[londons_explore]

TEC's are pretty cheap and can be had for around $2 for a 100 watts of cooling power unit (plenty for a typical refrigerator).

The thing that stops their widespread use is their very low efficiency. You need big noisy fans to get rid of all the waste heat from the hot side, and that drives up weight, price, size, etc. In nearly every application, gas based refrigeration systems win out overall.

[Joel_Mckay]

TECs have a very low delta-T limit, rapidly lose efficiency, and those internal losses quickly constrain multistage systems that try to workaround the limits.

Many consider them a niche part with narrow applications. =)