows are $600, $600 and $1,000 and the highs are $2,500, $3,100 and $2,700. The available stated averages, from Angi and Fixr, are $1,348 and $1,900.

Applying the median and rounding rules gives a low of $600, a typical cost of $1,600 and a high of $2,700. These are planning figures for the source scopes above, not a quote for a particular home.

The area level selects the lower, middle or upper part of the sourced range. It does not use your address or collect local prices.

The lower level uses the sourced low to typical range, with their midpoint as typical. The middle level keeps the sourced typical and uses the low-to-typical and typical-to-high midpoints as its bounds. The upper level uses the typical to high range, with their midpoint as typical. For a standard tank, choosing a size uses that size's sourced range instead of the overall tank range.

Applicable selected extras are added in full to the low, typical and high amounts before the final rounding. Installed ranges are treated as not including those extras. Labor is already inside the installed ranges; the separate labor figures are informational and are never added again.

A fact supported by a single source is shown with attribution to that source. It is not combined with other figures to produce a new cost range. Running costs, incentives and other facts should be read within the scope and dates stated by their source.

The Prices checked date records when the dataset was checked against its sources. Source update and access dates remain visible in the guide. The guide's modified date records an update to the page and cannot be earlier than its dataset's checked date. A checked date does not guarantee that a source or a contractor's prices have stayed unchanged.

Published ranges cannot tell you the condition of your home, the exact work required, local availability or the amount a contractor will quote. They do not replace an inspection, professional advice or written quotes. Use them to frame a budget and ask clearer questions, not to decide that a particular quote must be right or wrong.