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80/20 Rule for Energy and Homes

What is the 80/20 rule?

Also called the pareto principle in economics, it states that about 20% of the causes produce about 80% of the effects.

This rule has been altered and used by many to include real estate investing, marketing, and a host of other areas to produce a loose formula that has made at least some relative general sense for a lot of people. Specifically speaking, it can also apply to homes and energy use.

The 80/20 home

For instance, one could say that 20% of the features of a house (let’s say: single pane windows, minimal insulation, linoleum/wood flooring, and air infiltration/exchange), which are IN-efficient, can produce 80% of the energy WASTE that is used to heat or cool the home.

One could also reverse this by saying that if someone focused on making those same features (energy efficient windows, superinsulation, tile/concrete floors, and airtightness/exchange using MVHR (mechanical ventilation heat recovery)) that make up 20% of the home EFFICIENT then they could SAVE 80% of the energy that would otherwise be spent to heat and cool the home.

In this sense, anyone can see that this small difference or alteration in the 20% of features can change the outcome of the other 80%…

The 20% inefficiently designed home costs 80% more to run.
Whereas the 20% efficiently designed home costs 80% less to run.

These are generalities, of course, but most people get the idea.

passive solar

Conventional home compared to passive solar house design

It begs the question… why are building contractors not building all homes this way, where a small investment into the home can make a huge difference in the environmental impact and carbon footprint and utility costs of the homes they build?

Also, look at it this way….

A 20% investment in cost and materials can save 80% of the cost of heating and cooling the home.
Skimp out on the 20% cost and  spend 80% more monthly… over the lifetime of the house.

This is significant in the course of someone’s lifetime, which makes them look a lot closer at long-term sustainability.

Other applications and stacking functions

Green homes are energy efficient homes (perhaps 20-80% more than a conventional home). Energy efficiency in this respect is based mostly on insulation values.

Passive solar homes are even more efficient (perhaps 20-80% more than a conventional home). Energy efficiency in this is based mostly on both thermal mass and insulating the envelope, as well as solar orientation, so that the house becomes the solar collector.


Stacking functions – roof, garden, thermal buffer

Stack these two features (above) together and people can get a 90% energy efficient home, when it is designed properly, which is more than the sum of its parts, producing a greater “yield” in savings than either feature alone.

If someone is an owner-builder they can also construct a 80-90% energy efficient home for 10-20% of the cost. How? Because 60% the cost of building a house is labor–when someone does the labor themselves they save 2/3 the cost of the house, plus they can save further through buying natural, used/salvaged, bartered, or even free green materials.

80/20 in permaculture

In permaculture a person would focus on sustainability, meaning that 80% of the design features of anything you build (be it a house, a forest garden, aquaculture project, etc.) should be stacked, or overlap in different ways with each other, so only 20% of the work is required to produce the same yields as if they were stand-alone or monocrops, etc.

There are so many ways to look at this and use the 80/20 rule.

What else follows the 80/20 rule? Think on it.



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