AirScape Engineer's Blog » finance

cheapest way to reduce co2

neil — Wed, 01 Jun 2011 03:48:05 +0000

We have (at least) two huge problems facing us.

Climate Change (too much CO2 is being emitted)
No Money (we’re all in debt)

Logically, we should spend our limited resources to the best effect. So, what is the best bang for our buck ? The parameter to measure is Tons of Carbon Dioxide (avoided) per Dollar…. the lower the better. So, here are a few of the common things we can do to reduce energy usage. The spreadsheet shows most of the calculations (contact me if you want to know more details), but what is missing is the usual energy savings return on investment. This figure is all about environmental good. It just so happens that environmental good is good for your pocketbook.

So, please let’s spend our money wisely. Hint: Electric cars are cool (not as cool as pluggable hybrids), but they are not the best way to spend our money if we want to reduce carbon dioxide.

* There are many other energy and carbon dioxide reducing strategies not mentioned here.

financial value of green

neil — Fri, 25 Feb 2011 00:46:50 +0000

How much do ‘eco improvements’ such as whole house fans add to the value of your real estate? With a little bit of math, and some financial formulas, we can figure that out. Here is an example of a homeowner who installs one of our 4.4e WHF models. Let’s take a conservative value for energy savings ($500 per year), with a desired return on investment of 8% (you could not get that anywhere else..). What we do is use the financial formulas to figure how much money would need to be invested at 8% interest in order to return $500 per year, over the life of the whole house fan. At the end of the 20 year life span, we assume (also conservatively), that the WHF has no remaining value.

Plugging in the numbers: i = 0.08; n = 20; Savings per Year = $500, yields Present Value = $4909.

Wow! That means that if you paid up to $4,909 the return on investment would be 8%. (we don’t charge that much for the 4.4e…)

Saving Energy is a damned good investment. Who woulda thunk ?

First pass on energy savings

neil — Thu, 03 Sep 2009 23:12:09 +0000

We’re getting ourselves ready to build some software to help predict whole house fan energy savings. In the meantime, I put together this spreadsheet, which I think is a pretty good approximation for the coastal areas of California.

*Potential Whole House Fan Energy Savings per Year for California*

Input Energy cost		$0.24	Dollars per KWH

Application	High Speed Watts	Low Speed Watts	*Energy Savings (per Year)**
2.5WHF	288	250	$777.89
2.5eWHF	200	43	$826.70
Air Conditioning	2808	na	$0
* Assumptions are that the cooling season is 5 months, the WHF is run 10 hours/day, 40% use is at low speed, an average deltaT at night is 10Âº , and that all WHF cooling offsets AC use.