If YETI can make a cup that keeps water cold or hot for hours and a cooler that holds ice for hours, then why aren’t we building houses with that same material?


If YETI can make a cup that keeps water cold or hot for hours and a cooler that holds ice for hours, then why aren’t we building houses with that same material?

In: 824

YETI cups are made out of metal. You could certainly build houses out of metal, it would be vastly more expensive than making them out of wood.

Construction costs are quite high as it is…

Lots of houses have insulation, but it’s not as simple as a thermos. With a thermos there’s one opening with an airtight cap and the bottle itself is fully opaque. Its goal is simply to prevent as much heat transfer between inside and outside as possible. Houses have multiple doors, windows, none of which seal perfectly. They have windows through which to radiate/absorb heat, and their occupants produce heat themselves.

First of all a metal house especially one design with the material you use for Yeti would be very expensive.

Second of all it’s not practical because air and water have different properties when it comes to cooling or retaining temperature.

Third of all you do want some sort of temperature transfusion, sometimes you want sunlight to warm your home for example. Not to mention you definitely want and need air ventilation.

You want to make a double walled vacuum sealed house out of steel?

Yeti cups and other thermoses use a vacuum as insulation. Heat can transfer in three ways: radiation, convection, and conduction. You can’t *really* stop radiation, although you can slow it down. You also can’t really stop convection, but that isn’t relevant to keeping heat inside a thermos.

Conduction is the big one. Hot liquid touches the cup and makes it hot. The hot cup touches the air and makes *it* hot. Most insulation works by keeping the hot stuff from touching anything else. The insulation in your house does that: the fiberglass is full of pockets of air. Because air is less dense, it doesn’t transfer heat as well through conduction. So all the air trapped in the fiberglass slows down how fast heat transfers between the walls on either side.

Many thermoses work by using the best thermal insulation of all – *nothing*. The cup is made from two pieces. A vacuum pulls out most of the air between them. That means there’s nothing in there to conduct heat away. Some still does move through the walls of the cup itself, but it’s slower that way.

You can’t make buildings that way because it’s a lot harder to perfectly seal *all* of a building like that. Even if you did, a vacuum puts a lot of stress on the walls, trying to pull them in. You would have to reinforce the walls – again, not really a problem with a small cup made out of relatively thin metal that doesn’t have to hold anything up.

Various insulation solutions are a much better idea, especially because things like fiberglass help stop fires from spreading.

EDIT: I have been informed that vacuum panels for building insulation are a thing. Neat! I can imagine some of the limitations, like making it harder to change features on those walls, like adding power sockets and whatnot. Also, yes, double-pane windows are vacuum sealed, which is great for insulation but only a small part of the overall surface area of the wall (unless you’re talking commercial building that’s like 90% window).