TEMFAST is a drink-cooler-warmer. It warms or cools your drink; and mentains already hot or cold drink temperature fairly constant.
For our purpose drink cups are grouped in 3 categories:

1. metal-wall cups,thicknes about 1/16", for example: Aluminium, Stainless Steel, etc.
2. Non-metalic cups of about 1/32" thick such as paper or plastic cups, water bottles, etc.
3. Cups with thick insulation (over 1/16") such as mugs; solid-insulated, air or vacuum-insulated cups, mugs, drink-bottles, etc.

Number 1 cups are the BEST for Temfast usage, number 2 are good enough. Number 3 MUST NOT BE USED in Temfast because the thick or/and insulated wall slows heat-flow to or from Temfast chamber wall in cool or warm mode respectively.

Remember #3 group was used when there was no TEMFAST. Hence, they were right to reduce cooling or warming of hot or cold drinks. But they will fade away into history due to TEMFAST advanced new technologies. In general new technologies bring better products and services than in the past, such as:

1. Past land-line telephone compared to present cellular phone;
2. 1940 automobiles compared to present autos;
3. Past slide rule calculators compared to present electronic calculators and computers;
4. etc.

In all cooling and heating situations, it takes time to reach desired temperature. These we observe in our daily activities such as:

1. in heating and cooling our building from room temperature which takes many minutes or hours to reach comfortable temperature;
2. In cooling our fridge from room temperature; it takes also many minutes or hours to reach desired set temperature;
3. The same applies to our oven which could take many minutes to reach desired set temperature;
4. Present Thermoelectric coolers in the market take 80 to 180 minutes(RRT) to reach desired cooling temperature from 70 degrees F and 50% Relative Humidity;

This time , from start or re-start in ambient temperature of 70 degrees F and relative Humidity 50%, we at ESTCH Research Inc.( Estech=Energy and Environment Saver Technologies) call Restart Ready Time (RRT). It is a comparative measure of the equipment performeasure : The lower RRT the better.
Similarly, Temfast RRT (20 to 45 minutes) is lower than any thermoelectric cooler in the world, and lower than compressor coolers of the same internal and external ambient conditions.

You can apply the above General Educational Knowledge in any other situations beyond Temfast applications. This could be in your cup selection, and in your performance evaluation, expectation and selection (RRT) of any cooling and heating systems anywhere.