Editorial standards

• Figures are the maker's own, shown with their units, and never estimated.
• Words such as 'best' only appear with the rule that decides the list.
• Commissions never affect which heaters are listed or how they're ordered.
• Safety statements name their source and never replace the manual or local code.
• Errors are corrected when a reader or maker shows us the right figure.

What we won't do

• Accept payment, free products or gifts in exchange for listing or placing a heater.
• Describe a heater as suitable for a particular house; that's the installer's call.
• Fill a missing figure from another model.

Updated October 2026.