The 2.4 GHz frequency has greater penetration into tissue, but both types of phones are Non-licensed devices, meaning that the power density impinging on your person is extremely low. The exposure from your WiFi card or garage door opener is probably comparable to that from a cordless phone.
Bob Weller Member, SC-4, ICES (International Committee on Electromagnetic Safety)
From: snipped-for-privacy@panix.com (Scott Dorsey)
> Subject: Re: 2.4Ghz vs. 5.8Ghz Cordless Phones and
> Health Concerns
> Date: 30 Jul 2006 18:00:36 -0400
> Organization: Former users of Netcom shell (1989-2000)
>> Is there any information out there that would indicate which is
>> safer/healthier to use ... a 2.4Ghz or 5.8Ghz cordless phone?
>> I'm not trying to get into a discussion of whether cordless phones
>> actually pose a real health hazard, however, I would like to know
>> which of the two is considered less harmful ... 2.4Ghz or 5.8Ghz >> radio waves.
> If gophers could read, what books would they choose? Well, the
> truth is that gophers can't read, so that question can't be
> answered.
> As far as RF exposure is concerned, nobody has provided any real
> evidence for harm, so it's hard to say which is less harmful when
> there isn't any evidence of harm.
> If you're worried, use a beltpack unit and hold it away from your
> body. Or just use a wired phone.
> --scott