Why don't houses have lightning rods?

[Mark Spahn]

Where is the lightning rod that is nearest to your house?  Does your house have a lightning rod?  Why don't residential neighborhoods have lightning rods on their roofs?

Probably because only tall buildings are in danger of being struck by lightning.  And in a neighborhood of same-height buildings, the probability of lightning striking any given building is very low (e.g., less than once in three human lifespans?).  The extra insurance cost of protecting against lightning strikes is probably less than the cost of installing a lightning rod. 

A few comments from  https://en.wikipedia.org/wiki/Lightning_rod  ...

The principle of the lightning rod was first detailed by Benjamin Franklin in Pennsylvania in 1749,^[2] who in the subsequent years developed his invention for household application (published in 1753) and further improvements towards a reliable system around 1760.

A controversy over the assortment of operation theories dates back to the 18th century, when Benjamin Franklin himself stated that his lightning protectors protected buildings by dissipating electric charge. He later retracted the statement, stating that the device's exact mode of operation was something of a mystery at that point.

Nikola Tesla's U.S. Patent 1,266,175 was an improvement in lightning protectors. The patent was granted due to a fault in Franklin's original theory of operation; the pointed lightning rod actually ionizes the air around itself, rendering the air conductive, which in turn raises the probability of a strike. In 1919, many years after receiving his patent, Tesla wrote an article for The Electrical Experimenter entitled "Famous Scientific Illusions", in which he explains the logic of Franklin's pointed lightning rod and discloses his improved method and apparatus.

The majority of lightning protection systems in use today are of the traditional Franklin design. The fundamental principle used in Franklin-type lightning protections systems is to provide a sufficiently low impedance path for the lightning to travel through to reach ground without damaging the building. This is accomplished by surrounding the building in a kind of Faraday cage. A system of lightning protection conductors and lightning rods are installed on the roof of the building to intercept any lightning before it strikes the building.

The optimal shape for the tip of a lightning rod has been controversial since the 18th century. During the period of political confrontation between Britain and its American colonies, British scientists maintained that a lightning rod should have a ball on its end, while American scientists maintained that there should be a point. As of 2003, the controversy had not been completely resolved. It is difficult to resolve the controversy because proper controlled experiments are nearly impossible, but work performed by Charles B. Moore, et al., in 2000 has shed some light on the issue, finding that moderately rounded or blunt-tipped lightning rods act as marginally better strike receptors. As a result, round-tipped rods are installed on most new systems in the United States, though most existing systems still have pointed rods.